Page 37 - MetalForming August 2012

center of gravity. This will help prevent damage to the mandrel and the die.
In the past, mandrels were aligned using makeshift centerlines and bubble levels. This method often caused errors in the final feed, resulting in mainte- nance failures. Current leveling meth- ods include laser alignment of the equipment, whereby the centerlines of the mandrel are held within thou- sandths of an inch in relation to the centerline of the press or shear. The use of laser-alignment instrumenta- tion is the key to ensuring that the mandrel is properly set up prior to its running. Concerns with product qual- ity, tooling wear, maintenance and safe- ty all are minimized or eliminated when proper alignment is established.
During installation, it is critical that metalformers properly guard the man- drel and other coil-related equipment. OEM guards and any other auxiliary guarding should be fastened securely in place. Also be sure to eliminate pinch points and points of employee con- tact. Enforce OSHA standards to avoid injuries. In some installations, the addi- tion of safety light curtains and photo- electric sensors find use for guarding a mandrel and coil-related equipment, in addition to standard hard-guarding options.
Mandrel Upkeep and Maintenance
Mandrels are constantly subjected to coil-related damage. Their constant use in metalforming operations places tremendous loads on the mandrel, causing wear and damage to mandrel components. The combination of improper operation and normal wear and tear on a mandrel can create main- tenance headaches. Preventive main- tenance and inspection should take place in several areas:
• Coiler frame—Frames require careful inspection. They should be fab- ricated rather than held together with fasteners, because under normal load conditions mandrels endure so much vibration that fasteners can fail, caus- ing the frame to become unstable. Any frame that does include fasteners
should be checked regularly to ensure all fasteners are properly torqued. Additionally, metalformers should inspect frames every six months for squareness, alignment and bearing bore dimensions. All welds and other structures should be nondestructively inspected at least every two years using dye-penetrant testing to look for cracks caused by overuse or misalignment. Check all wear points and make
required repairs immediately.
• Gearbox (if applicable)—Gear- boxes are a constant source of wear. Check gear tooth profiles and back- lash with a feeler gauge to monitor tooth wear. Excessive backlash will result in damage and destruction of the gearing. Every two years, employ a qualified bearing engineer to remove and inspect all bearings. Also check bores for dimensions and alignment,
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