Universal Robots UR5e: How should we compare contacts that leave witness marks?

OscarBarnes0532 · 23 May 2026, 11:26 UTC

Reply to discussion
OS
OscarBarnes0532
We're picking a gripper for Universal Robots UR5e to handle a polished cylindrical bezel during planning gentle handling of cylindrical components in a finished-parts handling station. Our bench samples have marks on the visible cylindrical surface. The supplier says softer pads; we haven't even agreed how to judge the marks. I need holding and release covered too.

15 replies

EL
ElliotBrown0944
Replying to OscarBarnes0532

@OscarBarnes0532 Does the customer have an appearance inspection method? Get that and the cosmetic zones on the drawing beside the samples before comparing pad materials.

12 points
OS
OscarBarnes0532
Replying to ElliotBrown0944

The drawing marks the outside cylinder as visible. Our pictures are just phone shots under workshop lights; nobody has linked them to the customer's inspection method.

19 points
EL
ElliotBrown0944
Replying to OscarBarnes0532

Get the viewing procedure, then compare handled and untouched samples using it. Include a softer pad as one candidate for reducing the marks.

6 points
HE
HenryBarnes0525
Replying to ElliotBrown0944

I'd qualify the softer-pad suggestion. Debris retention and dragging during release can matter, so softness alone could lead the comparison in the wrong direction.

22 points
EL
ElliotBrown0944
Replying to HenryBarnes0525

@HenryBarnes0525 Fair point; I gave softness too much emphasis. Compare geometry, actual surface condition and release as well. Softer is a candidate, not the expected winner.

22 points
OS
OscarBarnes0532
Replying to ElliotBrown0944

Would a marked sample and an untouched one from the same batch be enough to avoid blaming the gripper for incoming scratches?

18 points
NO
NoraBennett0757
Replying to OscarBarnes0532

That helps, and photograph each sample before contact too. Separate pieces from one batch can still arrive with different marks

4 points
DI
DineshCarter0995
Replying to NoraBennett0757

If lighting changes whether you can see a mark, which result counts?

1 points
EL
ElliotBrown0944
Replying to DineshCarter0995

@DineshCarter0995 The agreed customer method decides appearance acceptance. Extra views can help investigate a contact problem, but they shouldn't silently replace that method.

23 points
OS
OscarBarnes0532
Replying to ElliotBrown0944

The customer procedure is available in the quality pack. It specifies lighting and viewing, and our phone shots don't follow it. I'll use that for the comparison.

19 points
NO
NoraBennett0757
Replying to OscarBarnes0532

On a separate finished-sleeve job, an edge imprint mattered more than the broad contact haze. The accepted viewing method stopped us arguing over dramatic photos

2 points
OS
OscarBarnes0532
Replying to NoraBennett0757

Our samples also have a repeated line near the finger edge. I haven't compared them under the specified lighting yet, so it's a lead rather than a rejection.

12 points
EL
ElliotBrown0944
Replying to OscarBarnes0532

@OscarBarnes0532 Mark that contact edge on the supplier drawing. Ask how the contact shape spreads support and what happens as the fingers release.

9 points
OS
OscarBarnes0532
Replying to ElliotBrown0944

The comparison method is clear now: customer appearance criteria plus handling assessment. My selection-planning question is answered; the gripper choice will depend on those results.

3 points
EL
ElliotBrown0944
Replying to OscarBarnes0532

@OscarBarnes0532 That gives the selection review a clear basis while leaving the actual contact choice dependent on the comparison.

5 points

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