# US 5,707,578 A · Method for making mold inserts

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- Number: US 5,707,578 A
- Document ID: US5707578A
- Status: Granted
- Kind: A
- Application number: 08/664,344
- Filed: 1996-06-14
- Granted: 1998-01-13
- Earliest claimed: 1996-06-14
- Assignees: Hach Company
- Inventors: Gary W. Johnson; Joseph P. Myers; Mark A. Perrotto
- Web page: https://patentgrep.com/patent/US5707578A

## CPC

- B29C 33/40: Plastics, e.g. foam or rubber
- B29C 33/3857: {by making impressions of one or more parts of models, e.g. shaped articles and including possible subsequent assembly of the parts}
- B33Y 80/00: Products made by additive manufacturing
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B33Y: ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING

## Abstract

A method for preparing plastic injection mold inserts capable of forming a three-dimensional article in a plastic injection molding process. The method includes (a) forming a master mold insert having a recess therein which has a shape which is complementary to at least a portion of the shape of the three-dimensional article; (b) preparing a temporary reverse mold of the master mold insert; (c) positioning a metal gate in the reverse mold adjacent to and in contact with the article form; (d) introducing a hardenable plastic resin into the reverse mold; (e) allowing the resin to harden to form a mold insert; and (f) removing the mold insert from the reverse mold.

## Claims

### Claim 1

A method for preparing a plastic injection mold cavity insert, the method comprising the steps of:
(a) providing a master mold insert;
(b) preparing a temporary reverse mold of said master mold insert; wherein said reverse mold comprises a three-dimensional form of an article;
(c) positioning a metal gate in said reverse mold adjacent to and in contact with said three dimensional form of an article;
(d) introducing a hardenable plastic resin into said reverse mold;
(e) allowing said resin to harden to form a mold cavity insert; and
(f) removing said mold cavity insert from said reverse mold.

### Claim 2 (depends on 1)

A method in accordance with claim 1, wherein said reverse mold is composed of silicone rubber.

### Claim 3 (depends on 1)

A method in accordance with claim 1, wherein said hardenable plastic resin comprises epoxy resin.

### Claim 4 (depends on 1)

A method in accordance with claim 1, wherein said metal gate comprises an upstanding column having an upper end and a lip projecting outwardly from said upper end.

### Claim 5 (depends on 4)

A method in accordance with claim 4, wherein said lip portion includes an outer edge and an opening extending through said outer edge.

### Claim 6 (depends on 1)

A method in accordance with claim 1, wherein said reverse mold includes a cavity with a generally flat base portion, and wherein said three-dimensional form is supported on, and is integral with, said base portion.

### Claim 7 (depends on 1)

A method in accordance with claim 1, wherein said master mold insert is formed by means of stereolithography.

### Claim 8

A method for preparing a plastic injection mold cavity insert capable of forming a three-dimensional article in a plastic injection molding process, the method comprising the steps of:
(a) forming a master mold insert having a recess therein which has a shape which is complementary to at least a portion of the shape of said three-dimensional article;
(b) preparing a temporary reverse mold of said master mold insert; wherein said reverse mold comprises a three-dimensional form of said portion of said article;
(c) positioning a metal gate in said reverse mold adjacent to and in contact with said three-dimensional form;
(d) introducing a hardenable plastic resin into said reverse mold;
(e) allowing said resin to harden to form a mold cavity insert; and
(f) removing said mold cavity insert from said reverse mold.

### Claim 9 (depends on 8)

A method in accordance with claim 8, wherein said reverse mold is composed of silicone rubber.

### Claim 10 (depends on 8)

A method in accordance with claim 8, wherein said hardenable plastic resin comprises epoxy resin.

### Claim 11 (depends on 8)

A method in accordance with claim 8, wherein said metal gate comprises an upstanding column having an upper end and a lip projecting outwardly from said upper end.

### Claim 12 (depends on 8)

A method in accordance with claim 8, wherein said lip portion includes an outer edge and an opening extending through said outer edge.

### Claim 13 (depends on 8)

A method in accordance with claim 8, wherein said reverse mold includes a cavity with a generally flat base portion, and wherein said three-dimensional form is supported on, and is integral with, said base portion.

### Claim 14 (depends on 8)

A method in accordance with claim 8, wherein said master mold insert is formed by means of stereolithography.