Recommendations on robot grippers

[YoDoug]

All the cool kids just 3D print the fingers now. The Bambu C1 printer with their carbon filled filament makes designing/building robust gripper fingers with nice features like compliance and pre-load so easy.

Well designed printed gripper fingers are making thousands of cycles in machines around here. Totally worth the investment in a Bambu.

How well do they hold up to coolant residue? Coolant is usually pretty harsh on plastics. That is my worry about printed gripper jaws.

 

[Digital Factory]

How well do they hold up to coolant residue? Coolant is usually pretty harsh on plastics. That is my worry about printed gripper jaws.

Nylon absorbs water so avoid that.

Other materials hold up much better.

 

[GiroDyno]

How well do they hold up to coolant residue? Coolant is usually pretty harsh on plastics. That is my worry about printed gripper jaws.

I used PETG to print spring loaded "hands" on our lathe turrets when we need to hold parts and cycle the chucks in cycle. You can also get an assortment of reinforcements in PETG filament if you need add some beef to whatever you're printing.
PC would be another ideal material for this but PETG is so easy to print and readily available I've never bothered.

 

[DavidScott]

Nylon absorbs water so avoid that.

Other materials hold up much better.

Nylon would be an excellent resin for coolant exposure since it is very, very, resistant to chemical attack, as well as strong, abrasion resistant, and generally quite tough. If you use a grade that likes to absorb water, 6/6, then it will expand up to 3%. If you use a better grade in the 6/12 variety then it is far less of an issue. By the way, most plastics absorb water, just to a lesser extent. I used to design and make plastic parts for sailboarding so have quite a bit of experience with this topic.

Polycarbonate is about the worst resin to use with coolant/chemical exposure. Many grades will simply crumble in a few months with no load on them. Some will fail from exposure to oil from our skin.

 

[GiroDyno]

PC is resistant to water, oil and paint thinner (hopefully not a lot of that in your coolant!) my bad ass-u-me ing it would hold up to coolant as well... Got a few old Nalgene bottles that have been filled with just about everything other than water to prove it.
So stick to PETG if your printer doesn't have a high temp hotend and a heated chamber

 

[DavidScott]

I come here to learn so take this in that spirit. Please take note that I said GRADE of PC and not all PCs. Obviously whoever specced the grade of PC to make the Nalgene bottles did their homework, knowing that it would be exposed to many oils and who knows what will be put in them. I also think PC is often used for the windows in our machines with no or little ill effect. On the other hand, I personally have had the crystal of a vacuum gauge and the bowl of a water separator develop cracks and crumble away when exposed to my coolant, and Blum learned the hard way about it in the windows of their probes. Not all grades of PC will do this, but most will. So if you are going to use PC for an application that will see any chemical exposure, including skin oil and hand lotion, then you need to do your homework or you're pulling the lever on a slot machine, with worse odds of winning.