Machining Services: Machined Parts

How is the price of a machined part actually built?

A part price has four layers: material (alloy grade and scrap), machine time (set by process and tolerance), setup and programming (amortized over quantity), and finishing (any secondary operation). When a manufacturer quotes, it is adding these up, so a breakdown that names each layer tells you whether the price is honest, while a single bottom-line number hides which layer is heavy.

The layers stack — they do not sit side by side. Material sets the floor, tolerance decides how slowly you cut it, process decides how many times you set it up, and quantity amortizes the setup. Change one layer and the ones above it move too — a cheaper material that machines slower can cost more in machine time than a dearer material that cuts fast. That is why a transparent quote is a map of the cost, not just a number at the bottom.

Price layer	What it contains	How to read it
Material	Alloy grade plus scrap allowance	Name the grade; "aluminum" is a guess
Machine time	Cutting time set by process and tolerance	Tighter bands mean slower feeds
Setup / programming	Fixtures, tooling, first article	Amortizes over quantity
Finishing	Anodizing, plating, coating, heat treat	Each step should be a strikeable line

Which materials can this manufacturer machine?

The floor runs the alloys buyers actually put on drawings, and every incoming lot is XRF-checked against its mill certificate before it touches a machine. That check is a cost-saver for you: it catches a mixed or substituted grade at the door instead of in your assembly.

Material family	Grades run	Cost note
Aluminum	6061, 6063, 6082, 7075, 2014	Fast to machine, low cost floor
Stainless steel	303, 304, 316, 316L, 17-4PH	303 for free-machining, 316L for corrosion
Carbon / alloy steel	1018, 1045, 4140, 4340, 12L14	Carburizing or nitriding for wear parts
Brass / copper	C360, H62, C110	Lowest machinability penalty
Titanium	TA2, TC4 (Grade 2 / 5)	Higher cost; stress relief above 500 °C outsourced
Plastics	ABS, POM, nylon, PTFE, PEEK	For prototypes and insulators

Why do tolerances change the unit price?

Every tight tolerance is a decision to slow down and measure. A part toleranced at ±0.003 mm (milling) / ±0.002 mm (turning) across the board costs more than the same part with tight bands only on the few dimensions that control function. The manufacturer holds ±0.003 mm on CNC milling, ±0.002 mm on CNC turning and ±0.002 mm for grinding — the point is to apply those bands selectively, so you pay for precision only where it earns its keep.

Tolerance band	Typical process	What it buys you
±0.05 mm	Standard milling / turning	Clearance and non-mating surfaces, lowest cost
±0.003 mm (milling) / ±0.002 mm (turning)	Precision milling / turning	Press fits, bearing bores, locating features
±0.002 mm	Grinding after turning	Journals and seats that fail if out of round

The step between bands is not linear. Each tighter band adds a slower feed, a sharper tool, and a CMM check, so a drawing that pins every feature to the tightest band pays the grinding price on surfaces that never needed it. Read your own print and ask which dimensions actually carry load, locate, or seal — then tolerance only those, and leave the rest at a band that costs nothing to hold.

Which processes run in-house, and why does that matter to cost?

In-house processes mean fewer handoffs, and every handoff is a place where schedule and quality leak. Keeping milling, turning, mill-turn, and grinding under one roof means a part does not leave the building between operations, which keeps the cost down and one supplier accountable.

Process	Capacity	Max workpiece
3-axis milling	50+ centers	1300 × 700 × 600 mm (milling)
4-axis milling	20+ centers
5-axis milling	20+ centers
CNC turning	25+ lathes	Ø720 × 1280 mm
Mill-turn	Multi-task centers (Mazak / Brother class)	Single-setup complex geometry
Grinding	7+ (surface / centerless / cylindrical)	±0.002 mm finishes

How does quantity lower your per-part cost?

Setup and programming are paid once. At one piece, that fixed cost sits entirely on the single part; at a thousand, it disappears into the batch. The MOQ here is 1 piece, so the cost-efficient path is to validate a design with one part, then release volume where the unit price falls on its own.

The learning curve is the second effect. Early parts run slower as the operator proves out the program and tool life settles; later parts run at the process's steady-state speed. A short run never reaches that steady state, so every part carries the proving-out time. A longer run does, and the per-unit cost falls toward the floor the process can actually hold.

Which secondary operations can be bundled into the same job?

Bundling finishing into the same job removes separate vendor markups and transit. Surface treatments — standard and hard anodizing, plating, powder coating, painting, brushing, and polishing — plus heat treatment (vacuum, bright, carburizing, nitriding, stress-relief) can be folded into one flow. In-house ovens top out at 500 °C — enough for aluminum and low-temperature steel stress relief — while titanium stress relief above that goes to a qualified partner, keeping the cost honest.

The honesty about the split is what matters. A shop that tells you which finishing steps run in-house and which go to a partner is giving you the map of your own supply chain. A shop that claims everything in-house is either a rare vertically integrated floor or a shop that is hiding the handoff, and the handoff is where your schedule and quality leak.

What should you check before placing an order?

Before you commit, confirm the quote names the alloy grade, states the tolerance band per feature, and separates finishing. A manufacturer that flags a DFM problem before quoting — a wall too thin, a tolerance it cannot hold — is saving you money a yes-to-everything shop would spend for you.

How do you read a quote back against your drawing?

A quote is a mirror of your drawing. If the number comes back with no breakdown, the manufacturer has not told you which lever is heavy, which means you cannot negotiate it down. Read the quote line by line against the print and challenge every layer that does not earn its keep.

• Material: does the grade on the quote match the grade on your print, or does it just say "aluminum"?
• Tolerance: are tight bands tied to named features, or applied as a blanket across the whole part?
• Process: is the part routed to the lowest axis count and fewest setups that still hold the geometry?
• Finish: is every secondary operation a separate line you can strike, or bundled and vague?
• Documentation: does the quote state what ships with the parts — CMM report, SPC chart, material certificate?

What DFM feedback should a parts manufacturer give you?

A good manufacturer reads your drawing before it prices it, and the reading produces feedback. The feedback is the signal that the shop understood your part: a wall flagged as too thin, a tolerance flagged as tighter than the function needs, a corner flagged as impossible to cut sharp. Each flag is a cost you can remove before the first chip is cut, and a shop that offers none is either pricing a guess or agreeing to everything.

Treat the DFM feedback as a competence test. The manufacturer that catches the impossible tolerance on paper is the manufacturer that will not discover it in metal after your purchase order is open. The one that agrees to everything has not looked, and the first time the part fails is on your bill, not theirs.

What documentation should ship with your machined parts?

Parts are only as good as the evidence that travels with them. A material certificate proves the alloy is the grade you paid for; a CMM report proves the dimensions are the ones you toleranced; an SPC chart proves the process held them by capability, not by luck. Together they turn a shipment of metal into a verifiable delivery, and for regulated or automotive work they are the price of admission.

• Material certificate — matches the XRF check and proves the grade at the door.
• CMM dimensional report — measured values against your drawing, not a "passed" stamp.
• SPC chart — the Cpk evidence that the process held the band repeatedly.
• First-article report — the prototype's full dimensional record, before volume.

Ask what ships before you order, not after. A shop that documents its work is a shop you can re-audit against a future batch; a shop that ships bare parts is asking you to trust a claim you cannot check.

How do you cut a part's cost without weakening it?

Cost reduction is a design exercise, not a negotiation exercise. The savings that stick are the ones you bake into the print before quoting — a looser tolerance on a non-mating surface, a freer-cutting alloy that meets the same strength, a pocket radius that avoids a second pass. These changes do not weaken the part; they remove cost that was never buying function.

• Loosen the non-critical tolerances. Leave clearance surfaces at ±0.05 mm and spend the tight band only where it locates or seals.
• Downgrade the alloy where strength allows. 6061 instead of 7075 when the load does not demand the extra yield.
• Add a corner radius. A radiused internal corner mills in one pass where a sharp one needs two.
• Shorten the deep hole or tap. A shallower hole costs less and holds as much where the function allows.

The discipline is to ask, for each change, whether the function still holds. If it does, the saving is real and it repeats on every unit for the life of the part, which is why the cheapest part is designed, not bought.

What this shop actually runs

If you ask for capability evidence, you deserve a specific answer. This facility operates 100+ CNC machines across 6,800 m2 in Dongguan, China, staffed by 100+ people. The machines, listed by category:

• 5-axis machining centres (10+) - Mazak VARIAXIS I-600 (510/910/510 mm travel, 12,000 rpm, 22 kW, 71.6 N·m, 30-tool BT40) and Mazak INTEGREX I-250H S (B-axis 0.0001°, 24 kW, 124 N·m, 38-tool HSK-A63). Used on compound-angle parts, single-setup multi-face prismatic work, and aerospace fittings where datum transfer loss is unacceptable.
• 3-axis / 4-axis machining centres (50+) - Brother SPEEDIO S500Z2N / S700Z2N (10,000 rpm, 14/21-tool ATC, 0.7 s tool-to-tool, Z-axis 2.2 G) and Mazak VCE-430A L / VCE-570C L (10,000 rpm, 118 N·m, 24-tool ATC). Used on prismatic parts, plates, brackets, housings.
• Swiss-type turning centres (10+) - Citizen Cincom A20-3F7 (Φ20 mm, 10,000 rpm), TSUGAMI B0206-III / B0205-III (Φ20 mm, 0.1 µm), STAR SR-32JII / SR-32J Type N (Φ32 mm, 8,000 rpm). Used on long, slender rotational parts at ±0.002 mm.
• CNC turning centres (20+) - HEADMAN T70M/1250 (720 mm swing, 117 mm bore, 3,000 rpm, BMT75 12-station turret). Used on shafts, bushings, flanges up to ±0.002 mm.
• Wire EDM (5+) - Sodick AQ535L (550/350/300 mm travel, ±20° taper, 800 kg workpiece). Used on hardened tool steel, internal splines, sharp internal corners that milling cannot reach.
• Inspection: Hexagon CMM + 20+ gauges - Hexagon CMM for coordinate measurement, plus vision system, profilometer, hardness tester, coating thickness gauge, XRF for material verification. The 10:1 rule (gauge 10x more accurate than the band) is applied to every feature.
• Machine highlights - VARIAXIS I-600: one-setup multi-face 5-axis + MAZA-CHECK auto-calibration; INTEGREX I-250H S: DONE-IN-ONE mill-turn, B-axis 0.0001° + Ai thermal shield; SPEEDIO S500Z2N / S700Z2N: Z-axis 2.2 G + 0.7 s ATC; Swiss-type: guide-bush switchable + 0.1 µm resolution.

Tolerance bands: ±0.003 mm milled, ±0.002 mm turned, ±0.002 mm ground or wire-cut. Capability indices: Ppk >= 1.67 at the initial study; Cpk >= 1.33 ongoing in production.

Certifications: ISO 9001:2015 (116024/A/0001/UK/En) · IATF 16949:2016 (131941/A/0001/SM/En, design clause 8.3 excluded) · ISO 14001:2015 (116024/B/0001/UK/En), held by Dongguan Zhuohang Ltd (USCC 91441900MA4UWT6X39, since 2005).

Service area: we supply Austria, Belgium, the Czech Republic, Denmark, France, Germany, Greece, Hungary, Ireland, Italy, the Netherlands, Spain, Sweden and the United Kingdom in Europe; Brazil, Canada, Mexico and the United States in the Americas; China, Israel, Japan, Singapore and Sri Lanka in Asia; Australia and New Zealand in Oceania; and South Africa in Africa, with worldwide delivery from China.

Contact: Felipe Iglesias, [email protected], +86 13126536955.

Frequently Asked Questions

Standards referenced on this page

• ASTM B211/B211M-19 — Standard Specification for Aluminum-Alloy Rolled or Cold Finished Bar, Rod, and Wire
• ASTM A276/A276M-17 — Standard Specification for Stainless Steel Bars and Shapes
• ISO 9001 — Quality management systems — Requirements