Complete daily operation and maintenance procedures for Dry Milling Machine

Suitable for 5-axis dry milling machines for dental.

Core risks: Ultrafine zirconia dust can wear down the spindle, guide rails, and chuck, causing vibration, tool breakage, bur shedding, and accuracy drift. Maintenance includes daily cleaning before operation, during processing, and after each shift, weekly maintenance, and monthly maintenance.

Pre-start inspection, 3-5 minutes before daily processing.

1. **Air Supply System Check:** Manually drain the three-stage oil-water filter of the air compressor. The air pressure should be stable between 0.5 and 0.7 MPa. Ensure the air pipes are free of leaks, aging, or cracks. The dryer should be operating normally. Water and oil-containing gases must not enter the machine tool; oil mist will adhere to zirconium powder, causing agglomeration and jamming the chuck.

2. **Dust Collection System Pre-Check:** Check the dust collection bin for dust height. Empty it if it exceeds half capacity. Check the main filter bag and HEPA filter for blockages and blackening. Start the vacuum system under no-load; ensure no dust overflows from the chamber and sufficient suction power.

3. **Machine Tool Safety and Lubrication:** Reset the safety doors, emergency stop, and limit switches. Ensure the alarm lights show no fault indications. The guide rail/lead screw lubrication oil level should be between the upper and lower marks. Add genuine factory-specific grease if low; do not mix different types of oil.

4. Inspect the spindle, chuck, fixture, and cutting tools. Open the hatch and use an air gun to blow away zirconium powder from the spindle taper hole and the inner wall of the chuck. Wipe clean with a lint-free cloth dampened with anhydrous alcohol. Ensure the broaching jaws are free of powder accumulation, deformation, and jamming. Clean the feed tray base, locating pins, and locking screws; ensure the screws are not loose or stripped. Inspect the milling spool: ensure the shank is free of wear, the head is free of chipping, large areas of sand shedding, and bending deformation; any spools that fail to meet these standards are scrapped. Clamp the spool in place and tighten it to the standard torque.

5. Preheat the spindle by running it at low speed under no-load for 2-3 minutes. Ensure there are no abnormal noises or noticeable vibrations throughout the entire stroke. Perform full-stroke reciprocating movement of each axis without jamming or abnormal noises.

During processing, an inspection should be conducted every 3 to 5 discs processed.

01. No dust should escape from the suction chamber during operation. If dust leakage occurs, immediately stop the machine and clean the filter/dust collection bin.
02. The cutting sound should be free of sharp whistling and periodic vibration. Excessive vibration usually indicates dust accumulation in the chuck, bur wear, or a clogged suction system.

03. The spindle housing should not be hot to the touch. After 1 hour of continuous machining, it is recommended to stop the machine for 5 minutes to cool down. High temperatures will accelerate the softening and shedding of the diamond bur plating.
04. Observe the workpieces for batch chipping and dimensional deviations. This is most likely caused by dust leading to unstable clamping and guide rail jamming.

05. Avoid fixed-point heavy pressure to slow down bur shedding. Prolonged fixed-point heavy pressure cutting is prohibited. Reducing alternating impact will exacerbate bur head shedding.