3D Printed Parts

The actuator module uses two categories of 3D printed parts, each requiring different printing technologies for optimal results.

​

Printing Technologies

​

Large Structural Parts

For large structural parts like shells and robot body structures, use:

• FDM (Fused Deposition Modeling) printer
• SLS (Selective Laser Sintering) printer

These technologies are suitable for parts that require strength and durability but not extremely fine detail.

​

Small Precision Parts

For small parts requiring high precision like timing belt pulleys, use:

• Multijet printer
• SLA (Stereolithography) printer

These technologies provide the accuracy needed for components with tight tolerances, such as the AT3 timing belt pulley tooth profile. Comparison of 3D printed parts: Body structure from FDM printer (left) and pulley from Multijet printer (right)

​

Printing Tolerances

​

Critical Surfaces

The most critical surfaces for shell parts are the bearing seats (colored yellow in technical drawings). These require precise dimensions:

• If bearing seat diameters are too tight, use an end mill to adjust the diameter
• If bearing seat diameters are much too large, bearings will not be held securely and parts may be unusable

​

MPI Tübingen Printer Specifications

​

Fortus FDM Printer

The Fortus 360mc FDM Printer is used for structural components with the following specifications: Material and Settings:

• Model Material: PC-ABS black
• Support Material: SR20
• Nozzle: T12 nozzle for material and support
• Slice Height: 0.178mm
• Support Removal: Mechanical removal or alkaline bath
• Interior Settings:
  • Standard solid interior for shell and body parts
  • Sparse double dense for lower legs

​

Projet Multijet Printer

The Projet 3500 HD Max Multijet Printer is used for precision components: Material and Post-Processing:

• Model Material: VisiJet M3X
• Support Material: S300 Wax
• Post-Processing Steps:
  1. Oven for removing wax support material
  2. Ultrasonic bath with baby oil for removing remaining wax
  3. Ultrasonic bath with soap water for cleaning
  4. Quenching in ice water

​

Ordering from 3D Systems

​

Shell Parts (SLS Printing)

Shells should be printed using Selective Laser Sintering (SLS) with high-strength material. Ordering Instructions:

1. Go to 3D Systems Part on Demand Service
2. Login or create an account
3. Upload STL files:
   • actuator_shell_base.stl
   • actuator_shell_cover.stl
4. Choose Printing Technology: SLS - Selective Laser Sintering
5. Choose Material: Duraform HST
6. Select number of copies
7. Do NOT order online - save order and note the order number
8. Email 3D Systems engineering support with:
   • Order number
   • Request for quote with printing direction in positive z-axis direction of STL files

Recommended Print Direction:

• Positive z-axis direction of STL files
• This ensures critical bearing seat surfaces are oriented correctly

​

Pulleys and Code Wheel Mount (SLA Printing)

These precision parts should be printed using Stereolithography (SLA) or Multijet. Ordering Instructions:

1. Go to 3D Systems Part on Demand Service
2. Login or create account
3. Upload STL files:
   • encoder_codewheel_pwb_mount.stl
   • transmission_pulley_at3_t30_center.stl
   • transmission_pulley_at3_t30_output.stl
4. Choose Printing Technology: SLA - Stereolithography
5. Choose Material: Accura Extreme Grey
6. Select number of copies
7. Do NOT order online - save order and note order number
8. Email engineering support with:
   • Order number
   • Request for quote with printing direction in positive z-axis direction

​

3D Systems Engineering Support

​

3D Printed Parts List

All STL files are available in the source repository’s stl_files directory.

​

Encoder Mount

Encoder Codewheel PWB Mount

• Weight: 0.3g
• File: encoder_codewheel_pwb_mount.STL
• Use: For Broadcom AEDT-9810-Z00 encoder
• Printer: SLA, Polyjet, or Multijet

Encoder Codewheel Kit Mount

• Weight: 0.3g
• File: encoder_codewheel_kit_mount.STL
• Use: For AEDM-5810-Z12 encoder kit
• Printer: SLA, Polyjet, or Multijet

​

Transmission Pulleys

Transmission Pulley AT3 T30 Center

• Weight: 4.2g
• Teeth: 30
• File: transmission_pulley_at3_t30_center.STL
• Printer: SLA, Polyjet, or Multijet
• Note: Tooth profile requires high precision

Transmission Pulley AT3 T30 Output

• Weight: 6.7g
• Teeth: 30
• File: transmission_pulley_at3_t30_output.STL
• Printer: SLA, Polyjet, or Multijet
• Note: Tooth profile requires high precision

​

Timing Belt Tensioner Rollers

Transmission Belt Tensioner Rollers

• Weight: 0.2g each
• Quantity Required: 2
• Printer: SLA, Polyjet, or Multijet

Multiple diameter options available to adjust timing belt tension: Default: 10.0mm diameter

​

Shell Parts

Actuator Shell Base and Cover

• Printer: FDM (Fortus) or SLS
• Material: PC-ABS (FDM) or Duraform HST (SLS)
• Files: actuator_shell_base.STL, actuator_shell_cover.STL

​

Printing Direction

​

Quality Control

​

Critical Dimensions

After printing, verify these critical dimensions:

1. Bearing seat diameters - must hold bearings securely without excessive force
2. Pulley tooth profiles - must mesh properly with timing belts
3. Mounting hole locations - must align with mating parts
4. Thread boss dimensions - must accept helicoil inserts properly

​

Test Fitting

Before final assembly:

• Test fit bearings in their seats
• Check pulley/belt engagement
• Verify all fastener holes
• Test encoder mount alignment

​

Material Properties

​

PC-ABS (FDM)

• Good impact resistance
• Suitable for structural components
• Can be post-machined if needed

​

Duraform HST (SLS)

• High strength and stiffness
• Excellent dimensional accuracy
• Good fatigue resistance

​

VisiJet M3X (Multijet)

• High detail resolution
• Smooth surface finish
• Suitable for precision mechanical parts

​

Accura Extreme Grey (SLA)

• High tensile strength
• Good dimensional stability
• Excellent surface finish