Scratches that appear during the glass-edging process are a common concern for manufacturers, fabricators, and workshop operators. These marks often reduce product quality, affect final aesthetics, and increase rejection rates. Understanding the specific causes behind them helps optimize workflow and protects the integrity of the glass. In this article, the main origins of edging scratches are explored from a practical manufacturing perspective, together with solutions and prevention methods suitable for factories of all sizes. For businesses looking for precision glass-processing equipment, ADDTECH offers advanced machines designed to minimize surface defects and improve edging stability.

Contamination on the Glass Surface

One of the most frequent contributors to scratches is debris left on the glass before it enters the edging machine. Tiny particles such as silica dust, metal fragments, or dried coating residues become trapped between the glass and conveyor pads. When the glass moves, these particles drag across the surface and form lines. Proper pre-washing, air-blowing, and regular cleaning of feeding tables significantly reduce the chance of such contamination. In high-volume plants, automated rinsing systems can ensure consistent surface cleanliness.

Worn or Damaged grinding wheels

The condition of the grinding wheel directly affects the finish quality. When a wheel becomes glazed, uneven, or chipped, it no longer cuts uniformly. Instead, it creates sharp microscopic points that dig into the surface. Inadequate dressing routines or using wheels beyond their service life often lead to this issue. Many facilities establish timed dressing intervals, while others use sensors to monitor wheel performance. Choosing stable, long-life wheels also ensures the glass receives a smoother, more controlled grind.

Incorrect Coolant Flow

Coolant prevents temperature buildup and removes glass chips from the grinding zone. When the flow becomes insufficient, localized temperatures rise and micro-fractures develop along the edge. These thermal marks may appear as scratches or dull streaks. Blocked nozzles, low pump pressure, or contaminated water tanks commonly cause inconsistent coolant delivery. A recommended approach is to inspect coolant paths daily and replace water regularly to avoid slurry accumulation. Proper coolant flow also prolongs tool life and improves final edge clarity.

Misaligned Conveyors or Support Pads

Mechanical misalignment pushes the glass unevenly against the wheels. Even a small angular deviation can cause the edge to contact abrasive surfaces with excessive force. This results in side-scratching or long parallel marks along the length of the panel. Regular calibration of conveyor belts, support rollers, and side-pressure mechanisms is essential. Operators often use laser alignment devices to ensure machines remain within tolerance and prevent mechanical stress on the glass.

Common Alignment Factors

Poor Quality or Contaminated Coolant

Besides flow rate, the quality of the coolant itself impacts surface condition. Dirty coolant containing glass chips becomes highly abrasive. As the slurry recycles through the system, it repeatedly passes over the glass edges and introduces scratch marks. Over time, the water’s abrasive load increases and acts like uncontrolled grinding material. Implementing a filtration system or regular tank flushing helps maintain clean coolant and a smooth cutting environment.

Excessive Feed Speed

Feeding the glass too quickly causes unstable cutting conditions. High speeds reduce the wheel’s ability to maintain consistent pressure and discharge waste chips. This often leads to chatter marks and visible scratches. Manufacturers typically adjust feed speed based on glass thickness, wheel grit, and desired finish level. Slower, well-controlled feeds produce cleaner edges and reduce mechanical stress on both the wheel and the panel.

Inadequate Machine Maintenance

Loose screws, worn bearings, unstable support arms, and vibration inside the edging unit all contribute to surface defects. Even minor vibration transfers directly to the glass, causing inconsistent contact between the wheel and the edge. Establishing a structured maintenance schedule is one of the most effective long-term solutions. Many operators perform weekly checks to tighten hardware, inspect belts, and test vibration levels.

Residual Chips on the Edge

During multi-stage edging, leftover chips from the first pass can scratch the glass in the subsequent pass. If the cleaning between stages is insufficient, these fragments remain lodged along the edge and cause repeated marks. Automated brushing and spray-cleaning modules are effective for removing debris between steps and ensuring a smooth progression to fine polishing.

How to Prevent Scratches in Production

To minimize surface defects, facilities generally adopt a combined process approach. This includes:

• Cleaning the glass thoroughly before edging

• Monitoring grinding wheel condition

• Ensuring clean and abundant coolant circulation

• Regularly calibrating conveyor systems

• Controlling feed speed according to glass specifications

• Implementing strict maintenance routines

For factories seeking stable and high-precision edging performance, ADDTECH provides advanced edging solutions built with strong structural rigidity, reliable coolant systems, and intelligent monitoring features that help reduce scratch formation and improve consistency.

Conclusion

Scratches during glass edging originate from a combination of mechanical, environmental, and operational factors. Contaminants, worn tools, poor coolant conditions, and misalignments are the most common sources. By establishing strict cleaning standards, maintaining equipment properly, and optimizing feed parameters, manufacturers achieve clearer, smoother edges with reduced defect rates. With reliable equipment such as the solutions offered by ADDTECH, production becomes more stable, precise, and cost-effective.