Edge Delete Solutions for High Performance ‘Low E’ / Solar Control Glass
Innovations in ‘Low E’ glass coatings are making the process of Edge Deletion much more challenging, from single layer / multi-layer coatings (commonly known as offline coated products), and the applications for which the glass is designed, all making the types of coating available becoming thicker and harder to remove.
This is especially the case with the new EasyPro from Saint-Gobain Glass which we will go into more information later on in this article.
This article covers:
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What is 'Low E' Glass?
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Why do we need to remove the coating?
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How do we remove the coating?
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Norton Edge Deletion Stock Wheel Products
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EasyPro from Saint-Gobain Glass
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Further information
Why do we need to remove the coating?
These glass panels will be made into a double or triple glazed ‘unit’, which involves ‘gluing’ these panes together using various types of sealant. As the soft coat is susceptible to corrosion this coating must be removed from the outer edge of the glass prior to gluing, so we are bonding to the substrate (glass) and not the silver based coating. If this is not done, moisture from the sealant and the external environment will corrode the silver, resulting in delamination (moisture inside the unit).
So, how do we remove it?
An important part of the glass industry is the Edge Deletion process. This involves the removal or stripping of the Soft Coat using an Edge Deletion Wheel. Edge deletion is normally done on the cutting table of which there are 4 main OEM’s - Hegla, Lisec, Botero & Bystronic. Although there are subtle differences between these machines all manufacturers delete and cut the glass in a similar way. See below a typical Cutting Table (Fig. 2):
The edge deletion wheel traverses across the glass jumbo on a CNC controlled bridge (above). The grinding head motor usually spins the wheel at a speed of around 2000 rpm and the wheel is pneumatically pushed against the glass surface with anywhere from 1 to 3 bar of pressure. As the cutting head travels across the glass surface in its pre-programmed pattern, the wheel removes the coating. The main adjustable parameters for this process are very simple: traverse speed, grinding head pressure, and sometimes wheel rotational speed.
See below 2 examples of edge deletion quality. Fig. 3 shows unsuccessful deletion with much of the coating left on the glass surface, where Fig. 4 shows the coating completely removed.
Fig. 3 - Unsuccessful edge deletion | Fig. 4 - Successful edge deletion |
Inspection is normally a visual check, but a secondary inspection can be done with a fuse tester / multi meter as pictured below. If the green led is lit, then the deletion is not sufficient (Fig. 5). If the green led is not lit, then the surface is not conductive and has been deleted successfully (Fig. 6).
Fig. 5 – Showing conductivity | Fig. 6 – No conductivity |
Norton Edge Deletion Stock Wheels:
New generation RED Convolute - All Coatings and NEW HIGH SPEED TABLES |
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Diameter | Width | Bore | Spec | Part number | Coating Type |
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200 | 10 | 76.2 | C4315 8SM | 78072720077 | ALL Coatings |
200 | 20 | 76.2 | C4315 8SM | 78072711539 | ALL Coatings |
General Purpose Grey Convolute - Regular Coatings |
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Diameter | Width | Bore | Spec | Part number | Coating Type |
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200 | 10 | 76.2 | Series 1000 9-SM | 66623397185 | ALL Coatings |
200 | 20 | 76.2 | Series 1000 9-SM | 66261097796 | ALL Coatings |
Polybond Pro SOFT - For perfect deletion on harder coatings. (Recommended for SG Easypro, Guardian TPF and Hard Coatings) |
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Diameter | Width | Bore | Spec | Part number | Coating Type |
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200 | 10 | 76.2 | P4M01 NOR 80 | 66261133527 | Easypro & TPF |
200 | 20 | 76.2 | P4M01 NOR 80 | 66261125662 | Easypro & TPF |
Polybond Pro HARD - For Bottero Tables & long life on softer coatings. |
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Diameter | Width | Bore | Spec | Part number | Coating Type |
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200 | 10 | 76.2 | PAM01 NOR 80 HD | 69957341059 | Standard Low E |
200 | 20 | 76.2 | PAM01 NOR 80 HD | 69957341041 | Standard Low E |
EasyPro - New innovation from Saint-Gobain Glass – What is it?