Mechanical Redesign & Automation of an Industrial Tube-Coating System

Led the complete electromechanical overhaul of a legacy aerosol deposition system. By transitioning from manual controls to G-code automation and redesigning critical mechanical assemblies, I improved coating uniformity by 2x and eliminated 100% of motor failures.

The Challenges / Problems

Critical Issues Identified in Legacy System:

Structural Instability: Severe vibration transfer from the shaker to the frame, compromising coating precision.
Electrical Hazards & Noise: A cluttered electrical box with 9 manual switches caused significant EMI noise and wiring failures.
Mechanical Interference: Constant cable entanglement in the rotating nozzle holder led to frequent motor burnouts and process downtime.
Inaccurate Motion Control: Lack of synchronization in vertical (Z-axis) movement and absence of programmable automation.
Poor Ergonomics: Insufficient workspace for the powder jar and vibrator units.

Electrical System Modernization – From Manual Toggles to CNC Automation

The legacy control interface, a cluttered array of nine manual switches, was replaced with a Tiny-G high-performance motion control board. This upgrade transformed the system from a manual operation to a programmable CNC environment. By centralizing the control logic, I eliminated signal EMI noise and wiring congestion, enabling the execution of complex, G-code-driven helical paths that ensure 100% repeatability across multiple coating cycles.

Process Reliability Improvement: Mechanical Redesign of Nozzle Positioning System

The legacy design utilized low-torque linear actuators for nozzle positioning, which frequently resulted in electromechanical failures and severe cable entanglement around the rotating spindle. To resolve these intermittency issues, I engineered a purely mechanical, high-reliability nozzle-holder assembly. This design eliminated the need for internal wiring, effectively neutralizing the cable-wrap failure mode. The mechanism features a robust, adjustable-angle architecture (inspired by heavy-duty gym equipment) that ensures precise angular positioning without the complexity of electronic failure points.

Improved Z-Axis Motion System:
The legacy system relied on a single Z-axis motor, which resulted in uneven vertical movement.
The redesigned version uses dual synchronized motors on the left and right sides. This modification significantly enhanced the structural rigidity and ensured a uniform, jitter-free vertical motion and significantly increasing the uniformity and smoothness of vertical motion.

Enhanced Nozzle Rotation Mechanism:
The nozzle rotation motor was replaced with a higher-torque unit, ensuring stable rotation even under higher vibration and gas-flow conditions.

Integrated Vacuum Pressure Monitoring:
A dedicated fixed port was added to the frame for mounting a vacuum pressure gauge, providing real-time monitoring and enabling more precise system control during powder feeding and deposition.

Total cost of Renovation:
Below is the full rebuild cost of the Tube Coater system

Coating Quality after renovation:
Despite the low total cost, the upgrade had a major impact on coating quality and system reliability. The rebuilt platform provides smooth nozzle rotation without cable interference, enabling consistent coverage inside the tube. The addition of dual stepper motors allowed controlled vertical translation of the nozzle, improving layer uniformity along the entire tube length.
Redesigning the electrical system and integrating the motion control with a Tiny-G board, which made it possible to program continuous helical (spiral) deposition paths—something the old system could not achieve. Removing the mechanical limit-switches reduced electrical noise and made the motion more stable, leading to repeatable, high-quality internal coatings.

Mechanical Redesign & Performance Optimization of an Automated Tube Coater