Focus on Heavy-Gauge Thermoforming

The annual SPE Thermoforming Conference always brings new ideas and inspiration. Given the customized nature of many heavy-gauge thermoforming projects, we usually get into the weeds pretty quickly with companies that are working on new stuff. Often, heavy gauge formers do not use full-size syntactic foam plugs due to low volumes.  However, syntactic foam can be used as localized pushers, as mold inserts, on the clamp frame, and for prototype/low volume tooling.

Even though the majority of HYTAC products are made in stock sizes for thin-gauge thermoforming, most of them can also be found in the heavy-gauge sector in some form or fashion. Here’s a brief summary of tools and materials that we offer to the heavy-gauge vacuum- and pressure-forming industry:

1. Custom cast solid plugs

Whether poured into your mold or cast as a near-net billet in a temporary mold, large, solid syntactic foam plugs offer improved performance over traditional materials used in heavy-gauge forming such as wood, felt or MDF board. The consistent surface of solid (and LP) plugs eliminates tool marks commonly associated with wood or quickly-assembled plugs. Especially when running higher volume jobs run on rotary machines, solid syntactic plugs can provide dramatic cost savings through reduced sheet thickness, lower heating costs and improved material distribution. Download our appliance case study for a full understanding of how this works in practice.

2. Custom cast LP plugs

HYTAC LP is a 2-part plug system consisting of a core of epoxy-coated large, hollow composite spheres and an exterior coating of thick, high-performance syntactic foam (W, WF, LPX, FLX, FLXT or C1R). The LP option is used to reduce overall plug weight and costs. As with solid syntactic plugs, processors see the greatest benefit during medium to high volume jobs. And though the initial cost is higher than wood, the overall increase in production rates and yield due to consistent wall thickness translates to reduced scrap and lower reject rates. That definitely helps the bottom line.


3. Custom cast male tools

For medium-volume runs, the usual benefits of syntactic foam – low heat transfer, durability, machinability, design predictability – enable some processors to capture savings and improve performance. In some instances, heavy gauge formers are choosing HYTAC over wood or MDF for male molds. This was studied in some detail by a student at Penn College in a paper that was published by Thermoforming Quarterly in 2012 (pp.22-28). The study found that MDF, despite its low cost, was not suitable as a mold material “by any means” due to mark-off and molded fibers sticking to the formed part. On the other side of the spectrum, HYTAC can be less expensive than aluminum. And without the need for heating and cooling, syntactic offers lower operating costs. We continue to work on new materials for this segment of the market. Get in touch if you want to discuss a particular application.


HYVAC is a fixturing product that provides a fast and economical way to hold contoured parts in place during the trimming operation. It is a porous material that can be easily shaped using existing parts, eliminating the need for costly machining of large holding fixtures. Its final structure allows vacuum airflow throughout, providing uniform hold-down during manual or automated trimming.

Beyond these specific products, here are some other ways heavy-gauge formers use syntactic foam:

– machine small sections of foam to function as pushers on existing tools to eliminate webbing and to improve part definition

– attach foam to clamp frames in order to minimize chilling of the sheet

– for prototyping in place of bonded materials, thereby eliminating ‘witness marks’ or bond lines

It’s clear that HTYAC is not just for the thin-gauge guys! Let us know what you’re working on. Perhaps there’s a new application for HYTAC that we haven’t discovered yet.