…they were wrong!



Injection Molded Filter

Toth Mold/Die Inc. was approached by our customer to assist in the development of an injection molded filter for screening for an application in a very large industry. This product involved two parts which include the grid as well as a bar.  There were numerous challenging requirements that needed to be achieved.

The grid itself is made with a certain grade of thermoplastic that would be exposed to heat, extreme abrasive material and chemicals. The material we used is also a metal replacement material.  The grid has a finished dimension of 24″ x 29″ with an arc cast in it. This part could not be molded in one piece.

Toth Mold/Die Inc. developed a snap feature for assembly on all four sides. The part size is 2″ x 6″ which is then snapped together to make a grid panel equal to the above size of 24” x 29”.  There are both flat and triangle shape grids that make up the finished panel. The images below show the triangular shaped part with the snap features.

A bar was needed to be molded to attach to the finished grid panel as well. The size of the bar itself needed to be 7/8″ x 7/8″ x 29″.  Molding a 7/8″ square x 29″ long without any warpage was a huge challenge in and of itself.

Triangular Grid
Flat Grid
Grid Attachment
Three Piece Grid

Injection Molded Filter

The injection molded filter screen is a part that in theory should not have been able to be molded.  The specifics of the screen are as follows:

  • The part size ended up being 2″ x 3″ and also 1″ x 6″
  • The openings in the screen are .0022/in. – 56 µm.
  • The rib thickness that cast the openings are .007/in.
  • There are 2,880 ribs and 2,880 nit lines.

Toth Mold/Die Inc. was told by material manufacturers and engineers that this part could not be molded. After a great deal of R&D, we succeeded in making the screen. In addition to making a mold to produce the part, we had to find a material that would meet the required specifications for the extreme conditions that the screen needed to perform in. After sampling over 65 different materials, a glass filled TPU (which is not an easy material to injection mold) was selected.

1 inch by 6 inch screen

Screen to Grid Attachment

Attaching the screen to the grid was another issue that needed to be resolved. The original design was heat staking. The screen had .048/in. diameter holes cast through and the grid had .046/in. diameter post standing .187/in. It was a task in and of itself to mold due to the 50% glass filled material. The heat staking did not work well in holding the screen in place. Our customer decided on utilizing cutting edge technology of laser welding to attach the screens.  Through R&D with Toth Mold/Die Inc., our customer and the laser welding company, we achieved success as the screens were able to be laser welded in place.

Grid with Assembly
Triangular Assembly

The Finished Product for the Injection Molded Filter

After four years of R&D on this project, the injection molded filter for screening was completed. The next step will be the customer’s extensive testing before it is released to the market. There have been numerous changes and additions from the original concept that were needed to improve function of the panel and extend the life.

This unique design developed by Toth Mold/Die Inc. can be made to a variety of sizes due to the “snap together” design and used in a variety of applications or industries. This design can produce a panel 1′ x 1′ to 10′ x 10′ or larger with the same 2″ x 6″ part. Below is a picture of ten pieces of the 2″ x 6″ grids snapped together which ends up being 4 1/2′ long. In addition, with this design, the flatness of the product exceeds the industry standards.

4 inch Grid Assembly
Assembled Panel
Three Piece Screen Assembly
1 inch by 6 inch Screen Assembly

These are the types of projects that Toth Mold/Die Inc. welcomes, as we thrive on new challenges. Our success stems from our wealth of hands-on combined 80+ years of experience in this industry and our mindset of “It can be done and nothing is impossible”.  As a true “One-Stop Shop” our services encompass it all …from concept to final part production and everything in between. We always entertain a new project, regardless of the complexity. No matter how big or small your project is, you can trust Toth Mold/Die Inc. to be your “One-Stop Shop”.