Cutting engineered quartz on a CNC bridge saw

Engineered quartz properties that matter for cutting

Engineered quartz (quartz surfaces) is crushed quartz bound with a polymer resin, plus pigments. OSHA and NIOSH put crystalline silica at up to 95% of the material, with resins, pigments and adhesives making up the rest. Some newer products contain less than 50% silica in a resin matrix, and some cement-bound recycled-glass products contain less than 0.2%. Check the safety data sheet of the slab you are cutting.

For the saw, engineered quartz is a consistent material. There are no fissures, the hardness does not change across the slab, and thickness tolerance is tight. Slabs are usually 12, 20 or 30 mm (1/2, 3/4 or 1 1/4 in). Two things are different from natural stone:

• Resin binder: The resin softens with heat. A cut that runs short of water or feeds too hard can burn or discolor the edge, and the damage shows on light colors.
• Internal stress: Large slabs carry stress from production. A long cut that runs close to an edge can crack near the end as the stress releases. Trim the edges first and make long cuts before short ones.

Blade selection

Most granite blades are also sold for engineered stone, and many fabricators use one blade for both. A blade with a medium bond works on most quartz surfaces. Very hard, high-quartz products cut more like quartzite and need a softer bond. A silent core cuts noise, which matters in a shop that runs quartz all day. Ø350–400 mm (14–16 in) blades are the usual choice for countertop thicknesses.

Blade speed and feed rate

Alpha gives a peripheral speed of 32–35 m/s for engineered stone, the same as soft granite:

Blade diameter	Engineered quartz rpm (Alpha)
350 mm (14 in)	1,700–1,900
400 mm (16 in)	1,500–1,700
450 mm (18 in)	1,400–1,500
500 mm (20 in)	1,200–1,300

Feed rates from blade makers:

• Alpha chart: 5.0 m/min in 12 mm, 3.0 m/min in 20 mm and 2.0 m/min in 30 mm straight cuts.
• Spider II: 1.8–3.7 m/min (6–12 ft/min) on engineered stone.
• ZENESIS Z-Pattern: 1.5–3.0 m/min (5–10 ft/min) on granite and engineered stone.
• DIABU Red Eagle: 2.0–3.0 m/min (80–120 in/min) on quartz.

These figures overlap but do not agree. A working range of 2–5 m/min covers most 20–30 mm quartz, set by blade, product hardness and machine power. If the edge comes out yellowed or smells of burnt resin, the feed is too high for the water and blade condition.

Entry, exit and water

Reduce feed at entry and exit to avoid chipping the factory-polished face. Water does two jobs on quartz: it keeps the resin below the temperature where it marks, and it is the main dust control. Under California rules water must cover the whole contact area (see below).

Miter cuts

Mitered quartz edges are a large part of countertop work. Alpha halves the feed for 45° cuts: 1.5 m/min in 20 mm. The color of quartz is consistent through the body, so a precise miter gives an almost invisible joint. On a 5-axis CNC bridge saw the A-axis head tilt cuts the miter on the flat slab, and the C-axis head rotation lets the saw miter every edge of a nested part without moving it. See mitered edges.

Sink cutouts and core drilling

Cut sink cutouts with radius corners: core drill the corners, then join with saw cuts or a finger bit. Sharp inside corners concentrate stress and are where quartz countertops crack after installation. Keep water on the core bit for the full depth; a dry core bit burns the resin around the hole.

How machine features reduce defects

• Nesting and DXF import: Quartz slabs are uniform, so nesting can pack parts tightly and raise slab yield.
• Vacuum manipulator: Moves cut parts without hand handling, which also keeps operators away from the cutting area.
• Slab thickness reader: Confirms each slab before cutting and sets blade depth.
• Unattended wet cutting: The saw is the main source of dust. A CNC saw that runs a nested program with water on the cut reduces how long an operator spends near the blade.

Silica: the main issue with this material

The CDC’s 2019 report described 18 cases of severe silicosis, including 2 deaths, among U.S. engineered stone fabrication workers. National Jewish Health compares more than 90% silica in engineered stone with less than 45% in granite.

California. Cal/OSHA Title 8, Section 5204 defines cutting artificial stone with more than 0.1% crystalline silica as a high-exposure trigger task. CDPH reports that Cal/OSHA adopted the updated permanent rule on December 19, 2024. Employers must use effective wet methods; dry cutting and dry sweeping are prohibited and count as imminent hazards that let inspectors shut the operation down. The rule also requires regulated areas, a PAPR with some exceptions, air monitoring against a 25 µg/m³ action level, medical surveillance, and reporting of confirmed silicosis cases within 24 hours.

Australia. Engineered stone benchtops, panels and slabs have been banned since 1 July 2024. The definition covers artificial products with at least 1% crystalline silica made by combining natural stone with materials such as resins and then hardening. Removal, repair and minor modification of installed engineered stone is still allowed under controls, with notification to the regulator. Check current state rules before quoting work there.

Next step

Send us your most common quartz slab and edge detail and we will run a cutting and miter test with full water and recorded feeds. Request it through request a configuration or see it on a factory visit.