Analysis of the Causes and Solutions for Burning Glass during CNC Grinding of 3mm Thin Glass Sheets

In modern manufacturing, Computer Numerical Control (CNC) technology has become a critical means to achieve high-precision machining. However, operators occasionally encounter a challenging problem when using CNC technology to grind 3mm thin glass sheets – burning of the glass. This phenomenon not only affects the surface quality of the product but can also lead to workpiece scrapping and increased production costs. Therefore, understanding the causes of burning glass and finding effective solutions are important for improving production efficiency and product quality.

Cause Analysis:

1. Inappropriate Grinding Parameters: High grinding speed or excessive feed rate can cause a sharp increase in temperature in the grinding area, leading to localized melting of the glass surface, known as "burning glass." High-speed grinding increases friction between the grinding wheel and the glass, generating more heat. Additionally, an overly fast feed rate can increase stress on the grinding contact surface, also causing overheating.

2. Inappropriate Selection of Grinding Wheel: Using a grinding wheel that is too hard or has a coarse grit size intensifies friction during the grinding process, producing excess heat. A harder grinding wheel causes greater pressure on the glass surface, while a coarser grit wheel results in more severe scratching of the glass surface due to larger particle gaps, both of which increase grinding temperature.

3. Insufficient Cooling System: Inadequate flow of coolant or improper cooling methods cannot effectively lower the temperature of the grinding area, leading to overheating. If the cooling system fails to provide sufficient coolant at the grinding point, it cannot carry away the heat generated during grinding, resulting in an increase in glass surface temperature.

4. Material Issues: Uneven glass material or the presence of micro-cracks makes it easier for localized areas to generate high temperatures during grinding. Non-uniform glass presents different grinding resistances in different areas during grinding, leading to localized overheating.

5. Poor Machine Tool Condition: A decline in precision or wear of CNC machine tools can also cause unstable grinding forces, leading to burning glass. Fluctuations in machine tool condition directly affect the stability of the contact surface between the grinding wheel and the glass, resulting in uneven grinding and overheating.

6. Variation in Glass Thickness: Inconsistencies in glass sheet thickness may lead to uneven distribution of grinding pressure, with thicker parts requiring more grinding to reach the same dimension as thinner parts. This results in more heat generation in thicker areas during grinding, increasing the risk of burning glass.

Solutions:

1. Optimize Grinding Parameters: Reduce grinding speed and adjust feed rate to decrease heat accumulation in the grinding area.

2. Choose Appropriate Grinding Wheel: Select a grinding wheel hardness and grit size suitable for the physical properties of the glass to reduce frictional heat during grinding.

3. Enhance Cooling System: Improve coolant flow and direction of spray to ensure effective cooling of the grinding area.

4. Control Material Quality: Strictly screen raw glass materials to avoid using defective ones.

5. Regular Maintenance of Machine Tools: Maintain CNC machine tools in good working condition and regularly inspect and replace worn parts.

Conclusion: By analyzing the causes of burning glass during CNC grinding of 3mm thin glass sheets and implementing corresponding solutions, the quality and efficiency of glass processing can be significantly improved. In practice, strategies should be adjusted flexibly according to specific conditions to ensure optimal processing results.