Modular moulding halves

A modular plastics injection mould system halves that of traditional tooling and can be used for ‘few-off’ or producing thousands of parts

Producing rapid metal tooling for injection molded plastics, K Hofmann of Fuerth in Bavaria, Germany whose registered and patented process is Space Puzzle Molding by protoform, have been serving a wide cross section of industries for the last 20 years or more. Claimed to be novel and completely different, the SPM process creates an ‘envelope’ of individual tool elements which, when manually assembled like a ‘Space Puzzle’, create the cavity which forms the product.

On the other hand, conventional metal tooling is bulky and relatively expensive.

The overall volume of an SPM tool assembly is often only 20% or so larger than the component itself, said protoform.

Each part of the tool is manufactured by high-speed CNC 5-axis milling to the same quality and accuracy of high-volume production tooling.

The assembly is then transformed into a working tool by placing it in an appropriately sized standard metal supporting frame rendering the whole unit compatible with conventional injection molding machines.

Timescales and costs for SPM tooling are approximately half that of traditional tooling and yet the moldings produced are indistinguishable from production item, said protoform to manufacturingtalkmold.wiki.

The volumes achievable range from a few off for prototype test/product evaluation to several thousand series identical items in any plastics material.

Inserts, outserts, reinforcements and multi-material co-injection techniques can all apply with the added bonus that any design modifications, niche market variants, or mold flow changes required can be simply and economically achieved.

If an ultra rapid response is required, protoform operates an express track system known colloquially as the ‘ICE Window’ (after the German Inter City Express rail system) and this can be accessed for a small premium charge.

The recent acquisition of two additional 5-axis machining centers with custom robotics ensures the immediacy of attention to client’s requirements.

Space Puzzle Molding gives the most effective service if built into the very start of any plastics molding project.

Used immediately after the ‘touchy/feely’ models produced by various rapid modeling techniques, SPM yields working prototypes in production intent materials, often absolutely essential for ‘flight-critical’ approval or environmental evaluation.

It facilitates the de-bugging of unknown design and performance factors and optimises the product for strength and cosmetics.

For example, in the automotive industry, a vehicle carries many plastic items falling within the scope of SPM, which can handle shot weights from 0.3g to 2.5kg within an envelope of up to 200 x 400 x 800mm.

Porsche, BMW, Mercedes and others are regular clients for both simple moldings through to items such as the complex heater ducting illustrated.

For high volume production the information gained from the Space Puzzle stage is transferable to the volume tooling manufacturer and the SPM production of up to 3000 items serves to support manufacture until this comes on stream.

protoform has recently started to access the aeronautic/aerospace industry by attending industry specific exhibitions and shows.

This has highlighted two vital contributions that can be made by the SPM system.

* In Aeronautics there appears to be a tradition of machining metal instead of using custom moldings in modern high-performance plastics.

protoform now operates a design optimization consultancy service whereby one of their expert mold designers can advise on using plastics instead of metal.

The cost of this service is deducted from any subsequent mold charge as and when the project goes ‘live’.

This enables the client’s in-house expertise in plastics to build steadily with each project.

* The close synergy in ultimate volumes and batch sizes for aeronautic components and those required in, say, the medical industry, where protoform operates extensively.

It means that any possible hold-back in considering tooling-up for plastics manufacture due to its perceived initial cost and pay back calculation could be overcome by the true economics of this rapid, low-cost method of achieving production-quality items.

The production rates in both industries appear to be well below automotive volumes, therefore the Space Puzzle tooling could well fulfill all the demand required for the projected life of the product.

Protoform said that contacts so far in the industry have revealed that Space Puzzle Molding, whilst being immensely popular in other industries for which it is Quality Certified, has introduced a refreshing new factor for aeronautic design engineers to consider.