US20020046823A1 - Method of accurately measuring volume of injected metal in forming core elements for lost core molding process - Google Patents
Method of accurately measuring volume of injected metal in forming core elements for lost core molding process Download PDFInfo
- Publication number
- US20020046823A1 US20020046823A1 US09/842,419 US84241901A US2002046823A1 US 20020046823 A1 US20020046823 A1 US 20020046823A1 US 84241901 A US84241901 A US 84241901A US 2002046823 A1 US2002046823 A1 US 2002046823A1
- Authority
- US
- United States
- Prior art keywords
- flow meter
- cavity
- molten metal
- core
- amount
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D39/00—Equipment for supplying molten metal in rations
-
- 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
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/44—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles
- B29C33/52—Moulds or cores; Details thereof or accessories therefor with means for, or specially constructed to facilitate, the removal of articles, e.g. of undercut articles soluble or fusible
Definitions
- Lost core plastic molding techniques are becoming widely utilized in plastic molding operations.
- metal core elements are initially cast.
- the metal core elements are preferably formed of a material which has a relatively low melting point.
- the core elements are then placed into a plastic mold, and plastic is molded around the core elements.
- the plastic has a relatively high melt point.
- the core element is then melted, leaving the plastic molded body around a plurality of cavities where the core elements had been.
- Loss core molding techniques are becoming popular in that they provide a way of forming intricate surfaces on the interior of a plastic molded part.
- the core element there are challenges with the use of loss core molding, and in particular with the formation of the core element.
- the core element For the core element to provide an intricate surface within the molded plastic part, the core element itself must have a desired outer surface. It is the outer surface of the core element which forms the interior of the cavity in the molded plastic element.
- a flow meter is placed adjacent to the cavity in the core mold.
- the flow meter is a magnetic flow meter and is responsive for identifying the velocity of the flowing metal through a conduit associated with the flow meter.
- a control further controls a nozzle valve.
- the nozzle valve is controlled to close when the flow meter identifies that a correct amount of molten metal has moved into the cavity.
- the nozzle will close prior to any overflow and will not close until there is sufficient metal.
- the present invention ensures that the core will have sufficient material such that the core will be properly formed.
- the core is formed, it is placed into a plastic mold and it is utilized as part of a lost core molding process.
- FIG. 1 schematically shows a core molding process.
- FIG. 2 schematically shows a plastic molding process.
- a system 20 is illustrated for molding loss core elements in a loss core mold 22 . As shown, a plurality of cavities 24 , 26 and 28 are formed within the mold 22 .
- a molten metal supply 30 is provided with a pump 32 and controlled by a control 34 .
- a supply conduit 36 communicates with the cavity 28 , and similar conduits 36 communicate with the cavities 24 and 26 .
- the conduits 36 are each associated with a nozzle valve 38 which is controlled both to close flow through the conduits 36 and a flow meter 40 . While various types of flow meters may be utilized, most preferably, the flow meter is a magnetic flow meter which is able to sense the velocity of molten metal flowing through the conduit 36 due to the magnetic properties of the metal.
- the control 34 takes in feedback about the velocity of the metal through the conduit 36 .
- the control 34 is further programmed to know the cross-sectional area in the vicinity of the flow meter 40 . By knowing velocity and cross-sectional area the control can estimate with extreme accuracy the amount of liquid metal which has moved into any of the cavities.
- the control 34 is further programmed to know the desired amount of molten metal.
- the control 34 monitors the amount of molten metal moving into each of the cavities 24 , 26 and 28 through the flow meters 40 . If the flow of metal has stopped before the desired amount of molten metal has moved into one of the cavities, then a warning signal such as shown at 39 may be actuated. A worker controlling the molding operation will then be able to stop the molding operation prior to the formation of a part that will inevitably be scrapped.
- the control 34 in conjunction with the flow meter 40 controls the nozzle valve 38 to ensure adequate flow.
- the nozzle valve 38 remains open until the desired amount of molten metal has moved into the cavities 24 , 26 or 28 . At that time, the nozzle is closed. Thus, overfill will not occur.
- the nozzle remains open until sufficient metal has moved into the particular cavity.
- the nozzle is controlled by the control 34 . While a single control 34 is shown for each of the three cavities, it should also be understood that an individual control module can be associated with each valve and flow meter.
- One preferred magnetic flow meter is available from Endress Hauser.
- FIG. 2 shows a plastic loss core molding operation 50 having a cavity 52 .
- the core parts 124 and 126 are placed within the cavity 52 and a supply 54 of plastic in injected into the cavity 52 around the core elements 124 and 126 .
- a molded plastic part is formed having cavities of a desired and intricate inner periphery.
- the core elements 124 and 126 are then melted after formation of the plastic part, leaving the cavity.
- the present invention thus provides a way of making the core elements for a loss core plastic molding system more reliably.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
An improved method for forming cores to be utilized in a loss core plastic molding process includes the use of a flow meter. The flow meter ensures that sufficient molten metal is delivered into a cavity for the loss core elements. In this way, the present invention eliminates the occurrence of gaps, spaces or cavities in the molded loss core part. Most preferably a magnetic flow meter is utilized which can monitor the amount of molten metal having flown through the flow meter.
Description
- This application claims priority to Provisional Patent Application Serial No. 60/242,871, filed Oct. 24, 2000.
- Lost core plastic molding techniques are becoming widely utilized in plastic molding operations. In a typical lost core process, metal core elements are initially cast. The metal core elements are preferably formed of a material which has a relatively low melting point. The core elements are then placed into a plastic mold, and plastic is molded around the core elements. The plastic has a relatively high melt point. The core element is then melted, leaving the plastic molded body around a plurality of cavities where the core elements had been. Loss core molding techniques are becoming popular in that they provide a way of forming intricate surfaces on the interior of a plastic molded part.
- There are challenges with the use of loss core molding, and in particular with the formation of the core element. For the core element to provide an intricate surface within the molded plastic part, the core element itself must have a desired outer surface. It is the outer surface of the core element which forms the interior of the cavity in the molded plastic element.
- In the past, there have been problems with reliably forming the core element. If the core element is formed improperly, then there will be cavities within the core element, and the core element must thus be scrapped. The cavity occurs when an insufficient amount of metal is sent into the core mold cavity. There are other problems when too much metal is sent into the cavity. Either of these occurrences result in a scrapped part, which is undesirable.
- In the prior art, a pump for moving the molten metal into the cavities in a core mold has been monitored. The amount of movement in a piston in the pump has been utilized to provide feedback of when sufficient metal has been moved. This process, however, still results in the underfill and overfill problems as mentioned above.
- In the disclosed embodiment of this invention a flow meter is placed adjacent to the cavity in the core mold. Preferably, the flow meter is a magnetic flow meter and is responsive for identifying the velocity of the flowing metal through a conduit associated with the flow meter. By knowing the cross-sectional area and the velocity an easy determination can be made of the quantity of molten metal that has moved into a particular cavity. The quantity is compared to an expected quantity, and one of two processes can be utilized.
- In a first most basic process if the metal flow stops while there is insufficient metal flow, then a warning signal can be created. In a second embodiment, a control further controls a nozzle valve. The nozzle valve is controlled to close when the flow meter identifies that a correct amount of molten metal has moved into the cavity. Thus, the nozzle will close prior to any overflow and will not close until there is sufficient metal. In this fashion, the present invention ensures that the core will have sufficient material such that the core will be properly formed.
- Once the core is formed, it is placed into a plastic mold and it is utilized as part of a lost core molding process.
- These and other features of the present invention can be best understood from the following specification and drawings, the following which is a brief description.
- FIG. 1 schematically shows a core molding process.
- FIG. 2 schematically shows a plastic molding process.
- A
system 20 is illustrated for molding loss core elements in aloss core mold 22. As shown, a plurality ofcavities mold 22. Amolten metal supply 30 is provided with apump 32 and controlled by acontrol 34. Asupply conduit 36 communicates with thecavity 28, andsimilar conduits 36 communicate with thecavities conduits 36 are each associated with anozzle valve 38 which is controlled both to close flow through theconduits 36 and aflow meter 40. While various types of flow meters may be utilized, most preferably, the flow meter is a magnetic flow meter which is able to sense the velocity of molten metal flowing through theconduit 36 due to the magnetic properties of the metal. Thecontrol 34 takes in feedback about the velocity of the metal through theconduit 36. Thecontrol 34 is further programmed to know the cross-sectional area in the vicinity of theflow meter 40. By knowing velocity and cross-sectional area the control can estimate with extreme accuracy the amount of liquid metal which has moved into any of the cavities. Thecontrol 34 is further programmed to know the desired amount of molten metal. - Thus, during the filling operation, the
control 34 monitors the amount of molten metal moving into each of thecavities flow meters 40. If the flow of metal has stopped before the desired amount of molten metal has moved into one of the cavities, then a warning signal such as shown at 39 may be actuated. A worker controlling the molding operation will then be able to stop the molding operation prior to the formation of a part that will inevitably be scrapped. - In a second embodiment, the
control 34 in conjunction with theflow meter 40 controls thenozzle valve 38 to ensure adequate flow. Thenozzle valve 38 remains open until the desired amount of molten metal has moved into thecavities control 34. While asingle control 34 is shown for each of the three cavities, it should also be understood that an individual control module can be associated with each valve and flow meter. - One preferred magnetic flow meter is available from Endress Hauser.
- FIG. 2 shows a plastic loss
core molding operation 50 having acavity 52. As is known, thecore parts cavity 52 and asupply 54 of plastic in injected into thecavity 52 around thecore elements core elements - The present invention thus provides a way of making the core elements for a loss core plastic molding system more reliably.
- While a preferred embodiment has been disclosed, a worker in this art would recognize that various modifications would come within the scope of this invention. For that reason the following claims should be studied to determine the true scope and content of this invention.
Claims (4)
1. A method of forming a loss core part comprising the steps of:
1) providing a mold for forming a loss core element, said mold having at least one cavity, said cavity desirably receiving a first amount of molten metal to form said element;
2) delivering molten metal into said cavity; and
3) providing a flow meter on a delivery conduit delivering said molten metal to said cavity, said flow meter monitoring the amount of molten metal flowing into said cavity, and said flow meter acting to compare said amount of metal flowing into said cavity to said first amount of molten metal.
2. A method as set forth in claim 1 , wherein said flow meter controls a nozzle, said nozzle being maintained open until a desired amount of molten metal flows into said cavity, said nozzle then being shut.
3. A method as set forth in claim 1 , wherein said flow meter is magnetic, and said magnetic flow meter monitoring the movement of said molten metal through said conduit.
4. A method as set forth in claim 1 , wherein said core elements are then moved to a plastic loss core molding line, and placed into a plastic mold, plastic then being molded around said core elements.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US09/842,419 US20020046823A1 (en) | 2000-10-24 | 2001-04-25 | Method of accurately measuring volume of injected metal in forming core elements for lost core molding process |
GB0118308A GB2368305A (en) | 2000-10-24 | 2001-07-27 | A method for forming cores for lost core moulding processes |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US24287100P | 2000-10-24 | 2000-10-24 | |
US09/842,419 US20020046823A1 (en) | 2000-10-24 | 2001-04-25 | Method of accurately measuring volume of injected metal in forming core elements for lost core molding process |
Publications (1)
Publication Number | Publication Date |
---|---|
US20020046823A1 true US20020046823A1 (en) | 2002-04-25 |
Family
ID=26935411
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/842,419 Abandoned US20020046823A1 (en) | 2000-10-24 | 2001-04-25 | Method of accurately measuring volume of injected metal in forming core elements for lost core molding process |
Country Status (2)
Country | Link |
---|---|
US (1) | US20020046823A1 (en) |
GB (1) | GB2368305A (en) |
Family Cites Families (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6391535A (en) * | 1986-10-06 | 1988-04-22 | Toshiba Mach Co Ltd | Method and apparatus for detecting flow in mold in pressure casting |
GB9216043D0 (en) * | 1992-07-28 | 1992-09-09 | Dunlop Automotive Composites U | Manufacture of composite type plastics articles |
JPH081301A (en) * | 1994-06-21 | 1996-01-09 | Toyota Motor Corp | Method for controlling flowing of molten metal |
JP3377326B2 (en) * | 1995-01-26 | 2003-02-17 | アイシン高丘株式会社 | Melt flow detector for vanishing model casting |
JP3138611B2 (en) * | 1995-04-18 | 2001-02-26 | 新日本製鐵株式会社 | Flow control device for molten metal in continuous casting mold |
DE19833598A1 (en) * | 1998-07-25 | 2000-02-24 | Mann & Hummel Filter | Tool especially for making cores |
-
2001
- 2001-04-25 US US09/842,419 patent/US20020046823A1/en not_active Abandoned
- 2001-07-27 GB GB0118308A patent/GB2368305A/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
GB2368305A (en) | 2002-05-01 |
GB0118308D0 (en) | 2001-09-19 |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: SIEMENS AUTOMOTIVE CORPORATION, MICHIGAN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NARAYANASWAMY, KARTHIKEYAN R.;REEL/FRAME:011761/0145 Effective date: 20010418 |
|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE |