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Hydraulic Clamp Force Gauge Fixture Optimizes Drawbar Force

"Keeping heavy investment machines running while increasing tool life to optimize production rates is the ultimate goal of today's CNC machining center operations," said a JM Performance Products, Inc. (JMPP) spokesperson. "Just because a CNC machine is clamping does not mean it is functioning properly. Often, operators will realize that they cannot run the same job on different machines, or that tool life is better on one machine than another. Whether it is a new or old machine, the answer can often be found in the diminished clamping force of the drawbar."

Drawbar force is the measure of force being applied to a toolholder to keep it in full contact with the spindle. If the clamping force is diminished, it can cause serious issues such as decreased tool life, chatter, vibration and poor finishes. In extreme cases, the tool can pull out of the spindle during the cut, causing damage to the workpiece, tools and spindle.

Ultimately, fixing the spindle can result in costly downtime ranging anywhere from two to three days or two to four weeks.

Clamp Force Gage Solution

JMPP, a manufacturing innovator of CNC mill spindle optimization products since 2009, has engineered its patented hydraulic Clamp Force Gage to provide a quick and inexpensive method to regularly check and measure the clamping/pulling force of the spindle drawbar. The hydraulic gage instantly reads in ft/lbs the amount of pull force being applied to the toolholder. Once drawbar force drops below 80% of the original manufacturer's setting, it is time to schedule maintenance.

"The innovative engineering design of two main parts makes it the first universal gauge on the market, allowing it to be used anywhere in the shop to check all types of V-flange spindles," said the spokesperson.

Clamp Force Gage hydraulic heads are available in 3,000, 5,000, 10,000 and 15,000 lb. configurations. It is a suitable solution for the smaller shop that is looking for a quick and inexpensive method to check drawbar force. The hydraulic gauge head comes with a toolbox and protective packaging for easy storage. One gauge head will work in multiple size spindles with easy-change taper adapters available.

Design benefits of JMPP's Clamp Force Gage include:

  • Prevents expensive machine downtime by scheduling machine maintenance and avoiding machine crashes
  • Increases tool life and eliminates scrapped parts due to poor tolerance
  • Operator safety-a loose toolholder is dangerous
  • Adapters are available in many sizes and fit the universal gauge heads.

The drawbar works by using Belleville washer stacks or gas systems to generate the drawbar force. As the Belleville washers begin to collapse and gas systems begin to leak, the drawbar loses force. Because the drawbar is located out of sight and not easily accessed, it is often left unmonitored. If the Belleville washer stack is not rebuilt or the gas system recharged, the toolholder will fall out during cutting, potentially causing catastrophic damage. "Typically, operators can only tell when fatigue starts to set in, making the JMPP's Clamp Force Gage an optimal solution for frequent monitoring which is key for preventative maintenance, said the spokesperson."

According to JMPP President, John Stoneback, "If left alone, this out-of-sight/out-of-mind philosophy may result in the machine reaching zero draw force and you can lose the toolholder, workpiece and potentially damage the machine. Therefore, it is essential to implement a frequent monitoring system that operators should conduct at least once per week."

For more information contact:

JM Performance Products, Inc.

1234 High Street

Fairport Harbor, OH 44077

440-357-1234 / 800-322-7750

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