When the drag rack of the circular saw cutter is deformed, it needs to be replaced to ensure the normal operation of the machine and the correct delivery of paper. Here are the general steps to replace a paper carrier:
1. Drag Rack Pre-Replacement Preparation
| Activity | Technical Specification | Verification Method |
|---|---|---|
| Energy isolation | Lockout-Tagout (LOTO) procedure initiated | Multimeter voltage confirmation |
| Tool preparation | ISO 6789-certified torque wrench (3-25Nm) | Calibration certificate check |
| New rack inspection | Flatness ≤0.1mm/m (EN ISO 3650) | Surface plate with dial indicator |
2. Deformed Drag Rack Removal
Critical Sequence:
- Remove wear strips (retain M6×20mm SHCS)
- Detach linear guide blocks (preserve preload shims)
- Extract rack mounting bolts (M10×1.5, 8.8 grade)
Key Check:
- Document original backlash setting (0.05-0.15mm typical)
3. Precision Installation of Drag Rack
Alignment Parameters:
| Axis | Tolerance | Measurement Tool |
|---|---|---|
| Parallelism | ≤0.08mm/1000mm | Laser alignment system |
| Height | ±0.1mm from reference plane | Digital height gauge |
| Tooth engagement | 20-30% rack depth | Gear mesh pattern inspection |
Mounting Requirements:
- Bolt torque sequence: Center-out pattern
- Final torque values: 22±1.5Nm (M10) / 8±0.6Nm (M6)
4. Post-Installation Verification
Functional Test Matrix:
| Test | Acceptance Criteria | Measurement |
|---|---|---|
| Paper feed smoothness | No visible sheet oscillation | High-speed camera analysis |
| Speed consistency | ≤2% RPM variation @60m/min | Tachometer verification |
| Edge tracking accuracy | ±0.3mm lateral deviation | Laser displacement sensor |
5. Maintenance Integration of Drag Rack
Preventive Schedule:
- Daily: Visual rack tooth wear checks (SUJ2 hardness ≥HRC58)
- Weekly: Linear guide lubrication (VG32 grease, 0.5cm³/100mm)
- Monthly: Backlash measurement via ball-bar testing
Safety Recertification:
- Emergency stop response: <0.25s activation
- Guarding system integrity: IP54 sealing validation
This protocol maintains original equipment specifications while ensuring <0.05mm positioning repeatability. Always cross-reference manufacturer’s GD&T drawings for model-specific requirements. Post-replacement operational validation should include a 72-hour production trial with 10% overload testing.