System for detecting injection holding material

• US 6,943,348 B1
• Filed: 10/19/1999
• Issued: 09/13/2005
• Est. Priority Date: 10/19/1999
• Status: Expired due to Fees

• Current Assignee: Masimo Corporation
• Sponsoring Entity: Masimo Corporation
• Inventors: Coffin, James Price IV
• Primary Examiner(s): Porta, David
• Assistant Examiner(s): LEE, SHUN K
• Time in USPTO: 2156 Days
• Field of Search: 250/302, 250/461.1, 264/408, 252/301.5, 348/130
• US Class Current: 250/302
• CPC Class Codes: G01N 2021/646 : Detecting fluorescent inhomogeneities at a position, e.g. for detecting defects
• CPC Class Codes: G01N 21/6447 : by visual observation
• CPC Class Codes: G01N 21/94 : Investigating contamination, e.g. dust G01N21/85 takes precedence

Abstract

A system is provided for detecting a substantially transparent injection molding material. The injection molding material contains a fluorescent colorant, which is invisible when not exposed to ultraviolet light, but becomes visible when exposed to ultraviolet light. A method of detecting the injection molding material involves exposing the injection molding material to ultraviolet light and examining the material during exposure.

Claims

1. A method of determining whether an injection mold is substantially free from any leftover molding material, the method comprising:

injecting molding material including a fluorescent colorant into a mold to create a workpiece;

releasing the mold;

directing ultraviolet light into at least a portion of the mold with sufficient energy to cause emissions from the fluorescent colorant of any remaining molding material to be detectable; and

when remaining molding material is detected, removing the remaining molding material.

2. The method of claim 1, wherein the fluorescent colorant is substantially transparent in ambient light.

3. The method of claim 1, wherein the molding material is substantially transparent in ambient light.

4. The method of claim 1, wherein the fluorescent colorant and the molding material are substantially transparent in ambient light.

5. The method of claim 1, wherein the remaining molding material comprises the workpiece.

6. The method of claim 1, wherein the remaining molding material comprises small portions of the workpiece.

7. The method of claim 1, further comprising:

directing the ultraviolet light on the workpiece; and

inspecting the workpiece based on a reaction of the workpiece to the ultraviolet light.

8. An optical inspection system for determining whether an injection mold is suitable for reinjection of molding materials, the optical inspection system comprising:

a reusable mold which accepts flowable materials comprising a fluorescent colorant, wherein the flowable materials cool to form a workpiece in the shape of the mold; and

a light source which directs ultraviolet light toward the reusable mold with sufficient energy to energize the fluorescent colorant of any leftover flowable materials within the reusable mold.

9. The optical inspection system of claim 8, wherein the fluorescent colorant is substantially transparent in ambient light.

10. The optical inspection system of claim 8, wherein the flowable materials are substantially transparent in ambient light.

11. The optical inspection system of claim 8, wherein the flowable materials and the fluorescent colorant are substantially transparent in ambient light.

12. The optical inspection system of claim 8, wherein the leftover flowable materials comprise the workpiece.

13. The optical inspection system of claim 8, wherein the leftover flowable materials comprise small portions of the workpiece.

14. An optical inspection system for determining whether flaws or other abnormalities occurred in a workpiece made from an injection molding process, the optical inspection system comprising:

a light source which directs a first light toward a workpiece made from materials including a fluorescent colorant, wherein the first light comprises light of a wavelength not visible to humans with sufficient energy to cause the fluorescent colorant to emit a second light;

an inspection device which inspects the workpiece by detecting the second light, wherein the second light comprises light of a wavelength visible to humans.

15. The optical inspection system of claim 14, wherein the fluorescent colorant is substantially transparent in ambient light.

16. The optical inspection system of claim 14, wherein the materials are substantially transparent in ambient light.

17. The optical inspection system of claim 14, wherein the materials and the fluorescent colorant are substantially transparent in ambient light.