Equipment Selection
The appropriate knife grinding machine should be selected based on the length of the tool to be ground, the edge type (single-edge or multi-edge), the cutting material, and the required precision. For instance, knife grinding machines offer a maximum grinding length ranging from 1.6 meters to 10 meters, catering to the needs of flat blades of various lengths. Edge types typically consist of a single cutting edge, or can involve multiple compound edges achieved by adjusting the grinding angle.
Operation
1. Place the knife onto the knife table and adjust the overhang of the tool to approximately 0.5–1.0 cm; ensure that the overhang is identical at both ends of the knife, using the set screws for fine-tuning. Activate the magnetization switch on the electromagnetic chuck control panel to secure the knife firmly to the table. Adjust the relative position of the grinding wheel and the blade; if the blade is found to be in contact with the wheel, rotate the infeed handwheel to separate them.
2. Connect the power supply and switch on the main power switch to bring the machine into normal operating mode.
4. Rotate the infeed handwheel to advance the blade inward slowly and steadily until it makes contact with the grinding wheel. Adjust the contact pressure between the blade and the wheel to ensure optimal grinding performance.
When grinding drill bits, observe the following key points: First, align the main cutting edge of the drill bit parallel to the surface of the grinding wheel. Second, position the drill bit's axis at an angle of approximately 60 degrees relative to the wheel surface (corresponding to the drill's point angle). Once the cutting edge makes contact with the wheel, begin grinding slowly downward, starting from the main cutting edge and traversing across the entire flank face. During the grinding process, the cutting edge of the drill bit should be oscillated vertically; the tail end of the bit must not be allowed to lift up. Furthermore, ensure that the drill tip remains aligned with the central axis and that the grinding is performed symmetrically on both sides.
Maintenance
The knife grinding machine is a piece of high-precision mechanical equipment; regular maintenance will significantly extend its service life.
1. The guide rails and sliding surfaces should be lubricated frequently.
2. The machine should be thoroughly cleaned after each grinding session.
3. If the grinding wheel shows signs of cracking or chipping, it must be replaced immediately.
For knife grinding machines equipped with an electromagnetic chuck, please note: After prolonged use, the electromagnetic chuck may suffer burnout due to issues such as insulation failure; the cost of repairing or replacing the unit can be substantial. When users attempt repairs themselves, the complex nature of the electromagnetic coil insulation process presents certain difficulties; therefore, particular attention must be paid to the proper execution of the insulation procedure.
Common Fault Troubleshooting
Power indicator light does not illuminate: Check the power cord output, main power switch, fuses, and transformer. Failure to magnetize: Check the voltmeter reading (which should be between 110V and 130V), fuses, wiring, current relay, rectifier bridge, and the AC contactor associated with the magnetization button. Traverse motor or grinding wheel motor fails to operate: Check for motor damage, verify that the three-phase power supply is normal, check for loose wiring, and inspect the AC contactor contacts for signs of burning. Limit switch failure: Check the limit switch itself, the manual control buttons, the time relay, and inspect the wiring inside the cable carrier for damage or short circuits. Button failure preventing normal machine operation: Check the buttons, components within the electrical control cabinet, current relay, associated circuitry, aviation connectors, three-phase power supply, fuses, and transformer [9].