Sometimes the idea for a workholding solution takes some time to implement. That was the scenario at A to Z Machine Co., said Marc Manteufel, manufacturing engineer and IT manager. The 29-yearold, employee-owned CNC machine shop has 11,150 sq. m. (120,000 sq. ft.) spread over three buildings in Appleton, Wisconsin, where about 135 employees work during two shifts.

For a long-term job machining a part made from austempered ductile iron for the defense industry, the shop was using a pin-based system for clamping fixtures for about six years, Manteufel noted. With that system, a 20 mm (0.787") pin went through a receiver alignment bushing in the fixture plate into a receiver bushing in the base plate. “Then you have a thumb screw that you have to crank down.”

He added that there were eight clamps, or pins, on the fixture plate, and the operators had to unclamp the pins, clean them, change the fixture plate and line up the bushing holes so they could insert the pins every cycle. Not only did each changeover consume about 10 minutes, but the process was also physically awkward. “They were reaching up and over the fixture to get at the back pins, so ergonomically it was not very pleasant for them.”

Manteufel said he had known about zero-point clamping for years and decided he wanted to implement it with the fixture the company makes. He did an extensive amount of online research to learn more and then contacted a couple of distributors he has worked with who connected him to tooling representatives. After considering various systems, A to Z Machine turned to Lyndex-Nikken Inc. in Mundelein, Illinois, for a zero-point clamping system manufactured in Germany by Zero Clamp GmbH.

“The features of the product stood out from the competition,” he said. “Mechanically, it seemed a lot more sound and simpler. I wanted something that I felt was going to last trouble-free.”

Manteufel noted that the system from Lyndex-Nikken has a full contact collet like a drawbar on a machine tool. A low amount of air pressure pumps up an internal diaphragm and expands the die spring plates, which pulls the collet back. The collet clamps when the air pressure is removed.

“There’s just a lot more contact, so there are no concentrated points for wear,” he said. “Nobody else had anything like that at all.”

In addition, rubber seals between the clamping segments prevent dirt, coolant, moisture and other debris from entering, Manteufel added.

Because only one type of clamping stud, or retention knob, is required, the Lyndex-Nikken system beat the competition when it came to simplicity of operation, according to Manteufel. “Because their tapered ring on top that locates is able to expand slightly and then radial float ever so slightly, it takes up any difference in length measurements between the pots. You do not have different style knobs to worry about.”

Another attractive difference between the Lyndex- Nikken zero-point clamping system and those from the competition was cost. “For a superior product, it was actually considerably less money than the nearest competition. I was really happy about that. Some of the competition was almost double the cost.”

Prior to making the purchase, Manteufel said A to Z Machine received some zero-point clamping hardware to do bench testing and see how the system functions with the shop-produced base plate for holding the zero points and fixture plate positioned above. The shop also collaborated with counterparts from U.S. and German companies to determine if there would be any issues. “They gave me a thumbs up and said it’s a good design that should work well.”

The shop implemented Lyndex-Nikken zero-point clamping into a work cell with two machines, with 10 clamping pots in the 120 mm (4.72") size for each machine, he explained. The pots are plumbed into one air line. An operator opens the machine door and plugs the air line into the fixture plate to unclamp the top plate. A crane is used to lift the large top plate out and load the next plate that’s ready to go using pull studs that stick out to guide the plate into the zero points. Then the operator unplugs the air line — enabling the system to clamp the part — and closes the door.

The setup for A to Z Machine’s new zero-point clamping system is “foolproof,” Manteufel added. “They can’t run the machine unless the air line is unplugged and the operator door is closed.” With the previous pin-based workholding, an operator might forget to put some pins in or not tighten them enough and a part would come loose and start rattling around.

Before implementing the new clamping system, Manteufel said the setup time was 10 minutes. With the Lyndex-Nikken zero-point clamping system, the setup was reduced to three minutes. The time savings adds up when machining 140 parts a week, he noted, adding that the shop expects the project to continue for at least a decade. “That’s saving us $1,000 a week conservatively, so this ROI is going to be half a year.”

The payback for operators was immediate. Manteufel said they let him know that the new process eliminated back soreness and the risk of slipping caused by reaching up and over a large part to access the back pins. “To me, the safety and ergonomics of the employees were just as important as the setup savings.”

Because of the enhanced rigidity of the zero point setup, Manteufel estimates that the shop has seen a 5% increase in tool life and fewer fiascos. “We’re having a fraction of the tool failures.”

Although Lyndex-Nikken describes the zero-point clamping system as a predecessor to automation, Manteufel said the complexity of the cast part requires a lot of operator intervention when loading to get the part lined up properly on the fixture. “The castings experience a whole lot of inconsistencies and warp. It takes automation out of the picture for us.”