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Solutions for Flash and Peeling Defects on Rolling Mill Lines
During the rolling process, flash or peeling on wire can arise from a variety of causes. In addition to factors related to raw materials and production processes (e.g., melting temperature of tin ingots, extrusion temperature and speed of wire), abnormalities in the mechanical system are also important contributors. Below are specific troubleshooting and correction solutions for mechanical issues:
Inspection and Temporary Fix for Flash Caused by Twisted Wire
First, inspect the entry of the roll where flash occurs to check for wire twisting—this refers to a deflection of the major axis of the elliptical wire, causing it to enter the roll in direction ② instead of the intended direction ①. This misalignment leads to uneven stress during rolling, which is a primary cause of flash.
Temporary solution: Use needle-nose pliers to straighten the twisted wire from state ② to state ③, restoring the correct orientation of the elliptical axis. After correction, observe whether the flash defect is eliminated.
If flash defects persist after implementing the above measures, the rolls require adjustment. Misalignment or uneven gaps between the rolls, as illustrated in the diagram below, can also cause flash on the wire.
As shown in the first diagram, the grooves of the two rolls are not aligned on the same centerline, resulting in a distinct misalignment. This deviation in coaxiality causes uneven stress on the wire during rolling, which will inevitably lead to flash defects.
Solution: Follow the adjustment steps as indicated in the diagram below.
Part Number Identification: 1. Screw 2. Thrust Bearing 3. Bearing Housing 4. Thrust Bearing 5. Roll
1. Automatic Roll Alignment Adjustment
To level and align the two rolls in the same group, first loosen 1. Screws, then start the machine for a test run. Allow the rolls to self-align during rolling, and observe if the flash on the wire is reduced. If the rolled wire meets the required quality, retighten the loosened screws moderately to prevent them from falling out.
2. Disassembly Adjustment and Position Swapping
If the above method does not yield results, proceed with disassembly and adjustment:
Remove the parts in the order shown: 1. Screws → 2. Thrust Bearings → 3. Bearing Housings → 4. Thrust Bearings → 5. Rolls.
Use a flat-head crowbar to press down in the F direction as indicated in the diagram, allowing the roll to be easily removed from the shaft.
Adjustments can be made in two ways:
- Swap the left and right positions of the rolls before reinstalling
- Swap the shims under the rolls to change their horizontal positions
3. Roll Groove Grinding
If all previous methods fail to resolve severe flash or arching, the problematic rolls require grinding. Grinding can be performed either on-machine or offline, focusing on the sharp corners of the roll's curved groove. The recommended grinding depth per pass is 0.05~0.1 mm (adjust based on actual conditions).
Reinstall and test after grinding. If results are not optimal, perform minor regrinding. However, if flash persists after multiple grinding attempts, stop grinding and investigate other root causes to avoid compromising the precision of the roll grooves due to excessive material removal.
