Project Overview
Motionwell Automation delivered a series of cleanroom-grade Automatic Test Equipment (ATE) machines (Project P23018) for electronics manufacturers in Singapore. The ATE series performs mechanical and electrical testing of electronic components, connectors, and sensors within ISO Class 7/8 cleanroom conditions.
The project addressed the need for automated, repeatable testing with full data capture, replacing manual test processes that introduced human variability and limited throughput.
System Design
Cleanroom Integration
Each ATE machine is fully enclosed with 4-6 FFU (Fan Filter Unit) modules that maintain ISO Class 7/8 cleanroom conditions:
- HEPA-filtered air circulation within the test enclosure
- Positive pressure maintenance to prevent particle ingress
- Material selection compatible with cleanroom protocols
- Easy-clean surfaces for routine maintenance
Multi-Station Test Architecture
The ATE uses a circular transfer system with multiple test stations:
- Automated component loading via collaborative robot
- Sequential test execution across stations
- Real-time pressure and displacement monitoring
- Automated pass/fail sorting based on test limits
- Data logging in SPC-ready format
Cobot Loading System
A collaborative robot handles automatic loading and unloading of test specimens:
- Tray-based batch loading for high throughput
- Vision-guided pick-and-place for precise positioning
- Dual tray system for continuous operation (load while testing)
- Automatic sorting of tested parts by result
Technical Specifications
| Parameter | Specification |
|---|---|
| Cleanroom | ISO Class 7/8 (4-6 FFU units) |
| Transfer | Multi-station circular |
| Loading | Collaborative robot |
| Control | PLC + Siemens HMI |
| Data | SPC-ready logging |
| Tests | Force, fatigue, pressure, electrical |
Technical Details
Positioning and Repeatability
The cobot loading system achieves positioning repeatability of +/-0.05mm at the test fixture interface. This level of precision is necessary for connector insertion force testing, where even minor misalignment between the test probe and the connector housing introduces measurement error. The cobot’s tool center point is calibrated against a precision reference pin at the start of each production batch, with the calibration offset stored in the PLC for real-time compensation.
Jig and Fixture Materials
Test fixtures and specimen nests are machined from nylon (PA66) and POM (polyoxymethylene/acetal) engineering plastics. These materials serve dual purposes:
- Electrical insulation: Nylon and POM provide surface resistivity exceeding 10^12 ohm, preventing electrical interference with the device under test. This is essential for accurate resistance and continuity measurements on electronic connectors and sensors.
- Wear resistance: POM’s low friction coefficient (0.2-0.35) and dimensional stability ensure consistent specimen positioning over extended production runs. Unlike metallic fixtures, POM nests do not generate conductive particles that could contaminate the cleanroom environment or short-circuit test specimens.
Fixture changeover for different connector types uses a quick-change mounting system with dowel-pin alignment, enabling tool-free swaps in under 2 minutes.
Pneumatic System Architecture
The ATE machines use SMC and Festo pneumatic valve banks for actuator control throughout the test stations. Valve islands are centrally mounted within the machine enclosure, with individual solenoid valves controlling each pneumatic cylinder.
All pneumatic cylinders are equipped with magnetic reed switches for closed-loop position detection. The switches detect the piston’s extended and retracted positions, confirming that each actuation cycle completes fully before the PLC advances to the next test step. This prevents test sequence errors caused by incomplete cylinder strokes – for example, ensuring a connector is fully seated in the test socket before electrical measurements begin.
Air preparation units with filter-regulator-lubricator (FRL) assemblies maintain clean, dry air supply at each valve bank. Operating pressure is regulated to 0.4-0.6 MPa depending on the test force requirements.
SPC Data Export
The PLC logs all test measurements (force, displacement, resistance, continuity) in real-time and exports the data in SPC-ready format. Data can be filtered and exported by:
- Batch number: All test results from a single production batch grouped for statistical analysis
- Serial number: Individual device test history for traceability and warranty tracking
- Test parameter: Specific measurement types isolated for process capability studies (Cp/Cpk calculations)
Export formats include CSV for offline analysis and direct OPC-UA connectivity for real-time SPC charting on Siemens WinCC or equivalent SCADA platforms. Control limits and alarm thresholds are configurable per test parameter through the Siemens HMI interface.
Circular Belt Transfer with Pallet System
The multi-station test architecture uses a circular belt transfer system with a pallet-based workpiece carrier. Pallets circulate continuously around the loop, stopping at each test station via pneumatic stopper pins. Each pallet carries a single test specimen in a precision nest, maintaining the specimen’s orientation through all test stations.
The circular layout provides several advantages over linear transfer: pallets automatically return to the loading station after completing all tests, the cobot loads and unloads at a single station, and the system can buffer multiple pallets simultaneously to decouple station cycle times. Pallet identification uses RFID tags embedded in the pallet body, enabling the PLC to track each specimen’s position and test status throughout the loop.
Related
This project showcases Motionwell’s robotics integration and custom machine design expertise for the electronics & semiconductor industry.