High-torque stability key for exotic materials at the spindle

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JM Performance Products’ patented high torque retention knobs solve production issues vital for productivity using demanding aerospace, medical, and automotive super alloys. Representatives from JM Performance Products will be at IMTS 2018 at Booth 432188, West Building.

Titanium, stainless steel, aluminum, and other superalloys/exotic materials are on the rise for component manufacturing in industries such as aerospace, medical, and automotive. This creates a unique set of production machining challenges when considering that high speeds typically in excess of 20,000 rpms are often required. At these rates of speed, vibration and chatter can occur — leading to poor surface finishes that require secondary bench operations or result in critical damage to expensive workpieces.

Additional factors such as the lack of balance/concentricity of the toolholder, as well as improper seating within the spindle can slow down machining cycle times — dramatically reducing material removal rates and the time it takes to complete each part from start to finish.

For these industries, in which cycle times are directly related to operational costs and the ability to provide competitive bids, adopting advanced technologies to decrease machining time is paramount to gaining a competitive edge.

Stability is the essential factor for adopting methods for improving milling performance on demanding materials such as titanium, as the entire machining process has to be considered. Any one element could impede the overall process’ effectiveness as the tool, toolholder, spindle, column, ways, table, fixturing, and workpiece are all part of the interconnected ‘machining circle’ that require stability to achieve optimal results.

One stabilizing factor in achieving this ‘perfect circle’ is a properly balanced toolholder in the spindle. At the rates of speed required for exotic metals, even minor flaws in toolholder fit or concentricity can lead to less precise machining, reduced tool/spindle life, and even damaged workpieces.

Recently, Delta Machine Company, LLC, a company that specializes in titanium machining for the aerospace and the medical industries, addressed these issues by implementing JM Performance Products, Inc.’s patented High Torque retention knobs — one of the quickest, simplest, and most cost-effective stabilizing investments a job shop can make.

Since 1980, Delta has specialized in high-volume production precision machining of complex, tight tolerance parts out of titanium, stainless steel, and other exotic materials. President Janos Garaczi had investments in new high speed/high-torque CNC machining centers which featured four horizontal, three 5-axis, and two vertical machines. Significantly higher drawbar pressure exerted on the retention knobs makes eliminating any issues with the interface between the toolholder and spindle of critical importance.

With a focus on high-speed machining of new exotic materials (80 percent titanium, 15 percent stainless steel, 5 percent aluminum), Garaczi wanted to get through roughing as fast as possible, especially of titanium, which took approximately 90 percent of production time. Maximization of machining efficiencies enabling 24/7 production was critically important for key customer projects including Boeing 737 MAX, Tesla, and Chevrolet.

Standard, off-the-shelf retention knobs could be used on Delta’s new machines, but Garaczi wanted to avoid scenarios where the machine’s high torque could shear off or break the retention knob and destroy the spindle.

“For the aggressive types of machining we do, if you have a really strong retention knob, it’s going to further increase the rigidity of your set-up,” Garaczi said.

Garaczi checked out a recommendation from one of his machine suppliers that he convert to a specific High Torque retention knob from leading manufacturing innovator of CNC mill spindle optimization products JM Performance Products.

“The combination of the unique High Torque retention knobs, along with dual-contact spindles and a combination of high speed and conventional tool path approach, has decreased cycle times as much as 40 to 50 percent. This also allows us to often outbid the competition for projects involving titanium,” Garaczi said.

More than most industries, aerospace, medical, and automotive component manufacturing that machines a lot of exotic alloys and hard metals can take a toll on the carbide cutting tools used. The result is that the tools must be changed out more frequently as they dull or break.

By using the High Torque retention knob, Delta was able to resolve one of the most fundamental problems in machining: improper seating of the toolholder in the spindle. Since tight tolerances are essential in high-speed machining, if the toolholder doesn’t fit the spindle precisely, decreased productivity and reduced tool life are inevitable.

An essential element of JMPP’s design is a knob that is longer and reaches deeper into the cross section of the holder’s threaded bore. As a result, all thread engagement occurs in a region of the toolholder where the cross-section is thicker to resist deformation. A precision pilot also increases rigidity. By increasing the rigidity of the toolholder at higher rpms, the knob can increase tool life.

Implementing High Torque knobs in the new high-rpm/high-torque equipment Delta installed resolved a key design flaw inherent in CNC v-flange tooling — eliminating the toolholder expansion responsible for costly CNC milling and boring issues. By increasing contact of the holder and the spindle at the gage line, a wide range of CNC milling issues are overcome including vibration and chatter, poor tolerances, non-repeatability, poor finishes, shortened tool life, excessive spindle wear and tear, run-out, and shallow depths of cuts.

By implementing more than 800 of the High Torque retention knobs, every tool on Delta’s machines works better and faster to make their demanding exotic materials projects more competitive and increase profit margins dramatically.

“At the end of the day, we are able to run titanium and stainless steel much faster than most machine shops that run about 50” per minute, with tool life typically reaching 1.5-2 hours before replacement,” Garaczi said. “With the High Torque retention knob, we are running 150” IPM in titanium and our tools last about five hours before we have to change them, which is pretty incredible.”

“Typical CNC milling centers are running machines 20-40 percent slower than they should be,” said JMPP President John Stoneback. “Bridging this gap of missed productivity can conservatively help job shop operations achieve a 10-20 percent competitive advantage per hour via faster set-ups, better feed rates, and more rigid tools, reducing tooling cost by 20-50 percent or more. In essence, every tool on the machine works better and faster to make job shops more competitive and increase profit margins dramatically.”

More info  www.jmperformanceproducts.com