JP3596456B2 - Method for manufacturing resin molded products - Google Patents

Method for manufacturing resin molded products Download PDF

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Publication number
JP3596456B2
JP3596456B2 JP2000314084A JP2000314084A JP3596456B2 JP 3596456 B2 JP3596456 B2 JP 3596456B2 JP 2000314084 A JP2000314084 A JP 2000314084A JP 2000314084 A JP2000314084 A JP 2000314084A JP 3596456 B2 JP3596456 B2 JP 3596456B2
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resin material
permeable
laser light
molding
transparent resin
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JP2002120293A (en
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秀生 中村
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Toyota Motor Corp
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Toyota Motor Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/54—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
    • B29C66/547—Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles, e.g. endless tubes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1635—Laser beams characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. laser transmission welding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1629—Laser beams characterised by the way of heating the interface
    • B29C65/1654—Laser beams characterised by the way of heating the interface scanning at least one of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1677—Laser beams making use of an absorber or impact modifier
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/124—Tongue and groove joints
    • B29C66/1246—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove
    • B29C66/12463—Tongue and groove joints characterised by the female part, i.e. the part comprising the groove being tapered
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/13—Single flanged joints; Fin-type joints; Single hem joints; Edge joints; Interpenetrating fingered joints; Other specific particular designs of joint cross-sections not provided for in groups B29C66/11 - B29C66/12
    • B29C66/131—Single flanged joints, i.e. one of the parts to be joined being rigid and flanged in the joint area
    • B29C66/1312—Single flange to flange joints, the parts to be joined being rigid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/54—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/54—Joining several hollow-preforms, e.g. half-shells, to form hollow articles, e.g. for making balls, containers; Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles
    • B29C66/547—Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles, e.g. endless tubes
    • B29C66/5472—Joining several hollow-preforms, e.g. half-cylinders, to form tubular articles, e.g. endless tubes for making elbows or V-shaped pieces
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/737—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined
    • B29C66/7377—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined amorphous, semi-crystalline or crystalline
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/739—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/7392—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic
    • B29C66/73921—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the material of at least one of the parts being a thermoplastic characterised by the materials of both parts being thermoplastics
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/14—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using wave energy, i.e. electromagnetic radiation, or particle radiation
    • B29C65/16—Laser beams
    • B29C65/1603—Laser beams characterised by the type of electromagnetic radiation
    • B29C65/1612—Infrared [IR] radiation, e.g. by infrared lasers
    • B29C65/1616—Near infrared radiation [NIR], e.g. by YAG lasers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/71—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the composition of the plastics material of the parts to be joined
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/70—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material
    • B29C66/73—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset
    • B29C66/737—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined
    • B29C66/7377—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined amorphous, semi-crystalline or crystalline
    • B29C66/73773—General aspects of processes or apparatus for joining preformed parts characterised by the composition, physical properties or the structure of the material of the parts to be joined; Joining with non-plastics material characterised by the intensive physical properties of the material of the parts to be joined, by the optical properties of the material of the parts to be joined, by the extensive physical properties of the parts to be joined, by the state of the material of the parts to be joined or by the material of the parts to be joined being a thermoplastic or a thermoset characterised by the state of the material of the parts to be joined amorphous, semi-crystalline or crystalline the to-be-joined area of at least one of the parts to be joined being semi-crystalline
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0037—Other properties
    • B29K2995/0041—Crystalline
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2031/00—Other particular articles
    • B29L2031/748—Machines or parts thereof not otherwise provided for
    • B29L2031/749—Motors
    • B29L2031/7492—Intake manifold

Description

【０００１】
【発明の属する技術分野】
本発明は樹脂成形品の製造方法に関し、詳しくは、レーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをレーザ溶着により一体的に接合した樹脂成形品の製造方法に関する。
【０００２】
【従来の技術】
近年、軽量化及び低コスト化等の観点より、自動車部品等、各種分野の部品を樹脂化して樹脂成形品とすることが頻繁に行われている。また、樹脂成形品の高生産性化等の観点より、樹脂成形品を予め複数に分割して成形し、これらの分割成形品を互いに接合する手段が採られることが多い。
【０００３】
ここに、樹脂材同士の接合方法として、従来よりレーザ溶着方法が利用されている。例えば、特開昭６０−２１４９３１号公報には、レーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とを重ね合わせた後、該透過性樹脂材側からレーザ光を照射することにより、透過性樹脂材と非透過性樹脂材との当接面同士を加熱溶融させて両者を一体的に接合するレーザ溶着方法が開示されている。
【０００４】
このレーザ溶着方法では、透過性樹脂材内を透過したレーザ光が非透過性樹脂材の当接面に到達して吸収され、この当接面に吸収されたレーザ光がエネルギーとして蓄積される。その結果、非透過性樹脂材の当接面が加熱溶融されるとともに、この非透過性樹脂材の当接面からの熱伝達により透過性樹脂材の当接面が加熱溶融される。この状態で、透過性樹脂材及び非透過性樹脂材の当接面同士を圧着させれば、両者を一体的に接合することができる。
【０００５】
【発明が解決しようとする課題】
ところで、上記したようなレーザ溶着では、透過性樹脂材及び非透過性樹脂材の当接面同士を確実に溶着させて十分な接合強度を得るためには、非透過性樹脂材の当接面（吸収面）にレーザ光のエネルギーを十分に吸収させて、非透過性樹脂材及び透過性樹脂材の当接面を十分に加熱溶融させる必要がある。
【０００６】
しかしながら、透過性樹脂材やレーザ光の種類等によっては、具体的には透過性樹脂材のレーザ光透過率や加熱源として用いるレーザ光の波長等によっては、非透過性樹脂材の当接面に十分な量のレーザ光を到達、吸収させることが困難になるという問題があった。
【０００７】
本発明は上記実情に鑑みてなされたものであり、透過性樹脂材の当接端部におけるレーザ光透過率を増大させることにより、透過性樹脂材及び非透過性樹脂材の当接面同士を十分に加熱溶融させ、該当接面同士を確実に溶着させて十分な接合強度を得ることのできる樹脂成形品の製造方法を提供することを解決すべき技術課題とするものである。
【０００８】
【課題を解決するための手段】
（１）請求項１記載の樹脂成形品の製造方法は、成形型を用い、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、
上記成形工程で得られた上記透過性樹脂材及び上記非透過性樹脂材を当接させ、該透過性樹脂材及び該非透過性樹脂材の当接端部同士を該透過性樹脂材側からの上記レーザ光の照射により溶着して接合する接合工程とからなり、
上記成形工程で、上記透過性樹脂材を成形する上記成形型のうち上記当接端部を成形する部分を局所的に温度制御することにより、該透過性樹脂材の該当接端部におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材において該当接端部の樹脂結晶化度を他の部分より低くし、かつ、
上記接合工程で、上記透過性樹脂材の他の部分より樹脂結晶化度が低くされた上記当接端部を上記レーザ光を透過させ、該当接端部を透過した該レーザ光を上記非透過性樹脂材の上記当接端部の当接面に到達、吸収させることを特徴とするものである。
【０００９】
（２）請求項２記載の樹脂成形品の製造方法は、請求項１記載の樹脂成形品の製造方法において、前記成形工程で、前記透過性樹脂材の前記当接端部における樹脂結晶化度が４０％以下となるように温度制御することを特徴とするものである。
【００１０】
（３）請求項３記載の樹脂成形品の製造方法は、請求項１又は２記載の樹脂成形品の製造方法において、前記成形工程で、前記透過性樹脂材の前記当接端部における樹脂結晶粒径が５μｍ以上となるような樹脂材料を該透過性樹脂材に用いることを特徴とするものである。
【００１１】
（４）請求項４記載の樹脂成形品の製造方法は、請求項３記載の樹脂成形品の製造方法において、前記透過性樹脂材は、ポリプロピレン、ポリアミド及びポリエチレンのうちの一種であることを特徴とするものである。
（５）請求項５記載の樹脂成形品の製造方法は、請求項１、２、３又は４記載の樹脂成形品において、前記成形工程で、前記非透過性樹脂材の前記当接端部における前記レーザ光の吸収面に嵌合凹部を設けるとともに、前記透過性樹脂材の前記当接端部に該嵌合凹部と嵌合可能な嵌合凸部を設けることを特徴とするものである。
（６）請求項６記載の樹脂成形品の製造方法は、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、
上記成形工程で得られた上記透過性樹脂材及び上記非透過性樹脂材を当接させ、該透過性樹脂材及び該非透過性樹脂材の当接端部同士を該透過性樹脂材側からの上記レーザ光の照射により溶着して接合する接合工程とからなり、
上記成形工程で、上記透過性樹脂材を成形する上記成形型のうち少なくとも上記当接端部を成形する部分を温度制御することにより、該透過性樹脂材の該当接端部におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材のうち少なくとも該当接端部の樹脂結晶化度を４０％以下とし、かつ、
上記接合工程で、上記透過性樹脂材の樹脂結晶化度が４０％以下とされた上記当接端部を上記レーザ光を透過させ、該当接端部を透過した該レーザ光を上記非透過性樹脂材の上記当接端部の当接面に到達、吸収させることを特徴とするものである。
（７）請求項７記載の樹脂成形品の製造方法は、成形型を用い、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、
上記成形工程で得られた上記透過性樹脂材及び上記非透過性樹脂材を当接させ、該透過性樹脂材及び該非透過性樹脂材の当接端部同士を該透過性樹脂材側からの上記レーザ光の照射により溶着して接合する接合工程とからなり、
上記成形工程で、上記透過性樹脂材を成形する上記成形型の上記当接端部を成形する部分を温度制御することにより、該透過性樹脂材の該当接端部におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材の該当接端部の樹脂結晶粒径を５μｍ以上とし、かつ、
上記接合工程で、上記透過性樹脂材の樹脂結晶粒径が５μｍ以上とされた上記当接端部を上記レーザ光を透過させ、該当接端部を透過した該レーザ光を上記非透過性樹脂材の上記当接端部の当接面に到達、吸収させることを特徴とするものである。
（８）請求項８記載の樹脂成形品の製造方法は、請求項７記載の樹脂成形品の製造方法において、前記透過性樹脂材は、ポリプロピレン、ポリアミド及びポリエチレンのうちの一種であることを特徴とするものである。
【００１２】
【発明の実施の形態】
本発明の樹脂成形品の製造方法は、成形型を用い、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、この成形工程で得られた該透過性樹脂材及び該非透過性樹脂材をレーザ溶着により接合する接合工程とからなる。
【００１３】
このレーザ溶着は、透過性樹脂材及び非透過性樹脂材の当接端部同士を当接させた状態で、透過性樹脂材側からレーザ光を照射することにより行われる。透過性樹脂材側から照射されたレーザ光は該透過性樹脂材内を透過して非透過性樹脂材の当接面に到達し、吸収される。この非透過性樹脂材の当接面に吸収されたレーザ光がエネルギーとして蓄積される結果、非透過性樹脂材の当接面が加熱溶融されるとともに、この非透過性樹脂材の当接面からの熱伝達により透過性樹脂材の当接面が加熱溶融される。この状態で、透過性樹脂材及び非透過性樹脂材の当接面同士を圧着させれば、両者を一体的に接合することができる。
【００１４】
こうして得られた接合部では、当接面同士が溶融されて接合されており、該当接面同士の間では両成形部材を構成する両樹脂が溶融して互いに入り込み絡まった状態が形成されているため、強固な接合状態を構成して高い接合強度及び耐圧強度を有している。
【００１５】
ここに、本発明の樹脂成形品の製造方法は、上記成形工程で、上記透過性樹脂材を成形する上記成形型のうち上記当接端部を成形する部分を局所的に温度制御することにより、該透過性樹脂材において該当接端部の樹脂結晶化度を他の部分より低くすることを特徴とする。
【００１６】
このように透過性樹脂材において当接端部の樹脂結晶化度を他の部分より低くすることにより、該当接端部を透過するレーザ光の透過率を高くすることができる。このため、非透過性樹脂材の当接面により多くのレーザ光が到達、吸収される。その結果、透過性樹脂材及び非透過性樹脂材の当接面同士を十分に加熱溶融させることができ、該当接面同士を確実にレーザ溶着させて十分な接合強度を得ることが可能となる。
【００１７】
したがって、本発明の樹脂成形品の製造方法によれば、透過性樹脂材の樹脂材料として、レーザ光透過率が低すぎて従来採用することができなかったようなものでも採用することが可能となる。
【００１８】
そして、レーザ溶着する際の透過性樹脂材におけるレーザ光透過率が２６％以上であれば、レーザ溶着による溶着強度を格段と向上させることができる。このため、透過性樹脂材に用いる樹脂のレーザ光に対する透過性や加熱源として用いるレーザ光の波長等に応じて、透過性樹脂材におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材の当接端部における樹脂結晶化度を低くする。なお、レーザ光透過率とは、透過性樹脂材を透過したレーザ光のエネルギーの入射光のエネルギーに対する百分率をいう。
【００１９】
透過性樹脂材を成形する成形型のうち当接端部を成形する部分を局所的に温度制御するための手段としては特に限定されないが、例えば、透過性樹脂材の当接端部を成形する部分の成形型内に冷却水通路を設ける手段等を採用することができる。こうして冷却水路内を流通する冷却水により、透過性樹脂材の当接端部における溶融樹脂を急速冷却することにより、該当接端部における樹脂結晶化度を低くすることができる。
【００２０】
ここで、レーザ光透過率と樹脂結晶化度との間には、樹脂結晶化度が低いほどレーザ光透過率が高くなる関係にあることが、本発明者の実験により確認されている。このため、２６％以上のレーザ光透過率を確保すべく、透過性樹脂材の当接端部における樹脂結晶化度は４０％以下であることが好ましく、３０％以下であることが特に好ましい。なお、樹脂結晶化度の下限値は０％である。
【００２１】
また、レーザ光透過率と樹脂結晶粒径との間には、樹脂結晶粒径が大きいほどレーザ光透過率が高くなる関係にあることが、本発明者の実験により確認されている。このため、２６％以上のレーザ光透過率を確保すべく、透過性樹脂材の当接端部における樹脂結晶粒径は５μｍ以上であることが好ましく、１０μｍ以上であることが特に好ましい。
【００２２】
そして、樹脂結晶粒径は、溶融樹脂を冷却、固化する際の冷却条件（温度制御）によってもある程度調整することが可能であるが、透過性樹脂材に用いる樹脂材料の種類によってほとんど決まってしまう。したがって、透過性樹脂材の当接端部における樹脂結晶粒径が５μｍ以上となるような樹脂材料を透過性樹脂材に用いることが好ましい。具体的には、後述する透過性樹脂材に用いることのできる樹脂のうち、ポリプロピレン（ＰＰ）、ポリアミド（ＰＡ）やポリエチレン（ＰＥ）等を用いることが好ましい。
【００２３】
また、本発明の樹脂成形品の製造方法は、上述のとおり、透過性樹脂材において当接端部の樹脂結晶化度を他の部分よりも低くしておき、接合工程におけるレーザ溶着時に該当接端部内を透過するレーザ光の透過率を高くするものである。このため、透過性樹脂材の当接端部が、樹脂結晶化度の低さに起因して他の部分よりも強度低下することが懸念される。
【００２４】
この点、本発明の樹脂成形品の製造方法では、接合工程におけるレーザ溶着時に透過性樹脂材の当接端部をレーザ光が透過する際、輻射熱により結晶部分が内部発熱し、この熱により未結晶部分の結晶化が進む。このため、本発明の製造方法で得られた樹脂成形品は、透過性樹脂材の当接端部においても他の部分と同程度又はそれ以上の強度が確保される。
【００２５】
したがって、上記接合工程においては、レーザ溶着時の輻射熱により透過性樹脂材の当接端部を十分に結晶化させて、該当接端部において他の部分と同程度の強度を確実に確保することができるように、レーザ照射条件を設定することが好ましい。具体的には、レーザ光透過率２６％で、２００Ｗ／ｓｅｃとすることが好ましい。
【００２６】
また、上記成形工程で、上記透過性樹脂材を成形する上記成形型のうち少なくとも上記当接端部を成形する部分を温度制御することにより、該透過性樹脂材のうち少なくとも該当接端部の樹脂結晶化度を４０％以下としてもよい。すなわち、透過性樹脂材のうち当接端部以外の部分が特に高強度を必要としないような場合は、透過性樹脂材を成形する成形型のうち当接端部を成形する部分のみを局所的に温度制御するのではなく、当接端部以外の部分を成形する成形型の部分を含めて（場合によっては透過性樹脂材を成形する成形型全体を）温度制御することにより、透過性樹脂材のうち当接端部及び該当接端部以外の部分の樹脂結晶化度を４０％以下としてもよい。そして、この場合、必要に応じて、接合工程後に該当接端部以外の部分を熱処理等して結晶化を促進させることにより、高強度化を図ることもできる。
【００２７】
上記透過性樹脂材に用いる樹脂の種類としては、熱可塑性を有し、加熱源としてのレーザ光を所定の透過率以上で透過させうるものであれば特に限定されない。例えば、ナイロン６（ＰＡ６）やナイロン６６（ＰＡ６６）等のポリアミド（ＰＡ）、ポリエチレン（ＰＥ）、ポリプロピレン（ＰＰ）、スチレン−アクリロニトリル共重合体、ポリエチレンテレフタレート（ＰＥＴ）、ポリスチレン、ＡＢＳ、アクリル（ＰＭＭＡ）やポリカーボネート（ＰＣ）等の他に、レーザ光透過率が低すぎて透過性樹脂材の樹脂材料として従来採用することができなかったＰＰＳ（ポリフェニレンサルファイド）、ポリブチレンテレフタレート（ＰＢＴ）やポリスチレン（ＰＳ）等を採用することも可能である。なお、必要に応じて、ガラス繊維、カーボン繊維等の補強繊維や着色材を添加したものを用いてもよい。
【００２８】
上記非透過性樹脂材に用いる樹脂の種類としては、熱可塑性を有し、加熱源としてのレーザ光を透過させずに吸収しうるものであれば特に限定されない。例えば、ナイロン６（ＰＡ６）やナイロン６６（ＰＡ６６）等のポリアミド（ＰＡ）、ポリエチレン（ＰＥ）、ポリプロピレン（ＰＰ）、スチレン−アクリロニトリル共重合体、ポリエチレンテレフタレート（ＰＥＴ）、ポリスチレン、ＡＢＳ、アクリル（ＰＭＭＡ）、ポリカーボネート（ＰＣ）、ポリブチレンテレフタレート（ＰＢＴ）、ＰＰＳ等に、カーボンブラック、染料や顔料等の所定の着色材を混入したものを挙げることができる。なお、必要に応じて、ガラス繊維やカーボン繊維等の補強繊維を添加したものを用いてもよい。
【００２９】
また、上記透過性樹脂材に用いる樹脂と上記非透過性樹脂材に用いる樹脂との組合せについては、互いに相溶性のあるもの同士の組合せとされる。かかる組合せとしては、ナイロン６同士やナイロン６６同士等、同種の樹脂同士の組合せの他、ナイロン６とナイロン６６との組合せ、ＰＥＴとＰＣとの組合せやＰＣとＰＢＴとの組合せ等を挙げることができる。
【００３０】
また、加熱源として用いるレーザ光の種類としては、レーザ光を透過させる透過性樹脂材の吸収スペクトルや板厚（透過長）等との関係で、透過性樹脂材内での透過率が所定値以上となるような波長を有するものが適宜選定される。例えば、ＹＡＧ：Ｎｄ３＋レーザ（レーザ光の波長：１０６０ｎｍ）や半導体レーザ（レーザ光の波長：５００〜１０００ｎｍ）を用いることができる。
【００３１】
なお、レーザの出力、照射密度や加工速度（移動速度）等の照射条件は、樹脂の種類等に応じて適宜設定可能である。
【００３２】
【実施例】
以下、本発明の具体的な実施例を図面に基づいて説明する。
【００３３】
本実施例は、本発明に係る樹脂成形品を合成樹脂製のインテークマニホールドに適用したものである。
【００３４】
図１はインテークマニホールドの平面図である。図２はインテークマニホールドの図１におけるＡ−Ａ線で切断した切断端面を拡大して示している。
【００３５】
このインテークマニホールド１０は、上下に２分割されていて、上側分割体である第１成形部材１１と下側分割体である第２成形部材１２とから構成された中空体である。第１成形部材１１及び第２成形部材１２は、互いに整合して当接し合うフランジ部よりなる当接端部１１ａ及び１２ａをそれぞれ有している。そして、第１成形部材１１の当接端部１１ａ及び第２成形部材１２の当接端部１２ａの当接面１１ｂ及び１２ｂ同士がレーザ溶着により一体的に接合されている。
【００３６】
第１成形部材１１は、加熱源としてのレーザ光に対して透過性のある透過性樹脂よりなるもので、この透過性樹脂として、本実施例ではＰＡ６６に補強材であるガラスファイバーを３０ｗｔ％添加してなる強化プラスチックを用いた。なお、照射に使用するレーザ光はＹＡＧ：Ｎｄ３＋レーザ（波長：１０６０ｎｍ）である。
【００３７】
また、第２成形部材１２は、加熱源としてのレーザ光に対して透過性のない非透過性樹脂よりなるもので、この非透過性樹脂として、本実施例ではＰＡ６６に補強材であるガラスファイバーを３０ｗｔ％、補助剤（着色材）であるカーボンブラックを適宜量添加してなる強化プラスチックを用いた。
【００３８】
なお、第１成形部材１１及び第２成形部材１２は、いずれもＰＡ６６を母材樹脂とするもので、互いに相溶性のあるものである。
【００３９】
第１成形部材１１は、図１のＡ−Ａ線で示す部位が図２で拡大して示されているように、断面形状が略半円筒状を呈している。この略半円筒状をなす第１成形部材１１の開口端部に、遠心方向に膨出するフランジ部よりなる当接端部１１ａが設けられている。
【００４０】
そして、この部分がさらに拡大して図３に示されているように、当接端部１１ａには、その下面（当接面１１ｂ）に、下方に突出する環状の嵌合凸部１１ｃが設けられている。この嵌合凸部１１ｃは、先端側（下方側）に向かって漸次縮小して突出する略台形状の断面形状をなしている。
【００４１】
一方、第２成形部材１２の当接端部１２ａには、その上面（レーザ光の吸収面となる当接面１２ｂ）に、上記嵌合凸部１１ｃと嵌合可能な環状の嵌合凹部１２ｃが設けられている。この嵌合凹部１２ｃは、上記嵌合凸部１１ｃと整合する形状とされ、底面から上方（レーザ光が照射される側）に向かって漸次開口が拡がる略台形状の断面形状をなしている。
【００４２】
そして、第１成形部材１１の嵌合凸部１１ｃ及び第２成形部材１２の嵌合凹部１２ｃ同士が嵌合されるとともに、第１成形部材１１の当接面１１ｂ（嵌合凸部１１ｃの傾斜側面及び先端面を含む）及び第２成形部材１２の当接面１２ｂ（嵌合凹部１２ｃの傾斜側面及び底面を含む）同士がレーザ溶着により一体的に接合されている。
【００４３】
上記構成を有する本実施例に係る樹脂成形品は、以下のようにして製造した。
【００４４】
（成形工程）
まず、所定の射出成形型を用いて、第１成形部材１１及び第２成形部材１２を予め所定形状に射出成形した。
【００４５】
このとき、透過性樹脂材よりなる第１成形部材１１は、図４に示すように、第１〜第３成形型２１〜２３を用いて射出成形した。第１成形部材１１の当接端部１１ａを成形する第２及び第３成形型２２及び２３には、該当接端部１１ａを成形する型面の近傍に冷却水通路２２ａ及び２３ａが設けられている。そして、各冷却水通路２２ａ及び２３ａに冷却水を流通させつつ、射出成形することにより、第１成形部材１１を成形する第１〜第３成形型において当接端部１１ａを成形する部分のみを局所的に温度制御した。こうして第１成形部材１１において、当接端部１１ａにおける溶融樹脂を急冷して、該当接端部１１ａにおける樹脂結晶化度を他の部分よりも低くした。
【００４６】
具体的には、冷却水により第２及び第３成形型２２及び２３のうち当接端部１１ａを成形する部分のみを局所的に２０〜２５℃程度の型温に冷却した。こうして、第１成形部材１１において、当接端部１１ａにおける樹脂結晶化度を２０〜２５％程度とし、またこの当接端部１１ａにおける樹脂結晶粒径を５〜１０μｍ程度とした。したがって、この当接端部１１ａにおけるレーザ光透過率は４０〜５０％程度とされている。なお、第１成形部材１１の当接端部１１ａ以外の部分を成形する第１〜第３成形型２１〜２３の他の部分は６０〜８０℃程度の型温である。また、第１成形部材１１において当接端部１１ａ以外の部分における樹脂結晶化度は３０〜３５％程度である。
【００４７】
（接合工程）
そして、第１成形部材１１の嵌合凸部１１ｃと第２成形部材１２の嵌合凹部１２ｃとを嵌合させるとともに、第１成形部材１１及び第２成形部材１２の当接面１１ｂ及び１２ｂ同士を当接させた。この状態で、図示しないレーザトーチを用い、第１成形部材１１側からレーザ光を照射した。すなわち、第１成形部材１１の当接端部１１ａの上面側からレーザ光を照射して該当接端部１１ａの上面からレーザ光を入射させることにより、第１成形部材１１の当接端部１１ａと第２成形部材１２の当接端部１２ａとの当接面１１ｂ及び１２ｂ同士を全面的に加熱溶融させて、レーザ溶着により両者を一体的に接合した。
【００４８】
こうして得られた接合部では、当接面１１ｂ及び１２ｂ同士が全面的に溶融されて接合されており、該当接面１１ｂ及び１２ｂ同士の間では両成形部材１１及び１２を構成する両樹脂が溶融して互いに入り込み絡まった状態が形成されているため、強固な接合状態を構成して高い接合強度及び耐圧強度を有している。
【００４９】
特に、本実施例では、上記成形工程で得られた透過性樹脂材よりなる第１成形部材１１の当接端部１１ａは、樹脂結晶化度が２０〜２５％程度と低く、また樹脂結晶粒径が５〜１０μｍ程度と大きい。このため、この当接端部１１ａにおけるレーザ光透過率は４０〜５０％程度と高くなっている。したがって、上記接合工程におけるレーザ溶着時に、非透過性樹脂材よりなる第２成形部材１２の当接面１２ｂにより多くのレーザ光が到達、吸収される。その結果、第１成形部材１１及び第２成形部材１２の当接面１１ｂ及び１２ｂ同士を十分に加熱溶融させることができ、該当接面１１ｂ及び１２ｂ同士を確実にレーザ溶着させて十分な接合強度を得ることが可能となる。
【００５０】
また、上記接合工程におけるレーザ溶着時に透過性樹脂材よりなる第１成形部材１１の当接端部１１ａをレーザ光が透過する際、輻射熱により結晶部分が内部発熱し、この熱により未結晶部分の結晶化が進む。このため、上記成形工程では、第１成形部材１１において当接端部１１ａにおける樹脂結晶化度が他の部分よりも低いものであったが、接合工程を経て得られた本実施例に係る樹脂成形品は、該当接端部１１ａにおいても他の部分と同程度又はそれ以上の強度が確保される。
【００５１】
一方、本実施例に係る樹脂成形品では、第１成形部材１１の嵌合凸部１１ｃと第２成形部材１２の嵌合凹部１２ｃとの凹凸嵌合により、両者間に機械的な結合力が付与せしめられるので、両者の接合強度をより向上させることができる。
【００５２】
また、凹凸嵌合による機械的な結合力により、第１成形部材１１及び第２成形部材１２の当接端部１１ａ及び１２ａにおける反り等が矯正されるので、第１成形部材１１及び第２成形部材１２の当接面１１ｂ及び１２ｂ同士の間に隙間が発生することを抑えることができる。このため、非透過性樹脂材よりなる第２成形部材１２の当接面１２ｂにおける発熱を透過性樹脂材よりなる第１成形部材１１の当接面１１ｂに確実に熱伝達させて、第１成形部材１１の当接面１１ｂを確実に加熱溶融させることができる。したがって、第１成形部材１１及び第２成形部材１２の当接面１１ｂ及び１２ｂ同士を確実にレーザ溶着させることが可能となる。
【００５３】
また、上記凹凸嵌合により、第１成形部材１１の上記当接面１１ｂ（嵌合凸部１１ｄの傾斜側面及び先端面を含む）と第２成形部材１２の上記当接面１２ｂ（嵌合凹部１２ｄの傾斜側面及び底面を含む）との当接面積、すなわちレーザ溶着による接合面積も増大することから、これによっても接合強度の向上を図ることができる。
【００５４】
さらに、透過性樹脂材よりなる第１成形部材１１に上記嵌合凸部１１ｃを設けるとともに、非透過性樹脂材よりなる第２成形部材１２に上記嵌合凹部１２ｃを設けているので、該嵌合凹部１２ｃの内面（底面及び傾斜側面）でレーザ光の一部が反射することを利用することができ、より均一にレーザ溶着するのに有利となる。
【００５５】
（樹脂結晶化度及び樹脂結晶粒径とレーザ光透過率との関係）
射出成形時の成形型温を変更することにより、種々の樹脂結晶化度を有する板厚３ｍｍの透過性樹脂材を成形した。
【００５６】
また、透過性樹脂材として用いる樹脂材料の種類を種々変更することにより、種々の樹脂結晶粒径を有する板厚３ｍｍの透過性樹脂材を成形した。
【００５７】
そして、ＹＡＧ：Ｎｄ３＋レーザ（波長：１０６０ｎｍ）を各透過性樹脂材に板厚方向に照射して、各該透過性樹脂材におけるレーザ光透過率を測定し、樹脂結晶化度及び樹脂結晶粒径とレーザ光透過率との関係を調べた。このときのレーザの出力は４００Ｗとした。また、レーザ光透過率は、入射エネルギーをワーク有無で算出することにより測定した。
【００５８】
樹脂結晶化度とレーザ光透過率との関係を図５に示すように、樹脂結晶化度が低いほどレーザ光透過率が高くなり、樹脂結晶化度が４０％以下であれば、レーザ光透過率が２６％以上になることがわかる。
【００５９】
また、樹脂結晶粒径とレーザ光透過率との関係を図６に示すように、樹脂結晶粒径が大きいほどレーザ光透過率が高くなり、樹脂結晶粒径が５μｍ以上であれば、レーザ光透過率が２６％以上になることがわかる。
【００６０】
なお、図６において、樹脂結晶粒径が２μｍとなった透過性樹脂材の樹脂材料はＰＢＴであり、樹脂結晶粒径が５μｍとなった透過性樹脂材の樹脂材料はＰＡ６６である。
【００６１】
次に、ＰＡ６６とＰＰＳの２種類の樹脂材料を準備した。
【００６２】
そして、一方の樹脂材料（ＰＡ６６）について、射出成形時の成形型温を２０℃、８０℃と変更することにより、それぞれ３０％、４０％の樹脂結晶化度を有し、樹脂結晶粒径が５〜１０μｍで板厚１〜５ｍｍの透過性樹脂材料を成形した。
【００６３】
また、他方の樹脂材料（ＰＰＳ）について、射出成形時の成形型温を２０℃、８０℃と変更することにより、それぞれ３０％、６０％の樹脂結晶化度を有し、樹脂結晶粒径が１μｍ以下で板厚１〜５ｍｍの透過性樹脂材料を成形した。
【００６４】
そして、上記と同様にＹＡＧ：Ｎｄ３＋レーザ（波長：１０６０ｎｍ）を各透過性樹脂材に板厚方向に照射して、各該透過性樹脂材におけるレーザ光透過率を測定した。
【００６５】
その結果を図７に示すように、樹脂結晶化度の低下と樹脂結晶粒径のサイズアップがレーザ光透過の決め手であることがわかる。
【００６６】
（レーザ光透過率と溶着強度との関係）
ガラス繊維が３０ｗｔ％添加されて強化されたナイロン６からなる板厚３ｍｍの透過性樹脂材と、カーボンブラックが所定量添加されたナイロン６からなる板厚３ｍｍの非透過樹脂材とを重ね合わせ、ＹＡＧ：Ｎｄ３＋レーザ（波長：１０６０ｎｍ）を透過性樹脂材側から照射して、レーザ溶着により一体的に接合した。なお、レーザの出力は４００Ｗ、加工速度は４ｍ／ｍｉｎとした。
【００６７】
そして、透過性樹脂材に着色剤としての染料を添加し、その添加量を種々変更することにより、透過性樹脂材におけるレーザ光透過率を種々変更して、透過性樹脂材におけるレーザ光透過率と溶着強度との関係を調べた。なお、レーザ光透過率は上記と同様に測定し、また溶着強度は溶着部を引張り破断することにより測定した。その結果を図８に示す。
【００６８】
図８から明らかなように、透過性樹脂材におけるレーザ光透過率が２６％以上あれば、溶着強度が４５ＭＰａ以上となり、十分な溶着強度を達成できることがわかる。
【００６９】
【発明の効果】
以上詳述したように、本発明の樹脂成形品の製造方法によれば、透過性樹脂材の当接端部における樹脂結晶化度を低くしてレーザ光透過率を増大させることにより、レーザ溶着時に透過性樹脂材及び非透過性樹脂材の当接面同士を十分に加熱溶融させ、該当接面同士を確実にレーザ溶着させて十分な接合強度を得ることができる。
【００７０】
また、上記当接端部はレーザ溶着時の輻射熱で結晶化が進むから、本発明方法で得られた樹脂成形品においては、樹脂結晶化度の低さに起因して上記当接端部で強度低下するようなこともない。
【００７１】
さらに、透過樹脂材におけるレーザ光透過率が増大すれば、レーザ光のエネルギーをより効率的にレーザ溶着に利用することが可能となり、消費エネルギーの節約によりコスト低減にも寄与しうる。
【図面の簡単な説明】
【図１】実施例に係り、本発明に係る樹脂成形品を適用する合成樹脂製のインテークマニホールドの平面図である。
【図２】実施例に係り、図１の矢印Ａ−Ａ線で示す部位の断面図である。
【図３】実施例に係り、第１成形部材と第２成形部材との接合構造を示す拡大部分断面図である。
【図４】実施例に係り、透過性樹脂材よりなる第１成形部材の当接端部を成形する様子を示す部分断面図である。
【図５】樹脂結晶化度とレーザ光透過率との関係を示す線図である。
【図６】樹脂結晶粒径とレーザ光透過率との関係を示す線図である。
【図７】樹脂結晶化度及び樹脂結晶粒径とレーザ光透過率との関係を示す線図である。
【図８】透過性樹脂材におけるレーザ光透過率と溶着強度との関係を示す線図である。
【符号の説明】
１１…第１成形部材（透過性樹脂材）
１２…第２成形部材（非透過性樹脂材）
１１ａ、１２ａ…当接端部
１１ｂ、１２ｂ…当接面
１１ｃ…嵌合凸部
１２ｃ…嵌合凹部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method of manufacturing a resin molded product, and more specifically, a laser-transmissive permeable resin material and a laser-impermeable non-transmissive resin material are integrated by laser welding. TECHNICAL FIELD The present invention relates to a method for manufacturing a resin molded product which is joined to each other.
[0002]
[Prior art]
2. Description of the Related Art In recent years, from the viewpoints of weight reduction and cost reduction, parts of various fields such as automobile parts are frequently resinified to be resin molded products. In addition, from the viewpoint of increasing the productivity of the resin molded product and the like, a method is often employed in which the resin molded product is divided into a plurality of pieces in advance, and these divided molded articles are joined to each other.
[0003]
Here, a laser welding method has conventionally been used as a method for joining the resin materials. For example, in Japanese Patent Application Laid-Open No. Sho 60-214931, after a transparent resin material that is permeable to laser light and a non-transparent resin material that is not permeable to laser light, By irradiating a laser beam from the transparent resin material side, the contact surfaces of the transparent resin material and the non-transparent resin material are heated and melted, and a laser welding method of integrally joining the two is disclosed. I have.
[0004]
In this laser welding method, the laser light transmitted through the transparent resin material reaches the contact surface of the non-transparent resin material and is absorbed, and the absorbed laser light is accumulated as energy. As a result, the contact surface of the non-transparent resin material is heated and melted, and the contact surface of the transparent resin material is heated and melted by heat transfer from the contact surface of the non-permeable resin material. In this state, if the contact surfaces of the permeable resin material and the non-permeable resin material are pressed together, they can be integrally joined.
[0005]
[Problems to be solved by the invention]
By the way, in the laser welding as described above, in order to ensure that the contact surfaces of the transparent resin material and the non-transparent resin material are welded to each other and to obtain a sufficient bonding strength, the contact surface of the non-transparent resin material is required. It is necessary that the energy of the laser beam be sufficiently absorbed by the (absorbing surface) and the contact surface between the non-transmissive resin material and the transmissive resin material be sufficiently heated and melted.
[0006]
However, depending on the type of the transparent resin material and the laser light, specifically, depending on the laser light transmittance of the transparent resin material and the wavelength of the laser light used as a heating source, the contact surface of the non-transparent resin material may be used. However, it is difficult to reach and absorb a sufficient amount of laser light.
[0007]
The present invention has been made in view of the above circumstances, and by increasing the laser light transmittance at the contact end of a transparent resin material, the contact surfaces of the transparent resin material and the non-transparent resin material are brought together. An object of the present invention is to provide a method of manufacturing a resin molded product that can be sufficiently heated and melted and the corresponding contact surfaces are reliably welded to each other to obtain a sufficient bonding strength.
[0008]
[Means for Solving the Problems]
(1) A method of manufacturing a resin molded product according to claim 1, wherein a molding die is used, and a transparent resin material that is permeable to laser light as a heating source and a resin that is not permeable to the laser light. A molding step of molding the non-permeable resin material,
The permeable resin material and the non-permeable resin material obtained in the molding step are brought into contact with each other, and the contact ends of the permeable resin material and the non-permeable resin material are separated from the permeable resin material side. A joining step of welding and joining by irradiation of the laser light,
In the molding step, by locally controlling the temperature of a portion of the molding die for molding the transparent resin material, the portion for molding the contact end portion,The laser beam transmittance at the corresponding contact end of the transparent resin material is 26% or more.In the permeable resin material, the resin crystallinity at the corresponding contact end portion is lower than that of other portions.And
In the joining step, the laser light is transmitted through the abutting end portion having a lower resin crystallinity than other portions of the transmissive resin material, and the laser light transmitted through the corresponding abutting end portion is not transmitted through the laser light. Reaches and absorbs the contact surface at the contact end of the conductive resin materialIt is characterized by the following.
[0009]
(2) The method for manufacturing a resin molded product according to claim 2 is the method for manufacturing a resin molded product according to claim 1, wherein in the molding step, the degree of resin crystallinity at the contact end of the transparent resin material is increased. Is controlled to be 40% or less.
[0010]
(3) The method for producing a resin molded product according to claim 3 is the method for producing a resin molded product according to claim 1 or 2, wherein the resin crystal at the contact end of the transparent resin material is used in the molding step. A resin material having a particle size of 5 μm or more is used for the transparent resin material.
[0011]
(4) The method for producing a resin molded product according to claim 4 is as follows:The method of manufacturing a resin molded product according to claim 3, wherein the permeable resin material is one of polypropylene, polyamide, and polyethylene.
(5) The method of manufacturing a resin molded product according to claim 5, wherein in the resin molded product according to claim 1, 2, 3 or 4, in the molding step, the non-permeable resin material is provided at the contact end portion. A fitting concave portion is provided on the laser light absorbing surface, and a fitting convex portion capable of fitting with the fitting concave portion is provided at the abutting end of the transparent resin material.
(6) The method for producing a resin molded product according to claim 6 is as follows:A molding step of molding a transparent resin material that is permeable to laser light as a heating source, and a non-permeable resin material that is not permeable to the laser light,
The permeable resin material and the non-permeable resin material obtained in the molding step are brought into contact with each other, and the contact ends of the permeable resin material and the non-permeable resin material are separated from the permeable resin material side. A joining step of welding and joining by irradiation of the laser light,
In the molding step, by controlling the temperature of at least a portion of the molding die for molding the transparent resin material, the portion for molding the contact end portion,The laser beam transmittance at the corresponding contact end of the transparent resin material is 26% or more.The resin crystallinity of at least the corresponding end of the permeable resin material is 40% or less.And
In the bonding step, the laser light is transmitted through the abutting end where the resin crystallinity of the transparent resin material is set to 40% or less, and the laser light transmitted through the corresponding abutting end is subjected to the non-transmitting property. Reach and absorb the contact surface at the contact end of the resin materialIt is characterized by the following.
(7) A method of manufacturing a resin molded product according to claim 7, wherein a molding die is used, and a transparent resin material that is permeable to a laser beam as a heating source and a resin that is not permeable to the laser beam. A molding step of molding the non-permeable resin material,
The permeable resin material and the non-permeable resin material obtained in the molding step are brought into contact with each other, and the contact ends of the permeable resin material and the non-permeable resin material are separated from the permeable resin material side. A joining step of welding and joining by irradiation of the laser light,
In the molding step, by controlling the temperature of the portion where the contact end of the molding die for molding the transparent resin material is formed, the laser light transmittance at the corresponding contact end of the transparent resin material becomes 26%. %, The resin crystal grain size at the corresponding contact end of the transparent resin material is 5 μm or more, and
In the joining step, the laser light is transmitted through the contact end where the resin crystal grain size of the transparent resin material is 5 μm or more, and the laser light transmitted through the contact end is used as the non-transparent resin. The material reaches and abuts on the contact surface of the contact end of the material.
(8) The method for producing a resin molded product according to claim 8 is the method for producing a resin molded product according to claim 7, wherein the permeable resin material is one of polypropylene, polyamide, and polyethylene. It is assumed that.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The method for producing a resin molded product according to the present invention uses a molding die, and a transparent resin material that is permeable to laser light as a heating source, and a non-permeable resin material that is not permeable to the laser light. And a joining step of joining the permeable resin material and the non-permeable resin material obtained in the molding step by laser welding.
[0013]
This laser welding is performed by irradiating laser light from the transparent resin material side in a state where the contact ends of the transparent resin material and the non-transparent resin material are in contact with each other. The laser light emitted from the transparent resin material side passes through the transparent resin material, reaches the contact surface of the non-transparent resin material, and is absorbed. As a result of the laser light absorbed by the contact surface of the non-transparent resin material being stored as energy, the contact surface of the non-transparent resin material is heated and melted, and the contact surface of the non-transparent resin material is heated. Then, the contact surface of the permeable resin material is heated and melted by the heat transfer from the contact member. In this state, if the contact surfaces of the permeable resin material and the non-permeable resin material are pressed together, they can be integrally joined.
[0014]
In the joining portion thus obtained, the contact surfaces are melted and joined, and between the corresponding contact surfaces, a state is formed in which both resins forming both molding members melt and enter each other and become entangled with each other. Therefore, it has a strong joining state and a high joining strength and high pressure resistance.
[0015]
Here, the method for producing a resin molded product of the present invention is characterized in that, in the molding step, by locally controlling the temperature of a portion of the molding die for molding the permeable resin material, the portion for molding the contact end portion. The transparent resin material is characterized in that the degree of crystallinity of the resin at the corresponding contact end portion is lower than that of other portions.
[0016]
As described above, by setting the resin crystallinity at the contact end portion of the transparent resin material to be lower than that of other portions, the transmittance of the laser beam transmitted through the contact end portion can be increased. Therefore, more laser light reaches and is absorbed by the contact surface of the non-transparent resin material. As a result, the contact surfaces of the permeable resin material and the non-permeable resin material can be sufficiently heated and melted, and the corresponding contact surfaces can be reliably laser-welded to obtain sufficient bonding strength. .
[0017]
Therefore, according to the method of manufacturing a resin molded product of the present invention, it is possible to employ a resin material of a transparent resin material that has a laser light transmittance that is too low and cannot be conventionally used. Become.
[0018]
If the laser beam transmittance of the transparent resin material at the time of laser welding is 26% or more, the welding strength by laser welding can be significantly improved. For this reason, depending on the transparency of the resin used for the transmissive resin material to the laser light, the wavelength of the laser light used as the heating source, and the like, the transmissive resin material has a laser light transmittance of 26% or more. Lower the crystallinity of the resin at the contact end of the conductive resin materialYou.Note that the laser light transmittance refers to a percentage of the energy of the laser light transmitted through the transparent resin material with respect to the energy of the incident light.
[0019]
Means for locally controlling the temperature of the portion where the contact end is formed in the molding die for forming the transparent resin material is not particularly limited. For example, the contact end of the transparent resin material is formed. Means for providing a cooling water passage in the mold part may be employed. By rapidly cooling the molten resin at the abutting end of the permeable resin material by the cooling water flowing in the cooling water passage, the degree of resin crystallinity at the abutting end can be reduced.
[0020]
Here, it has been confirmed by experiments by the present inventor that the relationship between the laser light transmittance and the resin crystallinity is such that the lower the resin crystallinity, the higher the laser light transmittance. For this reason, in order to secure a laser beam transmittance of 26% or more, the resin crystallinity at the contact end of the transparent resin material is preferably 40% or less, and particularly preferably 30% or less. Note that the lower limit of the resin crystallinity is 0%.
[0021]
In addition, it has been confirmed by experiments of the present inventors that the relationship between the laser light transmittance and the resin crystal particle size is such that the larger the resin crystal particle size, the higher the laser light transmittance. For this reason, in order to secure a laser beam transmittance of 26% or more, the resin crystal grain size at the contact end of the transparent resin material is preferably 5 μm or more, particularly preferably 10 μm or more.
[0022]
The resin crystal grain size can be adjusted to some extent by cooling conditions (temperature control) when cooling and solidifying the molten resin, but it is almost determined by the type of resin material used for the permeable resin material. . Therefore, it is preferable to use a resin material having a crystal grain size of the resin of 5 μm or more at the contact end of the transparent resin material as the transparent resin material. Specifically, it is preferable to use polypropylene (PP), polyamide (PA), polyethylene (PE), or the like among resins that can be used for a transparent resin material described later.
[0023]
Further, as described above, in the method of manufacturing a resin molded product of the present invention, the resin crystallinity at the contact end portion of the transparent resin material is set lower than that of the other portions, and the relevant contact is made during laser welding in the joining step. This is to increase the transmittance of the laser light transmitted through the end. For this reason, there is a concern that the strength of the abutting end portion of the permeable resin material is lower than that of other portions due to the low degree of resin crystallinity.
[0024]
In this regard, in the method of manufacturing a resin molded product of the present invention, when laser light is transmitted through the abutting end of the transparent resin material during laser welding in the joining step, the crystal part generates internal heat due to radiant heat, and this heat causes the crystal part to generate heat. Crystallization of the crystal part proceeds. For this reason, the resin molded product obtained by the production method of the present invention has the same or higher strength at the contact end portion of the permeable resin material as at other portions.
[0025]
Therefore, in the joining step, the contact end of the transparent resin material is sufficiently crystallized by radiant heat at the time of laser welding, and the strength at the corresponding contact end is assured as much as that of other parts. It is preferable to set the laser irradiation conditions so that the above conditions can be achieved. Specifically, it is preferable that the laser beam transmittance is 26% and the power is 200 W / sec.
[0026]
Further, in the molding step, by controlling the temperature of at least a portion of the molding die for molding the permeable resin material, the portion for molding the abutting end portion, at least a portion of the permeable resin material corresponding to the abutting end portion. The resin crystallinity may be 40% or less. In other words, when a portion of the permeable resin material other than the contact end does not particularly require high strength, only a portion of the mold for molding the permeable resin material where the contact end is formed is locally Instead of controlling the temperature, the temperature of the mold including the part of the mold that molds the part other than the abutting end (and in some cases the entire mold that molds the transparent resin material) can be controlled by controlling the temperature. The resin crystallinity of the resin material other than the contact end and the contact end may be 40% or less. In this case, if necessary, a portion other than the contact end portion may be subjected to a heat treatment or the like after the joining step to promote crystallization, thereby increasing strength.
[0027]
The type of the resin used for the transparent resin material is not particularly limited as long as it has thermoplasticity and can transmit laser light as a heating source at a predetermined transmittance or higher. For example, polyamide (PA) such as nylon 6 (PA6) or nylon 66 (PA66), polyethylene (PE), polypropylene (PP), styrene-acrylonitrile copolymer, polyethylene terephthalate (PET), polystyrene, ABS, acrylic (PMMA) ), Polycarbonate (PC), and the like, PPS (polyphenylene sulfide), polybutylene terephthalate (PBT), and polystyrene (PBT), which have not been able to be conventionally used as a resin material of a transparent resin material because the laser light transmittance is too low. PS) or the like can be adopted. If necessary, a reinforcing fiber such as glass fiber or carbon fiber or a coloring material may be used.
[0028]
The type of the resin used for the non-transparent resin material is not particularly limited as long as it has thermoplasticity and can absorb laser light as a heating source without transmitting it. For example, polyamide (PA) such as nylon 6 (PA6) or nylon 66 (PA66), polyethylene (PE), polypropylene (PP), styrene-acrylonitrile copolymer, polyethylene terephthalate (PET), polystyrene, ABS, acrylic (PMMA) ), Polycarbonate (PC), polybutylene terephthalate (PBT), PPS, or the like, into which a predetermined coloring material such as carbon black, a dye, or a pigment is mixed. In addition, what added the reinforcement fiber, such as a glass fiber and a carbon fiber, as needed may be used.
[0029]
Further, the combination of the resin used for the transparent resin material and the resin used for the non-permeable resin material is a combination of mutually compatible resins. Examples of such a combination include a combination of resins of the same type, such as nylon 6 and nylon 66, a combination of nylon 6 and nylon 66, a combination of PET and PC, and a combination of PC and PBT. it can.
[0030]
The type of the laser light used as the heating source is such that the transmittance in the transparent resin material is a predetermined value depending on the absorption spectrum and the plate thickness (transmission length) of the transparent resin material transmitting the laser light. Those having the wavelengths as described above are appropriately selected. For example, YAG: Nd3+A laser (wavelength of laser light: 1060 nm) or a semiconductor laser (wavelength of laser light: 500 to 1000 nm) can be used.
[0031]
Irradiation conditions such as laser output, irradiation density, and processing speed (moving speed) can be appropriately set according to the type of resin and the like.
[0032]
【Example】
Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
[0033]
In this embodiment, the resin molded product according to the present invention is applied to an intake manifold made of synthetic resin.
[0034]
FIG. 1 is a plan view of the intake manifold. FIG. 2 is an enlarged view of a cut end surface of the intake manifold taken along line AA in FIG.
[0035]
The intake manifold 10 is a hollow body that is vertically divided into two parts and includes a first molded member 11 that is an upper divided body and a second molded member 12 that is a lower divided body. The first molding member 11 and the second molding member 12 have contact ends 11a and 12a, respectively, which are flange portions that are aligned and abut on each other. The contact surfaces 11b and 12b of the contact end 11a of the first molding member 11 and the contact end 12a of the second molding member 12 are integrally joined by laser welding.
[0036]
The first molding member 11 is made of a transparent resin that is transparent to a laser beam as a heating source. In this embodiment, 30 wt% of glass fiber as a reinforcing material is added to PA66 in this embodiment. Reinforced plastic was used. The laser beam used for irradiation is YAG: Nd3+It is a laser (wavelength: 1060 nm).
[0037]
The second molding member 12 is made of a non-transmissive resin that does not transmit laser light as a heating source. In the present embodiment, as the non-transparent resin, a glass fiber as a reinforcing material is used for PA66. Reinforced plastic obtained by adding an appropriate amount of carbon black as an auxiliary agent (coloring material) to 30 wt%.
[0038]
The first molded member 11 and the second molded member 12 both use PA66 as a base resin and are compatible with each other.
[0039]
The first molded member 11 has a substantially semi-cylindrical cross-sectional shape as shown in an enlarged view in FIG. 2 at a portion indicated by line AA in FIG. At the opening end of the first molding member 11 having a substantially semi-cylindrical shape, a contact end 11a formed of a flange bulging in the centrifugal direction is provided.
[0040]
As shown in FIG. 3 in which this portion is further enlarged, an annular fitting convex portion 11c is provided on the lower surface (contact surface 11b) of the contact end portion 11a so as to protrude downward. Have been. The fitting projection 11c has a substantially trapezoidal cross-sectional shape that gradually reduces and projects toward the distal end side (downward side).
[0041]
On the other hand, an abutting end portion 12a of the second molding member 12 has an annular fitting concave portion 12c on its upper surface (a contact surface 12b serving as a laser light absorbing surface) which can be fitted with the fitting convex portion 11c. Is provided. The fitting concave portion 12c has a shape matching the fitting convex portion 11c, and has a substantially trapezoidal cross-sectional shape in which the opening gradually expands upward from the bottom surface (the side to which the laser beam is irradiated).
[0042]
The fitting projection 11c of the first molding member 11 and the fitting recess 12c of the second molding member 12 are fitted together, and the contact surface 11b of the first molding member 11 (the inclination of the fitting projection 11c) is set. The contact surface 12b (including the inclined side surface and the bottom surface of the fitting concave portion 12c) of the second molded member 12 is integrally joined to each other by laser welding.
[0043]
The resin molded product according to the present example having the above configuration was manufactured as follows.
[0044]
(Molding process)
First, the first molding member 11 and the second molding member 12 were injection molded in a predetermined shape using a predetermined injection molding die.
[0045]
At this time, the first molding member 11 made of a transparent resin material was injection-molded using first to third molding dies 21 to 23 as shown in FIG. The second and third molds 22 and 23 for molding the contact end 11a of the first molding member 11 are provided with cooling water passages 22a and 23a near the mold surface for molding the contact end 11a. I have. Injection molding is performed while flowing cooling water through the cooling water passages 22a and 23a, so that only the part where the contact end 11a is formed in the first to third molding dies for molding the first molding member 11 is formed. The temperature was controlled locally. In this way, in the first molded member 11, the molten resin at the contact end 11a was rapidly cooled to make the resin crystallinity at the contact end 11a lower than other portions.
[0046]
Specifically, only the part of the second and third molding dies 22 and 23 where the contact end 11a was molded was locally cooled to a mold temperature of about 20 to 25 ° C. by cooling water. Thus, in the first molded member 11, the resin crystallinity at the contact end 11a was set to about 20 to 25%, and the resin crystal grain size at the contact end 11a was set to about 5 to 10 μm. Therefore, the laser beam transmittance at this contact end 11a is about 40 to 50%. The other parts of the first to third molding dies 21 to 23 for molding parts other than the contact end 11a of the first molding member 11 have a mold temperature of about 60 to 80 ° C. In the first molded member 11, the resin crystallinity in a portion other than the contact end 11a is about 30 to 35%.
[0047]
(Joining process)
Then, the fitting projection 11c of the first molding member 11 and the fitting recess 12c of the second molding member 12 are fitted, and the contact surfaces 11b and 12b of the first molding member 11 and the second molding member 12 are connected to each other. Contacted. In this state, a laser beam was irradiated from the first forming member 11 side using a laser torch (not shown). That is, by irradiating the laser light from the upper surface side of the contact end 11a of the first molding member 11 and causing the laser light to enter from the upper surface of the contact end 11a, the contact end 11a of the first molding member 11 is formed. The contact surfaces 11b and 12b of the second molding member 12 and the contact end portion 12a were entirely heated and melted, and the two were integrally joined by laser welding.
[0048]
At the joint thus obtained, the contact surfaces 11b and 12b are entirely melted and joined, and between the corresponding contact surfaces 11b and 12b, both resins constituting both molding members 11 and 12 are melted. As a result, a state in which they are entangled with each other is formed, so that they form a strong bonding state and have high bonding strength and pressure resistance.
[0049]
In particular, in this embodiment, the contact end portion 11a of the first molded member 11 made of the transparent resin material obtained in the above molding step has a low resin crystallinity of about 20 to 25%, The diameter is as large as about 5 to 10 μm. Therefore, the laser light transmittance at the contact end 11a is as high as about 40 to 50%. Therefore, at the time of laser welding in the joining step, more laser light reaches and is absorbed by the contact surface 12b of the second molding member 12 made of the non-transparent resin material. As a result, the contact surfaces 11b and 12b of the first molded member 11 and the second molded member 12 can be sufficiently heated and melted, and the corresponding contact surfaces 11b and 12b can be reliably laser-welded to have sufficient bonding strength. Can be obtained.
[0050]
Further, when the laser beam is transmitted through the contact end portion 11a of the first molding member 11 made of a transparent resin material at the time of laser welding in the above-described bonding step, the crystalline portion generates heat internally due to radiant heat, and this heat causes the non-crystalline portion to generate heat. Crystallization proceeds. For this reason, in the above-mentioned molding step, the resin crystallinity at the contact end 11a of the first molded member 11 was lower than that of the other parts, but the resin according to the present embodiment obtained through the joining step was obtained. The molded product has the same or higher strength at the corresponding contact end 11a as at other portions.
[0051]
On the other hand, in the resin molded product according to the present embodiment, a mechanical coupling force is formed between the fitting protrusion 11c of the first molding member 11 and the fitting recess 12c of the second molding member 12 due to the concave and convex fitting. Since it is provided, the bonding strength between the two can be further improved.
[0052]
In addition, warpage or the like at the contact end portions 11a and 12a of the first molding member 11 and the second molding member 12 is corrected by the mechanical coupling force due to the concave-convex fitting. The generation of a gap between the contact surfaces 11b and 12b of the member 12 can be suppressed. For this reason, the heat generated at the contact surface 12b of the second molding member 12 made of the non-transparent resin material is reliably transmitted to the contact surface 11b of the first molding member 11 made of the transparent resin material. The contact surface 11b of the member 11 can be reliably heated and melted. Therefore, the contact surfaces 11b and 12b of the first molded member 11 and the second molded member 12 can be reliably laser welded to each other.
[0053]
Further, by the above-mentioned concave and convex fitting, the contact surface 11b of the first molding member 11 (including the inclined side surface and the tip end surface of the fitting convex portion 11d) and the contact surface 12b of the second molding member 12 (the fitting concave portion). (Including the inclined side surface and the bottom surface of 12d), that is, the bonding area by laser welding also increases, so that the bonding strength can also be improved.
[0054]
Further, the fitting protrusion 11c is provided on the first molding member 11 made of a transparent resin material, and the fitting recess 12c is provided on the second molding member 12 made of a non-permeable resin material. The fact that a part of the laser light is reflected on the inner surface (bottom surface and inclined side surface) of the joint concave portion 12c can be used, which is advantageous for more uniformly laser welding.
[0055]
(Relationship between resin crystallinity, resin crystal particle size and laser light transmittance)
By changing the temperature of the mold during injection molding, a permeable resin material having a thickness of 3 mm having various degrees of resin crystallinity was molded.
[0056]
Also, by changing the type of the resin material used as the transparent resin material in various ways, a transparent resin material having a thickness of 3 mm and having various resin crystal grain sizes was formed.
[0057]
And YAG: Nd3+A laser (wavelength: 1060 nm) is applied to each transparent resin material in the thickness direction, and the laser light transmittance of each transparent resin material is measured. And examined the relationship. The output of the laser at this time was 400 W. The laser beam transmittance was measured by calculating the incident energy based on the presence or absence of a work.
[0058]
As shown in FIG. 5, the relationship between the resin crystallinity and the laser light transmittance is such that the lower the resin crystallinity, the higher the laser light transmittance. It can be seen that the ratio becomes 26% or more.
[0059]
As shown in FIG. 6, the relationship between the resin crystal grain size and the laser light transmittance is such that the larger the resin crystal grain size is, the higher the laser light transmittance is. It can be seen that the transmittance is 26% or more.
[0060]
In FIG. 6, the resin material of the transparent resin material having the resin crystal particle size of 2 μm is PBT, and the resin material of the transparent resin material having the resin crystal particle size of 5 μm is PA66.
[0061]
Next, two types of resin materials, PA66 and PPS, were prepared.
[0062]
By changing the mold temperature at the time of injection molding to 20 ° C. and 80 ° C. for one resin material (PA66), the resin crystallinity is 30% and 40%, respectively, and the resin crystal grain size is 30%. A transparent resin material having a thickness of 5 to 10 μm and a thickness of 1 to 5 mm was formed.
[0063]
Further, the other resin material (PPS) has a resin crystallinity of 30% and 60% by changing the mold temperature during injection molding to 20 ° C. and 80 ° C., respectively. A transparent resin material having a thickness of 1 to 5 mm and a thickness of 1 μm or less was molded.
[0064]
Then, similarly to the above, YAG: Nd3+A laser (wavelength: 1060 nm) was applied to each transparent resin material in the thickness direction, and the laser light transmittance of each transparent resin material was measured.
[0065]
As shown in FIG. 7, the results show that the reduction in the crystallinity of the resin and the increase in the particle size of the resin crystal are crucial factors in the transmission of the laser beam.
[0066]
(Relationship between laser beam transmittance and welding strength)
A 3 mm-thick permeable resin material made of nylon 6 reinforced by adding 30 wt% of glass fiber and a 3 mm-thick non-permeable resin material made of nylon 6 to which a predetermined amount of carbon black has been added, YAG: Nd3+A laser (wavelength: 1060 nm) was irradiated from the transparent resin material side, and joined together by laser welding. The output of the laser was 400 W and the processing speed was 4 m / min.
[0067]
Then, a dye as a coloring agent is added to the transparent resin material, and the amount of the dye is variously changed, so that the laser light transmittance of the transparent resin material is variously changed, and the laser light transmittance of the transparent resin material is changed. And the relationship between welding strength and welding strength were examined. The laser light transmittance was measured in the same manner as described above, and the welding strength was measured by pulling and breaking the welded portion. FIG. 8 shows the result.
[0068]
As is clear from FIG. 8, when the laser beam transmittance of the transparent resin material is 26% or more, the welding strength becomes 45 MPa or more, and a sufficient welding strength can be achieved.
[0069]
【The invention's effect】
As described in detail above, according to the method for manufacturing a resin molded product of the present invention, laser welding is performed by lowering the crystallinity of the resin at the contact end of the transparent resin material and increasing the laser light transmittance. Occasionally, the contact surfaces of the permeable resin material and the non-permeable resin material are sufficiently heated and melted, and the contact surfaces are reliably laser-welded to obtain a sufficient bonding strength.
[0070]
Further, since the crystallization proceeds at the contact end due to radiant heat at the time of laser welding, in the resin molded product obtained by the method of the present invention, the contact end at the contact end due to low resin crystallinity. There is no decrease in strength.
[0071]
Furthermore, if the transmittance of the laser beam in the transparent resin material increases, the energy of the laser beam can be more efficiently used for laser welding, and the energy consumption can be reduced, thereby contributing to cost reduction.
[Brief description of the drawings]
FIG. 1 is a plan view of a synthetic resin intake manifold to which a resin molded product according to the present invention is applied according to an embodiment.
FIG. 2 is a cross-sectional view of a portion indicated by an arrow AA line in FIG. 1 according to the embodiment.
FIG. 3 is an enlarged partial sectional view showing a joint structure between a first molding member and a second molding member according to the embodiment.
FIG. 4 is a partial cross-sectional view showing a state where a contact end of a first molding member made of a transparent resin material is molded according to the embodiment.
FIG. 5 is a diagram showing a relationship between a resin crystallinity and a laser beam transmittance.
FIG. 6 is a diagram showing a relationship between a resin crystal grain size and a laser beam transmittance.
FIG. 7 is a diagram showing a relationship between a resin crystallinity, a resin crystal particle size, and laser light transmittance.
FIG. 8 is a diagram showing a relationship between laser beam transmittance and welding strength in a transparent resin material.
[Explanation of symbols]
11 First molded member (permeable resin material)
12: Second molded member (non-permeable resin material)
11a, 12a ... contact end
11b, 12b ... contact surface
11c ... fitting projection
12c ... fitting recess

Claims (8)

成形型を用い、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、
上記成形工程で得られた上記透過性樹脂材及び上記非透過性樹脂材を当接させ、該透過性樹脂材及び該非透過性樹脂材の当接端部同士を該透過性樹脂材側からの上記レーザ光の照射により溶着して接合する接合工程とからなり、
上記成形工程で、上記透過性樹脂材を成形する上記成形型のうち上記当接端部を成形する部分を局所的に温度制御することにより、該透過性樹脂材の該当接端部におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材において該当接端部の樹脂結晶化度を他の部分より低くし、かつ、
上記接合工程で、上記透過性樹脂材の他の部分より樹脂結晶化度が低くされた上記当接端部を上記レーザ光を透過させ、該当接端部を透過した該レーザ光を上記非透過性樹脂材の上記当接端部の当接面に到達、吸収させることを特徴とする樹脂成形品の製造方法。Using a molding die, a molding process of molding a transparent resin material that is permeable to laser light as a heating source, and a non-permeable resin material that is not permeable to the laser light,
The permeable resin material and the non-permeable resin material obtained in the molding step are brought into contact with each other, and the contact ends of the permeable resin material and the non-permeable resin material are separated from the permeable resin material side. A joining step of welding and joining by irradiation of the laser light,
In the molding step, by locally controlling the temperature of a portion of the molding die for molding the transparent resin material where the contact end is molded, a laser beam at a corresponding contact end of the transparent resin material is formed. In the transparent resin material, the resin crystallinity at the corresponding contact end portion is lower than that of other portions so that the transmittance is 26% or more , and
In the joining step, the laser light is transmitted through the abutting end portion having a lower resin crystallinity than other portions of the transmissive resin material, and the laser light transmitted through the corresponding abutting end portion is not transmitted through the laser light. A method for producing a resin molded product , comprising: reaching and absorbing a contact surface of a contact end portion of a conductive resin material . 前記成形工程で、前記透過性樹脂材の前記当接端部における樹脂結晶化度が４０％以下となるように温度制御することを特徴とする請求項１記載の樹脂成形品の製造方法。2. The method according to claim 1, wherein in the forming step, the temperature is controlled such that the degree of crystallinity of the resin at the contact end of the transparent resin material is 40% or less. 3. 前記成形工程で、前記透過性樹脂材の前記当接端部における樹脂結晶粒径が５μｍ以上となるような樹脂材料を該透過性樹脂材に用いることを特徴とする請求項１又は２記載の樹脂成形品の製造方法。3. The transparent resin material according to claim 1, wherein in the molding step, a resin material having a resin crystal grain size of 5 μm or more at the contact end portion of the transparent resin material is used as the transparent resin material. Method for manufacturing resin molded products. 前記透過性樹脂材は、ポリプロピレン、ポリアミド及びポリエチレンのうちの一種であることを特徴とする請求項３記載の樹脂成形品の製造方法。The method according to claim 3, wherein the permeable resin material is one of polypropylene, polyamide, and polyethylene. 前記成形工程で、前記非透過性樹脂材の前記当接端部における前記レーザ光の吸収面に嵌合凹部を設けるとともに、前記透過性樹脂材の前記当接端部に該嵌合凹部と嵌合可能な嵌合凸部を設けることを特徴とする請求項１、２、３又は４記載の樹脂成形品の製造方法。In the molding step, a fitting recess is provided on the laser light absorbing surface at the contact end of the non-transparent resin material, and the fitting recess is fitted to the contact end of the transparent resin material. 5. The method for producing a resin molded product according to claim 1, wherein a mating convex portion is provided. 成形型を用い、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、
上記成形工程で得られた上記透過性樹脂材及び上記非透過性樹脂材を当接させ、該透過性樹脂材及び該非透過性樹脂材の当接端部同士を該透過性樹脂材側からの上記レーザ光の照射により溶着して接合する接合工程とからなり、
上記成形工程で、上記透過性樹脂材を成形する上記成形型のうち少なくとも上記当接端部を成形する部分を温度制御することにより、該透過性樹脂材の該当接端部におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材のうち少なくとも該当接端部の樹脂結晶化度を４０％以下とし、かつ、
上記接合工程で、上記透過性樹脂材の樹脂結晶化度が４０％以下とされた上記当接端部を上記レーザ光を透過させ、該当接端部を透過した該レーザ光を上記非透過性樹脂材の上記当接端部の当接面に到達、吸収させることを特徴とする樹脂成形品の製造方法。Using a molding die, a molding process of molding a transparent resin material that is permeable to laser light as a heating source, and a non-permeable resin material that is not permeable to the laser light,
The permeable resin material and the non-permeable resin material obtained in the molding step are brought into contact with each other, and the contact ends of the permeable resin material and the non-permeable resin material are separated from the permeable resin material side. A joining step of welding and joining by irradiation of the laser light,
In the molding step, by controlling the temperature of at least a portion of the molding die for molding the transparent resin material , the portion for molding the abutting end portion, the laser light transmittance at the corresponding contact end portion of the transparent resin material. so it becomes 26% or more, at least the abutting end portions of the resin crystallinity of the transparent resin material is 40% or less, and,
In the bonding step, the laser light is transmitted through the abutting end where the resin crystallinity of the transparent resin material is set to 40% or less, and the laser light transmitted through the corresponding abutting end is subjected to the non-transmitting property. A method of manufacturing a resin molded product, wherein the resin material reaches and absorbs a contact surface of the contact end of the resin material . 成形型を用い、加熱源としてのレーザ光に対して透過性のある透過性樹脂材と、該レーザ光に対して透過性のない非透過性樹脂材とをそれぞれ成形する成形工程と、Using a molding die, a molding process of molding a transparent resin material that is permeable to laser light as a heating source, and a non-permeable resin material that is not permeable to the laser light,
上記成形工程で得られた上記透過性樹脂材及び上記非透過性樹脂材を当接させ、該透過性樹脂材及び該非透過性樹脂材の当接端部同士を該透過性樹脂材側からの上記レーザ光の照射により溶着して接合する接合工程とからなり、The permeable resin material and the non-permeable resin material obtained in the molding step are brought into contact with each other, and the contact ends of the permeable resin material and the non-permeable resin material are separated from the permeable resin material side. A joining step of welding and joining by irradiation of the laser light,
上記成形工程で、上記透過性樹脂材を成形する上記成形型の上記当接端部を成形する部分を温度制御することにより、該透過性樹脂材の該当接端部におけるレーザ光透過率が２６％以上となるように、該透過性樹脂材の該当接端部の樹脂結晶粒径を５μｍ以上とし、かつ、In the molding step, by controlling the temperature of the portion where the contact end of the molding die for molding the transparent resin material is formed, the laser light transmittance at the corresponding contact end of the transparent resin material becomes 26%. %, The resin crystal grain size at the corresponding contact end of the transparent resin material is 5 μm or more, and
上記接合工程で、上記透過性樹脂材の樹脂結晶粒径が５μｍ以上とされた上記当接端部The contact end portion in which the resin crystal grain size of the transparent resin material is set to 5 μm or more in the joining step. を上記レーザ光を透過させ、該当接端部を透過した該レーザ光を上記非透過性樹脂材の上記当接端部の当接面に到達、吸収させることを特徴とする樹脂成形品の製造方法。Manufacturing the resin molded article, wherein the laser light is transmitted, and the laser light transmitted through the corresponding contact end reaches the contact surface of the contact end of the non-transparent resin material and is absorbed. Method. 前記透過性樹脂材は、ポリプロピレン、ポリアミド及びポリエチレンのうちの一種であることを特徴とする請求項７記載の樹脂成形品の製造方法。The method according to claim 7, wherein the permeable resin material is one of polypropylene, polyamide, and polyethylene.
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