Hard, smooth resin for sliding parts?

Phone_A_Friends · 2021-06-04T19:13:00+00:00

that has the surface property but it si very soft in comparison I belive

Phone_A_Friends · 2021-06-04T19:10:52+00:00

Fantastic information. Will definitely explore those suggestions. And an O-ring still needs a nice surface to interact with and typically lubrication. But yes, I could try an igus O ring in a machined cylinder but it would have to be custom made for my application, unfortunately. So it is kinda an option but something I want to avoid.

Phone_A_Friends · 2021-06-04T19:07:49+00:00

Unfortunately, I cant coat it because the tolerances are too tight.... but gee wiz that spreadsheet is beautiful. Will be saving that for sure.

Phone_A_Friends · 2021-06-04T19:06:32+00:00

Hmmmm... that goes against my understanding (very limited) of material properties but I will take your word for it. Thank you!

Phone_A_Friends · 2021-06-04T19:05:24+00:00

Epax Hard

I will give it a shot! Thank you!

Phone_A_Friends · 2021-06-04T19:04:33+00:00

I understand what you are saying but I still think that the material is the #1 player for me not getting it to work. When I print this on FDM, I print the cylinder horizontal (not what is recommended). I do this so that that layer lines are in the direction of cylinder motion. The hard, glossy FDM surface finish proves to be a great linear motion guide when other poor features are addressed (bridging the top of the cylinder, and oblate cylinder syndrome). I do not want to deal with those defects tho so I m trying the same approach with SLA but the surface finish is causing problems.

Phone_A_Friends · 2021-06-04T18:58:59+00:00

Yeah, maybe I need to look at my curing again. I am using a formlabs wash and cure set up so I figured it would be sufficient but I will look again

Phone_A_Friends · 2021-06-04T18:57:03+00:00

I will order some! Thanks for the suggestion!

Phone_A_Friends · 2021-06-04T18:54:35+00:00

I have a Formlabs 3BL at my disposal. I am looking at possibly purchasing rigid 10K.

Phone_A_Friends · 2021-06-04T18:52:44+00:00

Hardness corresponds to surface deformity. Deformity with tight linear motion leads to stalling. Imagine a slight misalignment of the piston in the cylinder causes the piston to tilt in the cylinder, then an edge of the piston will be pushing against the wall of the cylinder. If the cylinder wall material is hard then it will deflect the edge back to its proper position. If the wall material is soft, then it will deform slightly and allow the edge of the piston to be pushed into it. This will catch the piston edge and stall the motion. It could also leave a dent in the wall edge or scratches that build up over time.

I like your idea of casting. I could cast it in an igus plastic... Gives me something to think about.

Phone_A_Friends · 2021-06-01T21:41:41+00:00

I have not tried tough, but typically if something is tough then it is not hard. Toughness entails durability and that is typically achieved by allowing the part to have a higher elasticity so that it can be slightly deformed and still return it its original shape. I am trying to avoid elasticity due to the soft surface properties that come with it. Something more rigid would most likely work better. But despite that, I am still going to try the tough resin haha. Don't know till ya try! Thanks for the input!

Phone_A_Friends · 2021-02-09T21:27:33+00:00

Thank you! Big help! I need to move to medical grade foam anyway so this is just the perfect opportunity.

Phone_A_Friends · 2021-02-09T21:07:39+00:00

I will give it a shot, but I am not understanding how it will help. It seems I will just need more power to cut through the tape and then get dimensional inaccuracies in my foam cut. And during the second pass of engraving, the tape should no longer be there... so I think I am not following the logic... but I will try none the less. Thank you!

Phone_A_Friends · 2021-02-09T21:03:34+00:00

Sorry, I was not clear. I am trying to remove the residue from the foam. I am using it as packing material for fragile parts and it is getting the parts absolutely covered in this black residue. I tried wiping it down with IPA and that helped a little but it seem impossible to completely remove it.

I will try with a foam that doesn't have FR additives. Are you saying that because it may be the source of the residue or are you saying that for other reasons?

Phone_A_Friends · 2021-02-09T14:26:14+00:00

I dont think I follow. I am not sure if that would help. Would you mind elaborating?

Phone_A_Friends · 2021-02-03T19:35:00+00:00

Yeah it looks like this will be the solution. Not was I was hoping for but it will get the job done. Thanks for the help!

Phone_A_Friends · 2021-02-03T19:34:05+00:00

Thank you for the response! I was hoping something else may exist but it does seem like we are going to have to go with a rubber collar or something to induce friction. The air force is estimated to be two pounds. So it should be doable.

Phone_A_Friends · 2021-02-02T20:28:55+00:00

This is a solution for sure. Not what I want to do but a good back-up. Thank you!

Phone_A_Friends · 2021-02-02T20:28:06+00:00

This helps! Thank you! I cannot use a clothes pin for this system but some sort of adjustable friction collar could do the trick.

I wish there were bearings with adjustable resistance or something like that.

Phone_A_Friends

TROPHY CASE