Four‑Axis Vacuum Stage for Advanced Nano‑Manufacturing

A four‑degree‑of‑freedom robotic vacuum stage for uniform 3D nanocoating of irregular objects, designed to operate inside a magnetron sputtering chamber with high precision and reliability.

Overview

We designed and fabricated a Four‑Axis Vacuum Stage, a 4‑DOF aluminum robotic arm integrated directly into a magnetron sputtering chamber. It enables conformal nanocoating on both flat and complex 3D substrates under high‑vacuum and elevated temperatures, overcoming the uniformity challenges of traditional 2D frame processes.

GitHub Repository
Four‑Axis Vacuum Stage Code & Schematics

Project Implementation & Demo

High‑vacuum magnetron sputtering chamber used for uniform nanocoating experiments, with viewports for real‑time process monitoring.
Second‑generation aluminum arm with screw‑drive and electromagnetic brake, ready for vacuum integration.
Custom STM32F407‑based control board handling motion commands, RS‑485 communication, and HMI interface signals.
Left: Custom PCB with optical isolators and 24 V power routing for noise‑free operation. Right: Four Emm42 stepper drivers on DIN rail, providing precise open‑loop control via RS‑485.
User interface displaying preset motion routines, real‑time arm position, and emergency‑stop controls for safe operation.

Technical Details

  • Mechanical Design
    • 4‑DOF arm built from vacuum‑compatible aluminum and 2020 extrusions
    • Screw‑motor drive on Joint 2 for high torque and self‑locking
    • Integrated electromagnetic brake for power‑loss safety
  • Control System
    • STM32F407 MCU with RS‑485 bus to four Emm42 stepper drivers
    • Custom PCB distributes 24 V and isolates noise via optical couplers
    • Open‑loop motion with periodic status polling and TFT touchscreen UI
  • Nanocoating Experiments
    • Uniform 900 nm Cr film on flat substrate at 300 mA, 0.5 h, 300 °C
    • Conformal coverage on a rotating 3D brass cylinder, demonstrating 3D capability

Key Features

  • High‑precision 4‑axis manipulation in vacuum
  • Uniform 3D nanocoating for irregular geometries
  • Industrial‑grade RS‑485 communication and optical isolation
  • Modular aluminum construction for cost‑effective fabrication
  • User interface with preset motion routines and emergency stop

Technical Stack

PCB Layout (KiCad) · STM32 MCU · RS‑485 · Emm42 Steppers · Fusion 360 & FEA · Magnetron Sputtering

Project Advisor

Prof. Oleskiy Penkov, Zhejiang University

Video demo: Automated chromium sputtering on a 3D brass cylinder (right-click to play).