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DE1813298A1 - Venting of foamed polyurethane injection - moulds to prevent flash formation - Google Patents

Venting of foamed polyurethane injection - moulds to prevent flash formation

Info

Publication number
DE1813298A1
DE1813298A1 DE19681813298 DE1813298A DE1813298A1 DE 1813298 A1 DE1813298 A1 DE 1813298A1 DE 19681813298 DE19681813298 DE 19681813298 DE 1813298 A DE1813298 A DE 1813298A DE 1813298 A1 DE1813298 A1 DE 1813298A1
Authority
DE
Germany
Prior art keywords
venting
moulds
foamed polyurethane
polyurethane injection
prevent flash
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.)
Pending
Application number
DE19681813298
Other languages
German (de)
Inventor
Waldemar Fobbe
Georg Schlebach
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
SCHLEBACH HYDRAULIK GEORG SCHL
Original Assignee
SCHLEBACH HYDRAULIK GEORG SCHL
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by SCHLEBACH HYDRAULIK GEORG SCHL filed Critical SCHLEBACH HYDRAULIK GEORG SCHL
Priority to DE19681813298 priority Critical patent/DE1813298A1/en
Publication of DE1813298A1 publication Critical patent/DE1813298A1/en
Pending legal-status Critical Current

Links

Classifications

    • 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
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/34—Auxiliary operations
    • B29C44/58—Moulds
    • B29C44/588—Moulds with means for venting, e.g. releasing foaming gas
    • 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
    • B29C33/10—Moulds or cores; Details thereof or accessories therefor with incorporated venting means

Landscapes

  • Casting Or Compression Moulding Of Plastics Or The Like (AREA)

Abstract

Venting of foamed polyurethane injection moulds to prevent flash formation Is effected by evacuating the moulds automatically or by hand using hydraulic or pneumatic cylinder actuated venting valves or the return stroke of the single acting piston following manual actuation of a lever.

Description

Forientlüftung fur aufachäulenden Reaktions-Spritzguß (z.B. Polyurethan) Die bisher bekannten Arten der Formentlüftung bei aufschäumenden Kunststoffen haben vielfach den Nachteil, daß am fertigen Formling eine nachträgliche Beseitigung von Angüssen oder Graten erforderlich ist.Mold ventilation for post-reaction injection molding (e.g. polyurethane) The previously known types of mold ventilation for foaming plastics have often the disadvantage that on the finished molding a subsequent removal of Sprues or burrs are required.

Die vorliegende Erfindung behebt diesen Nachteil wie folgt: Im Formdeckel wird ein Entlüftungszylinder angebracht, dessen Kolbenstange im ausgefahrenen Zustand exakt mit der Innenkontur des Formdeckels und damit mat dem Formling abschließt. Die Betätigung dieses Zylinders kann hydraulisch, pneumatisch oder auch mechanisch mit Federkraftrückstellung erfolgen. An der Öffnung zum Forminneren liegt ständig ein starkes Vakuum an. Durch einen Mikroschalter wird nach dem Einspritzen des Rohstoffes und dem Verschluß der Form jeweils die Vakuumleitung zum Forminneren durch den Zylinder freigegeben und sofort wieder exakt verschlossen. Auf diese Weise wird die Form im Inneren, bevor das Spritzgemisch aus dem flüssigen über den hochviskosen Zustand aufzuschäumen beginnt, vollständig evakuiert, so daß nachher am Formling keine Lufteinschlüsse vorhanden sind. Dieser Entlüftungsvorgang kann sowohl bei vollautomatischen Anlagen in die Arbeitstakte einprogrammiert werden, als auch bei kleinen Anlagen manuell ausgeführt werden.The present invention overcomes this disadvantage as follows: In the molded lid a ventilation cylinder is attached with its piston rod in the extended position exactly with the inner contour of the mold lid and thus flush with the molding. The actuation of this cylinder can be hydraulic, pneumatic or mechanical take place with spring force reset. At the opening to the inside of the mold is constantly a strong vacuum. A microswitch is used after the raw material has been injected and the closure of the mold in each case the vacuum line to the inside of the mold through the cylinder released and immediately closed again exactly. This is how the shape becomes inside before the spray mixture from the liquid to the highly viscous state begins to foam, completely evacuated, so that afterwards no air pockets on the molding available. This venting process can be used in fully automatic systems can be programmed into the work cycles, as well as manually for small systems are executed.

Schutsanspruche: 1. Die Entlüftung von Formen für aufschäumenden Reaktions-Spritzguß (z.B. Polyurethan) durch Evakuierung.Protection claims: 1. The ventilation of molds for foaming reaction injection molding (e.g. polyurethane) by evacuation.

2. Die Funktion des Entlüftungsventils durch einen hydraulisch- oder pneuiatisch-betätigten Zylinder.2. The function of the vent valve by a hydraulic or pneumatically operated cylinder.

3. Die liandhebelbetätigung des Entlüftungsventils bei Fe#erkraftrückstellung des Kolbens.3. The hydraulic lever actuation of the vent valve when the spring force is reset of the piston.

Claims (1)

4. Die Einbeziehung des Entlüftungsvorganges in die Arbeitstakte der Formentransportanlage.4. The inclusion of the venting process in the work cycles of the Mold transport system.
DE19681813298 1968-12-07 1968-12-07 Venting of foamed polyurethane injection - moulds to prevent flash formation Pending DE1813298A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19681813298 DE1813298A1 (en) 1968-12-07 1968-12-07 Venting of foamed polyurethane injection - moulds to prevent flash formation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19681813298 DE1813298A1 (en) 1968-12-07 1968-12-07 Venting of foamed polyurethane injection - moulds to prevent flash formation

Publications (1)

Publication Number Publication Date
DE1813298A1 true DE1813298A1 (en) 1970-06-25

Family

ID=5715536

Family Applications (1)

Application Number Title Priority Date Filing Date
DE19681813298 Pending DE1813298A1 (en) 1968-12-07 1968-12-07 Venting of foamed polyurethane injection - moulds to prevent flash formation

Country Status (1)

Country Link
DE (1) DE1813298A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1800094B1 (en) * 1968-03-07 1970-05-14 Strebelwerk Gmbh Flat radiator
EP0006381A1 (en) * 1978-06-13 1980-01-09 INDUSTRIES ET TECHNIQUES D'AMEUBLEMENT Société dite: Device for moulding foamed plastic articles
EP0461522A2 (en) * 1990-06-12 1991-12-18 Toyoda Gosei Co., Ltd. Method for molding polyurethane foam
US5449698A (en) * 1991-09-26 1995-09-12 Toyoda Gosei Co., Ltd. Method and apparatus for producing integral skin polyurethane foam
US5633289A (en) * 1993-03-16 1997-05-27 Toyoda Gosei Co., Ltd. Process for molding an integral skin foam and a polyurethane material for molding the same

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1800094B1 (en) * 1968-03-07 1970-05-14 Strebelwerk Gmbh Flat radiator
EP0006381A1 (en) * 1978-06-13 1980-01-09 INDUSTRIES ET TECHNIQUES D'AMEUBLEMENT Société dite: Device for moulding foamed plastic articles
FR2428519A1 (en) * 1978-06-13 1980-01-11 Ameublement Ind Et Tech PLUG FOR CAST HOLE OF EXPANDED MATERIAL IN A MOLD
EP0461522A2 (en) * 1990-06-12 1991-12-18 Toyoda Gosei Co., Ltd. Method for molding polyurethane foam
EP0461522A3 (en) * 1990-06-12 1993-04-28 Toyoda Gosei Co., Ltd. Method and apparatus for molding polyurethane foam
EP0678367A1 (en) * 1990-06-12 1995-10-25 Toyoda Gosei Co., Ltd. Method and apparatus for molding polyurethane foam
US5464582A (en) * 1990-06-12 1995-11-07 Toyoda Gosei Co., Ltd. Method for molding polyurethane foam under subatmospheric pressures
US5589202A (en) * 1990-06-12 1996-12-31 Toyoda Gosei Co., Ltd. Apparatus for molding polyurethane foam
US5449698A (en) * 1991-09-26 1995-09-12 Toyoda Gosei Co., Ltd. Method and apparatus for producing integral skin polyurethane foam
US5633289A (en) * 1993-03-16 1997-05-27 Toyoda Gosei Co., Ltd. Process for molding an integral skin foam and a polyurethane material for molding the same

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