Our Process - Wolf Composites

What is Prepreg?

Prepreg is the common term for carbon fiber that has been pre-impregnated with a resin system. The resin system is typically an epoxy and already includes the proper curing agent. As a result, it’s ready to lay into a mold without the addition of resin or the steps required of a typical hand lay-up.

Why choose prepregs over standard fabric reinforcement and the wet lay-up process?

Improved cosmetics. No accidental drips of resin or dry spots to compromise appearance or performance.
Repeatable, uniform parts. Consistent resin content means prepreg parts that come out of a mold can, in theory, be identical.
Improved efficiency in the process. Prepregs translate to savings on wasted product, supplies, and time spent on wet lay-up and clean-up.
Reduced cure time. After the necessary heating cycle for cure is complete, prepreg parts are ready for service without additional waiting time.

How its Made?

1. DESIGN

Following CAD Consultation, the part file is finailzed. Pattern files are created from the finalized part file, taking best manufacturing practices into consideration. Mold lines and flanges are created, hard spot considerations are made, and designs for the master patterns are ready to use for machining.

2. MASTER PATTERN

Master pattern files are programmed into a 5-axis CNC router. Tool paths are created in order to achieve the most accurate part dimensions and shortest machining times. The tooling program is started and the part is machined into foam tooling board. Pins are added in order to hold drill sleeves or mold flanges.

3. MOLD MAKING

The master pattern is sanded and primed, in order to be polished into the smoothest surface possible. The smoothest surface means the glossiest final carbon part. Wet-layup carbon is applied to the master pattern and cured, resulting in a mirror of the master pattern. This mold will be used to lay-up the final part.

4. CNC PREFORMS

Carbon fabric patterns are created from the surfaces exported from the finalized part file. Lay-up scheduling is determined from final usage and intended weight, as well as part strength. The final fabric patterns are cut using a CNC fabric plotter. CNC cut fabric patterns allow for the lightest parts, as there is no unnecessary overlap.

5. LAYUP

Carbon patterns are applied to the mold by hand. Technicians determine proper overlap and layer placement to insure the lightest and strongest part. Permeable plastic sheet is applied, followed by breather cloth. The plastic sheet and breather allows vacuum to be applied to the part surface in order to pull out excess resin.

6. VACUUM BAGGING

The entire mold with carbon, plastic sheet, and breather are placed into a sealed bag. A valve on the bag is used to pull all air out, keeping pressure on all surfaces of the un-cured carbon. Pressure on the surface allow for the best part finish available in the industry. Autoclave cured process means lighter parts with less surface imperfections.

7.CURING

The bagged mold is placed into an autoclave. Vacuum is applied, and the autoclave is pressurized. The temperature is raised until proper curing heat is reached. Once reached, the carbon fabric and resin cures into its final form. The autoclave is depressurized and returned to ambient temperature. The mold is removed.

8.DEMOLDING

When cooled, the bag is cut open and the mold is removed. The breather blanket and plastic film are pulled from the inside surface and discarded. The part is removed from the mold manually or with air pressure. At the point the edges of the part are razor sharp. The mold will be cleaned and coated with “mold-release” for the next run.

9.TRIM & FINISHING

When the part is removed, the seams from the mold still show. They can be extremely sharp and must be removed before the part is complete. The seams are sanded down and any hardware is adhered or installed. The part is cleaned and polished for to mirror-like finish. Primer or paint is applied if desired. The part is complete.

Questions / Answers

Where are you located?

3991 Fondorf Drive
Columbus OH, 43202

Contact Us

Are you open for public tours?

The shop is closed to the public, however we do offer tours for interested clients. Please call us if you are in the neighborhood and interested in seeing what we do.

What types of composite fabric material do you keep in stock?

We stock over 500 linear yards of pre-preg lamina at all times. We can also order in custom fabric blends for specific requirements.

3k / 12k Weave Prepreg

4201m-285 Kevlar

Fiberglass

Xylon composite

Unidirectional dry-carbon

Film Adhesive

What is pre-preg?

Pre-preg is a term for “pre-impregnated” composite fibers where a matrix material, such as epoxy, is already present. The fibers often take the form of a weave and the matrix is used to bond them together and to other components during manufacture. The matrix is only partially cured to allow easy handling; this is called B-Stage material and requires cold storage to prevent complete curing. B-Stage pre-preg is always stored in cooled areas since heat accelerates complete polymerization. Hence, composite structures built of pre-pregs will mostly require an oven or autoclave to cure.

Pre-preg allows one to impregnate the fibers on a flat workable surface, or rather in an industrial process, and then later form the impregnated fibers to a shape which could prove to be problematic for the hot injection process. Pre-preg also allows one to impregnate a bulk amount of fiber and then store it in a cooled area (-20 C) for an extended period of time to cure later. Unfortunately the process can also be time consuming in comparison to the hot injection process and the added value for pre-preg preparation is at the stage of the material supplier.

Are you able to manufacture molds and tooling?

Wolf Composites manufactures tooling for many diverse industries. Please see the services page to view all of the solutions Wolf has to offer.

Our Services

Can you make just one part?

Yes, no project is too big or too small for Wolf Composites. From single prototypes to full scale 1000 piece production runs, we have you covered. Contact us to start your project today. Request a project quote directly through our website.

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Do you do carbon repairs?

In previous years, our company specialized in carbon repairs. Please call to discuss a repair project. Not all pieces can be repaired.

Ready to get started with your project?

Use our online form to submit a quote request.
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