Two machines people keep confusing
A CNC router and a CNC mill look similar — both move a spinning cutter over a workpiece — but they are built for different worlds. Pick the wrong one and you either pay too much or get a part that fails. This guide sorts it out.
CNC routing
Routers are built for large, flat, softer materials — wood, MDF, plywood, plastics, composites, foam and aluminium sheet. They have big beds (sheets of 1.2 × 2.4m and up), spin fast, and move quickly across broad areas. They excel at signage, furniture, cabinetry, panels, props, patterns and moulds. They are not built for the rigidity and precision metal cutting demands.
CNC milling
Mills are built for rigidity and precision in metal — aluminium, steel, stainless, titanium and engineering plastics. Smaller, far stiffer machines with powerful spindles, they hold tight tolerances (±0.01–0.1mm), cut deep and accurate features, and produce functional engineering parts. The trade-off is a smaller work envelope and slower cutting through metal.
Side by side
| Factor | CNC router | CNC mill |
|---|---|---|
| Best materials | Wood, MDF, plastic, composite, foam, ali sheet | Aluminium, steel, stainless, titanium, plastics |
| Work area | Large sheets | Smaller, contained |
| Rigidity / precision | Lower — built for speed over area | High — built for tight tolerances |
| Typical work | Signage, furniture, panels, patterns, moulds | Engineering parts, housings, fixtures |
| Tolerance | ~±0.1–0.5mm | ~±0.01–0.1mm |
How to choose
Ask two questions: what material? and how big? Wood, plastic, composite or a large flat panel → router. Metal, precise, functional → mill. A big timber sign is a router job; an aluminium bracket that bolts to a precise pattern is a mill job. Composite plugs and moulds often go to a router; the metal tooling around them to a mill.
Why it matters for your quote
Sending a metal precision part to a router shop, or a 2.4m timber sign to a precision mill, gets you a polite "not for us" — or worse, a bad part. Matching the part to the right machine first saves a quoting round-trip. See the choosing-a-shop checklist and, for the metal side, milling vs turning.
Irish shops for each
In our directory: for routing, CNC Works in Monaghan runs a 5-axis Biesse routing centre for timber, cabinetry and composite moulds, and CNC Ireland in Dublin routs wood, plastic and composite for signage and furniture. For metal milling, Donlouco (Cork), ProNum (nationwide), Advance CNC (Galway) and C.H.L. Engineering (Limerick) are the picks.
Frequently asked questions
What is the difference between a CNC router and a CNC mill?
A CNC router is built for large, flat, softer materials — wood, plastic, composite, foam — over big beds at high speed. A CNC mill is built for rigidity and precision in metal, holding tight tolerances on smaller, much stiffer machines.
Can a CNC router cut metal?
Routers can cut aluminium sheet and other soft metals, but they lack the rigidity for accurate steel, stainless or titanium work. For precise metal parts, use a CNC mill.
Which is more accurate, a router or a mill?
A mill — it typically holds ±0.01–0.1mm versus roughly ±0.1–0.5mm for a router, because mills are built stiffer for precision metal cutting.
Should I use a router or a mill for my part?
Match material and size: wood, plastic, composite or large flat panels go to a router; metal, precise, functional parts go to a mill.
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