Method of fabricating an injection molded component

Patent metadata

Field	Value
Publication number	US-9630346-B2
Application number	US-201313785563-A
Country	US
Kind code	B2
Filing date	Mar 5, 2013
Priority date	Mar 5, 2013
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A method of fabricating an injection-molded component is provided. The method includes the step of introducing pellets into an injection barrel of an injection molding machine. The pellets include a first supercritical fluid. The pellets are plasticized in the injection barrel and a second supercritical fluid is injected into the plasticized pellets. The second supercritical fluid and the plasticized pellets are mixed to form a mixed material. The mixed material is injected into a mold.

First claim

We claim:

1. A method of fabricating an injection-molded component, comprising the steps of:
introducing pellets including a first supercritical fluid and polymeric material into an injection barrel of an injection molding machine;
plasticizing the pellets within the injection barrel;
introducing a second supercritical fluid into the plasticized pellets to form an injection material: and
injecting the injection material into a mold; wherein:
the first supercritical fluid and the second supercritical fluid are formed from different components; and
the first supercritical fluid is formed from nitrogen and the second supercritical fluid is formed from carbon dioxide.

2. The method of claim 1 comprising the additional steps of
providing a polymeric material;
heating the polymeric material and the first supercritical fluid to produce a melt;
extruding the melt; and
forming the pellets from the extruded melt.

3. The method of claim 2 wherein the extruded melt is unfoamed.

4. The method of claim 1 comprising the additional step of mixing the injection material prior to injecting the injection material into the mold.

5. The method of claim 1 wherein the injection molding machine includes a hopper communicating with the injection barrel and wherein the method includes the additional step of introducing the pellets into the hopper prior to introduction of the pellets into the injection barrel.

6. A method of fabricating an injection-molded component:
comprising the steps of:
providing a polymeric material;
introducing a first supercritical fluid into the polymeric material;
forming pellets from the polymeric material and the first supercritical fluid;
introducing the pellets into an injection barrel of an injection molding machine:,
plasticizing the pellets;
introducing a second supercritical fluid into the plasticized pellets to form an injection material; and
injecting the injection material into a mold; wherein:
the first supercritical fluid and the second supercritical fluid are formed from different components; and
the first supercritical fluid is formed from nitrogen and the second supercritical fluid is formed from carbon dioxide.

7. The method of claim 6 wherein the step of forming pellets from the polymeric material and the first supercritical fluid includes the additional steps of:
heating the polymeric material id introducing first supercritical fluid to produce a melt;
extruding the melt; and
introducing the melt into a pelletizer.

8. The method of claim 7 wherein the extruded melt is unfoamed.

9. The method of claim 6 comprising the additional step of mixing the second supercritical fluid into the plasticized material prior to injecting the injection material into the mold.

10. The method of claim 6 wherein the injection molding machine includes a hopper communicating with the injection barrel and wherein the method includes the additional step of introducing the pellets into the hopper prior to introduction of the pellets into the injection barrel.

11. A method of fabricating an injection-molded component, comprising the steps of
introducing pellets into an injection barrel of an injection molding machine, the pellets including a first supercritical fluid;
plasticizing the pellets in the injection barrel;
mixing a second supercritical fluid and the plasticized pellets to form a mixed material; and
injecting the mixed material into a mold;
wherein the first supercritical fluid and the second supercritical fluid are formed from different components.

12. The method of claim 11 further comprising the additional step of forming pellets from a polymeric material and the first supercritical fluid.

13. The method of claim 12 wherein the step of forming pellets from the polymeric material and the first supercritical fluid includes the steps of:
heating the polymeric material and introducing the first supercritical fluid to produce a melt;
extruding the melt;
cooling the extruded melt into solid strands; and
introducing the strands into a pelletizer.

14. The method of claim 13 wherein the extruded melt is unfoamed.

15. The method of claim 11 wherein the first supercritical fluid is formed from nitrogen and the second supercritical fluid is carbon dioxide.

16. The method of claim 11 wherein the first supercritical fluid is formed from nitrogen.

17. The method of claim 11 wherein the second supercritical fluid is formed from carbon dioxide.

18. The method of claim 11 wherein the injection molding machine includes a hopper communicating with the injection barrel and wherein the method includes the additional step of introducing the pellets into the hopper prior to introduction of the pellets into the injection barrel.

Assignees

• Wisconsin Alumni Res Found

Inventors

• Turng Lih-Sheng
• Sun Xiaofei

Classifications

• B29C2948/92828

  Raw material handling or dosing, e.g. active hopper or feeding device · CPC title

• B29C48/0022

  combined with cutting · CPC title

• B29C48/919

  using a bath, e.g. extruding into an open bath to coagulate or cool the material · CPC title

• B29C48/04

  Particle-shaped (making granules B29B9/00) · CPC title

• B29C48/92

  Measuring, controlling or regulating · CPC title