Grinding scope
Grinding after heat treatment | Surfaces: flat faces, parallel faces, seating faces, mould plates.
- TypeSurface grinding and NC grinding. Flat and parallel work only, no cylindrical
- CapacityUp to 500 × 200 × 250 mm on the Okamoto PSG-52DX
- Tolerance±0.005 mm typical on ground faces
- FinishRa 0.4 μm achievable on a ground surface
- Material hardnessTool steel 58–62 HRC; hardened alloy steel.
- ProcessMachine soft stock → leave 0.2–0.5 mm stock → heat treatment → finish grinding.
- Hardness checkMitutoyo QMH 14BX on every hardened batch before the part is ground
- QualityISO 9001:2015, certified by URS under UKAS accreditation
Reference grinding stock: 0.2–0.5 mm before heat treatment | Defined per surface, flatness, parallelism and expected distortion.
Grinding machine list
Grinding equipment: 2 machines | Travels per machine list.
| Make / Model | Type | Work envelope X × Y × Z (mm) | Origin |
|---|---|---|---|
| OKAMOTO PSG-52DX | Surface grinder | 500 × 200 × 250 | Japan |
| CHEVALIER FSG-2A818 | NC grinder | 450 × 200 × 250 | Taiwan |
Grinding machines: Okamoto PSG-52DX; Chevalier FSG-2A818.
Typical ground parts
- Mould platesMould and die plates ground flat and parallel after hardening
- Slide blocksGuide blocks, slides and wear plates held on parallelism
- SeatsFinish grinding of seating faces after heat treatment.
- Punch facesPunch and die faces finished to size after the hardening cycle
- GaugesProfile blocks and gauge surfaces where flatness is the function
- Stock removalGrinding to create a datum face before the next operation.
Route: milling → heat treatment → grinding/wire cutting | Quote and lead time by operation chain. EDM and wire cutting →
Surface and NC grinding requirements
Maximum grinding size
Maximum grinding size on the Okamoto PSG-52DX is 500 × 200 × 250 mm.
Stress relief before finish grinding
For parts heavily roughed from one side, stress relief before finish grinding helps control movement and flatness.
Flatness measurement
Flatness and parallelism are reported from CMM measurements against a calibrated reference standard.
Grinding materials
- Tool steelSKD11, D2 | Hardness: 58–62 HRC. SKD11 notes →
- Hot workSKD61 and H13 die components, typically 44–52 HRC
- Alloy steel4140 and SCM440 after quench and temper. 4140 notes →
- Carbon steelS45C after induction hardening, ground on the hardened band. S45C notes →
- Stainless17-4PH after ageing, ground only on the features that must hold size. 17-4PH notes →
- Bearing steelSUJ2, annealed for machining, then hardened and ground
Heat treatment per drawing → hardness check on Mitutoyo QMH 14BX → grinding. The heat treatment table →
Measured before it ships
- CMMMitutoyo CRYSTA-APEX V in a climate-controlled lab for flatness and parallelism
- Material hardnessMitutoyo QMH 14BX reading reported with the batch, taken before grinding
- GaugeMitutoyo LK600 height gauge, dial indicators and a calibrated reference standard
- ReportDimensional report in both inch and millimetre, with the ground features called out
- RoomClimate-controlled | Part temperature controlled before measurement.
- PackingOiled and VCI wrapped, with ground faces partitioned so they never touch each other
Packing: each part wrapped separately; ground surfaces partitioned | Unplated steel: rust-preventive oil applied after machining.
Common questions
Grinding size limit?
500 × 200 × 250 mm on the Okamoto PSG-52DX. Larger plates go outside under our inspection.
What tolerance can you hold on a ground face?
Typical grinding tolerance: ±0.005 mm | Finish: up to Ra 0.4 μm | Flatness and parallelism: CMM results reported.
How much grinding stock should I allow?
Reference grinding stock: 0.2–0.5 mm | Critical faces specified on the drawing.
Heat treatment before grinding?
Heat treatment per technical requirement | Hardness check: Mitutoyo QMH 14BX before grinding.
Grinding to correct a part bowed after heat treatment?
Correction by grinding depends on stock, bow and residual stress | Assessed from the drawing and the heat treatment/machining sequence.
Flatness after grinding?
Flatness: capability and inspection assessed per drawing | Report states measured values.
Related information
EDM and wire cutting
EDM/wire cutting after heat treatment | Tolerance: up to ±0.003 mm | Internal corner machining.
Finishing and heat treatment
Heat treatment per drawing | Hardness check before shipment.
SKD11 / D2 tool steel
Most of our ground work is made from this grade. How it moves in hardening.