Machined Parts

The actuator module requires three precision-machined metal parts: motor shaft, motor pulley, and center pulley. These components are critical to the performance of the timing belt transmission system. Machined parts - motor shaft, motor pulley, and center pulley

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ODRI Encoder Kit Option

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Timing Belt Pulleys

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Critical Design Considerations

For best performance, the tooth profile of the pulleys must be very precise. Two manufacturing methods are available:

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Option A: Form Cutter (Recommended)

This method uses a custom form cutter to machine the precise tooth profile. Custom Form Cutter with AT3 tooth profile Form Cutter Specifications:

• Shaft Diameter: 3mm
• Teeth: 3 teeth
• Helix Angle: 20 degrees
• Material to Cut: 7075 aluminum

Manufacturing Instructions:

1. Order Custom Form Cutter:
   • Find a company that offers custom tooling and can produce custom form cutters
   • Provide this technical drawing: PDF Drawing - Pulley AT3 T10 Form Cutter
   • Specify that the tool will be used to machine 7075 aluminum
2. Machine the Pulleys:
   • Send the custom form cutter and drawings to a machine shop
   • Provide these technical drawings:
     • PDF Drawing - Motor Pulley AT3 T10
     • PDF Drawing - Center Pulley AT3 T10
   • Material: 7075 aluminum

Aluminum AT3 pulleys machined with custom form cutter

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Option B: Wire EDM Cutting

Alternatively, the tooth profile can be generated using Wire EDM (Wire Electrical Discharge Machining). Pulleys manufactured using Wire EDM Considerations:

• Initial testing has been completed to evaluate this option
• Cost: No significant advantage over form cutter method
• Surface Finish: Much rougher surface compared to form cutter method
• Durability Concerns: Unknown effect on timing belt lifespan due to rougher surface

Technical Files:

• PDF Drawing - Wire EDM Geometry
• DXF File - Wire EDM Geometry

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Remaining Machining Operations

After the tooth profile is created (using either method), the remaining machining steps are completed on a lathe:

• Outer diameter finishing
• Bore diameter
• Hub features
• Face features

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Motor Pulleys

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Motor Pulley Specifications

Motor Pulley AT3 T10

• Material: 7075 Aluminum
• Weight: 0.6g
• Teeth: 10 teeth, AT3 profile (modified)
• Technical Drawing: PDF Drawing - Motor Pulley

Manufacturing Process:

1. Create tooth profile using custom form cutter (Option A) or Wire EDM (Option B)
2. Complete remaining features on lathe
3. Ensure tight tolerances on bore to fit motor shaft

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Center Pulley Specifications

Center Pulley AT3 T10

• Material: 7075 Aluminum
• Weight: 2.1g
• Teeth: 10 teeth, AT3 profile (modified)
• Technical Drawing: PDF Drawing - Center Pulley

Manufacturing Process:

1. Create tooth profile using custom form cutter (Option A) or Wire EDM (Option B)
2. Complete remaining features on lathe
3. Ensure bearing seat dimensions are accurate

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Motor Shafts

Precision ground motor shaft

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Material Specifications

Stock Material:

• Material: Precision Ground Stainless Steel Rod 1.4301 EN10278 h9
• Diameter: 4.0mm (actual diameter: 3.97mm - 3.99mm)
• Tolerance: h9
• Supplier: Weinmann Aach (Germany)
• Product Code: erd4

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Motor Shaft Specifications

Motor Shaft

• Material: Stainless Steel 1.4301 (4mm h9 precision ground rod)
• Weight: 3.2g
• Technical Drawing: PDF Drawing - Motor Shaft

Manufacturing Process:

1. Start with 4mm h9 precision ground stainless steel rod
2. Machine according to technical drawing
3. Key features:
   • Precise diameter for motor bearing fit
   • Pulley mounting section
   • Code wheel mounting section
   • Shoulder dimensions

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Machining Tolerances

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Critical Tolerances

Ensure the following tolerances are maintained:

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Quality Checks

After machining, verify:

1. Tooth Profile: Check with timing belt for proper engagement
2. Bearing Fit: Test fit bearings (should be light press fit)
3. Concentricity: Measure runout with dial indicator
4. Surface Finish: Ensure smooth surfaces on bearing seats

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Material Properties

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7075 Aluminum (Pulleys)

Properties:

• High strength-to-weight ratio
• Good machinability
• Excellent fatigue resistance
• Lightweight (density: 2.81 g/cm³)

Heat Treatment:

• T6 temper recommended for maximum strength

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Stainless Steel 1.4301 (Motor Shaft)

Properties:

• Corrosion resistant
• Good mechanical properties
• Precision ground surface finish
• Non-magnetic

Equivalent Standards:

• AISI 304
• EN 1.4301

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Assembly Preparation

After machining, before assembly:

1. Deburr all edges - Remove any sharp edges or burrs
2. Clean thoroughly - Remove all machining oils and debris
3. Inspect dimensions - Verify all critical dimensions with calipers
4. Test fit components - Verify fit with bearings and shafts before final assembly

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Technical Drawing Summary

Total Weight of Machined Parts: 5.9g

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Supplier Contact Information

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Stock Material Supplier

Weinmann Aach (Germany)

• Website: weinmann-aach.de
• Product: Precision Ground Stainless Steel Rod 1.4301 EN10278 h9 4.0mm (erd4)
• Ships within Europe

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Form Cutter Manufacturers

Contact custom tooling companies that specialize in form cutters. Provide the technical drawing and specify:

• Profile geometry per drawing
• 3mm shaft diameter
• 3 teeth
• 20° helix angle
• Material to be cut: 7075 aluminum

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Machine Shops

Any qualified machine shop with:

• CNC or manual milling capability
• Lathe capability
• Ability to hold tight tolerances (±0.05mm)
• Experience with aluminum and stainless steel

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Cost Considerations

Form Cutter Method:

• Higher initial cost (custom form cutter)
• Lower per-part cost for multiple units
• Better surface finish
• Faster production for quantities >10 units

Wire EDM Method:

• Lower initial tooling cost
• Higher per-part cost
• Acceptable for prototype quantities
• Rougher surface finish