The test jig is the physical contact point between the DUT (Device Under Test) and the test bench. The choice of jig type — manual, pneumatic, or motorized — directly impacts the productivity, safety, ergonomics, and repeatability of tests on the line.
The ideal jig is one that balances robustness, cost, and efficiency for your production volume.
🔧 1. Manual Jig
Characteristics:
- Activation by operator force (lever or manual pressure closure)
- No consumption of compressed air or electrical energy
- Recommended for low cadence (up to 20 units/h) or prototype applications
Advantages:
- Lower cost
- Easy maintenance
- Good for simple operations or low volume
Disadvantages:
- Lower repeatability of force and position
- Higher physical effort for the operator
- Lower ergonomics and risk of fatigue
🔩 2. Pneumatic Jig
Characteristics:
- Closure by pneumatic actuator (air cylinder)
- Control via button, pedal, or test system signal
- Ideal for medium (20-50 units/h) or high cadence (above 50 units/h)
Advantages:
- Fast and ergonomic (no manual effort)
- Constant pressure force → better repeatability
- Can be integrated with safety systems (NR-12)
Disadvantages:
- Requires filtered compressed air
- More complex than manual (valves, sensors, actuators)
⚙️ 3. Motorized Jig (Electric)
Characteristics:
- Uses electric actuators (stepper, servo, or linear)
- Control by PLC, Arduino, LabVIEW, or tester system
- Ideal for highly automated or customized lines
Advantages:
- High precision in force and stroke control
- Integration with automated sequences (e.g., TestStand)
- Indicated for delicate products or multipoint tests
Disadvantages:
- Higher implementation cost
- Requires more advanced programming and electronic control
⚖️ Attention to Ergonomics: NR-17
When opting for a manual jig, it is essential to consider the effort and repeatability limits imposed by NR-17 (Ergonomics Regulatory Standard). The standard establishes that the workstation must avoid excessive efforts, forced postures, and repetitive cycles without adequate breaks. When the number of units per hour exceeds 20 pieces per operator, it is strongly recommended to adopt pneumatic or motorized jigs to reduce the risk of RSI/WRMD and ensure legal compliance.
🛠️ How AJOLLY Testing Assists in the Choice
AJOLLY Testing designs custom jigs, considering:
- Production volume (cadence per hour)
- Type and delicacy of the DUT
- Safety requirements (NR-12, use of two-hand operation, position sensors, protections, and enclosures)
- Ergonomics requirements (NR-17, avoiding excessive effort, forced postures, short repetitive cycles, and facilitating operation with comfort and safety)
- Integration with the test bench (hardware + software)
- Cost-benefit and ROI of the jig type for your scenario
Application Example:
For a line with 1,500 pieces/day, AJOLLY designed a pneumatic jig with cycle sensor, safety lock, and control via TestStand.
✅ Comparative Summary
| Jig Type | Ideal Volume | Ergonomics | Repeatability | Complexity | Recommendation |
|---|---|---|---|---|---|
| Manual | Low (up to 20 units/h) | Low | Medium | Low | Prototypes and small series |
| Pneumatic | Medium (20-50 units/h) High (above 50 units/h) | High | High | Medium | Production lines with fixed operator |
| Motorized | High/Automated (above 50 units/h) | Very high | Very high | High | Automatic lines or sensitive DUTs |
Jig is not just mechanics — it is ergonomics, repeatability, and safety integrated into your process.