Page 38 - MetalForming August 2012

Coilers, Payoffs
and contract with a qualified machine and fabrication shop for damage repair. • Mandrel leafs or segments (over- leafs)—To ensure proper coil gripping, segments should be straight, free of dam- age and, when a dial indicator is placed on any part of the OD, should not exhib- it excessive runout. Out-of-flat segments that exceed 0.015 in. of bend from end to end should be repaired or replaced. Also check segments with an indicator to
look for loose fit. If clearance exceeds 0.020 in., immediately repair or replace the segment. Take a total indicator read- ing (TIR) with the segments in place and a dial indicator placed on a seg- ment and the mandrel turned 360 deg. A TIR in excess of 0.010 in. indicates that damage has occurred and repairs should be made.
• Mandrel shaft and bearings— These components are the heart of the
coil-feed operation. Shafting should have the same TIR as the mandrel seg- ments. Use dye-penetrant inspection to uncover cracks and trigger repair or replace procedures. Inspect the bear- ings on the mandrel shaft at least every two years. Hire a qualified bearing inspector to determine if bearing life has been exceeded.
• Mandrel brake—The brake system is critical to any coiler mandrel, and should not require constant repair or relining. Inspect brake linings weekly, and replace the lining when it falls below the minimum OEM-specified thickness. Should the braking system fail to perform or require constant relining, consider use of a hydraulic brake system. If your system requires attention more than every six months, it’s time for an upgrade.
• Lubrication system—A well-func- tioning lubrication system ensures that bearings, slide surfaces, shafting and other moving components will last a lifetime. Each point of lubrication must be checked for proper operation. Dis- connect the lubrication line and engage the pump. Then check for the required amount of lubricant, and its cleanliness. Any point in the system that lacks clean and adequate lubricant should trigger maintenance procedures. Note: Metal- formers employing manually operated lubrication systems should consider upgrading to an automated pneumati- cally or electrically run system.
• Actuation devices—Inspect these devices, which actuate mandrel-seg- ment expansion and contraction, every six months. These devices include but are not limited to cylinders, wedges, slides and pull rods. Check each com- ponent for cracks, wear, distortion and other signs of deterioration. A thor- ough inspection will reveal troubles long before a breakdown occurs.
• Motors and other electrical appa- ratus—Although some coil systems do not have electric motors, most do and these systems should be checked week- ly to ensure proper functioning. Every five years, metalformers should remove and inspect motors, and clean, bake and dip as needed. MF
36 MetalForming/August 2012
www.metalformingmagazine.com