Basic CNC machine for your store: what to buy first

Most job shops and prototype stores open with a 3-axis vertical mill and a turning center. A 3-axis mill cuts prismatic parts: plates, housings, brackets, fixtures. A lathe handles anything round, from shafts to bushings to threaded fittings. Together they cover a large share of the metal and plastic parts that walk through a store door. Add a surface grinder only when you regularly hold flatness or finish on hardened stock.

The 4-axis mill is the first real upgrade. A rotary table, often Ø400 mm, lets the tool reach the fourth side of a part without a second setup. Setup time drops, and so do re-clamping errors. If your work is mostly one-sided plates, you do not need it yet. If your parts have features on three or four faces, it pays back quickly.

5-axis machining is a different decision. A simultaneous 5-axis center cuts impellers, medical implants, and contoured mold inserts in one setup. It is not a general-purpose upgrade for a store that cuts brackets. Buy it when the geometry demands it, or send that work to a partner and keep your capital free. GreatLight runs 16 simultaneous 5-axis machining centers for exactly this reason: complex work arrives in batches, not every day.

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  3-axis millBest first machine. Plates, pockets, housings, fixtures.
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  Turning centerRound parts, threads, bores. Often the second purchase.
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  4-axis millAdd when parts need three or four machined faces.
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  5-axis centerOnly for contoured or angled geometry. High cost per axis.

Travel is the first number to check against your actual part envelope. A compact mill with 500 × 500 × 450 mm travel covers most small-part work. Medium machines at 750 × 1,150 × 550 mm and 600 × 600 × 600 mm handle larger plates and molds. If you expect long parts, you need a machine rated to 4,000 mm, and that is a different class of foundation and floor space.

Spindle power and rigidity decide which materials are realistic. Aluminium 6061 and 7075 cut easily on a light mill. Stainless 304 and 17-4PH demand more torque and a rigid frame. Titanium TC4 and Inconel will punish a machine that was never built for them. Match the spindle to the material mix you expect, not to the brochure maximum.

Repeatability matters more than the best single measurement. A machine that holds ±0.005 mm across a full shift is worth more than one that hits it once on a warm afternoon. Ask how the builder verifies positioning accuracy and how often the machine needs re-calibration.

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  TravelMeasure your largest part plus fixture and tool clearance.
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  SpindlePick for your heaviest material, not your lightest.
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  RepeatabilityAsk for a test across a full working day.

A basic store should be honest about its material range. Aluminium grades 6061, 6061-T6, 2024, 5052, 6063, 6082 and 7075 cut cleanly on a well-rigged 3-axis mill. Brass C36000 and copper C110 machine fast and are good work for a new shop because they forgive small errors in speed and feed.

Stainless is where the machine class shows. Grades 303 and 304 are common; 316L and 17-4PH appear in medical and marine work and need slower feeds and more rigid setups. Tool steel and 4140 push the spindle harder again. If stainless becomes a large share of your orders, plan the upgrade before the orders arrive.

Plastics are often overlooked. ABS, POM, PC and PA machine well on the same mills, though workholding and chip evacuation need different attention. PEEK and carbon fibre are specialist jobs: PEEK is abrasive and expensive, and carbon fibre dust needs extraction. Do not promise these materials until you have cut them.

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  Easy startAluminium, brass, copper, ABS, POM.
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  Needs rigidity304, 316L, 17-4PH, 4140, tool steel.
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  Special handlingPEEK, carbon fibre, Inconel, magnesium.

No basic machine store covers every process, and pretending otherwise costs money. Deep pockets, fine slots, and sharp internal corners often need EDM or a high-speed spindle that a starter mill does not have. Hardened parts above 45 HRC usually go to grinding or wire EDM. Thin sheet with tight bend radii belongs on a press brake, not a mill.

Surface finishing is another common gap. Anodizing, electroless nickel, powder coating and laser marking all need dedicated lines and chemical handling. A store that machines well but finishes poorly still ships parts customers reject. Either build the finishing cell or work with a partner who runs one and understands your tolerances.

The practical rule: keep the work your machines do well, and outsource the rest with a clear drawing and a tolerance callout. Sending out a complex 5-axis job is not a loss. It is how a small store wins an order it could not otherwise quote.

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  Keep in-housePrismatic milling, turning, simple drilling.
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  Send outEDM, hard turning, tight sheet bends, specialist finishing.
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  Always sendA drawing with datums and a tolerance callout.

A machine alone does not make a store. You need workholding, tooling, a probe or a good edge finder, and a way to measure what you cut. A basic inspection kit with calipers, micrometers and a height gauge covers small parts. For anything tighter, plan for a coordinate measuring machine or an outside inspection service.

First-article inspection on every new job catches setup errors before you cut fifty parts. In-process checks catch tool wear. Final inspection before shipment catches the rest. GreatLight inspects 100% of parts before shipment and can supply reports on request; a small store can copy the discipline even without the same equipment.

Document what worked. Speeds, feeds, fixture notes, and the tool that failed at 1,200 rpm. This record becomes the store's real asset, more useful than any single machine purchase.

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  WorkholdingVises, soft jaws, vacuum plates, custom fixtures.
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  MetrologyCalipers and micrometers first, CMM when tolerances tighten.
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  RecordsSpeeds, feeds, fixture notes, failure causes.