Industrial Robot End Effector Precision Aluminum Timing Pulley CNC Machining Success Case

This case study details the complete machining process of a custom precision aluminum timing pulley for an industrial robot manufacturer. The pulley is used in the transmission system of the robot's end effector, requiring high precision (tooth profile accuracy grade 6 or above), lightweight (aluminum alloy), and wear resistance (tooth surface hardness ≥ HV800) to ensure smooth and accurate transmission during robot handling and assembly tasks.

1. Order Reception and Technical Review: The customer provided initial drawings and specifications (8M type timing pulley for industrial robot end effector, nominal diameter 102mm, width 44mm, with keyway, aluminum material). Our technical team reviewed the drawings, confirming tooth profile parameters, tolerance requirements (tooth profile accuracy grade 6 or above), surface treatment (natural color oxidation), and other details.

   

2. Material Preparation: Selected high-quality aluminum alloy blank, known for good strength, lightweight, and machinability.

   

3. Rough Machining and Forging: The blank was forged and then normalized to refine the grain structure and improve internal homogeneity. CNC lathes were used for rough machining to preliminarily shape the pulley's outer circle, end faces, and bore, leaving sufficient allowance for subsequent finishing.

   

4. Heat Treatment: Quenching and tempering (adjustment) treatment was performed to improve the comprehensive mechanical properties of the material.

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   Semi-Finishing and Stress Relief: Dimensions were further refined during semi-finishing. Stress relief annealing was conducted to eliminate internal machining stresses and ensure dimensional stability.

   

6. Precision Machining: High-precision CNC machining centers were used for fine machining of all pulley features, ensuring dimensions and geometric tolerances met design requirements. Surface roughness of key areas like the bore and end faces was controlled to Ra0.8 or better.

   

7. Wire EDM for Tooth Profile: A slow wire EDM machine was used for high-precision machining of the pulley's tooth profile. Parameters like pitch and tooth direction were strictly controlled to achieve tooth profile accuracy grade 6 or above and tooth surface roughness ≤ Ra1.6.

   

8. Surface Treatment and Nitriding: The tooth surface underwent nitriding treatment to significantly increase surface hardness (≥ HV800) and wear resistance. Other surfaces received natural color oxidation per customer requirements to enhance corrosion resistance.

   

9. Precision Grinding and Final Inspection: Critical mating surfaces underwent necessary precision grinding. The finished product was 100% inspected using precision measuring instruments (like CMMs and gear profile testers) to ensure all parameters met drawing requirements.

   

10. Cleaning, Packaging, and Delivery: The product was thoroughly cleaned, anti-rust packaged, and delivered on time.

    

• Challenge 1: High Tooth Profile Accuracy Requirements. Solution: Utilized high-precision slow wire EDM and implemented in-process inspection for timely error compensation.

• Challenge 2: Balancing Lightweight and High Strength. Solution: Selected high-strength aluminum alloy and optimized the pulley structure using FEA analysis, removing excess material without compromising strength.

• Challenge 3: Requirement for Tooth Surface Wear Resistance. Solution: Applied nitriding treatment to effectively increase tooth surface hardness above HV800, extending service life.

The machined precision aluminum timing pulley fully met customer requirements:

• Tooth profile accuracy met Grade 6 standards, ensuring accurate and smooth transmission.

• Weight was reduced by approximately 60% compared to traditional steel pulleys, effectively reducing the robot's end load.

• High tooth surface hardness and excellent wear resistance, expected to extend service life by 50%. After integration into the industrial robot end effector, the customer reported high transmission efficiency, low noise, and significantly improved robot operation accuracy and efficiency.