Where would you start with gradual pickup drift? (tray loading)

KaiChen1150 · 3 Aug 2026, 13:00 UTC

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KA
KaiChen1150
Our setup uses Universal Robots UR5e for tray loading with a rigid spacer block in a supervised production bench. 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.

20 replies

RO
RobinBrown0947
Replying to KaiChen1150

@KaiChen1150 Does the angle change before contact or as the fingers close? Existing footage may help you locate where things start going wrong.

8 points
KA
KaiChen1150
Replying to RobinBrown0947

@RobinBrown0947 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.

18 points
RO
RobinBrown0947
Replying to KaiChen1150

Preserve the current settings and pause further nudges. Have maintenance inspect finger mounting, contact surfaces and tray seating under the proper isolation procedure, using that observation to guide the checks.

9 points
KA
KaiChen1150
Replying to RobinBrown0947

@RobinBrown0947 The maintenance notes show contact pads were replaced before the first point adjustment. That's the first useful clue I've found in the history.

21 points
RO
RobinBrown0947
Replying to KaiChen1150

@KaiChen1150 That sounds like the pad replacement caused it. Check the installation against the specified arrangement.

16 points
RE
ReeceArcher0384
Replying to RobinBrown0947

Timing isn't enough to call it the cause. Check the pads, yes, but don't let one maintenance entry explain away fixture variation.

17 points
RO
RobinBrown0947
Replying to ReeceArcher0384

Agreed, I called it too early. Treat the replacement as a lead; verify installation and contact condition alongside tray location before assigning the cause.

16 points
ME
MeiBaker0516
Replying to RobinBrown0947

@RobinBrown0947 On my own setup, we found worn contact surfaces and inconsistent tray seating together. Fixing only the pickup point made the symptoms move around.

3 points
KA
KaiChen1150
Replying to MeiBaker0516

@MeiBaker0516 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?

15 points
ME
MeiBaker0516
Replying to KaiChen1150

For my setup, a documented reference configuration anchored the investigation while maintenance assessed individual conditions. Discovering wear didn't mean we automatically restored older pickup coordinates.

4 points
AM
AmaraBarnes0600
Replying to MeiBaker0516

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

7 points
RO
RobinBrown0947
Replying to AmaraBarnes0600

Only if they match the verified setup. Tooling, frames or presentation may have changed; your responsible technician should compare the configuration before any supervised validation.

21 points
KA
KaiChen1150
Replying to RobinBrown0947

@RobinBrown0947 The relationship between the initial points and the present setup hasn't been verified. I'm retaining the current configuration instead of assuming the original positions would restore a known condition.

15 points
RE
ReeceArcher0384
Replying to KaiChen1150

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

10 points
KA
KaiChen1150
Replying to ReeceArcher0384

@ReeceArcher0384 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.

9 points
AM
AmaraBarnes0600
Replying to KaiChen1150

Would you clean the pads or replace them? I can't tell where routine cleaning stops being enough.

10 points
RO
RobinBrown0947
Replying to AmaraBarnes0600

@AmaraBarnes0600 Use the tool maker's maintenance criteria and a qualified inspection. Appearance alone won't tell you whether cleaning restores an acceptable contact surface.

19 points
ME
MeiBaker0516
Replying to RobinBrown0947

For my own tooling, photographs attached to the maintenance history made condition changes easier to compare. They provided a more useful reference than recollections about how the grip once looked.

-1 points
KA
KaiChen1150
Replying to MeiBaker0516

@MeiBaker0516 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.

21 points
RO
RobinBrown0947
Replying to KaiChen1150

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

4 points

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