8/7/2019 Rapid Prototype Composite Tooling

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Rapid Prototype Composite Tooling Using CFOAM® Carbon Foam

Introduction

Asthe world movesfaster and partsare developed via computer aided design, the old

methodsof buildi ng masters(plugs) and pulling parts has become too slow and costly.

Designerswant to go from a CAD file to a composite part as fast aspossible.

At Touchstone Research Laboratory, there has been a breakthrough in the development of 

inexpensive, off-the-shelf coatings providing dimensionally stable, low coefficient of 

thermal expansion (CTE), large (and small) rapid prototypesof carbon fiber reinforced

plastics.

 

Rapid Prototype Composite Tooling Using CFOAM Carbon Foam

Touchstone is currently developing several processesto apply tooling surfacesto CFOAM carbon foam that are suited for prototype tools designed to

make lessthan ten parts. It is an inexpensive processthat can be manufactured quickly.

 

The “rapid prototype” surfacing concept begins with the

application of a filler material to the top layer of the

foam. The filler material has high use temperatures,suitable compressive strengths, and iseasily machined or 

sanded. The purpose of the filler material is to fill the

CFOAM pore structure in order to create the base for a

tool surface that will maintain vacuum integrity during

vacuum bagging on the surface.

High-temperature epoxy paint isthen applied to the fil led

foam surface in a carefully controlled manner in order to

manage the final tolerance that takesinto account the

paint thickness. This system can be seen in the

photomicrographsbelow.

Steps in Making a Rapid Prototype Tool Using CFOAM Carbon Foam

1. BLOCK AND MACHINE: First, panelsof CFOAM are bonded together and

machined to within 0.004" of the desired final geometry of the tool.

2. FILL AND CURE: The filler coat isthen applied to the surface of the machined

foam with a squeegee and adds no measurable thicknesswhen applied andprepared properly. The picture below showsa tool that hasbeen filled. An oven cure

in excessof 350° F istypically performed. A second coating of filler materialscould

be applied and oven cured if required.

Another optional processfor applying a different filler material isto apply it very

liberally over the entire surface of the machined tool, cure it at room temperature

within an hour while the tool ison the mill, and then re-machining the tool to the

finish dimensions. This eliminateshand workand the filler providesa very hard

surface.

3. PRIMER COATING: After the filler material has been completely smoothed,

consistent with the CFOAM carbon foam surface by hand or via machining, a primer 

coating isapplied by either spraying or rolling. The primer used istypically part of a

two part epoxy paint that has use temperature of 400° F (204° C). The primer coating

fillsany remaining porosity in the filled CFOAM surface.

After the primer coat isapplied, the surface isready for the second coat of the two part epoxy paint.

Below are two examplesof completed rapid prototype toolswith both coatsof the two part epoxy paint system. The tool on the l eft showsthe masking

paper on the edges. The paint system addsapproximately 0.004” to the surface of the tool.

To date, the rapid prototype tooling surfacesused at Touchstone have been used to successfully cure composite partswhen the tool was vacuum

bagged to a flat table, or the entire tool wasenvelope bagged.

Touchstone has a development plan to expand the robustnessof the rapid prototype surfacesfor autoclave processesand to achieve a vacuum integral

surface.

What We Offer 

We currently offer rapid prototype tools built to order.

In addition, Touchstone can manufacture a rapid prototype tool and pull a part . If the part isacceptable, Touchstone can machine away the

prototype surface and replace it with a durable rate tool surface.

We also supply CFOAM carbon foam eith er in panels or machined to shape for our customersto bu ild thei r own tools.

Although our customers are alwaystrying something new, we will provide the best advice we can offer and we do offer on-site consulting and

assistance in dev eloping new composite tooling specifically for your special needs.

For more information about our Rapid Composite Tooling, please call or email usfor a prompt response.

Telephone: 304.547.5800 email: CFOAMnfo@trl.com

 Voice: (304) 547-5800

Fax: (304) 547-5802

Email: CFOAMinfo@trl.com

CFOAM® isa regi stered trademarko f Touchstone Research Laboratory, Ltd.

CFOAM® productsmay be covered under the following patentswith more patents pending:

6,656,238 - 6,656,239 - 6,689,470 - 6,749,652 - 6,814,765 - 6,833,011 - 6,833,012 -

6,849,098 - 6,860,910 - 6,861,151 - 6,869,455 - 6,899,970 - 7,192,537 - 7,247,368

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2.2011 Rapid Prototype Composite Tooling

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