March 14, 2002
Looking for maintenance guidelines for coil feed lines? Find them here, in checklist terms, for coil cars, reels, straighteners, threading tables, and feeds.
Today's metal stamping facilities are faced with a variety of demands, including increasing production, improving quality, and reducing operating costs. How does a manufacturer attain all of these goals in both good and bad economic times?
Some of the simplest and least expensive ways to meet these demands are to carry out inspections, implement a preventive maintenance program, and perform troubleshooting. This article provides a checklist for maintaining coil feed lines.
Of course, specific maintenance guidelines vary, depending on the equipment's age and manufacturer. For the general purposes of this article, a coil line comprises a coil car, reel, straightener, threading table, and feed. The following checklists can be customized for the equipment's specific features.
A general inspection can help identify potential problems before they become major predicaments.
A preventive maintenance program can help reduce maintenance costs and downtime. An effective program will prevent major equipment problems and will allow stampers to maximize output, minimize cost, and ensure the quality of the parts being manufactured.
A general knowledge of troubleshooting also reduces downtime. Note that some control panels can describe the type of faults as well as its specific location.
Problem: Material is unwinding off-center.
Solution: Reposition the coil on the center of the mandrel and straightener.
Problem: Expansion does not pick up the coil.
Solution: Rotate the coil shoe to the 12 o'clock position.
Problem: Expansion does not stay constant in manual mode.
Solution: Replace the check valve.
Problem: The coil shoes have lateral movement.
Solution: Check the center guide bolt located in the center of the coil shoe. If the bolt is loose, remove it, add some threadlocking material, and refasten it.
Problem: The mandrel is coasting.
Solution: Increase air pressure if using an air braking system. Turn up the adjustment if using an electrical braking system.
Problem: The restrictor arm does not stay up.
Solution: Replace the check valve on the cylinder because it is leaking either internally or externally.
Problem: The double-end reel does not rotate.
Solution: Make sure the restrictor arm is in the up position.
Solution: Make sure that the shot pin is retracted.
Solution: Verify that the peeler blade is retracted.
Solution: Verify that the peeler table is down.
Problem: The material will not track on-center.
Solution: Position the straightener on the center of the coil and reel.
Solution: Verify that the stock guides are on the center of the straightener and reposition them if required.
Solution: Verify that the pinch rolls are parallel and realign them if required.
Solution: Verify that the upper straightening rolls are parallel.
Problem: The motors on the motorized head adjust trip out.
Solution: Tighten torque limiters to keep them from slipping.
Solution: Make sure the straightener head is not penetrating the material too far.
Problem: The material has scratches or marks on the surface.
Solution: Clean buildup from the pinch rolls or straightener rolls with solvent or an emery cloth.
Problem: The rolls are walking to one side.
Solution: Make sure the drive chain is not too tight.
Solution: Verify that the pinch rolls are parallel and adjust if necessary.
Solution: Check the stock guides and the coil's position on the reel to make sure it is on the center of the rolls.
Problem: The drive chain keeps breaking.
Solution: Make sure the sprockets have not moved, and retighten the set screws if necessary.
Solution: Make sure that the roll penetration is commensurate with the material.
Problem: The material does not stop running.
Solution: Recalibrate the device and evaluate the environment for excessive noise and sudden temperature changes caused by open doors and so forth. If the problem cannot be resolved, contact the manufacturer.
Problem: Material from the straightener does not keep up with the feed.
Solution: Adjust the speed from the sonar control.
Problem: The material does not stop running.
Solution: Check the photo-eyes for cleanliness before the start of each shift.
Solution: Reset the eyes if an object strikes them.
Problem: The material from the straightener does not keep up with the feed.
Solution: Check the voltage output relative to the straightener drive and adjust as needed.
Problem: Feed lengths are inconsistent (rack and pinion).
Solution: Replace the brake lining or readjust the pads.
Problem: The amount of backlash between the rack-and-pinion gears is too great.
Solution: Reshim the rack in the rack housing to tighten the backlash.
Problem: Keys are loose.
Solution: Check all keys in rolls and couplings for loose keys and replace as needed.
Problem: Backlash is occurring in the roll gear.
Solution: Replace the roll gears if the teeth are worn.
Problem: Backlash is occurring in the clutch (rack and pinion).
Solution: Flush and refill the clutch, or rebuild or replace if necessary.
Problem: Roll lift timing is incorrect.
Solution: Retime the lifters and check the cam switch.
Problem: Backlash is occurring in the crankpin and adjusting screw.
Solution: Replace the crankpin and adjusting screw.
Problem: Short-feed-length material is slipping on the rolls.
Solution: Check the roll surface for wear. If the chrome blast finish has worn off, resurface the rolls.
Solution: Increase the upper roll pressure by tightening the springs or increasing air pressure.
Solution: If all mechanical possibilities check out appropriately, consult the manual supplied with the drive. On an electronic feed, a short feed length should appear as a fault in the drive diagnostics.
Problem: The material is tracking off-center of the die.
Solution: Verify that the stock guides are not off-center; if they are, recenter them.
Problem: The upper roll is not parallel with the lower roll.
Solution: Make the roll parallel, and make sure the upper roll moves freely up and down.
Solution: Make sure the roll pressure is equal on both ends of the rolls, whether it is air or spring hold-down. If the pressures are not equal, adjust them accordingly.
Problem: The coil is not on the press centerline.
Solution: Verify that the coil is located properly on the reel. If the coil is not on the centerline, adjust it.
Solution: Verify that the reel and straightener are located on the centerline of the press, and relocate them if necessary.
Problem: Too much camber (curvature from edge to edge) or oil canning (center of strip longer than the edges) in the material is causing improper tracking.
Solution: Change the coil.
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