GLS-500 Two-in-One Uncoiler Straightener Strip Deviation Fault in Automotive Hardware Stamping Workshop

Root Cause Analysis & Permanent Improvement for GLS-500 Two-in-One Uncoiler Straightener Strip Deviation Fault in Automotive Hardware Stamping Workshop

1. Fault Overview

The customer’s GLS-500 2-in-1 uncoiler straightener feeds galvanized steel strip to a 160T mechanical punch for automotive bracket stamping. Continuous production suffered periodic strip side wandering. Material offset was unstable, leading to edge burr, blank out-of-tolerance and occasional die collision risk. The customer previously tried adjusting side guide pressure without obvious improvement and requested on-site after-sales support.

2. Fault Inspection & Root Cause Analysis

1. Visual inspection: Side guide roller bearings had slight jamming due to insufficient grease;
2. Measurement: Straightening upper and lower rollers had 0.42 mm parallelism deviation;
3. Parameter check: Uncoiling tension was set too high, which aggravated strip camber;
4. Environment: Coil loading was not centered on the uncoiler reel, introducing initial offset. Root cause: Combined mechanical assembly error, improper tension parameter and aging wearing parts.

Case Study Parameter Table

3. Rectification Actions

1. Replace 4 sets of side guide roller bearings and refill high-temperature lubricant;
2. Use dial indicator to calibrate straightening roller parallelism to 0.08 mm;
3. Reset uncoiler tension and add coil centering operation standard;
4. Train customer operators on pre-production coil centering check and daily roller inspection.

4. Long-term Preventive Suggestions

Form periodic maintenance checklist. Carry out roller parallelism measurement every 300 working hours. Replace guide bearings on schedule. Operators must confirm coil centering before starting each new coil.

Case Study Q&A

Q1: Why did adjusting side guide pressure fail to solve the wandering issue? A1: Side guides can only limit offset, but cannot fix the root problems of roller parallelism and strip camber. Q2: What risk will excessive uncoiling tension bring to thin galvanized steel? A2: Excessive tension stretches the strip unevenly, creates camber and easily scratches the zinc coating. Q3: How to judge whether the straightening roller parallelism drifts? A3: Use dial gauges to detect gap difference at both ends of rollers; compare measured value with equipment specification. Q4: If strip camber still exists after roller calibration, what other factors should be checked? A4: Check raw coil quality, material thickness uniformity and whether the straightening roller gap is correctly set. Q5: Is this GLS-500 model suitable for stainless steel strip feeding? A5: Yes, but tension and roller gap parameters need to be re-adjusted according to stainless steel material properties. Q6: What spare parts should be kept in stock for this 2-in-1 uncoiler straightener? A6: Guide roller bearings, polyurethane roller sleeves, tension sensor and lubrication grease are recommended spare parts.