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China Suppliers OEM Zinc Alloy Die Cast CNC Machining Auto Spare Parts from Reliable Factory
Manufacturing & Quality Control Process
Step 01
ZINC Die Casting
Specifications & Materials
138T zinc die casting machine; ZA 3# material.
Process Characteristics
- The furnace temperature is 420°±20°, and the material handle is 14±1 mm.
- Secondary materials cannot be used.
- Material composition must be tested to ensure it is suitable for production.
- First piece confirmation is required after die-casting.
Precautions
- Confirm surface filling quality (no bulging, no cold isolation, no shortage of materials in column).
- Avoid mold sticking, mold drawing, or poor ejector pin protrusion.
- Ejector pin should be concave 0-0.2mm (convex 0-0.2mm for machined surfaces).
Step 02
Remove WATER GAP
Tools
Stick / saw machine.
Things to note
- Surface must not be crushed; prevent lack of material.
- Maintain strict dimension control.
Step 03
IPQC Inspection
Testing Instruments
Three CMM, appearance visual evaluation, projection, Caliper.
Precautions
Use measuring tools correctly and check dimensions according to drawings.
Step 04
Deburring
Process Details
Sharp angle position inverted R angle, deburring, non-machining surface top needle draping, grinding and connecting shape.
Equipment
File, Wind mill, 120# sandpaper.
Note
- No residual segment difference.
- Don't grind over cut.
- Hold the product lightly to prevent pressure injury or deformation.
Step 05
IPQC Inspection
Testing Details
Visual inspection of appearance.
Equipment
Knife-edge ruler, shaping fixture, Rubber hammers, rubber pads.
Note
Visual inspection of appearance, according to SIP.
Step 06
CNC Machining & Full Inspection
Process Details
Drilling 1x ϕ2.0 through hole (through 2 sides), drilling 3x ϕ3.0 through hole on the side.
Equipment
Automatic drilling and tapping machine table, ϕ2.0 drills, CNC Drilling.
Note
- Do not over-cut or miss processing.
- Be careful not to scratch or burr the surface.
- Through-hole tolerance within +/-0.1mm.
Step 07
IPQC Inspection
Testing Details
Needle Gauge Inspection.
Note
Through-hole must pass the needle gauge, according to SOP.
Step 08
Grinding
Process Details
Sanding around and on the sides of the product.
Equipment
Wind grinder, 120# sandpaper.
Note
No processing should be missed, no sharp corners or burrs should be removed, and the R corners should be connected smoothly.
Step 09
IPQC Inspection
Testing Details
Visual inspection of appearance.
Step 10
Oil-Spraying
Materials
Sherwin-Williams paint.
Note
- The surface is smooth, with no different color or dirt.
- The surface cannot have orange peel or particles.
- The surface should not be scratched or stripped of paint.
- Color must align with the sample, uniform and consistent.
Step 11
IPQC Inspection
Inspection Focus
Post-spraying surface quality and dimensional checks.
Note
- Surface quality confirmation after oil spraying.
- Hole needs needle gauge sampling inspection.
Step 12
Full Inspection & Packaging
Equipment
Carton, knife card, clapboard, bubble bag.
Note
- Appearance according to the sample inspection; verify surface is not dirty, scratched, or dented.
- Each product is put into a bubble bag and placed into the packing box.
Step 13
FQC Inspection
Test Tools
Calipers, projectors, pin gauges, tooth gauges, visual and packaging inspection.
Note
Verify whether the measuring tool is within the calibration period.
Step 14
Transportation
Logistics Preparation
Final packing, boxing, and documentation setup.
Note
- Confirm that the quantity matches the order.
- Label and stamp the outer box.
- Send reports on shipments.
Step 15
OQC Shipping Inspection
Testing Instruments
Calipers, projectors, pin gauges, tooth gauges, outer packaging inspection, etc.
Note
Check if the measuring device is still within its calibration window. Ensure it meets both customer and SIP requirements.
Frequently Asked Questions (FAQ)
What materials and machinery are used in the zinc die casting process?
We utilize a 138T zinc die casting machine and ZA 3# material. The furnace temperature is strictly maintained at 420°±20° with a material handle of 14±1 mm to ensure optimal casting.
How do you prevent defectives during CNC machining?
During CNC machining, we control the through-hole tolerance strictly within +/-0.1mm. Operators are trained to avoid over-cutting, miss-processing, and scratching the surface.
What surface quality standards are set for the oil-spraying process?
We use premium Sherwin-Williams paint. The oil-sprayed surface must be smooth, color-consistent with the sample, and completely free of orange peel, particles, scratches, or paint peeling.
What testing instruments are used during IPQC and OQC inspections?
We employ high-precision instruments including three CMMs, projectors, calipers, needle gauges, and tooth gauges, alongside visual evaluations to guarantee part dimensions and quality.
How are parts packaged to prevent damage during transportation?
Each finished product is individually wrapped in a protective bubble bag and placed in a cardboard box separated by custom dividers (knife cards/clapboards) to prevent surface scratches and impacts.