01
A tolerance the process cannot hold
A ±0.01 mm true position on a 300 mm aluminum frame will move after stress relief. The print looks fine. The CMM report does not. Rework costs more than the original cut, and the schedule takes the hit twice.
Machinist Resources
Machinist Resources
A working reference for engineers and shop leads: tolerance stacks, thread milling, EDM selection, burr control, and the process limits behind every quote. Numbers you can put on a print.
±0.005 mm tolerance16 five-axis centersRa 0.2–0.8 μm12-hour quoteNo MOQ
127High-precision CNC machines
16Simultaneous 5-axis centers
±0.005 mmAchievable tolerance
15 yearsMachining since 2011
Where it goes wrong
Four problems that start on the print, not on the machine
Most scrap is decided before the first cut. These are the ones we see every week.
02
Thin walls that chatter
A 0.8 mm wall on a 6061 housing deflects under a 12 mm end mill. You get taper, a poor finish, and a wall thickness that varies across the part. Light passes fix the finish, not the cycle time.
03
Threads called out the wrong way
A tapped hole in 17-4PH at 3× diameter depth will break a tap. The drawing does not say thread mill, so the shop taps it anyway. One broken tool scraps a part that already has 6 hours in it.
04
Deburring left to the end
Burrs at an internal cross-hole are invisible until assembly. Cleaning them after anodizing removes the coating on the edge and leaves a bare ring. That is a reject at final inspection, not a touch-up.
How we work
Process selection before programming
Pick the machine from the geometry and the material, not from what is free this week.
Setup and workholding
Fewer setups, tighter stacks
Every setup adds a datum error. On a part with four faces of work, three setups can add 0.02 mm of stack-up before the tool touches metal. Mill-turn centers and 5-axis trunnion tables let us reach five faces in one fixturing, so the position between features comes from the machine, not from re-clamping.
For thin-wall parts we machine from a solid billet and leave a sacrificial web. The web holds the wall rigid through roughing, then comes off in a light finishing pass. On a 0.8 mm aluminum wall this is the difference between a parallel wall and a tapered one.
- 1One-fixturing 5-axis16 simultaneous 5-axis centers, Ø400 mm rotary table
- 2Large envelopeUp to 4,000 × 400 × 150 mm travel on large mills
- 3Sacrificial websKeeps thin walls supported through roughing
Edge finishing
Burrs, edges, and what the finish hides
Burr size follows the tool and the material, not the operator. A sharp 4-flute carbide end mill in 304 stainless rolls a burr at the exit face. A 0.05 mm edge break removes it. We specify edge breaks on the process sheet, so deburring is a controlled pass, not a bench guess.
Finishing changes the edge again. Bead blasting rounds a sharp edge to roughly 0.02 mm. Anodizing builds 5–25 μm depending on the type, which can close a thread if the pitch is fine. If a part gets both, the edge break and the thread allowance have to be planned together.
- 1Specified edge breaks0.05–0.2 mm, called out per edge on the traveler
- 2Finish before threadMask or re-tap after coating on fine pitches
- 3Surface rangeRa 0.2–0.8 μm fine, Ra 0.8–1.6 μm standard
Selection guide
Choosing a process from the feature
Match the cut to the geometry. The wrong column costs a second operation.
| Feature | First choice | When to avoid |
|---|---|---|
| Thin wall under 1 mm | 5-axis with sacrificial web | Heavy radial cuts on 3-axis |
| Deep tapped hole | Thread milling | Tapping past 2× diameter in 17-4PH |
| Sharp internal corner | Sinker EDM | End mill smaller than R0.5 |
| Hardened tool steel | Wire EDM | Roughing after heat treat |
| Cross-hole at an angle | 5-axis drilling | Re-clamped 3-axis setups |
| Fine pitch thread | Mill then mask | Anodize without thread allowance |
Shop capabilities
What we machine
One quote covers the whole route, from prototype to 10,000+ part runs.
01
5 Axis CNC Machining
Simultaneous 5-axis for contoured faces, impellers, and parts that need five sides in one setup. 16 centers available.
02
4 Axis and 3 Axis Machining
Prismatic parts, plates, and housings. 12 four-axis mills and 27 three-axis machines handle high-volume plate work.
03
CNC Milling & Turning
Mill-turn centers for shafts, fittings, and parts that combine turned and milled features without a second datum.
04
Rapid Prototyping
Machined and printed prototypes for fit checks. No minimum order quantity, so a single part is a normal job.
05
Sheet Metal and Die Casting
Brackets, enclosures, and cast housings when the geometry is better formed than cut. Tooling reviewed at quote.
06
Part Surface Finishing
Anodizing, plating, powder coating, bead blasting, and laser marking. Marking character height 1.5 mm minimum.
Scope
Machine envelope and material coverage
If the part falls outside a row, we will tell you at quote instead of after the first cut.
| Category | Range | Notes |
|---|---|---|
| Large travel | 4,000 × 400 × 150 mm | Long frames and rails |
| Medium travel | 750 × 1,150 × 550 mm | Housings and plates |
| Compact travel | 500 × 500 × 450 mm | Small high-mix parts |
| Aluminum | 6061, 7075, 2024, 6082 | ADC12 for castings |
| Stainless | 303, 316L, 17-4PH, 440C | 303 for free machining |
| Titanium and alloys | TC4, Inconel, AZ31B | Slower feeds, more wear |
| Plastics | POM, PEEK, PC, PMMA | Sharp tools, air blast |
Why GreatLight
Numbers we can be held to
Six things that decide whether a job ships on time and on print.
15Y
Machining since 2011
15 years of production work across aerospace, automotive, medical, and robotics parts. Process knowledge built on repeat orders.
±0.005
Tolerance in millimeters
±0.005 mm, or ±0.0002 in, on parts that fit the machine envelope. Achievable, not theoretical, and reported on a CMM.
99.99%
Qualification rate
Parts that pass final inspection on the first submission. Raw material checks and in-process monitoring feed the number.
3–5 d
Typical ship window
Production can start within 24 hours of a released order. Historical late-delivery probability is below 2%.
4
Quality certifications
ISO 9001:2015, IATF 16949:2016, ISO 13485:2016, and ISO 27001:2022. Reports issued on request.
0
Minimum order quantity
One prototype or a 10,000+ part run. Uploads are confidential and an NDA is available before you send files.
7,600 m²Manufacturing space
150Technicians
3Wholly-owned plants
12 hQuote and DFM turnaround
Industry fit
What each industry requires, and what we hold
Aerospace brackets
Wall thickness held across a pocketed rib, with edge breaks specified before anodizing.
- ±0.005 mm
- 5-axis
- Ra 0.8–1.6 μm
Automotive and EV housings
Sealing faces and bearing bores cut in one fixturing so the bore-to-face position stays inside the stack.
- IATF 16949
- 100% inspection
- 3–5 day ship
Medical instrument parts
Small stainless and titanium components with no visible burr at internal cross-holes, passivated after deburring.
- ISO 13485
- 316L
- Ra 0.2–0.8 μm
Robotics and automation
High-mix aluminum and steel parts in small batches, with the same program proven across repeat runs.
- No MOQ
- 12-hour quote
- 99.99% first pass
FAQs
Questions engineers ask before sending a print
What tolerance can I realistically call out on a machined part?
±0.005 mm is achievable on features that fit the machine envelope and are reachable in one or two setups. That is not the same as saying every dimension on a drawing can hold it.
Position between features cut in the same setup is the tightest. Position across re-clamped setups picks up fixturing error, so call out the critical few and leave the rest general.
When should a deep hole be thread milled instead of tapped?
Past about 2× diameter in stainless, titanium, or 17-4PH, thread milling is the safer route. The tool cuts on a helical path, so chip evacuation is better and there is no tap to break at the bottom.
Tapping is still fine for short through-holes in aluminum and free-machining brass. It is faster and the thread form is consistent.
How do I decide between milling and EDM for a sharp internal corner?
If the corner radius is smaller than the smallest practical end mill, milling cannot reach it. An end mill under R0.5 mm is fragile and slow, and it leaves a radius anyway.
Sinker EDM cuts the sharp corner and works on hardened material. The trade is cycle time and a second operation, so use it only on the features that need it.
Do burrs need to be called out on the drawing?
Yes. "Deburr all edges" is not a specification. It leaves the amount to whoever is at the bench, and a 0.3 mm edge break can be a reject on a sealing face.
Give a number and a limit. A 0.05 mm edge break on an internal cross-hole is a different process from a 0.2 mm chamfer on an outside edge.
What surface finish should I specify for a sliding or sealing surface?
Ra 0.8–1.6 μm covers most sealing and bearing surfaces. Ra 0.2–0.8 μm is for fine sealing faces and optical or fluid-contact surfaces where the finish is functional.
Do not specify a fine finish on a non-functional face. It adds a finishing pass and cost without changing how the part works.
How does anodizing change a thread or a bore?
Anodizing builds a coating on the surface, typically 5–25 μm depending on the type. On a fine pitch thread that buildup can be enough to stop a mating screw.
We plan thread allowance or mask the thread before coating. On tight bores the same applies. Tell us at quote if a coated feature has to mate.
Can you machine a single prototype without tooling cost?
Yes. There is no minimum order quantity, so a single machined part is a normal job. The cost is the setup and programming time, not tooling.
If the part later moves to casting or sheet metal, the tooling is reviewed separately at that stage.
What do you need to give a useful quote?
A 3D model or a dimensioned drawing, the material, the quantity, and the finish. If a tolerance or a surface is critical, mark it.
We return a quotation and a DFM analysis within 12 hours. Uploads stay confidential and an NDA can be signed before you send anything.
Send a print and get a process answer
Upload a model or drawing. We return a quote and a DFM review within 12 hours, with the process route and any tolerance risk marked.
12-hour quote100% inspectionNo MOQNDA on request
