Precise thread processing on a slant bed CNC lathe requires a series of rigorous operating steps and precautions. Here are some key points:
1. Tool selection and preparation
A. Tool type: Select appropriate tools such as taps, thread milling cutters or thread turning tools according to the form and processing method of the thread. Make sure that the angle of the tool is consistent with the thread standard to avoid processing errors or thread accuracy that does not meet the requirements.
B. Tool material: Select tool material according to the workpiece material. For high-hardness materials, it is recommended to choose carbide or coated tools to increase tool durability.
2. Processing parameter setting
A. Cutting speed: Too fast cutting speed may cause poor thread surface roughness and increased tool wear; too slow cutting speed will affect processing efficiency. Therefore, it is necessary to set a reasonable cutting speed.
B. Feed speed: The feed speed of the thread must be consistent with the pitch to ensure the accuracy and surface quality of the thread. Thread processing in the CNC system will automatically synchronize the spindle speed and feed speed.
C. Cutting depth: Usually, the thread is processed with a gradually decreasing cutting depth to avoid damage to the tool or deformation of the workpiece due to excessive feed at one time.
3. Programming and tool setting
A. Programming: Write a suitable CNC machining program according to the processing requirements of the thread. When programming, you need to consider parameters such as the starting position of the thread, the cutting method (such as straight or oblique), and the cutting depth.
B. Tool setting: When setting the tool, make sure that the center of the thread tool is consistent with the center of the workpiece to avoid eccentricity affecting the thread accuracy. You can use the trial cutting method or the tool setting instrument to automatically set the tool to ensure that the starting point of the tool is accurate.
4. Process control
A. Use of coolant: Thread processing will generate a lot of heat, especially thread processing of high-hardness materials. Using a suitable coolant can effectively reduce the temperature, reduce tool wear, and improve surface quality.
B. Lubrication: For processing environments where coolant is not suitable (such as cutting aluminum or stainless steel, which are easy to stick to the tool), lubricating oil or thread-specific cutting oil can be used for lubrication to reduce friction and extend tool life.
C. Workpiece clamping: The workpiece should be clamped firmly to avoid displacement or vibration during processing. Especially for long workpieces, support devices such as center frames should be used to ensure processing stability.
5. Multi-thread processing method
When processing multi-thread on a slant bed CNC lathe, the circular line division method or the axial line division method can be used.
A. Circular line division method: Use the spindle encoder to control the starting point pulse and feed the tool at different angles. This method is relatively simple, but it should be noted that some CNC systems may not support it.
B. Axial line division method: Change the coordinates of the starting point to use, suitable for multi-thread processing, and cycle instructions can be used to reduce programming workload. This method is not limited by the CNC system and is easy to use.
6. Thread measurement and quality control
A. Thread measurement: Use a thread ring gauge or plug gauge to measure the accuracy of the thread to ensure that the pitch and diameter meet the design requirements. Other measuring tools such as thread micrometers, tooth thickness vernier calipers, etc. can also be used for measurement.
B. Quality control: Check the thread surface for defects such as burrs and cracks. For precision thread processing, the surface quality needs to be carefully checked. At the same time, ensure that the starting position and retracting position of the thread are accurate to avoid problems such as misalignment or burrs.
In summary, precise thread processing on a slant bed CNC lathe requires comprehensive consideration of tool selection, processing parameter setting, programming and tool setting, processing process control, and thread measurement and quality control. By following these key points and precautions, you can ensure that the accuracy and quality of thread processing meet the design requirements.
