Andrew Tool Projects

Actuator Base

Written by Andrew Tool | Nov 6, 2023 4:18:00 PM

In the project highlighted here, we were tasked with creating an actuator base that would be used on the robotic arm attached to the Mars Rover “Curiosity”.

Project Description

At Andrew Tool & Machining, we specialize in high-precision machining for a wide range of high-tech industries. In the project highlighted here, we were tasked with creating an actuator base that would be used on the robotic arm attached to the Mars Rover “Curiosity”. The initial prototype parts were machined from titanium, with final parts crafted from ATI Vascomax, an iron-based steel alloyed with nickel and cobalt that was capable of withstanding the demands of the interplanetary mission. A complex five-axis machining process was used to create the components, followed by milling with wire electrical discharge machining (EDM) and a final step of precision grinding to provide a surface finish of 8 micro-inches (super-mirror finish). The assembly was built to dimensions of 6″ x 4″ x 6″ and to tolerances of ±0.0002″ concentricity on the gear pitch diameter as referenced to the axis of the bore.

The assembly met rigorous customer-provided specifications, which were required due to the environmental conditions and remoteness of the Rover’s final destination. Among these was a requirement for virtually zero backlash during gear operation due to the signal delay between Earth and Mars.

The testing and inspection process utilized a Zeiss ACCURA coordinate-measuring machine (CMM) with VAST XT gold active scanning sensor to provide a rigorous quality control scheme that repeatedly verified the dimensions of the multiple parts comprising the final assembly. Sixteen specific pieces were required to complete the actuator base, all of which were completed in six months. The project required ongoing coordination with the customer to ensure that the product met the needs of their operation and integrated seamlessly into the complicated Rover machinery.

Specifications

Capabilities Applied/Processes
  • Primary: 5 Axis Machining
  • Secondary: Wire EDM, Precision Grinding
Equipment Used to Manufacture Part
  • 3 Axis Vertical Mill
  • CNC Lathe
Overall Part Dimensions
  • 6 x  4 x 6 in
Tightest Tolerances
  • ±0.0002 in. concentricity on the gear pitch diameter to the bore
Material Used
  • Titanium (Prototypes)
  • Vascomax on Production Models
Material Finish
  • 8 micro-inches (superior-mirror finish)
In Process Testing/Inspection Performed
  • CMM - Zeiss
Volume
  • 6 pieces of each - 16 different part numbers
Delivery/Turnaround Time
  • 6 months
Delivery Location
  • Ultimately Mars
Standards Met
  • 2D CAD Drawing
  • Customer Specifications
  • Zero Backlash

Why Did You Choose This Project to Showcase?

  • Magnitude of the Project
  • Material is Extremely Rare
  • Multi Axis Machining
  • Multiple Processes
  • The Coordination between us and the Customer