Pass Through Serrated Steel Rule Die Trim Technology

by George (Brad) Braddon III

It is a bit surprising that so many companies still use the same technology for cutting foam trays out of a web as they do for punching out steel parts for cars. It seems that there must be a better way to cut out trays. This was my father's (George Braddon II) mindset when he invented the "serrated" steel rule die trim tool.

Punch and Die
Figure 1 - Typical punch and die tool technology

After 15 years as a process engineer for Mobil Chemical (now Pactiv), George started his own company making Polystyrene (PS) foam food packaging trays. While new to the business, he was frustrated by the high cost and long lead times required for punch and die trim tools (Figure1). These complicated assemblies typically produce cracked tray edges and angel hair. Angel hairs are long strands of foam that are the result of the cutting process when using punch and die tooling and can be considered a source of foreign material in the eyes of the Global Food Safety Initiative (Figure 2). As a result, he set out to develop a new system that would be low in cost, easy to maintain, and have better cutting performance in terms of controlling foreign material.

Cracked edge on foam tray
Figure 2 - Typical looking edge cut using punch and die tooling

According to George, "We expiermented with the blade pushing into brush-type materials and upholstery foams, finding that pushing into a simple 'slot' was the most effective (Figure 4). The key to the technology is that the teeth on the steel rule die need to be sharp so it can cut the material cleanly with very low force."

Serrated steel rule  material
Figure 3 - Serrated steel rule die material
Diagram of Commodore Steel Rule Trim Technology
Figure 4 - Commodore steel rule trim technology

George was very happy with the results and was able to lower his tooling costs such that he was able to provide the full product line that his customers required. Today Commodore is well known in the industry as having the highest quality trays in the market.

Stacked foam trays showing the Commodore Cut
Figure 5 - PS trays cut out of web using serrated cutting technology

While the initial technology worked very well for supermarket trays, plates and hinge lid containers, the thick flange trays required additional development. Today, we are trimming thick flanges virtually dust free. If you have any questions or would like a proposal, please call me at 585-657-7777 ext 223 or click below to view our mold and trim tool brochure.

Mold and Trim Brochure