Answered Robot EOAT design to handle cylindrical workpieces

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Hi Jiang!

How do you have to grip the workpiece? I mean if the cylinder is on the face then the gripper is on the top of the cylinder or on the side of the cylinder?

Hi Gábos!

The gripper is beside of the workpiece, like on the first picture. Do you have any suggestions what type of gripper should I use?  

Another important data : the max. workpiece weight is 0.5 kg.

Hi!

I have very good experience with Schunk grippers. The KGG 80-60 type has 30 mm stroke per jaw, this is enough for your application. 

As a first step I suggest you to look after this gripper. 

Hello !

Thanks for the tipp.

I checked the Schunk portfolio, they have nice grippers. The KGG 80-60 looks good for my application. 

I started to design the fingers, could you please give me any guideline I can follow?

Thanks in advance.

Hi Jiang!

I can give you some keypoints:

• pay attention to the fittings ( fingers to gripper; gripper to robot ), so the part changeability is a must;
• the finger length must be in the acceptable domain of the gripper;
• the fingers must be made out of strength material ( aluminium or steel );
• at the end of the fingers can be a wearing part ( it contacts with the workpiece ), and these can be changed separately.

Please let me know if you have any other questions.   

Hi Gábos!

Thanks for your help, I appreciate it.

Your advices are really helpful for me, but the last one isn't clear. Can you please explicate that?

Hi!

OK. The part that makes contact with the workpiece is wearing. So if the robot is in an industrial environement it handles many workpieces ( 1k, 50k, 100 k ... per week) then the fingers can be weared frequently and the maintenance team must change them often. It's more cost effective if they have to change only a small part at the end of the fingers. Check the attached design as an example.  

Hi!

Thanks, now it's clear. Very nice design, I will apply it.

Hi Everyone!

I have an issue related to this topic.

I have to handle cylindrical parts (20mm dia and 43 mm legngth) with SCARA robot, but the workpieces are in a blister package so I can't use paralell gripper.

Could you please give me any advice how can I pick them up?

Thanks in advance.

Hi Zachary!

My first idea is : you can pick up somehow with vacuum, but I have some question:

Can you give us a picture or a drawing about the blister and the workpieces?

Does the workpiece has to be in an accurate position in the EOAT or not?  

Hello Ayan!

Sorry but I can't post picture because this project isn't public.

A vacuum picker seems to be good but the workpiece must be positioned and the EOAT must hold it rigidly.

Hi!

OK, I understand.

Another option is :

1. using a vaccum cup to pick the part out from the blister;
2. place the part in a holder;
3. change the robot tool to paralell gripper;
4. pick the part with the paralell gripper.

This is not an easy method but it could work.

As I was reading Ayan's post, I got an idea: the base of EOAT is a paralell gripper combined with a pneumatic cylinder + vacuum cup. The vacuum cup is at the end of the piston rod.

The pneumatic cyilinder moves the vacuum cup between the paralell gripper jaws. 

The cycle is:

1. the paralell gripper opens the jaws;
2. the pneumatic cylinder moves forward the vacuum cup;
3. the vacuum cup picks the part;
4. the pneumatic cylinder moves the vacuum cup + part between the jaws;
5. the paralell gripper closes the jaws.
6. vacuum off.

The advantage of this complex EOAT is that you don't loose cycle time with the tool change.

Hello !

Your ideas sounds great. I will discuss with my team and I will feedback to you about the conclusion.

Hi !

I have discussed with my team about the design and the solution is a vacuum suction cup combined with a prismatic base. The vacuum suction cup is located in a hole on the center of the base. So the suction cup pull the workpiece to the prismatic base. I hope it will be good.

Thank you again for your help.