Automotive industry manufacturers have basic requirements from their suppliers — they want on-time delivery, accuracy, and sufficient available stock. They want perfect parts, but they want them to be immediately available at a price they can control.
Tooling is a vital and often overlooked process in the production of automobiles, as every single part of a new car requires a unique tool. What if an invisible problem inherent to CNC manufacturing existed, robbing manufacturers of the ability to produce parts accurately, and interfering with the production rates and cost containment? The automotive manufacturing community is working to answer these challenging tooling cost containment questions and find progressive solutions therein.
A few years ago, Boeing contacted one of its tooling manufacturers, Briney Tooling Systems, a leading supplier of CNC tool holders and shrink-fit tooling systems in North America, reporting they had performed testing that revealed a flaw in the V-flange tooling they were using. Requesting a solution, Briney reached out to JM Performance Products, Inc. to get its assistance in resolving the problem Boeing described. JMPP investigated and ultimately designed a gage that mirrors the interior grind of a CNC spindle. This gage measures movement or growth of the toolholder taper down to 7.5 millionths of an inch in diameter.
JMPP identified the essential flaw, the invisible problem plaguing CNC manufacturers, as toolholder expansion. Using its gage to perform extensive testing, JMPP proved that toolholder expansion is caused by the installation of a standard retention knob into a V-Flange holder.
Briney had reported expansion of its holders with as little as 13 ft./lbs. of torque during retention knob installation. This expansion creates a bulge in the holder at the small end, causing the holder to make contact with the small end instead of the large end, effectively reversing the way the toolholder is designed to fit the spindle, allowing the holder to move randomly within the spindle. Using the taper shank test fixture, JMPP redesigned the knobs, finally reaching a design that eliminated or substantially eliminated toolholder expansion. Boeing’s major complaint was associated with the vibration and chatter that was causing tolerance and finish issues on extremely expensive parts. The introduction of the high-torque knobs effectively eliminated the chatter issues.
Increasingly, the automotive industry is using more carbide tools primarily because they can cut both aluminum and hard materials such as titanium, carbon, and exotic alloys at high speeds. Carbide tooling is expensive and also fragile.
Recently, Sandvik, Inc., a high-tech and global engineering group with about 42,000 employees, loaned one of its engineering representatives to test the best retention knobs for Caterpillar® with a $1,200 solid carbide tool. The specification included: a toolholder, retention knob, tightening spec, and proper placement. The test’s goal was to get the custom carbide tool to run without shattering.
When tested with JMPP’s high-torque knobs tightened to the provided torque specifications, it worked every time with no tool shatter. A carbide tip cannot vibrate when it makes contact, or it shatters. Essentially, carbide must smoothly enter into the pocket and maintain its position in the pocket or it breaks. JMPP’s high-torque knobs have been proven to extend carbide tooling life.
Ultimately, by making a simple change — moving to the high torque retention knobs — CNC manufacturers can eliminate the vast majority of issues, improve milling operations, and get the best results while saving money. This high-torque solution is so successful that JMPP guarantees the results its customers have been realizing on any V-flange toolholder that is made to the AT3 or better taper tolerances. They offer to provide high-torque retention knobs at no charge for testing purposes to any manufacturer willing to provide tracked tool life prior to and post-installation of the knobs. JMPP maintains that its high-torque retention knobs are the only tool that can deliver increased productivity and performance on virtually every V-flange tool used in CNC manufacturing.
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