Need advise on a strong filament,

Bambu Lab X Series
1

I have been tasked to create a wrench set, The main reason is to be used on custom connectors so they are not scratched by the tool. So far the only issue I am worried about is stretching , I have used ASA , PC, ASA-CF and Nylon. When I test the wrench what I notice is as I pull harder the wrench seems to stretch just a bit and slip on the nut. I am looking for advise on a filament to try that will not stretch under rotational load. I am printing with 100% infill and have started with the BAMBU Strength preset.

Thank you for any advise.
John

2

From your description I am picturing an open ended wrench opening up under load. Could you use a larger steel wrench and print an insert so the insert fit your connecter and wrench supported it? or what about a wrench like this with 3d printed jaws to match your connector?

1 Like
3

Correct its an open end wrench I did think of the insert idea. I did try a few but gave that up. I did not mention that the reason for designing the wrench is there are some custom bends to make it fit the location of the fittings. Its a custom built machine so the tools need to be custom to make it easy to maintain. Sorry for being vague about the use case, The customer asked me not to show what its used for. I may be more worried that I need to be but I want to be safe as far as stretching.

john

4

In broad strokes, PLA stretches the least but is one of the most brittle, and the engineering grades (nylon, ASA, ABS and etc) stretch more but are less brittle. You can add buttressing and reduce stress risers to help make PLA do the job but then you may run into clearance issues. There are PLA’s that can be annealed, you could use that and place a nut in the jaws to ensure that as it shrinks, you maintain the correct tolerance in the jaws.

Spend so time cruising CNC Kitchen’s channel for side by side scientific tests that may help you make a decision.

Another option is something like these non sparking aluminum bronze wrenches. Spendy as all get out at $45 and up each but one and done. Just don’t use in in contact with acetylene for some reason.

5

I would give PC-CF a try.

But in the end, everything is still plastic, and if you work a wrench made of plastic on metal, the plastic will give in before the metal.

You could also increase infill, wall count and switch to honeycomb 3d infill patten.

6

I may be more worried then I need to be. The torque on the bolts is quite low, I have had success with the ASA , I am pushing the wrench to its slipping point to see what lasts the longest. I will check out CNC Kitchen’s channel. Thank you all for the advise.

john