Albuquerque CNC machining precision for metal parts
A process guide for engineers and buyers sourcing machined metal parts for Albuquerque programs. It covers what 5-axis work can hold, which materials and finishes fit which duty, and where machining stops being the right call. Read it to decide process, tolerance class and inspection scope before you send an RFQ.
What precision machining actually controls
Tolerance, surface, material and setup count decide whether a part is machinable at the price you want.
What a CNC machine holds, and what it does not
CNC machining removes metal with a rotating cutter driven by a controlled program. The machine does not decide tolerance for you. What decides it is the rigidity of the setup, the number of times the part is re-fixtured, and how the datum is carried from operation to operation. A part held in one orientation with a single datum can hold ±0.005 mm. The same part flipped four times will drift, no matter how good the machine is.
For Albuquerque CNC machining precision work, the practical ceiling is ±0.005 mm on featured dimensions, with surface finish between Ra 0.2 and 0.8 μm when the operation calls for it. As-machined surfaces typically sit at Ra 1.6–3.2 μm. Tightening both at once is possible but costs money, because fine finish usually needs a separate finishing pass with a smaller stepover and a different tool.
The size of the part sets the machine class. We run 16 simultaneous 5-axis centers, 12 four-axis mills, 27 three-axis machines and 16 mill-turn centers across three plants, 7,600 m² total. Maximum processing size is 4,000 mm, with common travels at 4,000 × 400 × 150 mm, 750 × 1,150 × 550 mm, 600 × 600 × 600 mm, 500 × 500 × 450 mm and 500 × 310 × 200 mm. A Ø400 mm rotary table handles round work that would otherwise need two setups.
- 1One setup winsFewer re-fixtures means less stacked error and a shorter print-to-part path.
- 2Datum disciplinePick a datum you can reach in every operation. If you cannot, the tolerance will not hold.
- 3Finish is a second costRa 0.2–0.8 μm usually means a separate pass, not one heavy cut.
- 4Size drives machine choiceA 3,000 mm frame will not fit a 500 mm travel machine, so plan the blank size early.
Machine class and what it is good for
Use this to pick the process before you pick the shop.
| Machine class | Typical work | Where it stops |
|---|---|---|
| 3-axis | Prismatic parts, plates, housings | Undercuts and angled holes need a second setup |
| 4-axis | Shafts, manifolds, parts with indexed faces | Continuous freeform surfaces are slow to program |
| 5-axis simultaneous | Impellers, medical instruments, complex aerospace forms | Not economical for simple flat plates |
| Mill-turn | Round parts with milled flats and cross holes | Long slender parts can chatter without a steady rest |
| Large travel | Frames, rails, long structural parts up to 4,000 mm | Thin walls distort unless stress-relieved stock is used |
Matching the alloy to the duty
Aluminum is the default for prototypes and low-load parts. 6061-T6 machines cleanly and anodizes well. 7075 gives higher strength for brackets and stressed housings but is less weldable. 2024 has good fatigue behavior and poor corrosion resistance unless it is coated or anodized. ADC12 is a die casting alloy, so it only makes sense when the part is cast, not cut from plate.
Stainless is where the finish and the application usually decide. 303 is the easiest to machine and is fine for fittings and bushings. 304 and 316L are common for medical and food-contact parts; 316L resists chlorides better. 17-4PH can be aged to high strength and is often used for surgical instruments and valve parts. 440C holds a sharp edge and is used for wear surfaces.
For steel, 1018 is a low-carbon general-purpose choice, 1045 and 4140 cover shafts and wear parts, and 4340 is used when toughness matters more than machinability. Titanium TC4 (Ti-6Al-4V) is common in aerospace and medical work; it cuts slowly and needs sharp tooling and good coolant. Inconel and magnesium AZ31B / AZ91D are ordered when the application demands them, not to save cost.
- 16061-T6General aluminum, good finish, anodizes predictably.
- 27075Higher strength brackets, less corrosion resistance than 6061.
- 3316LChloride resistance for medical and marine-adjacent parts.
- 4TC4High strength-to-weight, slow to cut, plan for longer cycle time.
When machining is the wrong process
Machining is a subtractive process, so it pays off when the part count is low to medium and the geometry needs to be exact. It stops making sense when the same part is needed in the tens of thousands with no tight tolerance. At that point die casting or another casting route wins on unit cost. We offer both, so the recommendation is usually about your volume, not about what we prefer to run.
It also stops making sense when the part is mostly flat and thin. A sheet metal enclosure with a few holes should be laser cut and formed, not milled from a billet. The material cost and cycle time diverge by an order of magnitude. If you are unsure, send the drawing and the annual quantity; we will tell you which route fits.
There is a third case: a part that is machinable but not inspectable. If a critical feature sits inside a closed cavity with no line of sight, you cannot verify it after the fact. In that case we either add a witness feature, split the part, or agree on a first-article inspection plan before cutting chips. Better to settle that in the DFM review than after the parts arrive.
Tolerance and finish selection guide
Choose the loosest class the function allows.
| Class | Tolerance | Typical finish | Use for |
|---|---|---|---|
| General | ±0.1 mm | Ra 1.6–3.2 μm | Brackets, covers, non-mating faces |
| Precision | ±0.02 mm | Ra 0.8–1.6 μm | Bearing bores, mating faces, alignment features |
| Fine | ±0.005 mm | Ra 0.2–0.8 μm | Seals, spindles, optical and medical interfaces |
Finishes, inspection and what ships with the parts
Finishing is usually chosen for corrosion, wear or appearance, in that order. Anodizing in clear, color, hardcoat or conductive form covers most aluminum. Electroless nickel, zinc, silver and gold plating handle conductivity and wear. Powder coating and black oxide cover larger parts. Bead blasting, tumbling, brushing and polishing set the cosmetic baseline. Laser marking and engraving are available down to 1.5 mm character height.
Inspection is where precision is proven or lost. We check raw material on receipt, monitor in process, and inspect 100% before shipment, with reports on request. The qualification rate across production is 99.99%. For a part with a fine tolerance class, ask for the specific measurement method on the print, not just a general note, because a CMM report and a hand-tool check do not mean the same thing.
We hold ISO 9001:2015, IATF 16949:2016, ISO 13485:2016 and ISO 27001:2022. The first two matter for industrial and automotive buyers; ISO 13485 matters for medical device work; ISO 27001 covers how files and drawings are handled. Uploads are secure and confidential, and an NDA is available on request at the page linked below.
- 1AnodizingClear, color, hardcoat or conductive, depending on wear and grounding needs.
- 2PlatingElectroless nickel, zinc, silver, gold for wear or conductivity.
- 3MarkingLaser marking and engraving, 1.5 mm minimum character height.
- 4ReportsInspection reports on request; agree the method on the print.
Questions engineers ask before the first cut
What tolerance can you hold on a typical machined metal part?
Featured dimensions can be held to ±0.005 mm (±0.0002 in) on parts that are set up in one orientation with a stable datum. General features at ±0.1 mm are far cheaper and are enough for most brackets and covers.
The limiting factor is usually setup count and part rigidity, not the machine. Thin walls and long unsupported sections will move during cutting, so we plan the sequence around that.
Do I need 5-axis machining for my part?
Only if the geometry has undercuts, compound angles or freeform surfaces that would otherwise need three or four separate fixturings. A flat plate with a few holes is faster on a 3-axis machine.
Five-axis pays for itself when the alternative is multiple setups and hand blending. If the part is simple, 3-axis is the better call on cost and lead time.
What is the smallest order you accept?
There is no minimum order quantity. We run from one prototype to 10,000+ part runs, using the same programs and inspection plan.
For a single part, the setup still has to happen, so the unit price reflects programming and fixturing rather than material.
How fast can I get parts?
Quotation and a free DFM analysis come back within 12 hours. Production can start within 24 hours after that, and parts ship in 3–5 days.
These figures assume the drawing is released and the material is in stock. Non-standard alloys or heavy finishing add time, and we will say so in the quote.
How do you protect my drawings and files?
Uploads are secure and confidential. We hold ISO 27001:2022 for information security, and an NDA is available on request.
If your program requires it, we can restrict the files to the quoting and programming team only.
Can you inspect a feature that is internal or hard to reach?
Sometimes, but not always. If a critical dimension sits inside a closed cavity with no line of sight, it cannot be verified after machining without destructive sectioning.
In those cases we raise it during DFM: add a witness feature, split the part into two pieces, or agree on a first-article plan before cutting. It is better to settle this before the first operation.
Send the drawing, get a manufacturability answer
We review your model, flag the features that will not hold, and quote the process that fits your volume. Quotation and free DFM analysis within 12 hours.
12-hour quote100% inspectionNo MOQNDA on request
