The Start-Up That Skipped the Inspection
A line was restarted after a weekend shutdown. The operator pressed “auto” and walked away. Within 30 seconds, a robot collided with a fixture — the fixture had been loosened during a Friday maintenance task, and the bolts were never tightened. The machine ran into a problem that a 5-minute start-up inspection would have caught. The root cause was not the maintenance crew (they should have tightened the bolts). It was the missing start-up check. The operator had no procedure to verify the machine was safe before auto-running it. The fixture wobbled on Monday morning; the robot did not know. It just crashed.
A pre-use safety inspection is the last check before the machine runs. It catches the weekend’s mistakes. Here is how to do it without slowing the start-up.
The 5-Minute Start-Up Check
Before placing the machine in auto, the operator (or a designated person) walks through a short, written checklist. It takes 5 minutes and catches the obvious problems:
- Guards: Are all guards closed and in place? (Not propped open, not missing.)
- E-stop test: Press the mushroom; does the machine stop? Twist to reset; does it stay stopped?
- Safety light curtain: Wave a hand through; does the light change and the machine stop?
- Interlocked gate: Open the gate; does the machine stop? Close it; does it require a reset?
- Fixtures: Are the locating pins seated? Are the clamp bolts tight? (The loose fixture above.)
- Air pressure: Is the gauge at setpoint? Any leak hissing?
- Abnormal noise: Jog the machine one cycle; does it sound normal?
- Tools left in the machine: Any wrench, rag, or gauge left from maintenance? (These become projectiles when the machine runs.)
The start-up rule: Auto mode is earned, not assumed. The machine has been off; someone may have been inside it. Run the 5-minute check, then go to auto. The robot that crashed into a loose fixture would have wobbled visibly if the operator had run one manual cycle first.
Manual Jog Before Auto
The single most valuable start-up step: run one cycle in manual (jog) before switching to auto. Watch the full motion. Does the robot path clear the fixtures? Does the clamp close on the part? Does the sensor see the part? A manual cycle catches misalignment, loose fixtures, and wrong tooling that an auto run would crash through. The 30-second manual jog saves the 2-hour crash repair.
The Tools-Left-Behind Problem
Maintenance crews leave tools inside the machine. A wrench on a conveyor, a rag in a robot cell, a gauge in a press — when auto starts, these become projectiles. The pre-use check includes a visual sweep: look inside the cell, look at the tooling area, look at the conveyor. It takes 10 seconds and prevents a $5000 collision.
Who Does the Check, and When
The check should be done by the operator who is taking the machine over — not a supervisor, not the previous shift. The person who runs the machine every shift knows what “normal” sounds and looks like. They are the best detector of “not normal.” The check is documented (a sign-off sheet or a digital log) — so if something goes wrong, you know who checked it.
Daily vs Weekly: The Cadence
The 5-minute check is daily (or every shift). The deeper check (torque the fasteners, test the safety relay, verify the light curtain alignment) is weekly. The daily check catches the loose fixture; the weekly check catches the degraded safety relay. Both are needed.
A Pre-Use Checklist (Print It)
| Check | Done? |
|---|---|
| All guards closed and intact | ☐ |
| E-stop tested (stops and resets) | ☐ |
| Light curtain tested (hand blocks) | ☐ |
| Interlocked gate tested | ☐ |
| Fixtures seated and clamped | ☐ |
| Air pressure at setpoint | ☐ |
| No tools left inside | ☐ |
| One manual jog cycle sounds normal | ☐ |
| Who signed off (name/date) | ____ |
The Bottom Line
The robot that crashed into a loose fixture was a start-up that skipped the check. The 5-minute pre-use inspection is not bureaucracy — it is the last chance to catch the weekend’s maintenance mistakes before they become a crash. Run the manual jog, look for tools left behind, test the e-stop. The machine that runs without an accident is the one that was checked first.
