3. Shaft turning center

To describe this machine, we're going to take as our starting point the CTM25 lathe from Georg Fischer GF (figure 8 ), which has already been studied but abandoned. This machine is a genuine 5-axis machining center (X, Y, Z, B and C ), using fixed and rotating tools, which are housed in a large magazine. Rightly so, the designer got rid of the cumbersome turret, which was expensive, not very rigid and carried an insufficient number of tools. What's more, this lathe is equipped with a second spindle headstock that acts as tailstock, steady rest and backworking spindle, enabling complete machining of the shaft.

It's a very interesting and innovative machine, but we can easily understand the technical reasons for its failure. At the same time, we can define the ideal machine...