锌合金压铸尺寸不良导致装配失败案例
XSD Precision engineering resource for Zinc Alloy Die Casting Dimensional NG Assembly Failure Case Study, covering TPMS buyer checks, validation points, sourcing risk, and.
专业判断
XSD Precision 以品牌商、服务商、方案提供商和问题解决专家的身份，为 TPMS 与汽车精密工程项目提供从需求评审、工程验证到交付准备的专业支持。
XSD Precision engineering resource for Zinc Alloy Die Casting Dimensional NG Assembly Failure Case Study, covering TPMS buyer checks, validation points, sourcing risk, and.
Defect Symptom
- The local zinc alloy housing surface is too high, so the black decorative cover cannot sit flat.
- A visible step appears along the top or side edge after assembly.
- The assembled gap becomes inconsistent and can be judged as cosmetic NG or assembly NG.
- If the location is near a button or clip, it may also affect button travel, clip stress and cover lift.
Likely Causes
| Cause | Inspection Focus | Typical Symptom |
|---|---|---|
| Die casting dimensional variation | Mold temperature, injection pressure, holding pressure, cooling time, shrinkage and warpage | Batch drift or local raised height |
| Mold parting surface or insert wear | Parting line, insert step, cavity damage and vent area | Fixed-position step, burr or mismatch |
| Unstable secondary-process datum | CNC location, deburring, polishing, blasting or plating pretreatment | Cosmetic surface dimension is enlarged or uneven |
| Open assembly tolerance chain | Cover, glue area, clips, foam tape and housing datum | Individual parts pass, but assembly gap fails |
| Gauge coverage gap | Gauge checks outline only, not raised height, step gap or assembly flatness | Outgoing inspection passes, final assembly fails |
Recommended Inspection Points
- Raised feature height with height gauge, vision measurement or go/no-go gauge.
- Assembly step gap with feeler gauge, step gauge or 3D scan.
- Assembly surface flatness around cover seating, clip area and button support area.
- Cavity traceability to confirm whether the defect concentrates in one cavity or insert.
- Real assembly trial for each batch, not only individual part dimension inspection.
- Touch-feel criterion for visible and touchable cosmetic edges.
Corrective Actions
- Measure the actual raised amount first instead of judging only from photos.
- Build the tolerance chain of cover, zinc alloy housing, clip and glue area.
- If the same position repeats, check mold insert, parting surface damage and local burr.
- If the issue varies by batch, check die casting parameters, mold temperature and cooling rhythm.
- If single parts pass but assembly fails, revise the assembly gauge or add final assembly sampling.
- Before mass production, write key height, step gap and flatness into SIP, gauge drawing and outgoing criteria.
Production Control Recommendation
For automotive key housings, TPMS housings, decorative housings and visible cosmetic parts, dimensional control cannot rely only on individual drawing tolerance. The end customer sees the assembled gap, step and touch feel. XSD should evaluate single-part dimensions, assembly tolerance chain and cosmetic step criteria together.
The key is not only where the part is raised. The key is connecting raised amount, step gap, assembly interference and cavity or process source, so the team can decide whether to correct the mold, tune the process, revise the gauge or modify the assembly tolerance chain.
如需结合具体车型、产品型号、验证目标或制造准备要求进行评估，请向 XSD Precision 提供项目资料、图纸、规格、目标市场和验证边界。
提交项目资料与 RFQ资料适用边界与项目输入
本模块用于帮助读者将公开资料转化为可评审的项目输入，同时明确官网公开信息与受控项目文件的管理边界。
适用对象
面向汽车精密工程项目的采购、工程、质量、项目管理和供应链团队：用于在 RFQ 或量产准备前建立可审查的输入基础。
项目输入
2D / 3D 图纸、材料牌号、公差、表面处理、CTQ、工装检具、检验计划、样品验证、数量和交付条件。
输出边界
官网公开资料说明工程方法、质量边界和制造准备路径；客户图纸、规格版本、工艺参数、成本模型、检测数据和批准证据按 XSD Precision 工程文件与项目资料受控管理体系执行。