High-Precision Alloy Steel CNC Machined Parts Supplier

XCM CNC provides high-precision alloy steel CNC machining focused on stock allowance before and after heat treatment, bearing-seat and fit-bore control, and runout reinspection on long shafts and heavy-load components, supported by imported equipment from brands such as DMG and Mazak.

Working under ISO 9001 and IATF 16949 based systems, with MOQ from 1 piece and sample lead time often reviewed in the 3-7 day range, we confirm h6 and h7, H7 and H8, surface finish, and inspection datums before arranging finish machining and reinspection on parts such as gear shafts, hydraulic rods, sleeves, and couplings.

Machining Parameters and Tolerances

• Materials: 40Cr, 42CrMo, 20CrMnTi, GCr15
• Tolerance: +/-0.03 mm standard, +/-0.003 mm for selected critical features under 100 mm after drawing review
• Surface Finish: Ra 3.2 um milled, Ra 1.6 um precision machined, Ra 0.8 um turned or bored, Ra 0.4 um ground
• GD&T: Coaxiality 0.012 mm, runout 0.01 mm, roundness 0.006 mm, cylindricity 0.011 mm
• Max Size: Milling 3000 x 1600 x 1400 mm, turning diameter 1200 x 2500 mm
• Heat Treatment: Quench and temper, carburizing, nitriding
• Thread: M1.4-M220, NPT, BSP, G, PT
• Precision Limit: +/-0.003 mm size control, 0.006 mm roundness, and 0.01 mm position on specific features after review

Precision Dimensional Tolerance on Critical Features

Selected alloy steel precision features below 100 mm can be controlled to +/-0.003 mm after review. Bearing seats and sealing features can follow h6 and H7 classes, with shaft diameter around +/-0.005 mm and bore size around +/-0.006 mm. Fit-face tolerance at +/-0.003 mm should be reviewed together with surface finish and flatness.

Geometric Tolerance Control for Rotating Parts

Typical geometric values for rotating alloy steel parts include coaxiality 0.012 mm, circular runout 0.01 mm, total runout 0.012 mm, roundness 0.006 mm, and cylindricity 0.011 mm/1030 mm. These values are common for transmission shafts, pump shafts, and motor components, with datum setup and fixturing method confirmed to the drawing.

Surface Finish Grades for Functional Faces

Functional alloy steel faces can be graded by process: turned outer diameters at Ra 0.8 um, bored holes at Ra 1.6 um, honed internal bores at Ra 0.8 um, ground faces at Ra 0.4 um, and sealing faces at Ra 0.8 um. Roughness on fit positions should be reviewed together with tolerance and runout, and hydraulic bore faces at Ra 0.8 um still need the hole size and process route to be confirmed.

CMM and Profile Inspection for GD&T Verification

Geometric inspection can use a Hexagon CMM, roundness measurement equipment, a TRIMOS 600L height gauge, and a roughness tester. Position, coaxiality, and profile data can be issued in the CMM report, while threads can be checked by go and no-go gauges. FAI reports can be supplied for critical dimensions when required by the customer.

Qualified Systems and Equipment Coverage

XCM CNC can organize projects to ISO 9001, ISO 13485, IATF 16949, and GJB9001C system requirements, while arranging machining routes across DMG, Mazak, Matsuura, Brother, and other equipment brands. For precision alloy steel parts, that structure helps place heat-treatment datums, inspection requirements, and reinspection checkpoints into one process.

Broad Size Range for Long Shafts and Fit-Critical Parts

We support machining from small connector-scale parts to large structural components, with three-axis travel up to 3000 x 1600 x 1400 mm and turning diameter up to 1250 mm. For long shafts, hydraulic rods, and high-fit flange parts, this range helps confirm dimensional stability and fixturing strategy earlier.

Tiered Equipment Strategy for Cost and Quality

XCM CNC uses a tiered equipment strategy that includes mainland China, Taiwan, Japan, and Europe or US sourced CNC machines. Lower-tolerance operations can run on domestic or Taiwan equipment, while tighter precision work can move to imported machines such as DMG and Mazak. That keeps simple work from occupying high-hour-rate machines unnecessarily.

Runout Reinspection Planned in Advance

Long shafts, gear shafts, and high-load sleeves are more likely to see changes in runout and fit condition after heat treatment. We confirm the measurement points and reinspection method first, then arrange the final finish machining and acceptance route around those controls.

Inspection Planning Matched to the Drawing

High-precision alloy steel inspection should not rely on one generic template. We select CMM, go and no-go gauges, or roughness testing according to the fit class and critical features on the drawing. The inspection scope and judgment rules can be confirmed during the sample stage and then repeated for production.