Experts at Leitz Tooling help troubleshoot tool holding failure on new CNCs running faster than previous equipment.

Question: Our cabinets  business is growing and we were able to replace our old router.  Our new machine can run more than 25 percent faster. At higher RPMs we’re having a problem with tool holding and it’s having a negative impact on our accuracy.  We’re utilizing a cabinet assembly system with no room for error. Help!

Critical Link: As CNC spindle RPMs and processing speeds increase, operators must consider the importance of the link between the machine spindle and the cutting tool.  Tool holding is the first point in which deflection and run-out tolerances are introduced and can be tightly controlled.  
Reconsider Collets: Collet chuck systems are simple and inexpensive, but they are also the most common source of performance problems.  Collets provide a flexible connection between the very rigid machine spindle and the cutting tool, but this connection can be easily damaged by improper handling, use or maintenance.  
Performance Problems: Common issues from poor tool holding are diminished cut quality, excessive noise, limited tool life and less than optimal feed speeds.  Slowing the feed speed also overheats the cutting tool and dramatically reduces the tool service life.


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Important Balance:  Maintaining proper RPMs, feed-speed, and ideal chip load are critical.  Chip load, the amount of material cut with every revolution of the cutting edge, dissipates heat and protects the tool from premature thermal dulling.
Addressing Accuracy: To maintain the balance between material removal, speed and accuracy, the tool must run concentrically, with as little deflection as possible.  “Collet-free” tool holding systems offer the most effective means of controlling tool rigidity and center line.
Other Options: Hydro chucks have been considered the best premium tool holding system, but they are expensive, and the flexible grease wall integral to this technology still allows deflection under cutting pressure.  The performance results are only slightly better than collet chucks.  Newer mechanical and deformation-style chucks are also interesting, but each has drawbacks with regard to system maintenance and cost.
Optimal Balance Of Accuracy & Cost: Leitz ThermoGrip heat-shrink chucks offer the simplest and most rigid link between the machine spindle and cutting tool.  ThermoGrip chucks are inexpensive, one-piece tool holders, without moving or mechanical parts to wear or maintain.  Electromagnetic induction heat quickly expands the chuck.  Tools can be easily changed, and the chuck then shrinks tightly and concentrically around the shank, essentially creating a single-piece machining unit.  This eliminates the possibility of tool run-out, deflection, and balance issues.  By optimizing tool concentricity, you’ll get precise cutting at the fastest possible speeds, greatly extending both tool and spindle life.
Bottom Line: The annualized savings utilizing Leitz ThermoGrip can be astounding.  You can reduce tooling costs up to 25%, and increase machine and operator productivity by up to 20%.  ThermoGrip users have noted annualized savings of at least $15,000 per shift, with expanded production capacity.  
Payback: The ThermoGrip system generally pays for itself within months, and the maintenance-free chucks provide virtually unlimited service life.
Leitz ThermoGrip chucks are easily integrated alongside your existing system.  They will quickly demonstrate clear advantages when comparing the performance of identical tools currently held in collet or hydro chucks.
Optimized process efficiency is a moving target, changing with every machine, tool or raw material. Leitz is committed to ongoing R&D, focusing on continuous acceleration and optimization of machining processes, helping shape the future of the customer applications and industries we serve. 

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