When working a flat glass, the first step is to cut the desired size from the standard size. From this, after further processing of the glass, we may produce doors, windows, tables, handrails, shelves and so on.
When working a flat glass, the first step is to cut the desired size from the standard size. From this, after further processing of the glass, we may produce doors, windows, tables, handrails, shelves and so on.
Glass is a super cooled liquid. For our purposes, it is tough and rigid enough to be fragile as well. In spite of this, at the molecular level, the particles are barely organized and the structure is far from being crystalline. This lack of organization means that the structure lacks a certain axis and also lacks a definable arrangement of particles. The smallest crack on the surface can go in any direction, or more precisely, it will go where the local mass of tension will direct it. These characteristics make possible the cutting of glass.
The process is quite simple: we “cut” the surface of the glass, along which the plate may be easily broken off.
However, the cutting of the glass is not a classic cutting process. In case of cutting, the given object is exposed to such a shearing force that it splits into two parts. In case of glass cutting, however, the purpose is to control the direction of the crack moving along quickly on the surface by generating at the right time and in the right place a surface tension that is greater than the tensile strength of the matter.
The basic equipment needed to cut a glass is a simple glass cutter with cutting wheels. This equipment is made of tempered steel that can be used either as a manual tool or as the component of automatized cutting tables.
The small wheel seems to do nothing when it runs on the surface of the glass. The whetted wheel just barely scrapes the surface, still this is the most powerful glass cutter. This small wheel provides a great crushing force – it is far greater than the tension at which the glass fractures. The cracks cause micro-fractures deep in the glass that are in line with the direction of the compressive force. If we induce tensile stress along the line of the glass cutter, the surfaces will separate from each other and the cracks will follow the line of the micro-fractures on the surface and the micro-fractures deep in the glass. These micro-fractures caused by the cutting wheel are surprisingly effective in this sense. Seemingly, the glass cutter leaves only a small surface scrape behind, but it can also happen that a simple change in temperature causes the glass to break on itself.
In case of automatized glass cutting, the break out of the glass scraped by the cutting wheel is simplified since the cutting head of the glass cutter drops cutting oil on the surface. The hydroxyl-ions of the liquid effectively terminate silicon-oxygen bonds and enhance the release of molecular forces of the crack. Consequently, the oiled cracked edges give easier and is simpler to break out the desired size of plate along the line of the cracks. Experienced glazers also apply a similar smart practice, even if it only means that they lick their thumbs and swipe it along the crack before breaking out the lite.
Glass cutting seems to be a quite simple process, yet there can be major difference 0between quality cutting (carried out by well-set and run-in machines or by an experienced glazer) and poor cutting. Poor cutting may reduce the life span of the window (it is more likely to crack) or it may cause difficulties during further processing. Also, it may affect the aesthetic look of the product or it may even cause injuries.
This explains the importance of glass cutting to be carried out by an expert or by a modern, well set-up machine. There is a number of glass types that cannot be cut manually in a precise manner since in many cases, further complimentary processes are required.
Quality cutting cannot be realized without taking into consideration the thickness, the type, the coating or the protective foil covering the surface of the glass, according to which the pressured applied by the cutting wheel and the cutting speed must be chosen, along with the other complimentary operations that may be needed.
One of the complimentary operations, which is also the glass cutter’s task, is to remove by grinding the soft or hard coating from glass panes in the width of the sealing, in case the glass will be fitted into an insulation glass unit.
In case of laminated glasses, precise cutting and adequate equipment of the cutting table are indispensable since after the cutting and breakout of the lite, the overhanging foil between the laminated glasses can be removed only with the help of a special heating/melting knife.
CE Glass uses the latest automatic cutting tables to cut glasses. The most common form we cut is square, but our factory is also able to cut round, oval, curved or even wavy shapes. Besides cutting, special shapes can also be achieved by milling the glass.
Our factory tries to minimize the loss derived from cutting, therefore reducing the trim, that is, wastage In order to achieve this and to carry out quality cutting with our machines, it is indispensable to know the raw material and its size, and already during the cutting plan, that is, the optimalization of the cutting, we must consider other characteristics. It is extremely important to leave appropriate trimming; in other words, we have to cut the glass in a way so that it can be grabbed easily to break it off. In case of glasses with sharp edges and shaped glasses, this process has a key role.
It is good to know that after manufacturing, glass plates are stocked on each other and then packaged in different transport units. In case of large plates, they put the glasses in stocks, in case of smaller plates, they put them in boxes. Each manufacturer produces a specific size and sell the plates in the following transport units: Glasses with the size of 6000x3210 are put in stocks. Only one glass type is put in one stock; different glass types are never mixed. Other, less ordinary sizes are the following: 5000x3210 and 4500x3210. The number of plates in a single stock depends on the thickness and type of the glass.
| Float |
Coated glass |
|
| Plate/stock | Plate/stock | |
| 3mm | 20 plate | - |
| 4mm | 15 plate | 14 plate |
| 5mm | 12 plate | - |
| 6mm | 10 plate | 9 plate |
| 8mm | 7 plate | 7 plate |
| 10mm | 6 plate | 6 plate |
| 12mm | 5 plate | 5 plate |
Glasses of the same type with the size of 3210x2250 are put in boxes.
In case of box-sized glasses many other dimensions are common, especially with structured glasses (some common sizes include: 3210x2250, 2250x1605, 2160x1650, etc.) The number of plates in a single box depends on the glass type and its thickness:
| Float | Coated glass |
|
| Plate/stock | Plate/stock | |
| 3mm | 37-42 plate | - |
| 4mm | 27-29 plate | 26-28 plate |
| 5mm | 21-22 plate | - |
| 6mm | 18-19 plate | 17 plate |
| 8mm | 13-14 plate | - |
| 10mm | 10-11 plate | - |
| 12mm | 9 plate | - |
CE Glass stores about 400 glass types of different sizes. Many of these glass types are constantly used, and only a few of them are stored just to satisfy special and occasional demands.
Our industry is aware of the fact that it is impossible to use the whole plate. Sometimes it occurs that a larger part of the plate or even a whole standard-sized plate remains from a specific project. CE Glass installed two different high tech storage systems that provide the storage of the remnant glasses and their durability.
The glasses in our store can be purchased with discounts. Our offers and stock constantly change. For more updates, please contact our sales colleagues.
