To choose the right glass cutting wheel, match the wheel angle to the glass thickness, the wheel diameter to your cutting speed, and the wheel material to your production volume. The rule of thumb: the thicker the glass, the blunter the angle. The range runs from about 100° for ultra-thin glass up to 160° above 6 mm.
That is the short answer. The long answer explains why chipping, ragged edges and panels that will not break along the score are usually not machine problems at all, but wheel problems. This guide walks through the four decisions that determine whether your score line becomes a clean edge or a rework station.
Why the wheel decides the quality of the whole cut
A cutting wheel does not cut glass. It creates a controlled median crack that the breaking step then follows. If the crack geometry is wrong for the glass, no amount of breaking skill can fix it: the edge chips, splinters, and every microcrack left behind reduces the strength of the finished part. The edge you produce at scoring is the strength your product ships with.
Step 1: Match the wheel angle to the glass thickness
The angle of the wheel edge determines how deep the median crack runs and how much pressure the score needs. Thicker glass needs a blunter wheel:
| Glass thickness | Wheel angle (guide value) |
|---|---|
| up to 0.1 mm | 100–105° |
| 0.1 – 0.5 mm | 110–115° |
| 0.5 – 1 mm | 120° |
| 1 – 2 mm | 125° |
| 2 – 3 mm | 130° |
| 3 – 4 mm | 140° |
| 4 – 6 mm | 150° |
| above 6 mm | 160° |
Two refinements from practice: for borosilicate glass, subtract roughly 5° from the table values (identical from the 160° range upward). And treat every value as a starting point, not a law: the optimum shifts with your machine and the hardness of the cutting table.
A word on the differing tables you will encounter elsewhere: selection charts from hand-cutter manufacturers often list other angles for the same thickness. That is no contradiction. There, angles are tied to specific tool series and calibrated for manually dosed pressure. The values here apply to machine cutting with defined, repeatable cutting pressure.
Step 2: Match the wheel diameter to your cutting speed
Diameter is about dynamics. A small wheel presses its energy into a short contact zone, ideal for precision at low speed. A large wheel runs smoothly at production speed:
| Cutting speed | Wheel diameter | Typical setting |
|---|---|---|
| up to 10 m/min | Ø 2.0 mm | lab systems, precision work |
| up to 30 m/min | Ø 3.0 mm | thin-glass lines |
| above 30 m/min | Ø 5.0 mm | high-speed production lines |
Step 3: Tungsten carbide or diamond (PCD)?
In cut quality, the two materials are equals. The difference is lifetime: a polycrystalline diamond (PCD) wheel lasts roughly ten times longer than tungsten carbide. That turns the choice into simple arithmetic. In series production, tool changes cost machine time, and PCD pays for itself quickly. For lower volumes or budget-driven projects, carbide remains the sensible choice.
Step 4: Choose the wheel family for your breaking process
The final decision is what should happen after the score:
- APIO® (0.1–12 mm): engineered for maximum edge strength with minimal splintering. The choice when the edge quality of the finished part is the priority.
- Penett® (0.1–2 mm): drives the median crack up to 90% through the glass thickness, so parts separate with minimal breaking force. The choice when easy, reliable breaking matters most.
Where other tables end: thin glass below 0.5 mm
Notice something about the common selection charts? Most start at 2 mm; the more thorough ones at 0.75 mm. Display glass, sensor substrates and optical carriers sit well below that. This is exactly where our specialty begins: cutting wheels at 100–115° for the range down to 0.5 mm. Below 0.1 mm, where wheel scoring reaches its physical limits, dedicated solutions such as the SOLID-D™ mechanical blade take over, covering ultra-thin glass down to 30 µm.
Troubleshooting: what your score line is telling you
The score line is the most honest diagnostic tool in the process. The most common symptoms and their most likely causes:
| Symptom | Likely cause | First response |
|---|---|---|
| Chipping along the line | Angle too blunt for the thickness, or too much pressure | Check angle against the table, reduce pressure |
| Intermittent, broken score line | Worn wheel edge | Replace the wheel (far less frequent with PCD) |
| Wheel skips or hops | Damaged edge (e.g. after dropping the tool) | Replace the wheel, a nicked edge does not recover |
| Break wanders off the line | Median crack too shallow for the thickness | Increase pressure or review the wheel family (deep fissure: Penett®) |
| Glass dust and fine splinters while scoring | Too much pressure, the wheel is crushing the surface | Lower the pressure, possibly a sharper angle |
And keep in mind: angle, diameter and material are half the truth. Cutting pressure, speed and cutting fluid together form the process recipe. Change one, and the optimum of the others shifts.
The special cases that deserve a conversation
Chemically strengthened glass behaves according to its compressive stress and depth of layer (DoL). The right wheel depends on both, so have those numbers ready. Laminated and coated glass adds interlayers that change the process entirely. In both cases, application engineering beats any table.
Cutting by hand? The same thickness logic applies to hand cutters: the M17 series covers straight cuts and the M18 series free-form shapes, with Micro Penett® available exclusively for hand tools below 0.4 mm.
The fastest way to your configuration
You can work through these four steps with a catalog. Or you answer five questions and get the complete recommendation in about a minute, built on the same MDI application data as this guide.
Free tool
Five questions, one minute: wheel family, angle, diameter, matching axle and holder as a complete recommendation.
Frequently asked questions
Which wheel angle for 2 mm float glass?
Right at the boundary of two ranges: 125° is the guide value coming from 1–2 mm, 130° from 2–3 mm. Where your optimum lies depends on machine and cutting table. Start at 125° and evaluate the edge.
Can one wheel cover all my jobs?
Not across thicknesses, because the angle must follow the glass. Within one thickness range, however, a well-chosen wheel family covers a wide span: APIO® alone spans 0.1 to 12 mm.
How do I know when a wheel is worn?
The score line tells you: rising chipping along the edge, higher required pressure, or an intermittent crack are the classic signs. With PCD, these intervals stretch roughly tenfold compared to carbide.
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