The demands of high performance motorsports require constant high-tech carbon fiber part modifications on short notice. Complex on-screen designs are created and delivered to the track for immediate installation. For some teams, that time between design and delivery can be less than 45 hours.

How is this done? It’s all in the tooling.

Many carbon fiber parts are molded in an autoclave (high-pressure oven) at temperatures between 120°C and 180°C and under pressures up to 6 bar. The mold used to shape the part must be made of a material capable of performing in those conditions. To maintain accuracy, the mold must also match the part’s thermal expansion. Interestingly enough, the mold is typically made from the same material as the parts it’s molding—carbon fiber!

In high performance motorsports, carbon fiber parts are usually crafted from prepreg, a combination of carbon reinforcement in woven or uni-directional form, impregnated with a specific amount of resin—typically epoxy. A prepreg requires heat, time, and pressure to cure the resin and produce a finished laminate.

The part is created by assembling a series of precut prepreg pieces into a negative-shaped mold. After processing in the autoclave, the newly formed positive part is removed. Yet, before any of this can happen, the mold must be created. Therefore, fast production of the mold is a crucial part of the process. Molds are made from a more reactive-type product called tooling prepreg. Toray’s AmberTool® HX56 is the leading product in this market.

Mold Production

The tooling prepreg is laminated on the master/pattern, typically producing a mold thickness of around 5 to 6 mm. To maintain accuracy, it is initially cured at a low temperature (typically 55 to 60°C) while on a master/pattern, then post cured to higher temperatures up to 200°C in a freestanding state.

Production time is precious. As illustrated below, the initial curing time of eight hours and post cure time of 20 hours account for 63% of the 45 hours to fully produce a part. Therefore, it’s essential that the processing time for the mold materials is kept as short as possible while maintaining high surface quality.

A typical process route for a complex 1 m² part would be:

1. Design verification: 2 hours

2. Production of a master pattern (a positive shape that represents the eventual component shape): 3 hours

3. Carbon fiber mold lamination on the master pattern, typically using AmberTool® HX56: 4 hours

4. Initial mold cure (HX56 55°C cure = full time in autoclave): 8 hours

5. Mold finishing (including post cure): 20 hours

6. Lamination of carbon fiber part: 1 hour

7. Curing of carbon part (full time in autoclave): 6 hours

8. Trimming and finishing of final part: 1 hour

9. Delivery

Total production time: 45 hours

Note: If the performance characteristics of the final part do not require such a high specification, cure times can often be reduced, cutting total production time by eight to 10 hours.

Easy to use and delivering unsurpassed quality surface finish in this highly demanding market, Toray’s AmberTool® series tooling prepregs allow our customers to truly ‘tool for speed.’ Produced at Toray’s thermoset centre of excellence in Langley Mill, U.K., our products have a long, proven pedigree of consistent quality service, allowing Formula 1 teams and other high performance industries to deliver newly designed parts track side in less than two days.

From September 2020, Toray Advanced Composites is also pleased to announce AmberTool® HX56 is now stocked in the U.S. for faster delivery to North American high performance motorsport markets. Read the press release.

Additional Resources

Toray AmberTool® Tooling Prepreg Processing Guide

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