Originally Published MPMN May 2008

BREAKTHROUGHS

Spool-to-Spool Grinding System Streamlines Guidewire Manufacturing

Daniel Grace

Procedures for grinding medical guidewires commonly begin with cutting wires to length. A machine operator then hand-feeds the wires into a grinder one at a time. Next, an operator handles the guidewires once again in order to initiate a coating process. Any additional modifications require still more manual operations.

Responding to customer feedback regarding the inefficiency and costliness of their guidewire manufacturing processes, developers at Royal Master Grinders Inc. set out to produce a grinding system that could seamlessly integrate multiple processing steps, thereby reducing operator dependency. The result of the company’s efforts is an automated spool-to-spool system that enables the continuous grinding of guidewires.

“The spool-to-spool system eliminates the need for all of the normal handling steps,” says John Memmelaar Jr., company vice president. “The operator [can] simply put a spool onto the entrance side, walk away, and collect it at a later time with thousands of feet of wire ground.”

The operator could then carry the ground wire on a spool to the coating station, or coating could be integrated within the system to further automate operations. Finished guidewires are then cut to length at the end, rather than the beginning, of the process. In addition to grinding stainless-steel guidewires, the system is suitable for grinding a variety of spooled products, including catheter bodies and marker bands. It can also be used for oxide removal on nitinol wire.

The machine’s feeding system can take a spool of raw material weighing up to 30 lb, and measuring up to 4 in. in width and between 0.1 and 14 in. in diameter, and transfer it to another spool—all while rotating at 2000 rpm and providing level winding for a uniform wrap. After exiting the grinder, a laser gauge reads the diameter, and, if necessary, feeds the wire back into the grinder for size compensation. The payout and take-up spools use an encoder to track the length of outputted wire, and the system displays the amount of dispensed material. Operations can automatically be stopped after a preprogrammed amount of material has been ground.

Royal Master can assist customers with setting up the system in tandem with a centerless grinder from its product line. Alternatively, customers can purchase the system for use with their existing grinding equipment. “We encourage engineers to use their imaginations in deciding how best to use the system to address specific grinding needs,” Memmelaar says.

Royal Master Grinders Inc. , Oakland, NJ
www.royalmaster.com

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