Case

Project Type: Custom CNC Machining for Robotics (OEM) Material: 6061-T6 Aluminum Alloy / 304 Stainless Steel Process: 4-Axis & 5-Axis CNC Machining → Surface Treatment → Inspection
Project Overview
We manufactured precision components for a collaborative robot (cobot) manufacturer — joint housings, reduction gear mounting seats, and sensor brackets that form the critical structure of their robot arms. Every part was machined on our 4-axis and 5-axis CNC centers, with full dimensional inspection before delivery.
The Challenge
Robot joints demand extreme precision: components must mate perfectly with harmonic reducers and servo motors, where a few microns of error translates into visible play, vibration, or reduced positioning accuracy in the finished robot. The customer’s parts also carried complex features — angled mounting surfaces, deep pockets, and precisely positioned threaded holes — that are difficult to machine consistently.
Their requirements:

±0.01 mm tolerance on joint-mating and bearing-seat dimensions

Surface finish Ra 0.8 on sealing and mating faces

Multi-sided machining — features on 5 faces of each part, requiring 4-axis/5-axis capability

Strict concentricity and perpendicularity between bore and mounting faces — verified, not assumed

Batch-to-batch consistency — the same part must fit identically in every robot they assemble

Our Solution

Our Process

Surface treatment: Optional anodizing coordinated in-house, keeping machining and finishing under one quality system

DFM review: Our engineers reviewed their 3D models and flagged 2 critical features — the thin-walled bearing seat and the angled sensor-mounting face — proposing fixture design adjustments before quoting to guarantee repeatability

Sampling: Prototype parts machined on a 5-axis center in one setup, eliminating re-clamping error on angled features; full CMM report issued with every dimension verified

First article assembly test: The customer assembled samples with their harmonic reducers and motors — fit confirmed on the first attempt, no adjustments needed

Mass production: In-house machining only; in-process inspection every 50 pcs; final CMM inspection per batch with report included

Surface treatment: Optional anodizing coordinated in-house, keeping machining and finishing under one quality system

Quality Control

• CMM dimensional report covering all critical features, including bores, mating faces, and threaded-hole positions
• Concentricity and perpendicularity verified with dedicated gauging
• 100% visual inspection for burrs and edge damage; critical threads gauged with go/no-go gauges
• Produced under our ISO 9001 quality management system; inspection report included with shipment

The Result

The customer reported zero fit issues during robot assembly — joint housings and gear seats mated perfectly with reducers and motors on every unit. The consistent ±0.01 mm accuracy eliminated their incoming inspection workload, and the 5-axis single-setup machining kept delivery times predictable even on complex parts. The customer has since awarded us components for two additional robot models and is evaluating us for their next-generation arm design.

Let’s Talk About Your Robotics Project

Whether it is a joint housing, arm structure, end-effector bracket, or robot control cabinet, we can machine your components from drawing to finished, inspected parts. Send us your 3D file or drawing with quantity and tolerance requirements for a quotation.