I. Pre-Installation Preparation
1. Shutdown and Power Disconnection
Gradually reduce the machine speed to zero, turn off the slurry pump, and switch to manual mode.
Disconnect the power supply, air supply, and slurry pipeline valves. Hang a "Under Maintenance" warning sign on the control panel and ensure the equipment is locked.
2. Tool and Protective Equipment Preparation
Prepare specialized wrenches, rulers, angle gauges, etc.
Operators must wear cut-resistant gloves, goggles, and protective clothing. Long hair must be tied back to prevent it from being caught in the equipment.
3. Inspection of New Scraper Blade and Blade Holder
Confirm that the new scraper blade material meets the requirements (usually chromium-molybdenum-vanadium steel alloy), and is free from bending, chipping, or cracks.
Check that there is no residual slurry or foreign matter in the blade holder slot, and that the mounting surface is flat and clean.
The sharp corners at both ends of the scraper blade that contact the circular mesh should be pre-trimmed into an arc shape and polished to avoid damage to the circular mesh during operation.
II. Scraper Installation Steps
1. Correct Scraper Placement
Smoothly insert the scraper into the scraper holder, ensuring the blade extension length on both sides is consistent, with a deviation not exceeding ±0.5mm to prevent uneven pressure distribution.
The slurry supply pipe head should be slightly tilted upwards to avoid scratching the inner wall of the circular mesh during insertion.
2. Scraper Fixing
Use a special tool to evenly tighten the fixing bolts, alternating between the center and both ends to avoid deformation caused by unilateral force.
After installation, gently tap the scraper body and listen to the sound to check for a tight fit and any looseness.
3. Adjusting Scraper Angle and Position
Adjust the scraper angle to the required range (usually 75°～85°) so that its blade edge is tangent to the inner circle of the circular mesh.
The scraper should be installed on the center line of the circular mesh. The force distribution in each direction can be monitored using a reading device to ensure uniform pressure.
4. Connecting the Slurry Supply System
Connect the plastic hose to the scraper's central tube, ensuring a leak-free seal at the interface.
Check that the splash guard is properly installed to prevent ink splashing.
III. Post-Installation Commissioning and Trial Run
1. Initial Pressure Setting
Set the initial pressure to a light pressure (e.g., 0.2-0.3 MPa) to avoid damage to the doctor blade or rotary screen due to overpressure.
2. Low-Speed Idle Test
Start the equipment and run it at low speed. Observe whether the doctor blade and rotary screen are in stable contact, and whether there is any jumping or abnormal noise.
Visually check whether the ink is evenly transmitted through the screen, without leakage or accumulation.
3. Gradual Pressure Increase and Pattern Alignment
Gradually increase the pressure to the process value according to the pattern and ink characteristics.
Use the alignment device for longitudinal and lateral fine adjustments to ensure accurate pattern registration.
IV. Key Precautions
1. Never touch the blade with bare hands: Even if the blade appears dull, it can still easily cause cuts. Use a soft brush or sponge for cleaning or inspection.
2. Avoid excessive tension on the squeegee: Do not forcibly straighten the blade during installation, otherwise it will cause wavy deformation and lead to defects in the blade lines.
3. Match the design requirements: For fine lines, use a narrow-bladed, high-hardness squeegee with light pressure; for thicker ink printing, use a wide-bladed squeegee with appropriately increased pressure, but do not exceed the elastic limit.
Regular resharpening before reuse: Used squeegees must be resharpened before reuse to remove any burrs and ensure the blade edge is straight and sharp.
