DE102007036640A1 - Method for manufacturing hollow plastic articles, involves providing integrally plastic hollow body with plastic component on hollow body, where injection molding is done after blow molding completes - Google Patents

Abstract

The method involves providing integrally a plastic hollow body (12) with a plastic component (14) on a hollow body. The hollow body blanks are blow molded into the plastic hollow body in one of the blow molding cavities assigned to the plastic hollow body. One of the plastic components is injection molded in injection molding cavities assigned to the plastic components. Injection molding is done after the blow molding completes.

Description

• – Extrudieren eines Hohlkörperrohlings aus Kunststoff,
• – Blasformen des Hohlkörperrohlings zu dem Kunststoffhohlkörper in einer dem Kunststoffhohlkörper zugeordneten Blasformkavität,
• – Spritzgießen des wenigstens einen Kunststoffbauteils in einer dem Kunststoffbauteil zugeordneten von der Blasformkavität verschiedenen Spritzgusskavität.

The present invention relates to a method for the production of hollow plastic articles, comprising a plastic hollow body with at least one plastic component provided integrally thereon, in different mold cavities, comprising the following steps:

• Extruding a hollow body blank made of plastic,
• Blow molding the hollow body blank to the hollow plastic body in a blow mold cavity associated with the plastic hollow body,
• - Injection molding of the at least one plastic component in a plastic component associated with the injection mold cavity different from the Blasformkavität.

The basic possibility of extruding plastic hollow body, blow molding and integrally connect with a plastic component by molding or overmolding is from the WO 2004/022312 A known. The independent claim 1 is delimited from this document. However, this publication does not give precise information in which time sequence of process steps of the desired plastic article, which comprises the plastic hollow body and the at least one plastic component to be produced.

Farther It is well known to use solid plastic body To overmold plastic components or plastic components to such to inject massive plastic body. However, those are from the on or / and overmolding of plastic components to or due to solid plastic body achieved results the different properties of massive bodies and hollow bodies made of plastic can not be transferred to plastic hollow bodies.

It object of the present invention, the known method on to improve.

According to the invention this task in a generic method solved by the step of injection molding begins after the blow-molding step is completed.

Thereby, that the blow-molding step is terminated first, before the injection molding step begins, basically the possibility of hollow plastic bodies as semi-finished products of the final plastic product desired product, and continue processing at a convenient time. hereby a flexibilization of the manufacturing process is achieved.

When The end of the blow-molding step becomes the end of the change in shape the hollow body blank in the blow mold cavity considered. The blow molding step therefore ends when the Hollow body blank to the Blasformkavitätwand such has created that despite overpressure in the interior of the hollow body blank compared to the ambient pressure no further blown air Change in shape in the area of the blow mold cavity wall more is done.

Although it is possible in principle, as from the WO 2004/022312 A is known to produce the hollow plastic article in a single mold, which has both a Blasformkavität and an associated injection molding cavity, however, process steps to increase the effectiveness of the method according to the invention can be parallelized in an advantageous manner, if the method further comprises: a A step of demoulding the plastic hollow body from a blow mold having the blow mold cavity, and a step of inserting the plastic hollow body into an injection mold different from the blow mold and having the injection mold cavity.

there can be produced by blow molding plastic hollow body, if desired, stored in a warehouse be taken out of the warehouse and if necessary from the warehouse and the injection molding process be supplied. But it can also be thought of the plastic hollow body from the Blasformkavität and insert immediately afterwards in an injection mold with Spritzgusskavität, then at least one plastic component by an injection molding process integrally connect with the plastic hollow body.

The Removal or demolding of the plastic hollow body from the blow mold cavity or / and the insertion of the plastic hollow body in the injection mold can for further shortening the time required to make the plastic article by a suitable device, such as a multi-axis robot and the like, done automatically or automatically.

A particularly good material connection of the at least one plastic component with the hollow plastic body can be achieved by that for the production of the hollow plastic body and for the production at least one plastic component compatible plastics used become. With such materials, the impact is on of the hot injected material on the plastic hollow body particularly fast diffusion processes, which for a strong material connection between the plastic component and make the plastic hollow body. A particularly good one Material connection between plastic component and plastic hollow body can be achieved by using identical plastics.

Farther it is conceivable that at least one component of the plastic article: Plastic hollow body or plastic component, to increase its strength made from a filled plastic becomes. The plastic filling can in a conventional manner Glass fibers, glass beads or other fibrous or and spherical Fillers include. In case of use of filled Plastics it is to achieve the best possible Connection between plastic hollow body and plastic component advantageous, when the matrix plastic of the filled plastic material with the (matrix) plastic material of the other component is compatible or more preferably identical.

Possible Plastics for making the plastic articles discussed herein For example, PA 6, PA 6.6, PPS and the like.

to Generation of a high-strength connection between Plastic hollow body and a materially connected to this Plastic component, the plastic component, the plastic hollow body at least partially, preferably completely surrounding be provided.

For however, many applications may be sufficient that a plastic component to the plastic hollow body is attached and stands out from this. This allows Plastic objects manufactured with low volume which are suitable for assembly situations with low Available space are suitable.

at a concrete embodiment of a vehicle charge air tube, on which an integral fastening lug for attachment the charge air pipe is provided, a desired Plastic hollow body made of the material PA 6 be by first in a conventional manner, a hollow body blank extruded, this inserted into a blow mold and by initiating is blown by blowing air in the interior thereof in a conventional manner.

To the solidification of the charge air pipe and its removal from the blow mold the charge air pipe is inserted into a separate injection mold. In this a section of the charge air pipe forms a hike the injection molding cavity of the injection mold. After closing The injection mold is PA 6 at a temperature of about 305 injected to 310 ° C in the injection molding cavity. An injection pressure of approximately 150 bar acts on the cylinder, the injection pressure in the screw is approximately 2000 bar.

Surprisingly despite the high injection pressure even in the case of thin-walled Charge air pipes with a wall thickness of not more than 3 mm the charge air tube inserted into the injection mold through the comparatively high pressure injected hot plastic material not destroyed, but keeps the injection pressure stood for the necessary period of time. By the impact the hot injected plastic material on the already solidified plastic material of the charge air tube is material of the Charge air pipe softens, leaving a strong cohesive Connection between the hot injected plastic material and reached the identical plastic material of the charge air pipe becomes.

The The present invention will be described below with reference to the accompanying drawings Figures explained in more detail. These show an exemplary embodiments a plastic article produced by the method according to the invention. It shows:

1 an embodiment of a hollow plastic article, which can be produced by the method according to the invention, and

2 a cross section through the plastic article of 1 along the section plane II of 1 ,

In 1 For example, a plastic article made by a manufacturing method of the present invention is generally included 10 designated. This plastic article comprises a hollow plastic tube 12 as a plastic hollow body and includes one to the plastic pipe 12 molded eyelet 14 as a plastic component.

The plastic eyelet 14 has a passage opening 16 on which in the assembled state of the article 10 may be penetrated by a fastening screw or a similar fastening means, not shown.

At his in 1 upper longitudinal end has the plastic tube 12 a fixation education 18 for attaching a hose thereto.

The plastic pipe 12 along with the attachment training 18 is produced in a conventional manner by blow molding, ie by extrusion of a hollow body blank, by subsequent introduction of the extruded hollow body blank in a Blasformkavität and by subsequent blow molding.

After the end of the blow molding of the plastic pipe 12 , This is removed from the Blasformkavität and placed in a Spritzgusskavität. Then, with the injection of plastic material in the training for the mounting lug 14 provided Spritzgusskavität started. Parallel to this, another plastic tube can already be found in the blow mold cavity 12 getting produced.

In the Spritzgusskavität forms a portion of the plastic tube 12 a wall delimiting the injection molding cavity. When injecting plastic material into the injection mold cavity for the production of the fastening eyelet 14 meets the injected hot plastic material on the Spritzgusskavität limiting portion of the plastic tube 12 ,

Surprisingly, it has been shown that the solidified plastic tube 12 despite its wall thickness of at most a few millimeters of a tendency to deform from the action of the injection process to produce the attachment eyelet 14 withstands and the plastic material of the attachment eyelet 14 with the plastic material of the plastic tube that is identical in the illustrated example 12 - probably by diffusion processes - cohesively connects, wherein the plastic tube 12 even in the area of the molded eyelet 14 (please refer 2 ) remains circular as desired.

In 2 are for better distinction the cut plastic tube 12 and the cut eyelet 14 shown with different hatching, although both components of the plastic article 10 are cohesively connected to each other.

To recognize in 2 is the during the manufacturing process of the plastic pipe 12 indoor area filled with blast air 20 of the plastic pipe 12 as well as its mouth opening 22 at the longitudinal end of the attachment training 18 ,

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - WO 2004/022312 A [0002, 0008]

Claims (5)

Process for producing hollow plastic articles ( 10 ), comprising a plastic hollow body ( 12 ) with at least one integrally provided on this plastic component ( 14 ), in different mold cavities, the method comprising the following steps: extruding a hollow body blank of plastic, blow molding the hollow body blank to the hollow plastic body ( 12 ) in a plastic hollow body ( 12 ) associated Blasformkavität, - injection molding of at least one plastic component ( 14 ) in a plastic component ( 14 ) associated with the Blasformkavität different injection molding cavity, characterized in that the step of injection molding begins after the step of blow molding is completed. A method according to claim 1, characterized in that it further comprises a step of demolding the plastic hollow body ( 12 ) from a Blasformkavität having blow mold and a step of inserting the plastic hollow body ( 12 ) In a different from the blow mold, the Spritzgusskavität having injection mold. A method according to claim 1 or 2, characterized in that for the production of the hollow plastic body ( 12 ) and for producing at least one plastic component ( 14 ) compatible, preferably identical plastics are used. Method according to one of the preceding claims, characterized in that a plastic component ( 14 ) the hollow plastic body ( 12 ) at least partially, preferably completely surrounds. Method according to one of the preceding claims, characterized in that a plastic component ( 14 ) to the plastic hollow body ( 12 ) and is projected from this.