3D Printers

Porsche Legends Can Be Reconstructed with some TLC & 3D Printing

On 3DPI this week we’ve had some insight into how 3D printing can add a personal touch to new Ferrari’s and Lamborghini’s. The auto focus continues today with a look at how 3D printing can support some of the older Porsche marques. Anyone that owns a legendary Porsche 550 Spider, 904 or 356 Carrera owns a tiny piece of automotive history. These cars, among others, have experienced an enormous increase in value over the last few years as a result. While they maintain this position in history and special place in the hearts of their owners, specific parts for these marqes — like cylinder heads — are no longer available. Thus, in the event that they are damaged or fail due to wear and tear, the only way to produce a replacement is by manufacturing a customized replacement part or reverse engineering the original part. In this regard, 3D printing is a cost-effective production method.

Voxeljet, the German based 3D printer manufacturer, was involved in just such a project for a Carrera cylinder head. The challenge of reconstruction is compounded by the fact that there are no original drawings available from the OEM auto manufacturers. So for this particular case, the reconstruction of the Carrera cylinder head — made of aluminium — started with measuring and scanning of the original defective head.

reconstructed cylinder head 3d printing voxeljet porsche

Valve guides, seat rings, camshaft bearing, intake and exhaust ducts, cylinder head screws etc. all had to be taken into consideration and set up as 3D base bodies in a meticulously detailed process. The next step was the transfer to functional models and the adding of design features from casting technology like site measuring, bevels, and fillets.

Once the geometric reconstruction was completed by another German company, CAD Support, based inMössingen; the digital files could be used for the production of the sand cores and this is where voxeljet and its proprietary 3D printing process came to the fore. Producing conventional cores and working with traditional core-making tools proved nigh-on impossible and was highly cost prohibitive. The only reasonable solution was producing the cores on a 3D printer, and for this particular application, the voxeljet process is ideal.

raw part with gating system and risers 65
Raw part with gating system and risers

The order for printing the entire core package — with eleven cores in total —went to the voxeljet service center in Friedberg. The many years of experience and expertise at the Friedberg facility were brought to bear on this project and produced the cores easily, including the thin-walled cooling rib measuring 2 mm —without additional supporting structures in the inner and outer cores.

Finished part voxeljet 3d printing
Finished part

The final molding was completed by the foundry Rauleder & Rudolf based in Schwäbisch Gmünd, which specializes in constructing unique components. The hot isostatic pressing (HIP) treatment led to a tremendous improvement of the mechanical properties of the cylinder head, as well as a reduction of pores. The final T6 heat treatment provided the ultimate strength of the head and the finishing of the components was made on the basis of the 3D CAD files in a 5-axis machining center. After completion, the aluminum cylinder head was ready for assembly.