Overview
XCM CNC organizes precision zinc machining around critical tolerance control, GD&T management, and CMM-based verification, which is well suited to fit surfaces, hole patterns, and locating structures that need correction after die casting.
With ISO 9001 and IATF 16949 aligned systems, precision operations can run on equipment such as the DMG 80mono and Matsuura MX-520, while inspection is supported by the CMM. MOQ starts from 1 piece, sample lead time is often 3-7 days, and thin-wall fixture distortion, datum transfer, and post-finish reinspection are all checked during the sample stage.
Key Capabilities
Machining Parameters
- Materials: Zamak 3, Zamak 5, Zamak 8 by drawing review
- Tolerance: +/-0.003 mm (+/-0.00012 inch), IT5 or IT6 accuracy, +/-0.01 mm shaft and bore fits, with h6 and H7 available
- Surface Finish: Ra 3.2 um milled, Ra 1.6 um precision, Ra 0.8 um turned or bored
- GD&T: Coaxiality 0.012 mm, runout 0.01 mm, cylindricity 0.011 mm
- Max Size: Milling 3000 x 1600 x 1400 mm, turning diameter 1250 x 2000 mm
- Surface Treatment: Plating, powder coating, chromate finish, painting, or cosmetic prep by drawing review
- Thread: M1.4-M220, NPT, BSP, G, PT
- Precision Limit: +/-0.003 mm tolerance, 0.006 mm roundness, and 0.01 mm hole position on selected features by drawing review
Flatness and Position Control for Precision Datums
Zinc precision datums can be verified against 0.02 mm flatness and 0.015 mm position tolerance on the CMM. For die-cast mounting faces, parallelism can stay within 0.03 mm over a long datum length and perpendicularity can be checked where the drawing requires it, while incoming cast variation is measured before the toolpath is fixed.
Hole Position Accuracy in Single-Setup Machining
Zinc hole patterns machined in a single setup can achieve 0.01 mm hole position and 0.012 mm coaxiality on shaft-bore features. H7 fit holes can hold a bore tolerance near +/-0.006 mm, and thin-wall structures near 0.5 mm thickness need fixture-force and cutting-parameter control to reduce springback.
Surface Roughness Grading for Mating Features
Zinc mating features can combine Ra 1.6 um bored faces with Ra 0.8 um turned diameters, while standard milled faces remain at Ra 3.2 um. Visible faces before plating can be precision milled to Ra 1.6 um with the required tool-mark direction, and roughness is confirmed by instrument rather than visual review.
CMM Reinspection for Post-Finish Verification
Zinc post-finish reinspection can follow the same datum plan used during machining to verify selected +/-0.003 mm features after plating or coating. The CMM verifies positional and coaxial features, the 2.5D system supports smaller part geometry, and a height gauge can help recheck height steps when the finish route changes the fit size.
Specifications
| Product Name | High-Precision Zinc CNC Machined Parts Supplier |
|---|---|
| Manufacturer | XCM CNC |
| Factory Location | Shenzhen, Guangdong, China |
| Quality System | ISO 9001, ISO 13485, IATF 16949, GJB9001C |
| Machining Process | CNC machining |
| Material | Zinc |
| Material Grade | Zamak 3, Zamak 5, Zamak 8 by drawing review |
| Tolerance | +/-0.03 mm standard CNC machining tolerance |
| Precision Tolerance | +/-0.003 mm for selected critical features by drawing review |
| Surface Roughness | Ra 3.2 um milled, Ra 1.6 um precision, Ra 0.8 um turned or bored |
| Surface Treatment | Plating, powder coating, chromate finish, painting, or cosmetic prep by drawing review |
| Max Part Size | Milling 3000 x 1600 x 1400 mm / Turning diameter 1250 x 2000 mm |
| Inspection | CMM, roundness tester, height gauge, roughness tester, thread gauges |
| Application | Datum-corrected die-cast parts, precision lock fittings, and EMI shell interfaces |
| Typical Application | Precision zinc secondary machining |
| Key Features | Die-cast follow-up machining, datum transfer review, GD&T control, and fit-surface inspection |
| Critical QC Requirements | Casting datum review, fit-surface inspection, deformation control, finish allowance check, and post-process reinspection |
| Batch Range | Prototype to precision repeat orders |
| MOQ | 1 piece |
| Typical Lead Time | Samples 3-7 days, precision repeat orders by drawing review |
| Drawing Formats | STEP, IGS, DWG, PDF, X_T |
| Secondary Process | Deburring, tapping, cosmetic-prep machining, plating prep, and dimensional reinspection |
| Material Certificate | Material certificate by order requirements |
| Material Feature | Die-cast follow-up machining, fit-surface correction, and pre-finish machining review |
| Critical Tolerance Control | Flatness 0.02 mm, position tolerance 0.015 mm, and hole position 0.01 mm by drawing review |
Applications
Datum Faces and Fit Holes on Die-Cast Parts
Typical Parts: Door latch housing, throttle pedal bracket, interior adjustment knob base
Automotive zinc die-cast parts often need CNC correction on mounting faces and fit holes before final assembly. Mounting datums can be controlled to 0.02 mm flatness, locating hole groups to 0.015 mm position tolerance, and one controlled setup helps reduce datum-transfer error, with CMM reporting available by order.
Lock Bores and Handle Datum Faces
Typical Parts: Lock core housing, handle base, knob seat
Roundness and roughness on lock bores directly affect smooth rotation in service. Lock bores can be finished to 0.006 mm roundness and Ra 0.8 um, while handle datum faces can be precision milled to Ra 1.6 um and checked for flatness before plating starts.
Thin-Wall Shielding Cans and Clip Holes
Typical Parts: RF filter shield can, SFP plus module housing, edge connector mounting bracket
Thin-wall shielding cans are most sensitive to fixturing distortion and clip-hole drift. Structures near 0.5 mm wall thickness can use lower clamping force and staged cutting, while clip-hole position can be controlled to 0.01 mm and grounding-face flatness can be checked to 0.02 mm with support from the 2.5D system on smaller parts.
Small Covers and Clip-Slot Precision Work
Typical Parts: HMI push-button panel, non-load-bearing sensor mounting flange, cable-management clip
Small covers and clip parts often place insert holes, clip slots, and datum faces in a tight working area where tolerance buildup is sensitive. Narrow slots around 0.3 mm and insert holes at H7 class can be finished with CMM verification on the related positional features when the drawing requires that level of control.
Why Choose Us
Qualified Systems and Equipment Coverage
XCM CNC runs zinc die-cast secondary machining under ISO 9001, ISO 13485, IATF 16949, and GJB9001C aligned quality systems, while using equipment from brands such as DMG, Mazak, Matsuura, and Brother for fit-surface correction and multi-face machining. For Zamak series projects, we review datum choice, pre-finish allowance, and reinspection priorities during drawing review.
Broad Size Range for Zinc Finish Machining
We support zinc finish machining from small connector-scale parts to larger housings, covers, and medium-size structural parts. Three-axis travel reaches 3000 x 1600 x 1400 mm and turning capacity reaches diameter 1250 x 2000 mm, while the final route still follows the die-cast datum, the pre-finish allowance, and the fixture method.
Tiered Equipment Strategy for Cost and Quality
XCM CNC uses CNC equipment from mainland China, Taiwan, Japan, and Europe or the US in a tiered production mix. Lower-tolerance operations can run on domestic or Taiwan machines, while higher-precision critical work moves to imported machines such as DMG and Mazak. That helps reduce cost without placing simple operations onto high-hour machines.
GD&T Verified in Stages
Zinc die-cast flatness, position tolerance, and fit features are verified in stages instead of forcing maximum tolerance onto every surface by default. The incoming die-cast condition is measured first, then the critical geometry is rechecked after precision machining against the drawing datum. NDA support is available before review starts when drawings are sensitive.
Thin-Wall Fixturing and Deformation Control
Thin-wall zinc parts and appearance-sensitive pieces need the fixturing plan, cutting parameters, and surface-protection method confirmed during the first-article stage so later lots do not drift in dimension or leave clamp marks. Those settings can then carry forward into repeat orders through the process sheet.
FAQ
Why do zinc die-cast parts still need CNC finish machining?
Die-cast holes, datum faces, and fit-surface roughness usually cannot meet final assembly tolerance by themselves. CNC follow-up machining can bring hole position to 0.01 mm, flatness to 0.02 mm, and related fit features into the required assembly range when the drawing calls for that level of control.
What GD&T tolerances can you hold on zinc finish-machined parts?
Typical control targets include 0.012 mm coaxiality, 0.01 mm runout, 0.011 mm cylindricity, 0.02 mm flatness, and 0.015 mm position tolerance. The final feasibility still depends on part size, wall thickness, and the fixture path reviewed against the drawing.
What inspection equipment do you use for zinc precision parts?
Critical dimensions and GD&T are commonly checked on the CMM, roundness on a roundness tester, small-part hole distances and outlines on the 2.5D measuring system, roughness on a surface tester, and thread features with go and no-go gauges. The exact route follows the drawing and the required tolerance grade.
How does datum selection affect zinc die-cast finish machining accuracy?
The incoming die-cast datum usually carries more variation than a final-machined datum, so using it directly can push hole position and fit faces out of tolerance. Measuring the incoming part first and then defining the practical machining datum helps reduce datum-transfer error, especially when the part can be machined in one controlled setup.
Can you control flatness, position, and mating features on zinc finish-machined parts?
Yes. Zinc parts can be reviewed for flatness, position tolerance, and fit-surface precision, with common reference values such as 0.02 mm flatness, 0.015 mm position tolerance, and 0.01 mm hole position. The final route still depends on the die-cast condition and the part wall thickness.
How do you control deformation risk on thin-wall zinc alloy parts?
Thin-wall zinc parts use controlled clamp force, lower feed, and staged machining to reduce deformation risk. On walls near 0.5 mm, the first article confirms the fixturing route and then the CMM measures critical-feature shift after machining so later lots can stay on the same proven setup.
Request a CNC Machining Quote from XCM CNC
Send us your drawings. Our team will review the file and reply with a machining quote. MOQ: 1 piece, with competitive low-cost pricing.
Email: [email protected] | WhatsApp: +8618638951317
