Custom Precision Zinc CNC Milled Parts
Overview
Uneven cover mating faces and shifted locating holes are common assembly issues with zinc alloy die-cast housings. CNC milling can correct mounting-face flatness to 0.02 mm and locating holes to H7 / +/-0.005 mm. Near-net-shape blanks for housings, covers and mounts have cover mating faces, cavity steps and hole patterns finished on Brother CNC machining centers and the Matsuura MX-520, retaining the cast form in unmachined areas. XCM CNC is certified to ISO 9001, ISO 13485, IATF 16949 and GJB9001C. The MOQ is 1 piece, prototypes take 3-7 days and standard lead time is 10-15 days. Equipment listed for this machining service includes DMG 80mono, Mazak i-100S, Matsuura MX-520, Jingshang 80 automatic lathe, Brother / Taichung / Qiao Feng CNC 3016-4A machining centers, Shenyang CK61125X2000 lathe.
Key Capabilities
- Materials: Zinc alloy; specified Zamak or ZA grade verified against the drawing and material certificate
- Tolerance: +/-0.003 mm (+/-0.00012 inch) on precision metal features; IT5 or IT6 accuracy, +/-0.01 mm shaft/bore fits; h6/H7 available
- Surface Finish: General milling Ra 3.2 um; precision milled faces Ra 1.6 um; sealing faces Ra 0.8 um; lapped faces Ra 0.4 um
- GD&T: Flatness 0.02 mm over 1030 x 1030 mm; parallelism 0.03 mm / 1030 mm; hole-pattern position 0.015 mm; symmetry 0.02 mm
- Max Size: 3-axis travel 3000 x 1600 x 1400 mm; parts up to approx. 2600 mm long depending on fixturing
- Surface Treatment: Deburring, edge break 0.1 mm; zinc-compatible plating 3-20 um, depending on drawing and order requirements
- Thread: Internal M1.4 and external M2.0 up to M220; blind-hole effective depth 50 mm; NPT / BSP / G / PT; go/no-go gauge inspection
- Precision Limit: +/-0.003 mm on small critical features; roundness 0.006 mm; hole-pattern position 0.01 mm (specific features, by drawing review)
Zinc Housing Mating Faces: Flatness and Sealing Finish
Cover mating faces and mounting faces on zinc alloy die-cast housings can achieve flatness of 0.02 mm over 1030 x 1030 mm, with sealing-face roughness of Ra 0.8 um. Parallelism between upper and lower mounting faces is 0.03 mm / 1030 mm, specified according to ISO 1101 and measured using a TRIMOS 600L height gauge. Removing casting skin releases stress, so the cover mating face is generally rough milled first, the opposite side machined after flipping, then the original face finish milled.
Zinc Milled Locating Holes, Bore Sizes and Countersinks
Mating bores on zinc alloy housings can be machined to ISO 286 grades H7 / H8 or +/-0.006 mm. Pin and locating holes can achieve +/-0.005 mm. Minimum milled hole diameter is 0.3 mm. Countersink angle is 90 degrees with an angular tolerance of +/-0.1 degrees. Hole diameters and spacing are checked on a WanHao Rational VMS-3020G vision system, with plug gauges used to verify mating bores.
Zinc Narrow Slots and Deep Grooves in Milled Covers
Zinc alloy covers and lock bodies can have slots as narrow as 0.3 mm. At a width of 25 mm, maximum slot depth is 100 mm. Slot symmetry can be controlled to 0.02 mm. Zinc chips are soft and sticky and can adhere to cutting edges during narrow-slot machining, causing dimensional changes. Sharp tools, adequate cooling and chip clearing are therefore required.
Large Zinc Plates and Brackets on 3000 mm Milling Travel
The Qiao Feng CNC 3016-4A gantry mill has travel of 3000 x 1600 x 1400 mm, supporting workpieces approximately 2600 mm long depending on setup. Zinc alloy plates and brackets over 500 mm have a dimensional tolerance of +/-0.05 mm, with large mounting-face flatness of 0.02 mm. Finished dimensions receive sampling inspection on a Hexagon Inspector Classic 06.08.06 CMM.
Specifications
| Product Name | Custom Precision Zinc CNC Milled Parts |
|---|---|
| Manufacturer | XCM CNC (Shenzhen Xinchuangmeng Co., Ltd), Shenzhen, China |
| Factory Location | Shenzhen, Guangdong, China |
| Quality System | ISO 9001, ISO 13485, IATF 16949, GJB9001C |
| Machining Process | CNC milling of die-cast housings, faces, pockets, steps and hole patterns |
| Material | Zinc alloy |
| Material Grade | Specified Zamak or ZA grade by drawing and material certificate; no assumed grade equivalence |
| Tolerance | +/-0.003 mm on precision features; IT5/IT6; bores H7/H8 +/-0.006 mm; locating holes +/-0.005 mm; parts over 500 mm +/-0.05 mm |
| Surface Roughness | Ra 3.2 um general milling; Ra 1.6 um precision faces; Ra 0.8 um sealing faces; Ra 0.4 um lapped faces |
| Surface Treatment | Deburring; zinc-compatible plating 3-20 um, depending on drawing and order requirements |
| Max Part Size | 3-axis travel 3000 x 1600 x 1400 mm; 5-axis 800 x 600 x 900 mm |
| Inspection | Equipment: Hexagon Inspector Classic 06.08.06 CMM, WanHao Rational VMS-3020G, TRIMOS 600L height gauge; Documents: Dimensional inspection report; CMM / FAI report; material certificate and SGS report by order |
| Application | Die-cast housings, covers, lock-body mounting bases and precision small-batch components |
| Key Features | Mounting faces, pocket cavities, steps, hole patterns, slots and internal corners |
| Critical QC Requirements | Flatness, hole-pattern position, mounting dimensions, visible tool marks and post-plating fit |
| MOQ | 1 piece |
| Typical Lead Time | Prototype 3-7 days; standard 10-15 days depending on complexity and quantity |
| Drawing Formats | STEP, IGES, STP, DWG, PDF with dimensions |
Applications
EMI Shielding Housings for Electronic and Communications Equipment
Typical parts: Zinc die-cast shielding housing, cavity cover
Housing-to-cover contact faces are milled to flatness of 0.02 mm before mounting steps, cavities and hole patterns are machined, retaining the die-cast body form. Shielding effectiveness and contact resistance depend on complete-product design and verification requirements.
Lock Housings and Handle Mounting Bases
Typical parts: Die-cast lock housing, handle mounting base
Narrow slots from 0.3 mm and H7 locating holes correct assembly interfaces between lock bodies and adjacent parts, together with milled mounting faces and locating steps. Specific drawings define lock loading, coatings and wear requirements.
Zinc Die-Cast Mounts for Automotive Interiors
Typical parts: Interior equipment mount, wiring or trim retainer housing
Datum faces, planar steps and locating holes are milled under the IATF 16949 quality system for interior assembly relationships, retaining the cast form. Temperature, load and environmental suitability are evaluated against part requirements.
Small Housings for Industrial Sensors
Typical parts: Sensor housing, mounting cover
Sealing faces at Ra 0.8 um and countersinks at 90 degrees +/-0.1 degrees complete die-cast closure mating faces and fastening holes. This suits housings dominated by planes, cavities, registers and hole patterns. Load capacity and operating environment depend on the specific design.
Zinc Alloy Housing Components for Models and Toys
Typical parts: Scale-model housing, decorative cover
Cosmetic faces are milled to Ra 1.6 um with consistent texture and no pronounced tool marks to the touch, along with assembly faces, local slots and fastening holes. This suits small-to-medium batches of components. Drawings or approved samples can define appearance and assembly requirements.
Why Choose Us
Quality Systems and Equipment Support
Projects operate under ISO 9001, ISO 13485, IATF 16949 and GJB9001C quality systems. Equipment resources include DMG, Mazak, Matsuura and Brother, allocated according to parts and operations.
Coordinating Housing Faces and Cavity Machining
Mounting faces, steps, pockets and hole patterns on die-cast housings can be finished through milling, drilling and edge breaking. If plating is required, zinc substrate compatibility guides advance planning of post-plating dimensions for cover contact faces, fastening holes and assembly surfaces.
Tiered Equipment Strategy for Low-Cost CNC Machining, Quality-Assured Production
XCM CNC uses four tiers of CNC equipment from mainland China, Taiwan, Japan, and Europe and the United States. General exterior milled faces and through-holes use mainland Chinese or Taiwanese machines. High-precision cover mating faces and locating holes use imported equipment such as DMG and Mazak. Selecting machines for actual operation accuracy avoids using equipment with higher hourly costs for rough work and reduces costs while meeting drawings.
Optional Full Inspection of Critical Batch Dimensions
Critical dimensions and appearance on batch orders can receive 100% inspection rather than sampling alone. The scope follows drawings and the order. This suits housings whose cover mating faces or locating holes would prevent assembly if outside tolerance.
NDA Protection for New Housing Drawings
Prelaunch housing designs often contain confidential information. An NDA can be signed before drawings are received. Drawings and models are used only for quotation and production.
FAQ
Why does a zinc die-cast housing need CNC milling?
Milling corrects mounting faces, steps, cavities and hole patterns on die-cast housings so these mating features meet drawings. Whether the blank form is retained depends on the drawing and accessible machining areas.
How should pocket corners be designed for zinc milling?
Use a minimum internal radius of R0.5 mm for conventional end milling. At a cavity depth of approximately 40 mm, an internal radius of at least R1.0 mm is recommended.
Can you machine both the die-cast housing and its cover?
Yes. Housings and covers are machined from the same drawing datum system. Cover mating-face flatness can reach 0.02 mm, with screw-hole positions inspected against the same datums for easier assembly alignment.
How long does a repeat order for milled zinc housings take?
After approval of the first-order samples, repeat orders follow the standard lead time of 10-15 days depending on quantity and complexity. The first-order process is reused without new prototyping.
Can the FAI report follow our own template?
Yes. FAI reports can be completed in the customer’s report format, and CMM data can also be exported in the specified format.
Can you provide SGS or plating reports for zinc housings?
Material certificates and SGS environmental compliance reports can be supplied according to the order. Plated parts can also include coating-thickness or salt-spray reports. Specify the report type required during inquiry.
What are the payment, shipping and packaging options?
Payment options: T/T, PayPal, Western Union. Shipping options: DHL / FedEx / UPS / Sea freight. Packaging: Foam + carton; wooden case on request.
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.
