Point adjustments are hiding something in our handling setup (tray loading)

ThomasArcher0364 · 20 Apr 2026, 01:17 UTC

Closed
TH
ThomasArcher0364
Our setup uses Universal Robots UR5e for tray loading with a rigid spacer block in a small assembly handling cell. We've repeatedly adjusted pickup points as handling becomes unreliable. Although the tray appears unchanged, the grip no longer looks as square. I'd like an inspection sequence that helps us identify the cause before making further teaching changes or attributing it to the arm.

17 replies

RE
ReeceArcher0384
Replying to ThomasArcher0364

Does the angle change before contact or as the fingers close? Existing footage may help you locate where things start going wrong.

25points
TH
ThomasArcher0364
Replying to ReeceArcher0384

Reviewing the recording, I can see consistent seating in the checked fixture before pickup. The workpiece changes angle during gripping rather than arriving in that position.

6points
RE
ReeceArcher0384
Replying to ThomasArcher0364

Keep a copy of the current configuration and hold off on further coordinate changes. Under the appropriate isolation procedure, maintenance can use the observed rotation to focus inspection on tooling contact, mounting and tray seating.

9points
TH
ThomasArcher0364
Replying to ReeceArcher0384

I've checked the maintenance history and found a pad replacement preceding the initial pickup-point correction. That establishes a relevant sequence of changes to investigate.

14points
RE
ReeceArcher0384
Replying to ThomasArcher0364

That sounds like the pad replacement caused it. Check the installation against the specified arrangement.

15points
PA
PavelCarter0962
Replying to ReeceArcher0384

The sequence makes pad installation worth investigating, but it doesn't establish causation. Fixture variation remains a possible contributor even with that maintenance history.

11points
RE
ReeceArcher0384
Replying to PavelCarter0962

You're right; the history supports a check, not a conclusion. Inspect the pad installation and gripping surfaces while retaining tray location in the investigation.

18points
AI
AishaCarter1040
Replying to ReeceArcher0384

@ReeceArcher0384 On my own setup, we found worn contact surfaces and inconsistent tray seating together. Fixing only the pickup point made the symptoms move around.

7points
TH
ThomasArcher0364
Replying to AishaCarter1040

With multiple point changes already in our history, I'm unsure how to distinguish tooling and tray effects. How did you structure that comparison on your setup?

18points
AI
AishaCarter1040
Replying to ThomasArcher0364

@ThomasArcher0364 We kept a known reference configuration and had maintenance check one condition at a time. We didn't roll back points blindly after finding wear.

14points
NI
NinaBennett0762
Replying to AishaCarter1040

Why not just go back to the original points once the gripper's checked? Aren't those the good ones?

18points
RE
ReeceArcher0384
Replying to NinaBennett0762

The original points are only a suitable reference if the confirmed tooling, frames and presentation still match. Have the responsible technician review those relationships before planning a supervised check.

25points
TH
ThomasArcher0364
Replying to ReeceArcher0384

@ReeceArcher0384 We haven't verified that match yet. I've stopped treating 'original' as a magic undo button and kept the current configuration available.

13points
PA
PavelCarter0962
Replying to ThomasArcher0364

Good. Also, 'tray looks the same' isn't a seating measurement. Your pre-contact observation helps, but it doesn't cover every tray replacement.

6points
TH
ThomasArcher0364
Replying to PavelCarter0962

@PavelCarter0962 Our supervised comparison has identified variation in tray seating and wear on the contact surfaces. That gives us two observed conditions to address in the investigation.

9points
TH
ThomasArcher0364
Replying to ThomasArcher0364

The pre-contact and gripping observations have narrowed where the symptom develops. We haven't established an accepted remedy, so I'm holding further coordinate adjustments during the investigation.

19points
RE
ReeceArcher0384
Replying to ThomasArcher0364

You've located when the symptom appears, even though the remedy is still open.

15points

Discussion closed

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