JP2019063833A - Metal injection molding machine characterized in back flow prevention device - Google Patents
Metal injection molding machine characterized in back flow prevention device Download PDFInfo
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- JP2019063833A JP2019063833A JP2017193853A JP2017193853A JP2019063833A JP 2019063833 A JP2019063833 A JP 2019063833A JP 2017193853 A JP2017193853 A JP 2017193853A JP 2017193853 A JP2017193853 A JP 2017193853A JP 2019063833 A JP2019063833 A JP 2019063833A
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- backflow prevention
- injection molding
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- 230000002265 prevention Effects 0.000 title claims abstract description 62
- 229910052751 metal Inorganic materials 0.000 title claims abstract description 59
- 239000002184 metal Substances 0.000 title claims abstract description 59
- 238000001746 injection moulding Methods 0.000 title claims abstract description 57
- 229910000861 Mg alloy Inorganic materials 0.000 claims abstract description 46
- 238000010438 heat treatment Methods 0.000 claims abstract description 33
- 238000005259 measurement Methods 0.000 claims description 6
- 239000012530 fluid Substances 0.000 claims description 4
- 239000000243 solution Substances 0.000 abstract 1
- 238000000465 moulding Methods 0.000 description 22
- 238000000034 method Methods 0.000 description 13
- 238000002347 injection Methods 0.000 description 11
- 239000007924 injection Substances 0.000 description 11
- 239000007787 solid Substances 0.000 description 9
- 230000007547 defect Effects 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 230000008018 melting Effects 0.000 description 7
- 238000002844 melting Methods 0.000 description 7
- 238000004512 die casting Methods 0.000 description 5
- 238000003825 pressing Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 4
- 238000011144 upstream manufacturing Methods 0.000 description 4
- 239000000155 melt Substances 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000007711 solidification Methods 0.000 description 3
- 230000008023 solidification Effects 0.000 description 3
- 238000005266 casting Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 244000261422 Lysimachia clethroides Species 0.000 description 1
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 239000011777 magnesium Substances 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005303 weighing Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/20—Accessories: Details
- B22D17/2015—Means for forcing the molten metal into the die
- B22D17/2061—Means for forcing the molten metal into the die using screws
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
- B22D17/02—Hot chamber machines, i.e. with heated press chamber in which metal is melted
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
Description
本発明は、マグネシウム合金を射出材料とし金属成形品を成形する金属射出成形機に関するものである。 The present invention relates to a metal injection molding machine that uses a magnesium alloy as an injection material to form a metal molding.
マグネシウム合金から金属成形品を成形する方法は色々あり、広く実施されている方法としてダイカスト法が周知である。ダイカスト法には、コールドチャンバー方式とホットチャンバー方式とがあり、コールドチャンバー方式では射出装置に形成されているスリーブから溶融したマグネシウム合金を注入して、プランジャを駆動して金型に射出するようになっており、ホットチャンバー方式では溶融したマグネシウム合金で満たされた溶融炉にいわゆるグースネックを入れてマグネシウム合金を供給しプランジャを駆動して金型に射出するようになっている。つまりダイカスト法では、いずれの方式でもマグネシウム合金を完全に溶融する必要がある。従って、例えば汎用的なマグネシウム合金であり融点が５９５℃のＡＺ９１Ｄであれば、それよりかなり高温、例えば６５０〜６７０℃に加熱しなければならない。このようにダイカスト法ではマグネシウム合金を完全に溶融するために高温にする必要があるので凝固時にある程度の収縮が発生する。それによって引け巣が生じたり、ガスの巻き込みが生じるいわゆる鋳造欠陥が生じやすいという欠点もある。 There are various methods for forming metal moldings from magnesium alloys, and die casting is well known as a widely practiced method. The die casting method includes a cold chamber method and a hot chamber method. In the cold chamber method, molten magnesium alloy is injected from a sleeve formed in an injection device, and a plunger is driven to be injected into a mold. In the hot chamber method, a so-called gooseneck is placed in a melting furnace filled with molten magnesium alloy to supply the magnesium alloy, and the plunger is driven to be injected into the mold. That is, in the die casting method, it is necessary to completely melt the magnesium alloy in any method. Thus, for example, if it is a general purpose magnesium alloy and AZ91D having a melting point of 595.degree. C., it must be heated to a considerably higher temperature, for example, 650 to 670.degree. As described above, in the die casting method, since it is necessary to make the temperature high in order to completely melt the magnesium alloy, some shrinkage occurs during solidification. There is also a disadvantage that so-called casting defects are likely to occur as a result of shrinkage cavities and gas entrainment.
このようなダイカスト法に対して、インラインスクリュ式の射出成形機によってマグネシウム合金を溶融し金型に射出して成形する射出成形法も周知である。インラインスクリュ式の射出成形機は、射出装置が加熱シリンダとこの加熱シリンダ内で回転方向と軸方向とに駆動可能に設けられているスクリュとから構成され、金属を射出材料とする射出成形機は金属射出成形機と呼ばれている。例えば、特許文献１、２等のように、金属射出成形機に関連する色々な技術が本願の出願人によって提案されているが、金属射出成形機でマグネシウム合金を溶融すると、比較的低温で溶融して金型に射出することができる。具体的には、液相線温度近傍、あるいはそれよりも低温の５８０℃で半溶融状態に溶融し、射出することができる。 An injection molding method in which a magnesium alloy is melted by an in-line screw type injection molding machine and injected into a mold for injection molding is also known as well as such a die casting method. The in-line screw type injection molding machine is composed of a heating cylinder and a screw provided in the heating cylinder so as to be driven in the rotational direction and the axial direction in the heating cylinder, and an injection molding machine using metal as the injection material It is called a metal injection molding machine. For example, various techniques related to metal injection molding machines have been proposed by the applicant of the present application, as in Patent Documents 1 and 2, etc. However, when a magnesium alloy is melted in a metal injection molding machine, it melts at a relatively low temperature Can be injected into the mold. Specifically, it can be melted and injected in a semi-molten state at 580 ° C. near or below the liquidus temperature.
マグネシウム合金から成形品を得るとき金属射出成形機によって射出する射出成形法を実施すると、液相線温度近傍で溶融して射出することができるので、つまり比較的低温で溶融して射出することができるので、凝固時の収縮率が小さく鋳造欠陥の発生を抑制できる。また成形品の変形が小さくなるので精度の高い成形品が得られる。すなわちマグネシウム合金から成形品を得る方法として射出成形法は優れた点が多いと言える。しかしながら解決すべき問題も見受けられる。具体的には、液相線以下の温度で成形を繰り返すと流動性が悪くなり、逆流防止装置通過時の流動抵抗が増えることにより成形安定性が落ちる点である。高温で溶融して射出する場合には成形を繰り返しても成形不良が発生することはほとんど無いが、液相線温度より低い温度で溶融して射出する場合には成形不良が発生しやすい。本発明者の調査によると、成形不良が発生するときには、スクリュの逆流防止弁近傍において未溶融状態のマグネシウムの金属粒子が堆積して溶融した金属が流動する流路を塞いでいることが分かった。マグネシウム合金によって射出成形するとき、凝固時の収縮率を小さくするために比較的低温で溶融して射出したいという要求があり、特にそのような場合に成形が安定しない。 When a molded product is obtained from a magnesium alloy, if injection molding is performed using a metal injection molding machine, it can be melted and injected near the liquidus temperature, that is, it can be melted and injected at a relatively low temperature. Since it can be done, the shrinkage rate at the time of solidification is small, and the occurrence of casting defects can be suppressed. Further, since the deformation of the molded product is reduced, a molded product with high accuracy can be obtained. That is, it can be said that the injection molding method has many excellent points as a method of obtaining a molded product from a magnesium alloy. However, there are also problems to be solved. Specifically, when molding is repeated at a temperature lower than the liquidus, the flowability is deteriorated, and the flow resistance when passing the backflow prevention device is increased, whereby the molding stability is lowered. When melting and injecting at high temperature, molding defects hardly occur even if molding is repeated, but when melting and injecting at a temperature lower than the liquidus temperature, molding defects easily occur. According to the inventor's investigation, it was found that when molding failure occurs, metal particles of unmelted magnesium are deposited in the vicinity of the backflow prevention valve of the screw to block the flow path where the molten metal flows. . When injection molding is performed using a magnesium alloy, there is a demand for melting and injection at a relatively low temperature in order to reduce the shrinkage rate during solidification, and in particular, the molding is not stable in such a case.
本発明は、上記したような問題点を解決した金属射出成形機を提供することを目的とし、具体的には、マグネシウム合金を液相線温度の近傍あるいはそれより低温で溶融して射出するにも拘わらず、成形サイクルを繰り返し実施しても成形不良が発生しにくい金属射出成形機を提供することを目的としている。 An object of the present invention is to provide a metal injection molding machine which solves the problems as described above, and more specifically, for melting and injecting a magnesium alloy at or near a liquidus temperature. Nevertheless, it is an object of the present invention to provide a metal injection molding machine in which molding defects are less likely to occur even if the molding cycle is repeated.
本発明は上記目的を達成するために、加熱シリンダとスクリュとからなる金属射出成形機であって、逆流防止装置に特徴を有する金属射出成形機として構成する。逆流防止装置は、スクリュの先端に設けられている押金と、押金に固定されているスクリュヘッドと、逆流防止リングとから構成されている。そしてスクリュヘッドは所定径の軸部と頭部とからなり、逆流防止リングは加熱シリンダのボアに液密的に摺動されていると共に軸部に挿通されている。計量時には逆流防止リングは頭部に当接し、溶融したマグネシウム合金は、加熱シリンダのボアと押金の間に形成されている第１の流路、押金と逆流防止リングの間に形成されている第２の流路、軸部と逆流防止リングの間に形成されている第３の流路、頭部に形成されている第４の流路を順次流れる。本発明は、第２〜４の流路のそれぞれの断面積が、第１の流路の断面積と等しいかそれより大きいように構成する。 In order to achieve the above object, the present invention is a metal injection molding machine comprising a heating cylinder and a screw, and is configured as a metal injection molding machine characterized by a backflow prevention device. The backflow prevention device is composed of a pressing metal provided at the tip of the screw, a screw head fixed to the pressing metal, and a backflow prevention ring. The screw head is composed of a shaft portion and a head portion of a predetermined diameter, and the backflow prevention ring is in fluid tight sliding in the bore of the heating cylinder and is inserted in the shaft portion. During metering, the backflow prevention ring abuts against the head, and the molten magnesium alloy is formed between the bore of the heating cylinder and the first channel formed between the bore and the presser, and between the presser and the backflow prevention ring The second flow path, the third flow path formed between the shaft portion and the backflow prevention ring, and the fourth flow path formed in the head sequentially flow. The present invention is configured such that the cross-sectional area of each of the second to fourth flow channels is equal to or larger than the cross-sectional area of the first flow channel.
かくして、請求項１記載の発明は、上記目的を達成するために、加熱シリンダと、該加熱シリンダ内に回転方向と軸方向とに駆動可能に設けられているスクリュとからなりマグネシウム合金を射出する金属射出成形機であって、前記スクリュの先端に逆流防止装置が設けられ、該逆流防止装置は、前記スクリュの先端に設けられている押金と、前記押金に固定されているスクリュヘッドと、逆流防止リングとから構成され、前記スクリュヘッドは前記押金に固定されている所定径の軸部と該軸部に接続されている頭部とからなり、前記逆流防止リングは前記加熱シリンダのボアに液密的に摺動されていると共に前記軸部に挿通されており、計量時には前記逆流防止リングは前記頭部に当接し、溶融したマグネシウム合金は、前記加熱シリンダの前記ボアと前記押金の間に形成されている第１の流路、前記押金と前記逆流防止リングの間に形成されている第２の流路、前記軸部と前記逆流防止リングの間に形成されている第３の流路、前記頭部に形成されている第４の流路を順次流れて前記スクリュの先端に計量されるようになっており、前記第２〜４の流路のそれぞれの断面積は、前記第１の流路の断面積と等しいかそれより大きいことを特徴とする金属射出成形機として構成される。 Thus, in order to achieve the above object, the invention according to claim 1 comprises a heating cylinder, and a screw rotatably provided in the heating cylinder in the rotational direction and in the axial direction to inject a magnesium alloy. A metal injection molding machine, wherein a backflow prevention device is provided at the tip of the screw, and the backflow prevention device includes a presser provided at the tip of the screw, a screw head fixed to the presser, and a backflow. The screw head comprises a shaft portion of a predetermined diameter fixed to the pressing metal and a head portion connected to the shaft portion, and the backflow prevention ring is a liquid in the bore of the heating cylinder It is closely slid and inserted into the shaft, and at the time of measurement, the backflow prevention ring abuts against the head, and the molten magnesium alloy is the heating cylinder A first flow path formed between the bore and the press bar, a second flow path formed between the press bar and the backflow prevention ring, and a space formed between the shaft portion and the backflow prevention ring And the fourth flow path formed in the head sequentially flow to be metered at the tip of the screw, and each of the second to fourth flow paths The cross-sectional area of is configured as a metal injection molding machine characterized by being equal to or larger than the cross-sectional area of the first channel.
以上によると本発明は、加熱シリンダと、該加熱シリンダ内に回転方向と軸方向とに駆動可能に設けられているスクリュとからなりマグネシウム合金を射出する金属射出成形機として構成される。スクリュの先端に逆流防止装置が設けられ、逆流防止装置は、スクリュの先端に設けられている押金と、押金に固定されているスクリュヘッドと、逆流防止リングとから構成され、スクリュヘッドは押金に固定されている所定径の軸部と該軸部に接続されている頭部とからなり、逆流防止リングは加熱シリンダのボアに液密的に摺動されていると共に軸部に挿通されている。そして計量時には逆流防止リングは頭部に当接し、溶融したマグネシウム合金は、加熱シリンダのボアと押金の間に形成されている第１の流路、押金と逆流防止リングの間に形成されている第２の流路、軸部と逆流防止リングの間に形成されている第３の流路、頭部に形成されている第４の流路を順次流れてスクリュの先端に計量されるようになっている。本発明は、第２〜４の流路のそれぞれの断面積は、第１の流路の断面積と等しいかそれより大きいように構成されている。つまり流路の断面積は上流と下流において等しいか、下流側の方が大きい。従って、マグネシウム合金が液相線温度以下の比較的低い温度で溶融して、半溶融状態であっても、粒子状の固体のマグネシウム合金は溶融したマグネシウム合金と共に滑らかに流動して計量される。つまり粒子状の固体のマグネシウム合金が逆流防止装置において堆積しない。従って成形サイクルを繰り返し実施しても成形不良は発生しない。 According to the above, the present invention is configured as a metal injection molding machine for injecting a magnesium alloy comprising a heating cylinder and a screw provided rotatably in the heating cylinder in the rotational direction and the axial direction. A backflow prevention device is provided at the tip of the screw, and the backflow prevention device is composed of a pressing metal provided at the tip of the screw, a screw head fixed to the pressing metal, and a backflow prevention ring. It consists of a fixed diameter shaft and a head connected to the shaft, and the backflow prevention ring is in fluid tight sliding in the bore of the heating cylinder and is inserted in the shaft. . And at the time of measurement, the backflow prevention ring abuts on the head, and the molten magnesium alloy is formed between the presser and the backflow prevention ring, the first flow path formed between the bore of the heating cylinder and the presser The second flow passage, the third flow passage formed between the shaft portion and the backflow prevention ring, and the fourth flow passage formed in the head sequentially flow so as to be metered to the tip of the screw It has become. In the present invention, the cross-sectional area of each of the second to fourth flow channels is configured to be equal to or larger than the cross-sectional area of the first flow channel. That is, the cross-sectional area of the flow path is equal to the upstream and downstream or larger on the downstream side. Therefore, the magnesium alloy melts at a relatively low temperature below the liquidus temperature, and even in the semi-molten state, the particulate solid magnesium alloy flows smoothly and is metered with the molten magnesium alloy. That is, no particulate solid magnesium alloy is deposited in the backflow prevention device. Therefore, no molding failure occurs even if the molding cycle is repeated.
以下、本発明の実施の形態について説明する。本発明の実施の形態に係る金属射出成形機１は、図１に示されている射出装置２、図示されていない型締装置等から構成されている。射出装置２は、加熱シリンダ４と、この加熱シリンダ４内に回転方向と軸方向とに駆動可能に設けられている本実施の形態に係るスクリュ６とからなる。加熱シリンダ４には、その後方にホッパ７が設けられマグネシウム合金のチップ状原料が加熱シリンダ４内に供給されるようになっている。そして加熱シリンダ２の先端には射出ノズル８が設けられ、図１に示されていないが、加熱シリンダ２の外周面には複数のヒータが設けられ加熱されるようになっている。スクリュ６は、所定の駆動機構１０によって回転方向と軸方向に駆動されるようになっている。 Hereinafter, embodiments of the present invention will be described. The metal injection molding machine 1 according to the embodiment of the present invention comprises the injection device 2 shown in FIG. 1, a mold clamping device not shown, and the like. The injection device 2 comprises a heating cylinder 4 and a screw 6 according to the present embodiment provided in the heating cylinder 4 so as to be drivable in the rotational direction and in the axial direction. The heating cylinder 4 is provided with a hopper 7 at the rear thereof so that magnesium alloy tip material is supplied into the heating cylinder 4. And the injection | spray nozzle 8 is provided in the front-end | tip of the heating cylinder 2, and although not shown in FIG. 1, several heaters are provided in the outer peripheral surface of the heating cylinder 2, and it heats. The screw 6 is driven in a rotational direction and an axial direction by a predetermined drive mechanism 10.
本実施の形態に係る金属射出成形機１は、スクリュ６に設けられている逆流防止装置１２に特徴がある。逆流防止装置１２は、図２に拡大して示されているように、スクリュ６の先端に固定されている押金１４と、スクリュヘッド１５と、逆流防止リング１６とから構成されている。押金１４は上流側が高さの低い円柱部１８になっており、下流側がテーパ状に縮径した円錐部１９になっている。スクリュヘッド１５は、所定径の軸部２１と、この軸部２１に固着されている頭部２２とから構成されている。スクリュヘッド１５は、この軸部２１が押金１４に固定されることによってスクリュ６に取付けられている。逆流防止リング１６は筒状に形成され、スクリュヘッド１５の軸部２１が挿通しており、その外周面が加熱シリンダ４のボア２４に対して液密的に摺動するようになっている。逆流防止リング１６は、押金１４に近い部分においてテーパ面２５が形成されており、射出時には逆流防止リング１６はこのテーパ面２５において押金１４の円錐部１９に押し付けられる。つまり着座する。一方、計量時には逆流防止リング１６はスクリュヘッド１５の頭部２２に当接することになる。スクリュヘッド１５の頭部２２には複数個の切り欠き、あるいは複数個の貫通孔２７が形成されており、逆流防止リング１６が頭部２２に当接しても次に説明する第４の流路３４が確保されるようになっている。 The metal injection molding machine 1 according to the present embodiment is characterized in the backflow prevention device 12 provided in the screw 6. The backflow prevention device 12 is, as shown in an enlarged manner in FIG. 2, composed of a presser foot 14 fixed to the tip of the screw 6, a screw head 15, and a backflow prevention ring 16. The presser 14 is a cylindrical portion 18 having a low height on the upstream side, and a conical portion 19 having a tapered diameter on the downstream side. The screw head 15 includes a shaft 21 having a predetermined diameter and a head 22 fixed to the shaft 21. The screw head 15 is attached to the screw 6 by fixing the shaft 21 to the presser 14. The backflow prevention ring 16 is formed in a cylindrical shape, and the shaft portion 21 of the screw head 15 is inserted, and the outer peripheral surface thereof slides in a fluid tight manner against the bore 24 of the heating cylinder 4. The backflow prevention ring 16 is formed with a tapered surface 25 at a portion close to the presser metal 14. The non-backflow prevention ring 16 is pressed against the conical portion 19 of the presser metal 14 at the time of injection. In other words, you sit down. On the other hand, at the time of measurement, the backflow prevention ring 16 comes in contact with the head 22 of the screw head 15. A plurality of notches or a plurality of through holes 27 are formed in the head portion 22 of the screw head 15, and a fourth flow path to be described next even if the backflow prevention ring 16 abuts on the head portion 22. 34 are to be secured.
計量時には、逆流防止リング１６がスクリュヘッド１５の頭部２２に当接するが、次の複数の流路を経由して溶融したマグネシウム合金がスクリュ６の先端に送られる。まず、逆流防止装置１２における最上流の流路は、押金１４と加熱シリンダ４のボア２４との間に形成される第１の流路３１である。本実施の形態においては押金１４は円柱部１８を備えているので、第１の流路３１は円柱部１８の外周面とボア２４の間の環状の流路になる。このような第１の流路３１の下流側に第２の流路３２が形成されている。第２の流路３２は、押金１４の円錐部１９と逆流防止リング１６のテーパ面２５の間に形成されている。この第２の流路３２の下流側に第３の流路３３が形成されている。第３の流路３３はスクリュヘッド１５の軸部２１と逆流防止リング１６の間に形成され、円筒状になっている。第４の流路３４は、スクリュヘッド１５の頭部２２に形成されている流路であり、複数個の切り欠きあるいは複数個の貫通孔２７からなる。マグネシウム合金は第４の流路３４を流れてスクリュ６の先端に計量されることになる。 At the time of measurement, the backflow prevention ring 16 abuts on the head 22 of the screw head 15, but the molten magnesium alloy is fed to the tip of the screw 6 via the next plurality of flow paths. First, the most upstream flow passage in the backflow prevention device 12 is a first flow passage 31 formed between the presser metal 14 and the bore 24 of the heating cylinder 4. In the present embodiment, since the presser 14 includes the cylindrical portion 18, the first flow path 31 is an annular flow path between the outer peripheral surface of the cylindrical portion 18 and the bore 24. A second flow path 32 is formed on the downstream side of such a first flow path 31. The second flow passage 32 is formed between the conical portion 19 of the presser 14 and the tapered surface 25 of the backflow prevention ring 16. A third flow passage 33 is formed on the downstream side of the second flow passage 32. The third flow path 33 is formed between the shaft portion 21 of the screw head 15 and the backflow prevention ring 16 and has a cylindrical shape. The fourth flow path 34 is a flow path formed in the head portion 22 of the screw head 15 and comprises a plurality of notches or a plurality of through holes 27. The magnesium alloy flows through the fourth channel 34 and is metered to the tip of the screw 6.
本実施の形態に係る金属射出成形機１では、これら第１〜４の流路３１、３２、…の断面積の関係に特徴がある。具体的には、第２〜４の流路３２、３３、３４の断面積は、より詳しく言うと流れ方向と垂直な面における断面積は、第１の流路３１の断面積と実質的に等しいか、第１の流路３１の断面積より大きい。なお、第４の流路３４は、複数個の切り欠き、あるいは複数個の貫通孔２７からなるが、その断面積はそれらの合計の断面積とする。第１〜４の流路３１、３２、…の断面積の関係はこのようになっているが、従来の金属射出成形機では軸部２１が比較的径が大きく、第３の流路３３が第１の流路３１に比して断面積が約１／２と小さい。このため従来の金属射出成形機では粒状の固体のマグネシウム合金が逆流防止装置１２において堆積することがあった。これに対して本実施の形態に係る金属射出成形機１においては、流路の断面積が逆流防止装置１２において上流から下流まで等しいか、あるいは他の流路の断面積は第１の流路３１より大きいので、粒状の固体のマグネシウム合金が溶融したマグネシウム合金と共に流れても、粒状の固体のマグネシウム合金が逆流防止装置１２内で堆積しない。つまり計量において問題が生じない。マグネシウム合金は液相線温度の近傍、あるいは液相線温度より低温で溶融して射出すると、成形品の収縮率が小さく好ましいが、本実施の形態に係る金属射出成形機１は、このように比較的低温で溶融しても粒状の固体のマグネシウム合金が逆流防止装置１２に堆積しないで、良好に計量できる。 The metal injection molding machine 1 according to the present embodiment is characterized in the relationship of the cross-sectional areas of the first to fourth flow paths 31, 32,. Specifically, the cross-sectional areas of the second to fourth flow channels 32, 33, 34 are, more specifically, the cross-sectional area in a plane perpendicular to the flow direction substantially the same as the cross-sectional area of the first flow channel 31. Equal or larger than the cross-sectional area of the first channel 31. Although the fourth flow path 34 is composed of a plurality of notches or a plurality of through holes 27, the cross-sectional area thereof is the total cross-sectional area of them. The cross-sectional areas of the first to fourth channels 31, 32, ... have the relationship as described above, but in the conventional metal injection molding machine, the shaft 21 has a relatively large diameter, and the third channel 33 The cross-sectional area is smaller than about one half of that of the first flow path 31. For this reason, in the conventional metal injection molding machine, granular solid magnesium alloy may be deposited in the backflow prevention device 12. On the other hand, in the metal injection molding machine 1 according to the present embodiment, the cross-sectional area of the flow path is equal from the upstream to the downstream in the backflow prevention device 12 or the cross-sectional area of the other flow paths is the first flow path As it is greater than 31, even if the particulate solid magnesium alloy flows with the molten magnesium alloy, the particulate solid magnesium alloy does not deposit in the backflow prevention device 12. In other words, there is no problem in weighing. When the magnesium alloy is melted and injected near the liquidus temperature or at a temperature lower than the liquidus temperature, the shrinkage of the molded product is preferably small, but the metal injection molding machine 1 according to the present embodiment is thus Even if it melts at a relatively low temperature, granular solid magnesium alloy does not deposit on the backflow prevention device 12 and can be measured well.
本実施の形態に係る金属射出成形機１は、従来の金属射出成形機に比して計量が安定し、成形不良が発生し難いことを確認するため、実験を行った。
実験内容：
本発明の実施例の金属射出成形機１として、加熱シリンダ４の内径が５１ｍｍの金属射出成形機の機種を採用し、第１〜４の流路３１、３２、…の断面積の比率が下の表１のようになるように逆流防止装置１２を制作しスクリュ６に取付けた。すなわち、第２、３、４の流路３２、３３、３４のそれぞれの断面積が、第１の流路３１の断面積に対して、１．０３、１．１３、１．１１倍になるようにした。ただし、第２の流路３２については、流れ方向は円錐部１９の円錐面に平行になっているとして、その断面積を計算している。具体的には、円錐部１９の円錐面は一方の端部が円柱部１８に、そして他方の端部が軸部２１にそれぞれ接続されているが、これら両端部から等距離の位置、つまり円錐面の中央の位置から円錐面に対して垂直に延ばしてテーパ面２５に達する断面を考え、その面積を第２の流路３２の断面積であるとして計算している。
The metal injection molding machine 1 according to the present embodiment was tested in order to confirm that the measurement was stable compared to the conventional metal injection molding machine and that molding defects were less likely to occur.
Experiment contents:
As the metal injection molding machine 1 of the embodiment of the present invention, a model of a metal injection molding machine having an inner diameter of 51 mm of the heating cylinder 4 is adopted, and the ratio of the cross sectional areas of the first to fourth flow paths 31, 32,. The backflow prevention device 12 was produced and attached to the screw 6 as shown in Table 1 of FIG. That is, the cross-sectional area of each of the second, third, and fourth channels 32, 33, 34 is 1.03, 1.13, 1.11 times the cross-sectional area of the first channel 31. I did it. However, for the second channel 32, the cross-sectional area is calculated assuming that the flow direction is parallel to the conical surface of the conical portion 19. Specifically, the conical surface of the conical portion 19 is connected to the cylindrical portion 18 at one end and to the shaft 21 at the other end, but the equidistant positions from these both ends, that is, the cone The cross section from the central position of the surface extending perpendicularly to the conical surface to reach the tapered surface 25 is considered, and the area is calculated as the cross sectional area of the second channel 32.
比較例として同機種の金属射出成形機を用意し、従来の逆流防止装置をスクリュに取付けた。従来の逆流防止装置において第２、３、４の流路のそれぞれの断面積は、表１に示されているように、第１の流路の断面積に対して０．９７、０．５０、０．６３倍であった。 A metal injection molding machine of the same type was prepared as a comparative example, and a conventional backflow prevention device was attached to the screw. In the conventional backflow prevention device, the cross sectional area of each of the second, third and fourth flow channels is 0.97, 0.50 with respect to the cross sectional area of the first flow channel as shown in Table 1. , 0.63 times.
本発明の実施例の金属射出成形機１と、比較例の金属射出成形機のそれぞれにおいてマグネシウム合金ＡＺ９１Ｄを材料として溶融・射出し、１００×２００×２ｍｍの平板成形品を成形した。なお、表２のように加熱シリンダ４の設定温度は色々な温度を与え、それぞれの温度において５０個ずつ平板成形品を成形した。その結果を表２に示す。表２において○は成形した全ての成形品が正常であったことを、△は数個の成形品において成形不良が生じたことを、そして×は実質的に成形ができなかったことをそれぞれ示している。 In each of the metal injection molding machine 1 of the example of the present invention and the metal injection molding machine of the comparative example, a magnesium alloy AZ91D was melted and injected as a material to form a flat molded article of 100 × 200 × 2 mm. As shown in Table 2, the set temperature of the heating cylinder 4 was set to various temperatures, and 50 flat molded articles were formed at each temperature. The results are shown in Table 2. In Table 2, ○ indicates that all molded articles were normal, Δ indicates that molding defects occurred in several molded articles, and × indicates that substantially no molding was possible. ing.
考察：マグネシウム合金ＡＺ９１Ｄの融点は５９５℃であり、６００℃においては実質的に完全に溶融して射出されていると考えられる。この温度では本発明の実施例の金属射出成形機１においても、比較例の金属射出成形機においても正常に成形が実施できた。５９０℃は液相線温度よりわずかに低い温度であるが、この温度においても本発明の実施例の金属射出成形機１においても、比較例の金属射出成形機においても正常に成形が実施できた。液相線温度よりわずかに温度が低いだけであるので、溶融したマグネシウム合金の中に粒状の固体のマグネシウム合金が存在しているとしてもわずかであり、逆流防止装置１２において堆積しないからであると推測される。加熱シリンダ４の温度を５８０℃に設定して成形すると、比較例の金属射出成形機においては一部成形不良が発生した。比較例の金属射出成形機の逆流防止装置を調べたところ、粒状の固体のマグネシウム合金の堆積が見られた。これに対して本発明の実施例の金属射出成形機１においては正常に成形ができた。つまり逆流防止装置１２において堆積はなかったと考えられる。加熱シリンダ４の設定温度を５７５℃で成形すると、比較例の金属射出成形機では実質的に成形ができなかったが、本発明の実施例の金属射出成形機１においては正常に成形ができた。この５７５℃において本発明の実施例の金属射出成形機１において成形した平板成形品を切断し、その断面を撮影したものを図３に示す。成形品中に粒状のマグネシウム合金が多数含まれているが、これらは固体の状態で溶融したマグネシウム合金と共に射出されたものである。マグネシウム合金が半溶融状態で射出されていることが確認できた。加熱シリンダ４の設定温度を５７０℃にしても、本発明の実施例の金属射出成形機１では正常に成形品が成形できたが、５６５℃にすると、一部成形不良が見られた。以上の実験から、本発明の実施の形態に係る金属射出成形機１は、従来の射出成形機においては射出成形が困難な低い温度であっても、マグネシウム合金を半溶融状態にして安定的に射出でき、良好な成形品を成形できることが確認できた。 Discussion: The melting point of magnesium alloy AZ91D is 595.degree. C., and it is believed that at 600.degree. C., it is substantially completely melted and injected. At this temperature, molding could be carried out normally in the metal injection molding machine 1 of the embodiment of the present invention and in the metal injection molding machine of the comparative example. Although 590 ° C. is a temperature slightly lower than the liquidus temperature, molding could be carried out normally at this temperature as well as in the metal injection molding machine 1 of the example of the present invention and in the metal injection molding machine of the comparative example. . Because the temperature is only slightly lower than the liquidus temperature, there is little, if any, granular solid magnesium alloy in the molten magnesium alloy and it does not deposit in the backflow prevention device 12 It is guessed. When molding was performed with the temperature of the heating cylinder 4 set at 580 ° C., molding defects partially occurred in the metal injection molding machine of the comparative example. Examination of the backflow prevention device of the metal injection molding machine of the comparative example showed that deposition of granular solid magnesium alloy was observed. On the other hand, in the metal injection molding machine 1 of the embodiment of the present invention, molding was successfully performed. That is, it is considered that there was no deposition in the backflow prevention device 12. When the set temperature of the heating cylinder 4 was molded at 575 ° C., the metal injection molding machine of the comparative example could not substantially mold but the metal injection molding machine 1 of the embodiment of the present invention could be molded properly. . FIG. 3 shows a cross-sectional view of the flat-plate-formed product cut in the metal injection molding machine 1 of the embodiment of the present invention at 575 ° C. A large number of granular magnesium alloys are contained in the molded article, but these are injected together with the molten magnesium alloy in the solid state. It was confirmed that the magnesium alloy was injected in a semi-molten state. Even if the set temperature of the heating cylinder 4 is 570 ° C., a molded article can be molded normally in the metal injection molding machine 1 of the example of the present invention, but when it is 565 ° C., part molding failure was observed. From the above experiments, the metal injection molding machine 1 according to the embodiment of the present invention stably turns the magnesium alloy into a semi-molten state even at a low temperature where injection molding is difficult in a conventional injection molding machine. It has been confirmed that injection can be performed and good molded articles can be formed.
１ 金属射出成形機 ２ 射出装置
４ 加熱シリンダ ６ スクリュ
７ ホッパ ８ 射出ノズル
１２ 逆流防止装置 １４ 押金
１５ スクリュヘッド １６ 逆流防止リング
１８ 円柱部 １９ 円錐部
２１ 軸部 ２２ 頭部
２４ ボア ２５ テーパ面
３１ 第１の流路 ３２ 第２の流路
３３ 第３の流路 ３４ 第４の流路
DESCRIPTION OF SYMBOLS 1 metal injection molding machine 2 injection device 4 heating cylinder 6 screw 7 hopper 8 injection nozzle 12 backflow prevention device 14 press metal 15 screw head 16 backflow prevention ring 18 cylindrical part 19 conical part 21 shaft part 22 head 24 bore 25 tapered surface 31 1 flow path 32 second flow path 33 third flow path 34 fourth flow path
Claims (1)
前記スクリュの先端に逆流防止装置が設けられ、
該逆流防止装置は、前記スクリュの先端に設けられている押金と、前記押金に固定されているスクリュヘッドと、逆流防止リングとから構成され、前記スクリュヘッドは前記押金に固定されている所定径の軸部と該軸部に接続されている頭部とからなり、前記逆流防止リングは前記加熱シリンダのボアに液密的に摺動されていると共に前記軸部に挿通されており、
計量時には前記逆流防止リングは前記頭部に当接し、溶融したマグネシウム合金は、前記加熱シリンダの前記ボアと前記押金の間に形成されている第１の流路、前記押金と前記逆流防止リングの間に形成されている第２の流路、前記軸部と前記逆流防止リングの間に形成されている第３の流路、前記頭部に形成されている第４の流路を順次流れて前記スクリュの先端に計量されるようになっており、
前記第２〜４の流路のそれぞれの断面積は、前記第１の流路の断面積と等しいかそれより大きいことを特徴とする金属射出成形機。 A metal injection molding machine comprising a heating cylinder and a screw rotatably provided in the heating cylinder in a rotational direction and an axial direction, and injecting a magnesium alloy,
A backflow prevention device is provided at the tip of the screw,
The backflow prevention device includes a presser provided at the tip of the screw, a screw head fixed to the presser, and a backflow prevention ring, and the screw head has a predetermined diameter fixed to the presser. And the head portion connected to the shaft portion, the backflow prevention ring being in fluid tight sliding in the bore of the heating cylinder and being inserted in the shaft portion,
At the time of measurement, the backflow prevention ring abuts against the head, and the molten magnesium alloy is formed of a first flow path formed between the bore of the heating cylinder and the presser, and the presser and the backflow prevention ring. Flow sequentially through a second flow passage formed between them, a third flow passage formed between the shaft portion and the backflow prevention ring, and a fourth flow passage formed in the head Measured at the tip of the screw,
The cross-sectional area of each of the said 2nd-4th flow paths is equal to or larger than the cross-sectional area of a said 1st flow path, The metal injection molding machine characterized by the above-mentioned.
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| CN111940699A (en) * | 2020-07-20 | 2020-11-17 | 深圳市深汕特别合作区力劲科技有限公司 | Feeding device and die casting machine |
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| JPH07314510A (en) * | 1994-05-26 | 1995-12-05 | Japan Steel Works Ltd:The | Method and apparatus for preventing counter-flow in injection molding machine |
| US5680894A (en) * | 1996-10-23 | 1997-10-28 | Lindberg Corporation | Apparatus for the injection molding of a metal alloy: sub-ring concept |
| JP3903045B2 (en) * | 2004-01-09 | 2007-04-11 | 日精樹脂工業株式会社 | Injection plunger for metal forming machine |
| US7291006B2 (en) * | 2004-06-24 | 2007-11-06 | Husky Injection Molding Systems Ltd. | Check valve lip seal for an injection molding machine |
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| CN111940699A (en) * | 2020-07-20 | 2020-11-17 | 深圳市深汕特别合作区力劲科技有限公司 | Feeding device and die casting machine |
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| JP6713225B2 (en) | 2020-06-24 |
| CN109590446A (en) | 2019-04-09 |
| CN109590446B (en) | 2020-11-03 |
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