Requirements
- The system must cost a maximum of $500 and its components must be accessible in the market by anyone
- The system must be modular and easy to assemble (1h maximum assembly time) on a wax pot or tank of about 40 cm maximum diameter
- The system must be capable of operating with the voltage/frequency supplied in United States outlets (110V and 60Hz)
- The system must be capable of being operated from a computer and it must give the user information on:
- How the system is behaving
- The system’s electrical consumption
- If any error has occurred
- Control the depth of the dip to better control how much coating is desired, with a limit to minimize maintenance (cleaning) of the magnet
- The system must be able to detect an object on the conveyor, pick it up with an error margin of 2 to 3 cm and move it to the designated area to be picked up by the gripper within a period of 3 min
- The system must be able to lift the object (max 10kg) and be able to submerge it in hot Wax of around 250 F and resist that temperature without suffering damage
- The system must be capable of waiting the necessary time (1 to 3 min depending on the client’s set up)
- The system must be capable of positioning the object with the wax coating on the output conveyor in the indicated position with an error margin of 2 to 3 cm within a period of 3 min
- The system must have an EMERGENCY STOP and stop all operation immediately and proceed to execute the “Release the load safely” protocol within a period of 10 seconds. This will consist of moving the load (if present) to the designated area, thus preventing it from being released over the hot wax pot.
Objective 1: Motion System
The system shall use a two-axis stepper-driven motion system to pick up parts, dip them in the wax bath, and place them at the output station, achieving positional accuracy within ±1 cm on both axes. This will be confirmed by commanding each axis to a known target and measuring the offset with a ruler. NEMA 23 motors paired with compatible stepper drivers provide enough torque and control resolution to meet this accuracy target given the payload and travel range involved. Reliable, accurate motion is essential to completing the pick-dip-place cycle without dropping or misplacing parts, and this objective shall be completed and validated before final system integration testing begins.
Objective 2: Control and Sensing Reliability
The system shall use a microcontroller-based state machine that reads ultrasonic and limit switch inputs to safely sequence motor and end-effector actions, with correct part detection at the input station and correct motion stop at each axis limit confirmed through direct testing of each sensor. The selected microcontroller has sufficient GPIO, processing speed, and I/O compatibility to handle all required sensors and outputs, making this objective achievable within the current hardware design. Reliable sensing and state control are necessary to prevent collisions, missed parts, and unsafe operation, and this objective shall be completed, with sensor integration and state machine testing finished, before end-effector integration begins.
Objective 3: Safety and Communication
The system shall include a hardware emergency stop and an Ethernet-based Modbus TCP reporting system that communicates system state, position, and faults, with the E-stop confirmed to cut power immediately when actuated and require manual reset, and all state transitions and faults confirmed to appear correctly in Modbus TCP output during a full operating cycle. A normally-closed E-stop rated for peak current and an SPI-compatible Ethernet module both integrate directly with the existing power and control architecture, making this objective achievable without major redesign. Operator safety and system visibility are required for safe operation and effective troubleshooting, and this objective shall be validated during the final safety and communications review before project completion.