JEC COMPOSITES MAGAZINE - Issue #57 - May 2010 - 58

KNOW-HOW
Mould
g…/… Electroformed moulds: fabrication and applications

More information ...
When it extended its activities, Corima Technologies opted to apply the best technologies available to develop its production tools. As soon as the company’s managers decided on the investment, a sustainable-development and operational-costoptimization process was initiated. The company acquired 1,200 square meters of new geothermally heated facilities. Its pride and joy is the new, extra-large integrated electrodeposition facility with geothermally heated baths (145,000 litres). The use of geothermal heat is a relatively rare industrial application in “electro” plants. It required a complete design reassessment, but will lead to substantial energy savings over time. The plant also operates on a “zero emissions” basis. Corima is also looking at photovoltaics and has signed a partnership agreement with EDF Energies Renouvelables to install 600 m² of solar collectors on the south-facing roofs of the new buildings. The company is embracing the future by giving itself the means for cleaner, enhanced production.

cutters or blades. It is said that a nickel mould is designed to last the lifespan of the part to be moulded. The properties of nickel ensure a long service life for much larger series than carbon or glass/epoxy composite moulds, which tend to be used for producing prototype parts or preproduction series.

Resistance to chemicals
Nickel is not only mechanically strong, it also has high chemical resistance in aggressive environments, for example with phenolic resins.

Reproduction accuracy
Depositing the material at the atomic scale makes it easier to control the surface roughness. The surface aspect of the master model is accurately reproduced, and in case of embossed surfaces (leather, skin texture, etc.) or markings, the reproduction will be as accurate as the model. The results are the same as a silicon imprint, with the added bonus of hardness.

Lighter moulds
Electrodeposition produces moulds that weigh much less than standard machined moulds, but which are just as strong.

Key information about nickel moulds
An electroformed mould is not simply a composite mould on which nickel is deposited. It is a nickel shell created on a conductive model, then separated from the model and placed on a steel frame.The overall cost of an electroformed nickel mould is comparable to that of other metal technologies. However, it is important to understand that the tooling study and creating the machined polyurethane master model account for 50% of that cost, and the nickel mould for the other 50%. Therefore, when a number of identical moulds are created in electroformed nickel, the recurring cost is reduced by 50%. It takes 14 to 16 weeks to create an electroformed mould, about the same for a mould machined from steel or invar. That time period includes two weeks for CAD studies, four weeks to create and machine the model, six weeks for the electroforming, and two weeks to assemble the mould. In case of problems due to an impact or to a localized design change, a nickel mould can be altered. To this end, Corima Technologies has developed a number of touch-up solutions.

Fig.6 : RTM MOULD (Sand filter from PROCOPI)

machine’s frame to take up the loads on the shell. The shell is provided with a heat-transfer-fluid control system embedded in resin concrete, which distributes the heat and reinforces the mould (Fig. 6). For an RTM mould, temperature control is a major factor that affects the mould’s productivity. Nickel moulds have very good thermal conductivity, making short cycle times possible. Three parts can be produced per hour using this type of mould. Here, the mould has two cavities for a single male mould, allowing continuous work: while the operator is applying the gelcoat to one cavity assembly, the other cavity is being injected under the press. Other industrial parts that are suitable for electroformed RTM moulds include shower stalls, tanks, body parts for agricultural machinery, parts for construction, and truck roofs.

What types of parts are best suited to electroformed nickel moulds?
Electroforming can be used to “push the envelope” for advanced designs. Complex parts, extra large parts and Class A textured parts are best suited for electroformed nickel moulds. Some examples in aeronautics are radomes, leading edges, fairings, engine panels, belly fairings, and landing gear doors.
More information: www.corima-technologies.com Contact: vbelorgeot@corima-technologies.com

Advantages of the technology
Surface hardness and life span
Nickel hardness varies from 15 to 20 HRC, so an electroformed nickel mould can’t be scratched by milling accessories such as

jec composites magazine / No57 May 2010

http://www.corima-technologies.com

JEC COMPOSITES MAGAZINE - Issue #57 - May 2010

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #57 - May 2010