Printing chucks

What will an additively manufactured hydraulic chuck get you from a technology standpoint? This was the question asked by engineers at toolmaker Mapal Inc. The short answer is versatility, according to Jochen Schmidt, product manager for clamping technology at Mapal. Additive manufacturing is selectively employed at Mapal when production-related limitations hamper innovation.

The company’s High Torque Chuck (HTC) with narrow contour combines the benefits of hydraulic expansion technology with the 3° back taper of the shrink-fit chuck. This is made possible by the additive-manufacturing process employed at Mapal in the form of selective laser melting. SLM is a powder bed-based process. Loose metal powder is melted and laid down layer by layer onto the areas where material is required by a laser beam. During the production of the hybrid HTC, the functional area is applied to a conventionally manufactured tool body via SLM. Thanks to additive manufacturing, the adjustment device can be positioned close to the chuck tip, which would not have been possible with conventional manufacturing. This reportedly provides an optimal radial runout of less than 3µm at the location bore and less than 5µm at 2.5 times the diameter, as well as a high shape accuracy and effective vibration damping. The damping reduces microstructure cracking at the cutting edge, which, in turn, ensures long tool life and less strain on the machine spindle, according to the company.

Mapal created a hybrid High Torque Chuck with narrow contour via selective laser melting. Image courtesy MAPAL.

“The product’s unique selling point is that the benefits of hydraulic clamping technology, such as simple handling, are combined with the other advantages of the HTC, such as thermal stability up to 170° C and high-torque transmission,” Schmidt said. “These advantages can now be exploited in contour-critical areas.”

The new chuck also allows quick and simple clamping of the tool, and implementation requires no training, high retooling costs or expensive peripherals, Schmidt said, adding that there is no risk of being burned from heating a holder.

The HTC with narrow contour is available in clamping diameters of 6mm, 8mm, 10mm and 12mm (0.236 ", 0.315 ", 0.394 " and 0.472 ") for HSK A63 and SK 40. Intermediate sleeves enable additional diameter ranges to be covered. Mapal will continue to research the additive-manufacturing field, according to Schmidt. “There are so many possibilities left to meet the customers’ needs,” he said. “One possibility that we have already realized is printing a hydraulic chuck directly into special combination tools. It is thus possible to take advantage of hydraulic expansion technology, such as damping, easy handling and high thermal stability, within a combination tool.”

For example, in the case of a modular tool for manufacturing a valve seat, the printed chuck serves as a clamping device for a multiple-bladed reamer when finishing the valve guide while the other part of the tool machines the valve seat inserts.

For more information about Mapal Inc., Port Huron, Mich., call (810) 364-8020 or visit www.mapal.com.