THE UNAVAILABILITY of parts can lead to resto budgets blowing out or, worse still, being shelved. But not if you plan on reviving a Porsche.

Using the latest 3D printing technology, Porsche is reproducing rare and out of date parts that meet their original specification, from both a technical and visual perspective.

Currently the Porsche Classic range includes 52,000 parts and is growing. If a part is no longer in stock or dwindling in number, itís reproduced using the original tools; for larger quantities production may require the use of new tools.

But ensuring the continuity of small batch parts is a challenge as producing them using new tools can be inefficient.

This is where 3D printing comes into the picture.

Before producing a particular component Porsche Classic evaluates various manufacturing processes. As 3D printing continues to improve and costs generally decrease, with no loss of quality, this form of manufacturing is becoming a viable alternative.

Porsche uses the example of a clutch release lever for a 959, a part no longer available. It was originally made from grey cast iron and only 292 were made.

To reproduce the release lever, a layer of powdery tool steel less than 0.1 millimetres thick is applied to a processing plate in a computerised process.

A high energy light beam melts the powder in the desired locations to create a steel layer and the complete three dimensional component is produced, layer by layer.

The component is tested with a load of almost three tonnes followed by practical tests with the lever installed in a test vehicle and extensive driving tests to confirm its integrity.

Plastic components are manufactured using a selective laser sintering printer, where the material is heated to just below melting point and the remaining energy is applied through a laser to fuse the plastic powder at a selected point.

All parts are subject to the quality requirements of the original production period as a minimum, though they usually meet higher standards.

Accuracy in terms of size and fit is ensured by performing tests with the part installed. Depending on the area of application, plastic parts made of various materials as in the original must be resistant to oils, fuels, acids and light.