Ultimaker s5 or 3?

[ArthurG 0]

Not sure which product would suit my needs best. I am a research student who has been tasked with 3d printing multiple organ models out of flexible materials. If someone could give me the benefits and drawbacks of each that would be great.

[gr5 2,024]

Personally, if I had to do this, I would probably want to use the PVA support feature and I still prefer my UM3 over my S5 (unless I'm printing something too big for the UM3).  So I would get two Um3s.  Or one UM3 and spend the savings on filament.

 

Also you might want to consider casting - you can print the mold instead and cast the organ with silicone which you can get in many different softnesses.

 

For example mold max comes in hardness 10,20,25,30,40 (all of them flexible but 40 is 4X stiffer than moldmax 10).

[ArthurG 0]

Thanks, we originally wanted to use silicone but found that 3d printing out of it wasn't possible.

[fbrc8-erin 267]

TPU95A is about as soft as you'll want to print with a bowden fed FDM printer. About what size are the models you're doing? Would you benefit from the larger bed? The S5 does also have some other features (like the flow sensors so you know if you've run out of filament). It all depends on what your needs are.

[ArthurG 0]

Ninjaflex is 85A I think. Would it really not work if I tried to use it?

[fbrc8-erin 267]

I haven't tried anything more flexible than the 95A shore hardness. Someone on the Materials board may have and can let you know how it goes: https://community.ultimaker.com/forum/111-materials/

 

UM3 and UMS5 are both bowden fed (rather than direct drive). Being bowden fed means the printhead can be a lot lighter than a printer with direct drive, but it also means you've got more friction inside the tube, which can be difficult for more flexible materials. TPU95A is pretty flexible, and has profiles built in Cura already.

[kmanstudios 1,120]

I have printed with NinjaFlex. It was not that difficult. But, i was very new to printing and did not quite get settings as good as I can now. And, I did get it to work with PVA supports.

 

Size will be your issue if you are doing full sized anatomy. A pelvic bladder system would not fit into the UM3(E) series.

 

But, taking @gr5's advice, you have the ability to print in parts (Hard material) in parts, glue to gether, and then cast. One of the things about flexible materials is they are not really good at fine resolution and your printed parts could show a lot of distracting layers.

 

If you are doing softer materials, make sure that your work area is dry. Humidity can creep into the bowden tube and cause binding and then grinding. Also, I believe the flexible materials are a bit hygroscopic. That is something to keep in mind with all materials.

[gr5 2,024]

I have printed ninjaflex on UM3.  I had to print slow.

 

But you can go down to super soft organ like flexibilities with shore 30 silicone if you print a casting of the organ instead of the organ itself.  You print the mold.  The short explanation is in cad you take the organ and you take a cuboid a little bigger and then do a "boolean subtract" operation which gives you a cube with a hollow organ inside.  Then you hollow out some fill holes and air holes at the top, split the mold into two halves and print it.  Then fill it with that product I listed above and give it several hours to become solid.  Open the mold and voila.

 

[gr5 2,024]

Oh and if you are making these organs for teaching purposes then you can now quickly make multiple organs from one mold.

[kmanstudios 1,120]

3 minutes ago, gr5 said:

Oh and if you are making these organs for teaching purposes then you can now quickly make multiple organs from one mold.

y7eah, that sort of thing never lasts in the hands of students over time....dropped, pulled, contaminated, etc. The molding process described can be done several ways, but the molding process itself assures consistent copies from one produced object to the next.

[Brulti 176]

From personal experience, flexible material wouldn't fit the bill for printing organs. I've printed with TPU 95 and realized that it was very good for neat geometric designs, but the material is too viscous for printing organic shapes nicely. You'll end up with little blobs and stringing and such everywhere.

 

As @gr5 said, I believe that mold and cast would be your best solution.

[ArthurG 0]

I think we are going to go with the mold because we need the material to closely resemble human tissue.