Injection mold flash reduction

Patent metadata

Field	Value
Publication number	US-2016288384-A1
Application number	US-201514677383-A
Country	US
Kind code	A1
Filing date	Apr 2, 2015
Priority date	Apr 2, 2015
Publication date	Oct 6, 2016
Grant date	—

Abstract

A mold fabrication element has a hollowed volume defining a respective continuous inner surface. A fabricator resource disposes the mold fabrication element into a cavity of an injection mold assembly; surface contours on the inner surface of cavity as well as the respective continuous inner surface of the mold fabrication element exposed in the cavity define an outer surface of a resulting injection molded part. To create the injection molded part, the fabricator resource injects liquefied material into the cavity. The injected material contacts the continuous inner surface of the hollowed volume in the mold fabrication element as well as the surface contours of the cavity. After the injected material solidifies, the fabricator resource removes a combination of the injection molded part and the mold fabrication element. The fabricator resource separates the mold fabrication element from the injection molded part for further processing and use of the injection molded part.

First claim

We claim:

1 . A method comprising:
receiving a mold fabrication element, the mold fabrication element having a hollowed volume defining a respective continuous inner surface; disposing the mold fabrication element into a cavity of a mold assembly, the cavity defined by an inner surface of the mold assembly, the respective continuous inner surface of the mold fabrication element exposed in the cavity; and injecting plastic into the cavity to create a molded part, the injected plastic contacting the continuous inner surface of the hollowed volume in the mold fabrication element.

2 . The method as in claim 1 , wherein the mold fabrication element is a ring including a stepped inner diameter to produce a corresponding stepped region in the molded part.

3 . The method as in claim 2 , wherein the stepped region in the molded part is a region free of flash produced by injection of the plastic between gaps in between sides of the mold assembly.

4 . The method as in claim 1 , wherein the mold assembly includes a first mold side and a second mold side, the first mold side including a void to receive a first portion of the mold fabrication element, the second mold side including a void to receive a second portion of the mold fabrication element; and
wherein disposing the mold fabrication element into the cavity of the mold assembly includes: inserting the first portion of the mold fabrication element into the void of the first mold side; and joining the first mold side to the second mold side to produce the cavity, the void of the first mold side and the void of the second mold side retaining the mold fabrication element in a desired location of the cavity.

5 . The method as in claim 1 , wherein the respective continuous inner surface of the hollowed volume of the mold fabrication element resides substantially within a plane.

6 . The method as in claim 5 , wherein the mold assembly includes a first mold side and a second mold side; and
wherein disposing the mold fabrication element into the cavity of the mold assembly further comprises: moving the first mold side in a manner parallel to the plane to contact the first mold side to the second mold side of the mold assembly to form the cavity.

7 . The method as in claim 6 , wherein parting lines of the first mold side and the second mold side are disposed substantially orthogonal with respect to the plane of the mold fabrication element.

8 . The method as in claim 1 further comprising:
subsequent to injecting the plastic into the cavity to create the molded part, separating a first mold side and a second mold side of the mold assembly to remove a combination of the molded part and the mold fabrication element; and
separating the mold fabrication element from the molded part.

9 . The method as in claim 8 , wherein removing the mold fabrication element from the molded part further comprises:
sliding the mold fabrication element off an end of the molded part having a diameter that is smaller than a diameter of the respective continuous inner surface of the mold fabrication element.

10 . The method as in claim 1 , wherein a part line of separating the mold assembly to remove the molded part from the cavity extends along an axial length of the molded part, presence of the mold fabrication element in the cavity of the mold assembly producing a corresponding flash-free region in the molded part along a less-than-all portion of the axial length.

11 . A system comprising:
a mold assembly including an inner surface defining a cavity; a mold fabrication element, the mold fabrication element having a hollowed volume defining a respective continuous inner surface, the mold fabrication element disposed in the cavity of the mold assembly; and injected material disposed in the cavity, the injected material creating a molded part, a portion of the injected material contacting the respective continuous inner surface of the hollowed volume in the mold fabrication element.

12 . The system as in claim 11 , wherein the respective continuous inner surface is ring-shaped.

13 . The system as in claim 11 , wherein the mold fabrication element includes stepped inner diameters of multiple different sizes to produce a corresponding stepped region in the molded part.

14 . The system as in claim 13 , wherein the stepped region in the molded part is a region free of flash caused by injection of the material into gaps between multiple sides of the mold assembly.

15 . The system as in claim 11 , wherein the mold assembly includes a first mold side joined to a second mold side, the first mold side including a void in which a first portion of the mold fabrication element resides, the second mold side including a void in which a second portion of the mold fabrication element resides, the void of the first mold side and the void of the second mold side retaining the mold fabrication element in the cavity.

16 . The system as in claim 11 , wherein the respective continuous inner surface of the hollowed volume of the mold fabrication element resides within a plane substantially orthogonal to a parting line of the mold assembly.

17 . The system as in claim 16 , wherein the mold assembly includes a first mold side and a second mold side, the first mold side moved along an axis substantially parallel to the plane to contact the first mold side to the second mold side to form the cavity.

18 . The system as in claim 17 , wherein parting lines of the first mold side and the second mold side are disposed substantially orthogonal with respect to the plane of the mold fabrication element.

19 . The system as in claim 11 , wherein a part line of separating the mold assembly to remove the molded part from the cavity extends along an axial length of the molded part, presence of the mold fabrication element in the cavity of the mold assembly producing a corresponding flash-free region in the molded part along a less-than-all portion of the axial length.

20 . An apparatus comprising:
a mold fabrication element, the mold fabrication element having a hollowed volume defining a respective continuous inner surface; and injected plastic, a portion of the injected plastic disposed inside of the hollowed volume and contacting the respective continuous inner surface of the in the mold fabrication element.

Assignees

• Sensata Technologies Inc

Inventors

• Washburn Keith R

Classifications

• B29C45/0025 Primary

  Preventing defects on the moulded article, e.g. weld lines, shrinkage marks (preventing defects on the preformed parts or layers B29C45/14836) · CPC title

• B29C45/26

  Moulds · CPC title

• B29C33/005

  characterised by the location of the parting line of the mould parts · CPC title

• B29C2045/0037

  Moulding articles or parts thereof without parting line · CPC title

• B29C45/2608 Primary

  Mould seals · CPC title