Titanium alloy drilling processing has always been regarded as a difficult issue in the field of mechanical processing. Its high strength, poor thermal conductivity, and strong chemical activity make the drilling process prone to problems such as tool wear, difficulty in chip removal, and poor quality of the hole wall. Through long-term practice, we have developed a set of effective processing schemes, systematically improving the efficiency and yield of drilling.
Tool Selection and Structural Optimization
The drill bit is the key to the success or failure of drilling. Considering the properties of titanium alloy, we prefer to use carbide drill bits, which have higher hardness and wear resistance than ordinary high-speed steel, and are more suitable for stable cutting over a long period. In the geometric design of the drill bit, a 118° and 90° combined double apex angle structure is adopted. This not only effectively cuts the chips but also guides the chips to flow out smoothly, significantly reducing the risks of sticking and breaking the drill.
Cutting parameters and cooling strategies
Titanium alloys are prone to binding with the cutting tools under high temperature and high pressure, resulting in rapid tool failure. Therefore, we adopt a low-speed forced feed strategy, strictly controlling the cutting line speed to avoid local overheating. At the same time, a sufficient amount of high-pressure coolant is continuously injected into the cutting area, which not only lowers the temperature but also assists in flushing the chips, effectively delaying tool wear and ensuring the roundness and positional accuracy of the hole diameter.
Chip removal control and process monitoring
Poor chip removal is one of the main causes of drill bit fracture. During the processing, it is necessary to constantly monitor the chip shape. If there is a clogged chip or blocked chip removal, the drill should be withdrawn for cleaning in time. For through-hole processing, special attention should be paid to retracting the drill to remove chips before drilling through, and using a high feed rate during the final hole breaking process can achieve a smoother hole wall and reduce the exit burrs.
Targeted clamping and tool configuration
The workpiece must be securely fixed with a sturdy support to prevent deviation caused by drilling vibrations. For thick workpieces, heavy-duty short machine drill bits should be selected; for deep hole processing, oil-fed drills or a progressive drilling system composed of short drill bits should be used to ensure smooth chip removal paths. After drilling, if tapping is required, the quality of the bottom hole must be ensured; otherwise, the tap is prone to breakage.
Preventive maintenance and continuous improvement
Maintain sufficient coolant throughout the process, regularly clean the chip accumulation in the cutting area to avoid secondary cutting. Before and after each batch of processing, check the wear condition of the drill bit and replace or regrind it in time. Through the above systematic measures, we significantly increased the one-time qualification rate of titanium alloy drilling and extended the tool life by more than 30%.
With the introduction of new technologies such as coating techniques, micro-lubrication and intelligent monitoring, titanium alloy drilling will become more controllable and efficient. We will also continue to optimize and push this key process to a higher level.