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High-Precision Machining Solution for ADC12 EPS Steering Housing
This case study focuses on the precision machining of B/C holes in an EPS (Electric Power Steering) housing made of ADC12 aluminum. The primary challenge was replacing expensive imported Kennametal tools while strictly maintaining a high process capability index (CPK) of 1.67. By implementing an entirely in-house designed and manufactured tooling solution—including the custom tool body, holder, and inserts—Sundi delivered exceptional dimensional accuracy, successfully substituting the competitor's tooling and securing long-term production stability.
Project Overview
| Component Name | EPS Steering Housing |
| Workpiece Material | ADC12 Aluminum Alloy |
| Industry Segment | Automotive Tier 1 – Steering Systems (EPS) |
| Equipment Type | DOOSAN 4505 CNC Machining Center |
| Spindle Interface | BT40 (Emulsion Cooling) |
| Core Challenges | Replacing imported tooling, achieving CPK ≥ 1.67, strict tolerance control on B/C holes. |
Bore Characteristic And Requirements
The workpiece presents several technical hurdles related to quality control and cost optimization:
Strict Process Capability: The demanding CPK 1.67 requirement necessitates exceptional tool stability, wear resistance, and runout accuracy to ensure minimal variation between parts.
Import Substitution: Developing an independent, customized tool that matches or exceeds the high-performance benchmark set by premium imported tooling.
Precision Boring: Maintaining strict dimensional control and stability on the critical B/C holes consistently over high-volume production runs.
Sundi’s Integrated Tooling Solution
We developed a fully independent, customized boring tool to optimize this critical machining stage:
Precision Boring of B/C Holes
This stage focuses on achieving the final dimensions and surface finish for the critical B/C holes within the steering housing.
The Challenge & Solution:
100% In-House Manufacturing: Sundi designed and manufactured the complete tool assembly (tool body, holder, and inserts) to ensure perfect integration and eliminate reliance on imported supply chains.
Stable CPK Performance: The optimized cutting geometry and single-flute design (Z=1) guarantee that the first-off part passes inspection and dimensional data remains highly stable throughout the tool’s life.
High-Speed Efficiency: Engineered to run smoothly at 4,000 RPM with emulsion coolant, balancing high cutting speeds (590 m/min) with excellent chip evacuation.
Processing data
| Operation (OP) | Tool Diameter D (mm) | RPM (rev/min) | Vc (m/min) | fz (mm/Z) | Feed rate vf (mm/min) | Depth of cut ap (mm) | Teeth (Z) |
|---|---|---|---|---|---|---|---|
| Precision Boring | Φ47 (-0.01/-0.025) | 4,000 | 590 | 0.1 | 400 | 8 | 1 |
Proven Results & Efficiency
Exceptional Dimensional Stability (CMM Data Verified)
CMM inspection reports for the critical B/C holes demonstrate exceptional precision. With a strict tolerance requirement of ±0.0075 mm, Sundi’s custom tooling maintained actual deviations of merely 1 to 2 microns, proving highly stable CPK ≥ 1.67 performance.
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Successful Substitution
Fully replaced imported Kennametal tooling with no loss in performance or accuracy.
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Cost Reduction
Significantly lowered the cost-per-part (CPP) compared to the previous imported solution, with the client expressing high satisfaction regarding both tool life and unit cost.
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Expanded Partnership
This success led to the continuous use of Sundi's tools on this line, the comprehensive replacement of similar competitor tools, and the awarding of new tooling design projects to Sundi.
Wuxi Sundi Precision Tools Co.,LTD
- +86 18168312921
- +86 18168312921
- +86 18951588639
- info@sundicuttingtools.com
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Sundi’s custom tooling successfully replaced our imported solutions while maintaining incredibly stable CPK data. We are highly satisfied with both the extended tool life and the significant reduction in our cost-per-part.
Automotive EPS Manufacturer Production Manager