Page 34 - MetalForming June 2019

FABRICATION
Consider Adding CNC Punching Machines
No need to turn down profitable lower-volume runs, as flexibility
and tool capabilities make this technology a press-shop complement.
BY LOUIS A. KREN, SENIOR EDITOR
Traditional metal stampers would do well to incorporate CNC punching into their production regimens, thus providing the ability to gain new short- and medium-run work without the expense of hard tooling.
Providing reasons for making the jump is Jeff Tyl, North American sales manager-fabrication for Murata Machin- ery USA (www.muratec-usa.com). He’s met with and surveyed more than 200 metal stampers to help determine how CNC punching can be leveraged in a traditional metal stamping environment.
The majority of metal stampers sur- veyed do not employ punching- machine technology,” according to Tyl, “with lack of process familiarity and capabilities a possible reason why.
“Stampers should understand that stamping presses and punching machines operate in the same man- ner—down and up motion,” Tyl offers. “The major difference: Instead of employing a single tool for a single hit as is the case with the components in a stamping die, punching-machines provide multiple tools for multiple hits for multiple parts. And, just like presses,
punching-machine drives have evolved to employ hydraulic, mechanical and servo technology. In addition, these machines process similar materials with similar thicknesses. We need to remove the mindset that presses and punching machines are completely dif- ferent pieces of equipment.
“Punching machines perform a vari- ety of operations, many similar to those employed in stamping presses,” he continues. “They can produce contours and rounds, and much more, with applications for all types of industries, including agricultural, medical and many others. And, the material need not only be metal. If it comes in a sheet —anything flat and not brittle—it’s a candidate for a punching machine.”
Take Back the Short and Medium Runs
In his detailed discussions with stampers, Tyl found that many see long-run tooling as a sweet spot, and stamping presses truly do excel in such applications.
“But stampers can miss the boat with short-run and middle-volume
jobs, often opting to outsource this work,” he says. “One stamper told me that he outsources $300,000 in short- run work each year.”
The tooling capability of punching machines comes into play in these applications, and where the investment in CNC punching can produce a rapid ROI.
“For example,” Tyl says, “our stan- dard 20-ton turret punch press houses 44 tools. Depending on the size of a tool, users can punch round holes in diameters from 0.5 to 4.45 in. without changing a tool in the turret. And, should a new tool be needed to pro- duce a particular feature to accommo- date a part-design change, tool change- out is a simple process. On the other hand, revising a hard tool brings a high cost. Many times, a tool component or feature in a progressive die is ‘one and done,’ meaning that it produces a feature for one particular part. A part revision means altering the die or building a new die, with significant costs in time and money.”
In the turret punch press, a com- plete toolset may run $1000 to $1200,
32 MetalForming/June 2019
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