A kind of grippy filament.

[Bogaedo 2]

Hello everyone,

 

For my project I am looking for a strong hard as well even little elastic filament that provides grip like rubber on a metal surface. 

I am trying to make a cnc suction cup that slides over a metal beam. 

The cup which is sucked through itself and get clamped by the expanding beam when enabled is yet to slippery if printed with abs.

I thought of using PP but I dont know if that is grippy and I also consider using two different kinds of filaments in parts that later can be combined together by glue.

Below some pictures of the cup.

 

Can anyone help me out?

 

Thanks and best regards,

 

Bogaedo

 

[geert_2 556]

Have you considered designing and 3D-printing a mould, and then cast the cup in silicone or polyurethane?

 

Silicone is *very* grippy, temperature resistant, abrasion resistant, but not tear-resistant (tears apart easily). It is water-tight but not oil-tight: oils and solvents seep through slowly. Silicone for casting is usually non-stick (=does not glue to other parts). Be sure to use platinum-cured (=addition-cured) silicone, no tin-cured, because that is not stable and only good for short-term use.

 

PU is usually less grippy but still good, but far stronger than silicone. Think of skater wheels: it is very hard to grind or cut them (don't ask how I know). PU usually bonds very strongly to other parts: so you can cast it around a base and get a good chemical bonding to it.

 

[AndersK 59]

If  you dont want to cast, try TPE (my choice would be silicone though).

Less grippy than silicone and less wear resistant than PU but a good alternative.

 

PP is almost like PET so not grippy at all.

 

TIp for @geert_2 : If you want to cut or machine PU, put it in the freezer or use CO2. Makes life a lot easier 😎

Edited July 18, 2019 by AndersK

[geert_2 556]

5 minutes ago, AndersK said:

...

TIp for @geert_2 : If you want to cut or machine PU, put it in the freezer or use CO2. Makes life a lot easier 😎

Thanks for the tip. I once tried to grind down a skaterwheel to make it smaller. But after a full day of grinding on an agressive water-cooled disk, I still had gotten only 1mm off. That was when I realised that skater wheels are supposed to be *very* wear resistant...   :-)

 

 

Something else I just think about: any 3D-printed suction cup is likely to be *not* watertight. So it might not work at all. The indents caused by the layer- and printing lines will allow air to seep in and destroy the vacuum. Even in glass lab vacuum equipment, the tiniest scratch will quickly destroy the vacuum.

 

So, even if you make a 3D-printed mould for casting, that mould would require post-processing to remove or fill the indents.

 

Even a very smooth bottom like this won't hold vacuum at all. Unless you have a strong vacuum pump that keeps running all the time.

 

[Framar 37]

I would use a regular o ring that fits into the groove.

 

[johnse 31]

Most of the flexible filaments are not very grippy. They will compress and bend, but the surface is fairly low friction.

 

Flexion XC-60 (Shore 60A) is more like rubber in that respect. You need a really good direct extruder with a completely constrained filament path. Flexion claims their extruder is the only one that can print it. I modified a Monoprice Ultimate (Wanhau D6) to use their extruder.

 

Unfortunately, their partner in making the filament changed hands and is no longer making it. Flexion is working to line up another source. I luckily found a spool from a store in Canada.

[marceljoseph 0]

@johnse Could you please let me know which store in Canada carries this?

[johnse 31]

I got it from Spool3D. Flexion found a different filament manufacturer to work with and it is more available now.

TPU - 60A - 1.75mm 3D Printer Filament | Spool3D Canada