Keep machining circle unbroken

Demand for titanium, stainless steel and other difficult-to-cut workpiece materials is on the rise for components in vital growth industries, such as aerospace, medical and automotive. To compete, parts manufacturers typically must machine these parts at spindle speeds in excess of 20,000 rpm. Vibration and chatter can occur at these rates of speed, leading to poor surface finishes that require secondary bench operations to meet finish specifications and avoid critical damage to expensive workpieces.

Additional factors, such as an unbalanced toolholder or a toolholder improperly seated within the spindle, can dramatically reduce material-removal rates and increase cycle times. Even minor flaws in toolholder fit or concentricity can reduce part quality and cutting tool and spindle life.

A High Torque retention knob from JM Performance Products. Image courtesy of JM Performance Products

Stability is essential to achieve optimal results when milling challenging materials. The entire machining process must be considered. Any one element could impede the overall effectiveness of the process. The cutting tool, holder, spindle, machine tool, fixturing and workpiece are all part of the interconnected “machining circle.”

After investing in a Matsuura H.Plus-405 horizontal machining center, Delta Machine Co. LLC, Gardena, California, realized that one critical factor to not breaking this circle is to have a properly balanced toolholder in the spindle, said President Janos Garaczi. When he purchased the HMC, Garaczi followed the machine builder’s recommendation and purchased High Torque retention knobs from JM Performance Products Inc., Fairport Harbor, Ohio. The knobs, which enhance the seating of a holder in the spindle, are longer and reach deeper into the cross section of the holder’s threaded bore than standard retention knobs, JMPP reports. As a result, all thread engagement occurs in a region of the toolholder where the cross section is thicker to resist deformation.

Since 1980, Delta has specialized in high-volume production of complex parts. While working as a Delta shop foreman, Garaczi purchased the machine shop from his retiring boss in 2016. “The first thing I did was look for better customers and try to see what kind of equipment we could invest in because we only had old equipment,” Garaczi said, noting that his customers include Boeing, Tesla and Chevrolet.

About 80 percent of what Delta machines is titanium, mostly Ti6Al4V, Garaczi said. The rest is stainless steel (15 percent) and aluminum. He wanted to rough-machine as fast as possible, especially when cutting titanium, which consumed about 90 percent of production time.

After purchasing the HMC, “work just started flowing in,” Garaczi said, and he began buying more machines: a Matsuura H.Plus-500 HMC, three 5-axis Matsuura MX-520 vertical machining centers and a Toyoda FH550SX HMC. “I just ordered a Makino A7 HMC,” he added. “We are extremely busy.”

High Torque retention knobs help Delta Machine impart fine surface finishes and eliminate secondary benching operations. Image courtesy of Delta Machine