What CNC Machines Are There?
The question comes up on almost every RFQ we quote. The answer decides how many setups your part needs, how tight the tolerance holds, and what the cycle time looks like. This page walks through each machine type we run and the part shapes that fit it.
How Many Kinds of CNC Machines Are There by Axis Count
Every CNC machine is described by how many directions its cutting tool can move relative to the workpiece. Three linear axes cover X, Y and Z. Add a rotary axis and you get four. Add two rotary axes that work at the same time and you get five. That single number tells you more about what a shop can do than any brochure photo.
On a 3-axis vertical mill, the part sits still while the spindle moves. Every face you need to reach has to be presented to the tool by the fixture. If a part has features on five sides, someone has to stop the cycle, unclamp it, rotate it and re-zero it. Each of those steps adds setup time and a fresh chance for alignment error.
A 4-axis machine adds one rotary axis, usually the A axis, which turns the part around the X axis. Now the tool can reach around the perimeter of a cylindrical or shaft-type part in a single program. Think of a flange with a bolt circle on the outside diameter, or a shaft with flats and cross holes at several angles.
The 5-axis family splits into two layouts. Table-table machines tilt and rotate the workpiece on two rotary axes. Spindle-tilt machines swing the tool instead. Both let the cutter approach a surface from an angle, which is what makes undercut pockets and compound-angle faces machinable without a custom fixture.
3-Axis Machining: What It Handles Best
A 3-axis mill is still the workhorse. It cuts prismatic parts: plates, brackets, housings, manifolds and anything where the features sit on one or two parallel faces. Setup is simple and programming is predictable, so the cost per part stays low on runs from one piece to ten thousand.
The limit is reach. A deep pocket with a sharp internal corner needs a tool small enough to fit, and small tools deflect. On a 3-axis machine the tool always comes straight down, so a wall that leans away from the spindle is hard to finish cleanly. You end up with witness marks or a stepped surface.
We keep 27 three-axis machines for this kind of work, with travels like 750 × 1,150 × 550 mm and 600 × 600 × 600 mm. Typical tolerance holds at ±0.005 mm (±0.0002 in) on critical dimensions when the fixture is rigid and the tool is fresh.
Pick 3-axis when the part is flat, the quantity is high and the geometry is forgiving. It is the cheapest way to make a good bracket.
5-Axis Machining: When the Extra Axes Pay Off
Five-axis work earns its cost on three things: part complexity, setup count and surface quality. A single 5-axis setup can replace four or five 3-axis setups, and every removed setup removes a re-fixturing error. On a part with tight true-position callouts between faces, that matters more than spindle speed.
Simultaneous 5-axis also lets the tool stay normal to a curved surface. Instead of a ball nose dragging across a contoured face and leaving scallops, the cutter tilts to follow the slope. Finish improves and the polishing step shrinks. We run 16 simultaneous 5-axis machining centers for exactly this reason.
The trade-off is programming time and rigidity. A 5-axis toolpath takes longer to prove out, and a long tool held at an angle deflects more than the same tool held vertically. Deep, thin-walled pockets are still hard. For those, a 3-axis approach with a good fixture often wins.
Typical fits: impellers, turbine housings, medical instrument bodies, aerospace brackets with compound angles, and any prototype where the geometry is still moving.
Turning, Mill-Turn and Live Tooling
A lathe spins the workpiece against a stationary or slowly rotating tool. Anything round belongs here: shafts, bushings, pins, valve bodies, connector shells. Turning a diameter is far faster than milling around it, and the surface finish on a turned OD is usually better than a milled one.
The interesting machines are the mill-turn centers. They combine a turning spindle with a milling spindle and often a B axis, so one machine can turn the OD, mill a flat, drill a cross hole and cut a slot without moving the part. We run 16 of them alongside a Ø400 mm rotary table for larger work.
That matters for concentricity. Every time you move a part from a lathe to a mill, you re-chuck it and lose a little runout. Mill-turn keeps the part in one grip, so the bolt circle stays concentric with the bore. If your drawing has a 0.02 mm total runout between a turned bore and a milled pattern, this is the machine to ask for.
Live tooling on a standard lathe gives you part of that benefit at lower cost. It handles simple cross holes and flats. It will not do a deep pocket or a compound angle.
EDM, Grinding and the Non-Cutting Options
Not every feature can be cut by a spinning tool. Wire EDM burns a path with a thin wire and a spark, which lets it cut hardened steel, sharp internal corners and very thin walls without tool pressure. A punch die or a medical blade with a 0.2 mm slot is wire EDM work, not milling work.
Sinker EDM goes the other way. It burns a shaped electrode into a cavity, which is how you make a deep rib in a mold insert that no end mill can reach. It is slow and needs an electrode, so it is a targeted operation, not a whole-part strategy.
Surface grinding and cylindrical grinding handle the parts that need flatness or roundness tighter than milling can hold, or a finish down to Ra 0.2–0.8 μm. Hardened shafts, gauge blocks and sealing faces land here.
A quick note on the question itself. CNC machines are there in every shop, but the useful answer is not a list of names. It is which machine can hold your tolerance, in how many setups, at what cost.
Which CNC Machine Fits Which Part
Match the part geometry to the machine before you send the RFQ.
| Machine | Best part shape | Typical tolerance | Watch out for |
|---|---|---|---|
| 3-axis mill | Plates, brackets, flat housings | ±0.005 mm | Features on more than two faces |
| 4-axis mill | Shafts, flanges, bolt circles | ±0.005 mm | Deep pockets off the rotary axis |
| 5-axis mill | Compound angles, contoured surfaces | ±0.005 mm | Long tools held at an angle |
| Mill-turn | Round parts with milled features | ±0.005 mm | Bar size and chuck limits |
| Wire EDM | Hardened steel, thin slots, sharp corners | ±0.005 mm | Cut speed on thick sections |
| Grinding | Sealing faces, hardened shafts | Ra 0.2–0.8 μm | Part geometry must suit the wheel |
The Short Version
If your part is flat and the quantity is high, a 3-axis mill is the cheap and correct answer. If it has features on four or five sides, or a curved surface that must finish clean, pay for 5-axis and save the setups. If it is round with cross features, ask for mill-turn before you ask for a fixture.
Questions We Get on Machine Choice
Does a 5-axis machine always give a better part than 3-axis?
No. It gives you fewer setups and better tool access. If the part is a flat plate, 5-axis adds programming cost without improving the result.
The gain shows up on complex geometry and on parts with tight relationships between faces. On simple parts, a rigid 3-axis setup with a good fixture can hold the same tolerance for less money.
What is the largest part you can machine?
Our largest travel is 4,000 × 400 × 150 mm. Medium machines cover 750 × 1,150 × 550 mm and 600 × 600 × 600 mm, and compact machines handle 500 × 500 × 450 mm and 500 × 310 × 200 mm.
If your part falls outside these envelopes, tell us the size on the quote form. We will say straight away whether it fits or needs a different process.
How do you hold ±0.005 mm across a production run?
The tolerance comes from the whole setup, not the machine alone. Rigid fixturing, a warm spindle, sharp tooling and in-process checks all contribute.
We inspect 100% of parts before shipment, with raw material checks, in-process monitoring and a final inspection. Reports are available on request.
Can you machine hardened steel?
Yes. Wire EDM cuts hardened material without tool pressure, and grinding handles faces that need flatness or a fine finish.
For softer stock, milling and turning are the faster routes. Tell us the material and hardness on the RFQ and we will pick the process.
Which materials do you run most often?
Aluminium grades like 6061, 7075 and 6082, stainless 303, 304 and 17-4PH, steels including 4140 and 4340, plus brass, copper, titanium and engineering plastics such as POM and PEEK.
Material choice affects tool life, finish and which machine we schedule. It is worth naming the exact grade rather than writing aluminium.
Do you take small orders?
Yes. There is no minimum order quantity, so a single prototype and a 10,000-part run both go through the same process.
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