Challenges of turning abound.

Author:Dierks, Tom
Position:Brief Article

What does the future hold for turning? Three things are certain:

* Dimensional and surface finish tolerances will become tighter;

* The complexity of turned pieces will grow; and

* Cost pressures on manufacturers of turned parts will increase.

As consumers, we like and buy products that are made well and last a long time. To satisfy us, engineers need more durable part materials, tighter tolerances, and finer finishes to make our products better. As part of this chain reaction, machine tool manufacturers must address these issues, too.

Turning machines, in particular, will have to become more rigid to turn tougher materials and achieve better finishes. To reduce vibrations and harmonics even further, slides, ball screws, axis motors, linear motors, encoders, and glass scales need to undergo additional research and development to meet tighter tolerance and finish requirements.

In addition to rigidity, thermal expansion--inherent in all machine tools-will be a key challenge to overcome as we attempt to minimize variations in the machining process. Thermal growth can be controlled to a certain extent by using special materials and designing machines that are symmetrically balanced. Probably the best solution, however, is to integrate automatic temperature -sensing and offsetting devices into the machine tool to counteract thermal expansion.

Engineers are also designing more complex pieces as they try to eliminate numerous assembly tasks and tolerance build-up between assemblies. Many highly complex components comprise only two or three pieces. This means that most components require more than just turned parts. A majority of the parts today have a number of additional operations in them, including milling, drilling, tapping, broaching, and slotting. Generally, all of the functions are performed while the piece is stationary. (Tornos has some machines in the field on which the only bonafide turning operation occurs when the part is cut off. The rest of the time these "turning" machines are really operating as machining centers.)

With the growth of complex parts, machines must be highly flexible. They need numerous axes to approach the part from different directions and plenty of live tools to perform all of the ancillary...

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