Metal CNC Machine Price Guide

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  What decides the number
• 2
  What each parameter adds to the quote
• 3
  How axis count changes metal CNC machine price
• 4
  Travel limits and why small parts still pay for big tables
• 5
  Tolerance and finish: where cost jumps
• 6
  Material choice and tool wear
• 7
  Why two quotes for the same part differ by 3×
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  Step by step: how to compare metal CNC machine price quotes

Axis count is the first thing buyers ask about, and usually the wrong first question. A 3-axis mill cuts the top of the part, then you flip it and cut again. Each flip costs an operation, and each operation adds setup time and a small position error. For a bracket with two flat faces, that is fine.

A 5-axis center holds the part once and reaches five sides. The value shows up when a part has compound angles, deep pockets, or features that must stay concentric to a datum. On a hydraulic manifold with four angled ports, one 5-axis setup often beats three 3-axis setups on total cost, even though the hourly rate is higher.

The reverse is also true. If your part is a flat plate with through holes, paying for 5-axis capacity buys nothing. We see quotes come in 40–60% higher when a buyer asks for 5-axis on geometry that a 3-axis machine handles in one setup. Match the machine to the drawing, not to the spec sheet.

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  Use 3-axisPrismatic parts, flat datums, holes normal to a face.
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  Use 4-axisShafts, bushings, parts with features on four sides of a cylinder.
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  Use 5-axisCompound angles, contoured surfaces, tight true position across faces.

Work envelope is a hard limit. A 500 × 500 × 450 mm machine cannot cut a 900 mm housing, no matter how the programmer slices it. When a part exceeds the envelope, the shop either moves to a larger machine or splits the part into pieces to be joined later. Both routes raise metal CNC machine price and add risk.

Large travel does not automatically mean lower accuracy. A 4,000 × 400 × 150 mm machine with a good control holds ±0.005 mm on features near the spindle. The issue is thermal drift over a long cut. A 40-minute pass on a 3,000 mm rail lets the frame warm and move. Shops that hold tight tolerance on long parts run roughing and finishing in separate passes with a cool-down between them.

For most parts under 400 mm, the compact class at 500 × 310 × 200 mm is the economical choice. It is stiffer per unit of travel, and the shorter axis strokes mean faster rapids. Do not specify a large machine because the part might grow in two years. Pay for the part you have.

Tolerance is not a single number on the drawing. It is a set of requirements, and each one is priced. A general tolerance of ±0.05 mm on a milled outline is routine. A ±0.005 mm bore needs a different spindle, a warm-up cycle, and often a finish pass with a boring head or a ground pin gauge to verify.

The trap is applying tight tolerance to everything. If a drawing calls ±0.005 mm on a mounting face that only needs to sit flat, the shop must slow the cut, add inspection, and possibly scrap more parts. Those costs land in your quote. Mark the two or three features that truly control function and leave the rest at general tolerance.

Surface finish follows the same logic. Ra 1.6–3.2 μm is what comes off a normal finishing pass. Ra 0.8–1.6 μm needs a lighter stepover and a sharp tool. Ra 0.2–0.8 μm usually means polishing or lapping after machining, which is a separate operation with its own labor cost. Specify finish only on sealing faces, bearing seats, and sliding surfaces.

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  Call out datumsA tight tolerance without a datum is unmeasurable and gets priced as risk.
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  Group tight featuresPut critical dimensions on one face when possible to save setups.
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  Skip cosmetic RaAesthetic surfaces rarely need better than Ra 1.6 μm.

Aluminium 6061 machines fast. A 12 mm carbide end mill can run at high speed with good chip evacuation, and tool life is long. That is why aluminium prototypes are cheap per part. Move to 304 stainless and the same cut runs at roughly half the surface speed with more coolant and more tool changes.

Titanium and Inconel push it further. Ti-6Al-4V conducts heat poorly, so the cutting edge absorbs it. Tools wear quickly, feeds drop, and the cycle time can be three to five times the aluminium equivalent. Inconel is worse. If your design can use 17-4PH instead of Inconel, the savings are real and the mechanical properties are often still enough.

Material also changes the fixture. Thin-wall aluminium parts deflect and need support. Hardened steel above 40 HRC may need a pre-hardened blank and carbide tooling reserved for it. Tell the shop the final material and heat treat in the RFQ. A quote based on aluminium will not hold once the part is switched to 4140.

A wide spread between quotes usually means the shops read the drawing differently. One may plan three setups, the other one. One may include a fixture in the first-piece cost, the other amortizes it across the batch. One may quote the tolerance as drawn, the other may quote a looser process and hope you do not measure.

Ask for the assumptions, not just the total. Cycle time per part, number of setups, material cert, and inspection method are the four numbers that explain a quote. A shop that cannot state them is pricing on guesswork, and guesswork tends to get revised upward after the PO is signed.

Incoming inspection is the other hidden line item. A supplier running 100% inspection before shipment will charge more than one that samples. For medical and automotive work, that inspection is not optional. For a prototype bracket, it is overhead you may not need. Say which one you want up front.