Technology Spotlight: Machine Tool Probing Bumps Into the Digital World

New wireless probing systems allow radio and infrared transmission

Touch probes help reduce setup times, increase spindle uptime, and improve the quality of finished workpieces. Triggering touch probes on a machine tool are inserted in the toolholder manually or by the tool changer. These probe systems enable functions such as workpiece alignment, datum setting, measurement, and inspection of 3-D surfaces.

Traditionally these functions have been performed by wired probing systems. But parts manufacturers that need to probe large, long, or complex parts with such probes face a challenge: how to complete a cycle without entangling in the wire. Enter wireless technology.

Heidenhain produces touch probes with hybrid wireless technology that enables both radio and infrared signal transmissions. Called the TS 460, this probing system makes it easier to measure long parts, as well as parts that have deep cavities or other complex features.

“The user selects either the radio or infrared mode for the need, but the system’s strength is in combining the advantages of radio [when extended range is required] with the benefits offered by infrared signals, which have a 360-degree transmission range,” explained Julian Renz, TNC product specialist.

Using this type of wireless system, manufacturers require just one touch probe on any size machine, and tricky measuring applications, such as plunging into a cylinder or functions requiring articulation, can be accomplished.

“The radio transmission function has 16 channels and does not require a direct line of sight,” explained Renz. “This makes it a good choice for measuring long parts like those common in aerospace production.”

The range of the radio transmission usually is 15 m, but larger ranges are possible under ideal circumstances. “The range of the infrared signal is 7 m, but a direct line of sight is needed for this type of transmission,” he added.

According to Heidenhain, the carrier frequency method makes this transmission very reliable, and the high frequency ensures a short delay time. No matter which signal transmission is chosen, the user needs only one SE 660 transmitter-receiver unit, which has a 360-degree range of transmission like the probes do.

This system also has an optical sensor that will not wear, even after a large number of probing processes, allowing the necessary reproducibility to be maintained. The compact design makes it possible to use these touch probes even where installation space is limited. The smaller contours of the system, when compared to earlier probing systems, permit freedom of movement when tilting into position. These touch probes also have blower jets for cleaning the workpiece, either with coolant or compressed air.

In the event of a light collision against a fixture or workpiece, the touch probe can absorb the shock. At the same time, the integrated switch deactivates the ready signal and the control stops the machine. An optional adapter, placed between the touch probe and the taper shank, protects against collision and thermal decoupling.

Tool probe collision protection

Collision protection, an option for this technology, enables the device to absorb a small shock. This not only saves money in replacement costs, but reduces costs associated with the downtime.

“By having this collision protection, the probing system helps protect the machine and part from potential damage, and it also helps reduce any downtime caused by crashes,” said Renz.

Transmission Types

  • Infrared transmission. This type of wireless communication is suitable for compact machines with closed working spaces. Range: 7 m.
  • Radio transmission. This typically is used for large machine tools and operates in the free ISM band at 2.4 GHz. Range: 15 m (longer range is possible in ideal situation).
  • Hybrid technology. Transmission is via radio or infrared signals. The dual-signal capability of the TS 460 combines the advantages of radio waves (high range and large amounts of data) with infrared signals (highest accuracy and fast signal transmission). Users of hybrid technology can switch among pure infrared, pure radio, and mixed operation.

www.heidenhain.us