In modern manufacturing, CNC screw grinders, as key equipment for precision machining, undertake the important task of producing high-precision screws. However, in the actual production process, machining defects such as thread misalignment and dimensional fluctuations often occur, seriously affecting product quality and production efficiency. This article will delve into the troubleshooting methods for these two common machining defects.

1、 Troubleshooting of thread misalignment issues

1. Check programming parameters

Firstly, carefully check the parameter settings such as pitch and lead in the CNC program. Incorrect parameter input can cause disorder in the thread machining trajectory, leading to tooth misalignment. For example, if the actual pitch is 5mm but the program mistakenly sets it to 6mm, the grinding wheel will move according to the wrong instructions and will inevitably fail to form the correct thread. The operator needs to reconfirm the drawing requirements and correct the program parameters.

2. Examine the transmission system

　　Screw grinding machineThe transmission chain includes multiple components such as servo motors, couplings, ball screws, etc. Any looseness, wear, or excessive clearance at any point may cause the relative motion between the grinding wheel and the workpiece to be misaligned. Regularly check the tightness of the coupling connection and check for any reverse clearance between the ball screw nut pair. It can be measured using professional instruments such as laser interferometers, and if necessary, the gap compensation value can be adjusted or severely worn parts can be replaced.

3. Pay attention to clamping stability

Poor clamping of the workpiece can result in slight displacement under the action of grinding force. Especially during high-speed grinding, this displacement is sufficient to disrupt the thread accuracy. Ensure that the tightness of the top tip is moderate and the support of the center frame is stable. For slender shaft components, adopt a reasonable follower holder configuration to reduce deformation caused by insufficient rigidity. After each clamping, manually rotate the workpiece and feel if there is any obvious shaking.

4. Verify the status of the grinding wheel

The shape error and runout of the grinding wheel directly affect the cutting effect. The surface of the grinding wheel that is not repaired in a timely manner is rough and the edges are passivated, which can easily cause compression damage to the threaded side. Use a diamond pen to finely adjust the grinding wheel, and use a dial gauge to detect its radial runout, controlling it within the allowable range. At the same time, select the appropriate grinding wheel size and hardness based on the characteristics of the processing material to ensure sharpness and wear resistance.

2、 Troubleshooting of Size Fluctuations

1. Temperature control analysis

Thermal deformation is a common factor causing dimensional changes. The heat generated by the long-term operation of the machine tool will cause the structural components to expand, changing the original geometric accuracy. Install temperature control devices to monitor the temperature of key parts such as the spindle box and guide rails, and establish a temperature rise curve model. Preheat the machine tool to a stable working condition before starting up, maintain a constant temperature environment during the machining process, and use the cooling system to cool down if necessary.

2. Tool compensation calibration

The size reduction caused by grinding wheel wear is often overlooked. Establish a comprehensive tool life management system, regularly record changes in grinding wheel diameter, and update radius compensation values in a timely manner. Utilize online measuring instruments to provide real-time feedback on workpiece dimensions and dynamically adjust grinding depth. After completing a certain quantity of products, sample the size and compare it with historical data to determine the trend.

3. Optimization of process parameters

Unreasonable feed rate and acceleration settings may lead to increased vibration, affecting surface quality and dimensional consistency. Reduce the fast movement speed of the empty stroke and minimize the impact in non cutting states; Improve the smoothness of the reciprocating motion of the workbench and avoid sudden stops and starts. By using single factor testing method, gradually adjust the speed parameters of each section and find the best matching combination.

4. Electrical system inspection

Electrical issues such as encoder signal interference and driver failure can indirectly cause dimensional abnormalities. Is the shielded cable intact? Does the grounding resistance meet the standard? Identify potential sources of interference one by one, reinforce line connectors, and purify power supply quality. Use an oscilloscope to observe the integrity of the pulse waveform and ensure accurate transmission of control system instructions to the executing mechanism.

In the face of the problems of thread disorder and dimensional fluctuations in CNC screw grinders, only by systematically starting from multiple aspects such as mechanical structure, CNC system, and process flow, using scientific detection methods and rigorous analysis methods, can the crux of the problem be accurately located, effectively solved, and ensure the smooth progress of production.