Installation Guide: 6-DOF SACE Machining Center

This guide provides instructions for assembling and configuring the 6-Degree of Freedom (6-DOF) Spark Assisted Chemical Engraving (SACE) system.

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⚠️ Safety Information

Read before proceeding:

• Corrosive Hazard: Electrolytes (NaOH/KOH) are highly caustic. Wear chemical-resistant gloves and eye protection.
• High Voltage: The power module operates up to 50V DC. Ensure all capacitors are discharged before handling the PCB.
• Motion Hazard: The Meca500 robot moves with high precision and torque. Keep the workspace clear of obstructions during initialization.

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1. Prerequisites

Required Skills

• Mechanical assembly
• PCB soldering skill
• Arduino/ STM firmware
• Python

System Components

• Refer to BOM for detailed information
• Robot Selection: Mecademic Meca500 (Can be replaced with other precision robot in small scale)

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2. Mechanical Assembly

2.1 Tool-Holding Subsystem

1. After Printing the Structures: Check all printed components, insert all M2 nuts before assembly.
2. Spindle Assembly: Follow the CAD model to assemble the spindle structure, fasten the screw to ensure the rigidity of the structure.
3. Hold Protective Film Around Robot: Some thick soft foam tape can be used on the protect film mounting ring before mounting on the robot. Put M3 inserts on all small holes around the protection nozzle, and use film ring to fix the film around the robot.
4. Positive Pressured Shield: Slide the nozzle shield over the tool assembly. Connect the pneumatic line to the air inlet to prevent electrolyte vapor from entering the motor bearings.
5. Supplementary Electrolyte Flow: Use M2 inserts and screws to fix the supplementary electolyte tip around the protective nozzle.

2.2 Electrolyte Circulation

1. Reservoir Setup: A 2L reservoir is preferred under most of the experiment situation.
2. Before the operation: Check if there is a leakage in the system with just circulating water. Do not use electrolyte before leakage checking.
3. Level Control: Position the electrolyte cell 5cm above the table and mount the flow-back tube on the table to make sure electrolyte always flows back before flooding the table.

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3. Electronics & Firmware

3.1 Power Module Assembly

1. PCB Fabrication: Solder the components on the printed PCB, and perform a basic check with lower voltage and an oscilloscope.
2. Isolation Check: Use a multimeter to verify there is no continuity between the low-voltage logic ground (Arduino) and the high-voltage ground.
3. Heat Management: Turn on the cooling fan before operating the power module. Heat accumulation is extremely fast under the designed operational voltage and might cause malfunction of the MOSFET in short operation time.

3.2 Firmware Upload

1. Power Module: Connect the Arduino Nano via USB and flash Source\PowerModule\PowerModule_arduino\Motor_Fan_Screen_Control\Motor_Fan_Screen_Control.ino for the Arduino under "Motor/Fan/Screen Control" secion, and flash Source\PowerModule\PowerModule_arduino\PowerModule\PowerModule.ino for the "Power Control" Arduino
2. DAQ Configuration: Open STM32CubeIDE(1.9) project under Source\Realtime_signal_monitoring\ADC_USB, and flash to STM32F103C6T6 using ST-LINK. The python receiver is under Source\ADC_python_receiver

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4. Calibration & First Run

4.1 ADC Calibration

4.1.1 Hardware Gain Trimming

1. Apply regulated full-scale DC inputs (40V for the voltage channel, 300mA for the current channel) to the board’s input terminals.
2. Then fine-tune trim resistors in the voltage divider and non-inverting amplifier gain stages to map the maximum expected input to a 3.25V ADC input (0.05V safety margin below the 3.3V MCU limit)
3. Try slowly increase the voltage on each channel to make sure Zener diodes are functioning. Do not apply more than 5V in this test.

4.1.2 Software Calibration & Coefficient Calculation:

1. Collect 100 averaged raw ADC samples at 10 evenly spaced ascending and descending known input levels for each channel (10V, 20V, 30V 40V for voltage channel, and 0V, 100mV, 200mV and 300mV for current channel).
2. Run linear regression on the paired reference input and raw ADC data to generate linear conversion coefficients (slope k and offset b) for each channel for the model: $$\text{Actual Value} = k \cdot \text{ADC}_{\text{raw}} + b$$
3. Integration & Validation: Hard-code the validated voltage channel $(k_v, b_v)$ and current channel $(k_i, b_i)$ coefficients into the PC-side Python data streaming script

4. 4.2 Tool Alignment

5. Initialize the Meca500 robot.
6. Define the Tool Reference Frame (TRF) by touching the electrode tip to the center of the glass substrate.
7. Set the software "Zero" at this coordinate.

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5. Maintenance Schedule

Frequency	Task
Every Use	Inspect tool electrode for carbon buildup; replace if necessary.
Weekly	Flush circulation tubing with warm water (~50 degree C) to prevent salt crystallization.

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Note: For the complete Bill of Materials (BOM) and CAD files, refer to the repository linked in the "Source" section of the associated paper.