Common machining difficulties in drilling: insufficient rigidity of the tool and breakage; non-wearable tool material and improper selection of the drill bit structure lead to short tool life; poor surface quality of the tool forms a built-up edge; the impact of the drill bit structure causes poor chip removal in the machining process smooth.
The above problems are mainly due to the improper selection of the drill bit. For the common processing problems in the drilling process, we will analyze the typical causes, give the corresponding adjustment measures and evaluate the feasibility, and select the appropriate adjustment measures.
Analysis of common processing problems in the drilling process and corresponding adjustments
(1) Fracture problem---Analysis of typical causes and what adjustments can we make?
1. The clamping runout is too large (reduce the radial runout)
2. Unstable working conditions (improve clamping performance and reduce vibration during processing)
3. Chip clogging (check cutting fluid flow and pressure)
4. The feed is too high (lower the feed)
5. Insufficient tool rigidity (preferably tool structure)
6. Excessive wear (increase the frequency of inspection wear)
7. Insufficient spindle power (reduce cutting parameters)
(2) The problem of unsatisfactory life-analysis of typical causes
1. The recommended cutting parameters are inappropriate
2. The coolant supply is insufficient, the filter needs to be cleaned, and the coolant hole of the drill bit is blocked
3. The overhang of the drill bit is too long and the processing stability is poor
4. The tool material is not wear-resistant
5. The choice of drill bit structure is inappropriate
6. For typical wear types, see specific measures
Typical cause analysis-wear type
Flank wear
1. Excessive amount of beating
2. Cutting speed is too high
3. Feed is too low
4. Insufficient coolant supply
5. The tool material is not wear-resistant
Chisel edge wear
1. Excessive amount of beating
2. Cutting speed is too low
3. Too high feed
What adjustments can we make?
1. Check the amount of radial runout (flank wear, chisel edge wear)
2. Adjust the cutting speed (flank wear reduces Vc, chisel edge wear increases Vc)
3. Adjust the feed rate (flank wear increases Fn, chisel edge wear decreases Fn)
4. Check the cutting fluid supply (flank wear)
5. Optimal tool material (flank wear)
(3) The problem of built-up tumors-typical cause analysis and what adjustments can we make?
1. Inappropriate cutting parameters
Increase Vc when the built-up tumor is in the center;
Reduce Vc when the built-up tumor is located on the periphery;
2. The cutting edge is not sharp enough
Choose sharp-edged knives
3. The surface quality of the tool is poor
Improve surface quality and reduce friction between tool and chip in the second deformation zone
(4) Poor chip removal problem-typical cause analysis and what adjustments can we make?
1. Chip formation-influence of cutting parameters:
Adjust speed and feed
2. Insufficient coolant supply:
Increase the coolant flow, clean the filter, clean the coolant holes in the drill
3. Impact of drill bit structure:
Optimal tool structure
4. Excessive wear of the cutting edge of the drill:
Replace with new drill bit
5. Machinability changes due to the batch of workpieces:
Adjust to suitable cutting parameters
