After cutting and finishing glass, drilling is done where necessary. Glas Expert uses CNC machines for drilling glass, in order to diminish the possiblitiy of deviations. All drilling machines use Head-To-Head technology (drilling is done with 2 drills, head-to-head – one that runs under the glass and the other over the glass).
All the holes are embossed, eliminating all the tensions around the hole. The risks of glass breakage over time are considerably reduced by this procedure.
Deep chamfered holes
A deep chamfer is generally used for inserting the metal fittings into the glass so that the head of the fitting is flush with the surface.
0.5mm chamfered holes
Glas Expert creates a regular chamfer for every hole drilled. By removing the stresses that appear around the holes, the chamfer practically reduces the risk of the glass breaking. In the case of tempered glass, drilled holes are obligatory.
Drilling without chamfering reduces the cost per hole but is not recommended, as it increases the risk of the glass breaking by over 50%.
Hole placement Restrictions
The process itself must take some absolutely mandatory aspects into account, especially if the glass is tempered:
– The diameter of the holes (Ø) must not be less than the nominal glass thickness (D). For special cases with special requirements, you must first consult us and a 1: 1 scale sample is required.
– The distance (A), between the edge of the hole and the edge of the glass should not be less than 2 times the thickness of the glass (2xD). Eg: If the glass is 10mm thick, the distance (A) should be at least 20mm.
– The distance (B) between the edges of the two holes must not be less than twice the thickness of the glass (2xD). Ex: If the glass is 10mm thick, the distance (B) should be at least 20mm.
– The distance (C) between the edge of a hole and the corner of the glass sheet should not be less than 6 times the thickness of the glass (6xD). Ex: If the glass is 10mm thick, the distance (C) should be at least 60mm.
The recommendations indicated here are usually applicable and limited to glass sheets with a maximum of 4 holes. For sheets with more than 4 holes per piece, several technical aspects, including hole positioning, glass thickness, hole diameter, etc, need to be set out in detail.