Glass Edge Strength & Edge Quality
The edge decides whether glass breaks — in tempering, in handling, under bending load. This is how edges without micro-cracks are made.
Request sample parts →The edge decides between breaking and lasting
Glass almost never fails in the surface — it fails at the edge. Micro-cracks and chipping from the cutting process act as predetermined breaking points: in thermal tempering, in transport or under bending load, fracture starts exactly there. The cleaner the edge, the stronger the whole part.
That is why we judge every process by the edge it leaves behind — and verify it in-house with 3- and 4-point bending tests up to 10 kN.
4-point bend test: wheel vs. CO2 laser
Watch the direct comparison of how much more load the laser-cut edge carries before it breaks.
What good edges deliver
Three processes, one goal: the strong edge
Which route is right depends on glass thickness, geometry and volume — we choose it with you.
CO2 laser: thermal cutting
The guided thermal crack creates an optical glass edge without micro-cracks — with zero post-processing. For straight cuts from 0.1 to 3 mm.
View the CO2 laserSOLID-D® for ultra-thin glass
Mirror-fine edges without particles on 10–100 µm glass — enabling bend radii down to r ≈ 1.5 mm on laminated stacks.
View thin glassPenett® & APIO® wheels
The deep median crack (up to 90% of glass thickness) breaks controlled — clean edges even on coatings and at crossing points.
View cutting toolsFrequently asked questions about edge strength
Why does glass almost always break at the edge?
The surface of glass is extremely strong — weaknesses are created during cutting: micro-cracks and chips at the edge act like notches where stress concentrates. Under load (bending, thermal tempering, temperature cycles), fracture starts there.
What makes the laser-cut edge stronger?
The CO2 laser cut is contactless: a guided thermal crack separates the glass without mechanical load. No micro-cracks, no chipping — the result is optical glass edge quality straight from the cutting step, proven in 4-point bending tests.
What does “>200 MPa edge strength” mean?
The bending strength of the edge after cutting, depending on glass thickness. The higher the value, the more load and deformation the part tolerates before breaking — decisive for tempering, assembly and flexible applications.
Does a good edge need grinding?
Not with the CO2 laser cut — the cut edge is the finished edge, with no grinding, polishing or washing. That saves process steps and avoids the risk of introducing new defects during rework.
How do you verify edge strength?
In-house with 3- and 4-point bending tests up to a maximum force of 10 kN, complemented by glass analysis and measurement with software-assisted electron microscopes. On request we test your samples and document the results.
Does this apply to ultra-thin glass as well?
Yes — there the edge is everything. With SOLID-D®, edges of 10–100 µm glass reach mirror quality without particles or micro-cracks; combined with resin lamination, bend radii down to r ≈ 1.5 mm become possible.
Edge quality on the blog
Edges that have to hold? Put us to the test.
