The majority of elastomeric vacuum tools (EVTs) are constructed to fit specific molds or fixtures. These molds can vary from flat, precision plates to highly contoured shapes. Torr, using data gathered from the customer, tailors a vacuum bagging system specific to the process.

This large EVT was constructed in Torr's facility and shipped to the customer, ready for placement on their mold.

It illustrates a number of construction methods:

1. Instead of sending a 6000 lb. mold, customer provided a built-up form that was used to construct rate tools and assist in rebuilds.
2. The diaphragm, because of its size, is spliced from standard width material.
3. Complex areas were made from uncured material and spliced into the main diaphragm.
4. The frame is cut, formed, and welded to fit the complex mold perimeter precisely.
5. For handling, a cross brace structure is provided that integrates with a portable lifting device

Although the mold and part are somewhat complex, the construction of the EVT was relatively easy due to mold design discussions with the customer before construction of the mold began. Note the area allowed for vacuum and thermocouple ports. All mold perimeter radii have been rounded to make frame, diaphragm, and seal construction straightforward. This tool is hinged along the upper back edge. There is a spring-loaded detent pin on the upper back left corner that prevents accidental closure of the tool.

Two Invar molds with EVTs hinged on the end to provide mold access during layup. Gas-springs counterbalance the EVT to assist in opening and closing, as well as supporting it in the open position. Torr can provide gas-spring locks that prevent accidental closure of the tool.

It's common for customers to already have plates they use for vacuum bagging. We routinely construct flat tools, tailoring the diaphragm and hardware for the process, and send the tools to the customer for installation. This particular tool has hinges, gas-springs, and swing clamps along the front edge. The front clamps are hinged so they swing down and grip the edge of the mold, holding the seal in contact with the mold/plate surface during vacuum initiation.