01
You picked a geometry the die cannot fill
Sharp internal corners, deep narrow pockets and undercuts do not fill at room temperature. The die is cut, the press runs, and the corners come out rounded or short-filled. Rework means recutting a die.
Cold Forging
Cold Forging
We form metal at room temperature under high pressure to get grain flow and surface finish near net shape, then machine the critical features on 127 CNC machines. Tolerances to ±0.005 mm.
No minimum order quantityQuotation in 12 hoursISO 9001:2015IATF 16949:2016
2011Cold forging and machining since
±0.005 mmAchievable machining tolerance
127High-precision CNC machines
99.99%Qualification rate
Where the process hurts
Four ways a cold forging program goes wrong
Most of these show up after the tooling is cut, which is the expensive time to find them.
02
The material work-hardens and cracks
Stainless and high-carbon steels gain strength as they deform. Push the reduction too far in one hit and you get surface tearing or internal laps that only appear after machining opens the wall.
03
Forming tolerances do not match the drawing
A formed blank holds its dimensions loosely compared with a machined surface. Buyers who treat the forged blank as the finished part end up with a stack of out-of-tolerance features and no cheap way to bring them back.
04
Tooling cost never pays back at low volume
Dies, punches and setup are front-loaded. Run 200 parts a year and the amortized tooling cost per piece can exceed the part price. That decision belongs before the die is cut, not after.
How we run it
Form the blank, then machine what matters
One shop owns both steps, so the process split is planned from the first quote.
Process control
Room-temperature forming, then CNC to final size
Metal is deformed at or near room temperature with no preheat. The strain hardens the material, so the formed blank comes out stronger than the same alloy in an annealed bar. Grain flow follows the part contour instead of being cut through, which is why a formed and then machined part holds up better under fatigue than a part cut from solid.
We treat forming as the roughing step. Features that the die can produce near net shape stay formed. Bores, faces, threads, sealing surfaces and any dimension the drawing pins tightly get machined on our 127 CNC machines, including 16 simultaneous 5-axis centers and 16 mill-turn centers. Maximum machining envelope is 4,000 mm.
- 1Near net shapeLess stock removed, shorter cycle, fewer chips
- 2Grain flowMaterial follows the contour, not cut across it
- 3One tolerance ownerForming and machining under the same roof
Material and geometry
Which parts fit this route, and which do not
Good candidates are symmetric or near-symmetric solids with a solid cross-section: shafts, pins, bushings, flanges, fasteners, valve bodies, drive components. Carbon and alloy steel, stainless, copper and brass, and aluminium all run this way. If the part is hollow, thin-walled, or has a long slender stem, the die fill gets difficult and machined-from-solid or casting usually wins on total cost.
We say no when the numbers say no. If your annual volume is low, if the wall is under about 2 mm, or if the geometry has features the die cannot release, we will tell you at the quote stage and route the job to 5-axis machining, die casting or vacuum casting instead.
- 1Fits wellSolid cross-section, axial symmetry, medium to high volume
- 2MarginalDeep pockets, sharp internal corners, thin walls
- 3Wrong routeVery low volume, hollow sections, tight formed tolerances
Selection guide
Formed blank, machined part, or both
Use this to decide how much of the drawing the die should own.
| Feature | Formed only | Formed + machined |
|---|---|---|
| Outside diameter | Holds to forming tolerance | Machined to ±0.005 mm when required |
| Bore | Limited by punch geometry | Bored or reamed after forming |
| Surface finish | Ra 1.6–3.2 μm as formed | Ra 0.2–0.8 μm after finishing |
| Threads | Not practical to form | Cut or rolled in the CNC cycle |
| Internal corners | Rounded by die radius | Sharpened by milling |
| Volume that pays back | High, simple shapes | Medium to high, mixed features |
| Tooling risk | Borne by the customer | Shared with the machining plan |
What we run
Services around the forming step
Forming is one operation. These are the ones that finish the part.
01
Forming and CNC machining
Formed blank plus milling, turning and mill-turn work on the same order. One tolerance stack, one inspection report.
02
5-axis machining
16 simultaneous 5-axis centers. Undercuts, compound angles and contoured faces the die cannot release.
03
Rapid prototyping
Machined prototypes before the die is cut, so fit and function get checked on real metal.
04
Die casting
For hollow and thin-wall parts, die casting often beats forming on total cost per piece.
05
Surface finishing
Anodizing, plating, powder coating, black oxide, bead blasting and laser marking.
06
Inspection and reporting
100% inspection before shipment. Raw material check, in-process monitoring, final report on request.
Capability
Forming and machining scope
| Item | Specification | Notes |
|---|---|---|
| Materials | Carbon steel, alloy steel, stainless, copper, brass, aluminium | Full list confirmed at quote |
| Machining tolerance | ±0.005 mm (±0.0002 in) | Where the drawing requires it |
| Fine finish | Ra 0.2–0.8 μm | After polishing or fine turning |
| Maximum part size | 4,000 mm | Largest machining envelope |
| Order quantity | One prototype to 10,000+ parts | No minimum order quantity |
| Quotation | Within 12 hours with DFM analysis | Upload a drawing to start |
Why GreatLight
Numbers behind the forming program
15Y
In the trade since 2011
Forming, machining and finishing under one roof in Dongguan.
127
CNC machines on site
16 five-axis, 16 mill-turn, 12 four-axis and 27 three-axis machines.
±0.005 mm
Machining tolerance
Achievable on formed blanks after the critical features are cut.
99.99%
Qualification rate
Measured across inspected production lots before shipment.
12 h
Quote turnaround
Quotation and free DFM analysis within 12 hours of upload.
4
Quality systems in place
ISO 9001, IATF 16949, ISO 13485 and ISO 27001 certified.
7,600 m²Manufacturing space
3Wholly-owned plants
150Technicians
< 2%Historical late-delivery probability
What the work demands
Industry requirements and what we hand over
Automotive and EV drivetrain
Powertrain and chassis parts need fatigue strength plus traceable inspection.
- IATF 16949
- ±0.005 mm
- 100% inspection
Aerospace and defence hardware
Formed blanks with machined interfaces, documented material and finish records.
- ISO 9001
- Ra 0.2–0.8 μm
- Full traceability
Industrial machinery and hydraulics
Valve bodies and drive components where bore alignment decides the fit.
- ±0.005 mm
- Bore reaming
- Batch reports
Medical and instrument parts
Small formed components with clean surfaces and controlled radii.
- ISO 13485
- Ra 0.2–0.8 μm
- Deburred edges
FAQs
Cold forging questions we get from engineers
What exactly happens to the metal?
The blank is squeezed between a punch and a die at or near room temperature, with no preheat. The metal flows into the die cavity and takes its shape.
Because the material is cold, it strain hardens as it deforms. The finished part is stronger than the same alloy in annealed bar stock. Grain flow follows the part contour rather than being cut through, which helps under cyclic loading.
Which materials can you run?
Carbon and alloy steels including 1018, 1045, 4130, 4140 and 4340; stainless grades 303, 304, 316, 316L, 420, 430, 431, 440C and 17-4PH; copper and brass including C101, C110, C36000; and aluminium grades 6061, 6061-T6, 2024, 5052, 6082 and 7075.
High-carbon and stainless grades work-harden quickly, so the reduction per pass has to be planned. We confirm the material route at quote stage before any die is cut.
How tight a tolerance should I put on the formed surface?
Do not pin a tight tolerance on a surface the die produces. Forming holds a wider band than machining.
Reserve ±0.005 mm for features that get machined after forming: bores, faces, sealing surfaces, bearing seats. That split keeps tooling simple and avoids paying for precision in the wrong place.
When is forming the wrong choice?
Low annual volume is the clearest case. Tooling is front-loaded, so at a few hundred parts a year the amortized die cost per piece can exceed the part price.
Hollow and thin-walled parts are the second case. If the wall is under about 2 mm or the section is not solid, die fill gets unreliable and die casting or machined-from-solid usually wins.
Do you machine the formed part in the same shop?
Yes. Forming and machining run in the same facility, which means one tolerance stack and one inspection record.
The machining side covers 127 CNC machines, including 16 simultaneous 5-axis centers and 16 mill-turn centers, with a maximum envelope of 4,000 mm.
What finishes can go on a formed part?
Anodizing in clear, colour, hardcoat and conductive types; electroless nickel, zinc, silver and gold plating; powder coating and black oxide; bead blasting, tumbling, brushing and polishing; laser marking with a minimum character height of 1.5 mm.
Pick the finish after the machining plan is fixed. Some finishes change dimensions enough to matter on a tight bore.
What are your order quantities and lead times?
There is no minimum order quantity. We run from a single prototype to 10,000+ part runs.
Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours and parts typically ship in 3–5 days. Our historical late-delivery probability is below 2%.
How do you handle drawings and confidentiality?
Uploads are secure and confidential. We can sign an NDA on request before you send any drawing.
Inspection reports from raw material check, in-process monitoring and final inspection are available on request.
Send the drawing, get a forming and machining plan
We will tell you at quote stage whether the part should be formed, cast or cut from solid, and what it costs each way.
12-hour quote100% inspectionNo minimum order quantity
