Detecting Glass Defects Before They Cost You

The most expensive glass defect is not necessarily the most serious one. Often, it is simply the one that gets found too late. That’s according to Flat Glass Solutions. We investigate.

For glass processors, effective quality control is about when a defect is detected, not just whether it is detected at all. By the time a scratch, inclusion, coating mark or other defect becomes visible, glass may have passed through several processes, been transported to site and installed. What could have been a straightforward rejection or rework can turn into delays, added costs and an unhappy customer.

“Once you have invested time and materials into processing a pane, the cost of getting it wrong starts to climb very quickly,” David Cahill, the MD of Flat Glass Solutions (FGS), told Fabrication & Glazing Eye.

But automated inspection gives processors the opportunity to identify those problems earlier, when they are still relatively easy to deal with.”

Viprotron

FGS is the exclusive UK and Ireland distributor for Viprotron, whose inspection systems identify defects at different stages of manufacture, helping processors stop problems before they have added value which would then potentially go to waste. Viprotron technology uses different inspection methods and lighting conditions to reveal defects from scratches and fingerprints to pinholes, coating defects and optical distortion.

The ECO Scanner and ECO Scanner Pro provide inspection options after washing, while the Quality Scanner 3D uses multiple camera channels to identify a broader range of surface defects. For toughened glass, the Temper Scanner 5D provides inspection after the furnace, including roller wave, edge kink and anisotropy.

The objective is not to remove operators from quality control but to give them better and more consistent information.

“People are very good at spotting problems, yet automation gives you another level of consistency,” said Cahill. “It can flag what needs attention while also providing useful information about what is happening in the process. And help you avoid those six glass nightmares that you really don't want to deal with.

The six nightmares:

1. The defect trapped inside an IGU. A particle, fingerprint, scratch or stain that survives washing can become a permanent feature once an insulated glass unit is sealed. The finished unit may need to be broken down and remade, consuming another pane, spacer, sealant, gas, labour and machine time. Inspection after washing, followed by inspection at the finished-unit stage, provides opportunities to catch problems before they become part of the sealed product.

2. The one that gets more expensive at every stage. Glass can pass through a long chain of value-adding operations: edge processing, drilling, toughening, coating, laminating and IGU assembly. A defect that could have been dealt with at the start can therefore become considerably more expensive by the end. You don't want to keep adding value to glass when there is already a reason why that pane shouldn't be progressing.

3. The problem that only appears after installation. Roller wave, anisotropy, white haze, scratches and coating defects can be difficult to assess consistently on a factory floor, only becoming particularly apparent under different lighting or once glass forms part of a larger façade. Finding the problem at that stage can mean far more than replacing a pane, potentially involving specialist transport, access equipment, installers and other trades.

Once a problem reaches site it stops being just a factory problem and can become everyone’s problem.

4. The defect with potential performance implications. Not every inclusion, scratch or visible characteristic represents a problem, however, significant edge or surface damage or certain manufacturing characteristics, may warrant further investigation because of their potential implications for performance. The important thing is accurate detection and classification against agreed quality criteria, rather than blanket rejection.

5. The one nobody knows how it got there. A customer reports a defect after installation. Was it present when the glass left the factory? Did it happen during transport or site handling? Without inspection records, establishing the answer can be difficult. Viprotron systems can document and archive inspection results, giving processors an objective record of what was detected during manufacture.

6. The issue that was missed by the human eye.

Production speed, lighting, viewing angle, glass type and operator fatigue can all affect whether a subtle defect is spotted. Viprotron's automated systems provide a consistent inspection process, helping operators identify defects that might otherwise be missed.

Conclusion

The principle is simple: catch the problem early and reliably and it is far less likely to become a glass nightmare.

Picture: Detecting flaws in glass before they arrive with you and cause costly problems is a specialist task which is automated by Viprotron before is supplies its products to UK distributor, Flat Glass Solutions.

www.flatglasssolutions.com