Workholding Collet Changeouts Get Totally Automated

A workholding manufacturer has collaborated with a machine tool OEM and together they have accomplished what could be considered an industry first. The two companies successfully automated the process of changing out workholding quick-change collets on a twin-spindle turning machine. The key to this project is a special end-of-arm device that allows a collaborative robot (cobot) to perform the operation. This capability saves huge amounts of time during any setup and is particularly advantageous for shops that routinely run small batches of parts, where frequent workholding changes significantly limit productivity because operators must manually change out the workholding after each batch of only a few parts. The time consumed to do so then limits the number of batches that can be run per shift.

Now, instead of having operators spend hours on frequent change outs, this automated collet changer sets up the machine with a new collet in as few as 10 seconds or 20 seconds. The system’s end-of-arm pneumatic tooling/grippers, developed by advanced workholding manufacturer Röhm Products of America (Suwanee, GA), work with an adaptor developed by CNC machine tool builder Yama Seiki USA, Inc. (Chino, CA). The pneumatic system clamps and unclamps the grippers that function like a trigger-gun-style hand tool to remove and install collet heads.

For one aerospace company, this workholding automation system holds up to ten collets and changes them in a cell comprised of several machine tools. This provides lights-out setups and operations for several different parts on each machine – as opposed to interrupted runs of single parts. The system heightens the shop’s unattended machining capabilities and optimizes their efficiency, flexibility and overall output. Not only is the new automated workholding ideal for short-run jobs, it also makes two-sided part machining possible on single-spindle machines. The robot changes the collets to fit two different diameters in seconds, whereas an operator needs a few hours to accomplish the same task.

The touch-sensitive cobot, from FANUC America Corporation (Rochester Hills, MI), stops when it comes into contact with a human. However, automated workholding systems can also employ a zone scanner to further enhance safety. The zone scanner stops the robot if a human or object moves in close to the robot’s operating zone. Once the zone is clear, the robot will automatically continue its tasks. Such safety precautions are necessary because the collaborative robot, while finely tuned to quickly pause its motions, is still powerful and fast enough when running at full speed and its momentum could jar an operator. The zone scanner also ensures that the automation runs as fast as possible.

High-performance components are critically important to automated workholding systems because they have a tremendous impact on finished part quality. Yama Seiki chose to collaborate with Röhm for this project because their collets and grippers offer high precision, accuracy and reliability, and Röhm engineers helped to develop the successful strategies for this innovative project. Cutting edge automation technology such as this is only the start of advanced automated workholding technology that will open up wide ranges of application possibilities. Manufacturers will benefit greatly, and especially when automated workholding is incorporated with that of workpiece loading/unloading – via one robot – for total machine automation.

Röhm Products of America, 2500 Northlake Drive, Suwanee, GA 30024, 770-963-8440, Fax: 770-963-8407, www.rohm-products.com.

Yama Seiki USA, Inc., 5788 Schaefer Avenue, Chino, CA 91710, 909-628-5568, www.yamaseiki.com.

FANUC America Corporation, 3900 West Hamlin Road, Rochester Hills, MI 48309, 248-377-7000,www.fanucamerica.com.