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THIN-WALL MOLDED PART AND METHOD OF MANUFACTURING THEREOF

IP.com Disclosure Number: IPCOM000241000D
Publication Date: 2015-Mar-17
Document File: 6 page(s) / 241K

Publishing Venue

The IP.com Prior Art Database

Related People

Nicholas T. Moelker, Tory G. Bowman, Timothy J. Spahr, Frank Neuber III: INVENTOR

Abstract

A thin-wall molded part made by an injection molding process includes a main body having a first portion with a gate mark and a second portion that is remote from the gate mark. The part also includes at least one cutoff tab adjacent the second portion that is removed from the main body after the injection molding process is completed.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 27% of the total text.

Page 01 of 6

Attorney Docket No. 032299-9028-US00

THIN-WALL MOLDED PART AND METHOD OF MANUFACTURING THEREOF

FIELD OF THE INVENTION


[0001]The present invention relates to injection molding, and more specifically injection molding of thin-wall parts.

BACKGROUND OF THE INVENTION


[0002]To comply with more stringent government regulations, automobile manufacturers have been improving fuel efficiency of their vehicles. One way to improve fuel efficiency is to reduce a vehicle's mass such as, for example, reducing the wall thickness of plastic parts used in the vehicle. Conventional methods of making the plastic parts thinner typically cause sink or the formation of depressions on the plastic part. Another common problem with conventional thin- wall molding techniques involves disruptions in the flow of the plastic melt as it fills the mold. The disruptions appear on the surface of the part and are commonly seen as white streaks or speckles commonly known as splay. Chemical foaming agents are commonly added to plastic pellets used during an injection molding process to decrease the mass of the plastic part; however, gas that is created by the chemical foaming agent can leave undesirable white speckles on the surface of the plastic part.

SUMMARY OF THE INVENTION


[0003]The invention provides, in one aspect, a thin-wall molded part made by an injection molding process. The part includes a main body having a first portion with a gate mark and a second portion that is remote from the gate mark. The part also includes at least one cutoff tab adjacent the second portion that is removed from the main body after the injection molding process is completed.


[0004]The invention provides, in another aspect, a mold for making a thin-wall molded part by an injection molding process. The mold includes a main cavity that defines a final shape of the part and at least one gate in fluid communication with the main cavity through which a melt material is injected into the main cavity. The mold also includes at least one additional cavity adjacent the main cavity into which some of the melt material flows after filling the main cavity.

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Page 02 of 6

Attorney Docket No. 032299-9028-US00


[0005]The invention provides, in yet another aspect, a method of molding a thin-wall part by an injection molding process. The method includes injecting a melt material into a mold at a first injection rate and then reducing the first injection rate after a predetermined amount of the mold has been filled with melt material. Additionally, the method includes forming at least one cutoff tab on the thin-wall part with melt material after the first injection rate is reduced.


[0006]The cutoff tab may be removed after the injection molding process is completed.


[0007]Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS


[0008]FIG. 1 is a perspective view of a test plaque in accordan...