When looking at the stripes closer, they actually seem a bit furry. In case of this print, the situation could be saved by increasing the temperature to 230C - by just 5C!
The holes are for 3mm screws, so they are relatively small details. While the ones printed at 230C seem quite OK, the ones printed at 235C are somewhat malformed.
For the prints in this post I used Flex PLA from Ultimaker, 0.075mm layer height, 130% material flow (!) and 40mm/s speed. So far my conclusion is - after ditching UM2's original feeder, it is possible to make nice prints with Flex PLA - and you can make things you can't make with harder materials. However, the material is fairly sensitive for different parameters. Also, UM2's original filament reel holder should not be used as soft filament can get stuck to the reel when the reel is rotated by pulling the filament. I'm using a lazy Susan on the floor, it works nicely.
For the recent prints I haven't used any additional oil for the filament; with IRobertI's feeder it doesn't seem to be necessary.
What did you do for sticking the Flex PLA on the bed? What was your bed temperature and did you use and additional things like glue stick or blue tape?
So far I have used glue stick for bed adhesion. I haven't yet worried about the aesthetics of the first layer. Instead, as I now needed to print fairly thin strips (the center is only 0.6mm thick), I used uniform layer height (0.075mm) right from the beginning.
As bed temperatures, I have used 40-60C. In general Flex PLA sticks to the bed really well. I have used warm water to remove the prints from the bed, other methods have proven to be either very time consuming or too violent for Flex PLA.
It looks like Flex PLA is quite a tricky material - not only when it's used but also for a long time after.
Well, not very good. Even with Robert feeder I have problems.
The material is flexible, but not elastic. It is difficult to explain. Just print a ring. You can deform the ring very easily, but you cannot expand it, you cannot make it bigger.
The filament produces a tie/spiral in robert's feeder. I do not know what to do!!
Did you try adding a drop of oil?
Did you try printing slower (maybe 10mm/sec)?
Did you increase nozzle temp?
No. I printed it at 50 mm/s... and I saw some under extrusion. I want to try increasing flow rate and I will follow your advices.
So, As I said, Plastic2Print Flexible Polyester, is flexible but not elastic. You cannot increase the size of a ring.
Can people recommend me one flex material with this property after printed (elasticity)?
1) I have high hopes on Roberts feeder for printing flexible filament, but no time to test it myself yet.
Did you cut off a part of the Bowden tube to use as an insert to have "guiding walls" for flexible filament?
This would be necessary or otherwise the filament would curl, especially at high volume extrusion speeds. Also, 50mm/s at 0.2mm layer height is a pretty high volume extrusion speed (lower either the speed or the layer height to reduce the, but you still need the guiding Bowden).
2) You can measure rubber-like filament with Shore hardness. NinjaFlex is about 85A which is the softest/most rubber-like filament I know of. After that comes The FPE40D which you tested (the link you provided) which is actually pretty soft I think. The FPE45D is a bit harder and can be successfully extruded in the UM2 stock feeder.
"- print at a completely constant velocity, for perimeters, infill, everything. Make it quite slow - around 30mm/s all round - don't use a slower first layer. The reason for this is that we want to print this stuff in as much of a steady state system as possible. Changes in velocity and extrude rate affect the output flow rate of the extrudate in a drastic way. Travel moves should be made as quickly as your machine can handle them. Retraction should be aggressive and quite long.
- Printing too quickly, or having the slightest glitch in you extruder-hotend filament path will cause buckling.
- these filaments act like a spring when compressed and driven down to the hotend. If your hobbed bolt stops turning there is still stored pressure in the system and filament will continue to extrude/ooze."
I guess this thread is as good as any to post my first test with Ninja Flex which was provided by gadgetfreak above (thanks!) with my new feeder. So far it seems to work pretty decent. The knurled bolt seems to want to twist the filament though which is a bit of an issue for prints that use a lot of filament. This print only used 4-5m and it was still twisting it enough that it wanted to jump off the spool.
Also my print quality on this first attempt is pretty crap. But, more experimentation is needed. For the first test I just picked settings semi-randomly. 0.1mm, 30mm/s, 230C, retraction enabled, 0.8mm top/bottom.
I think this is too hot because the surface is "fluffy", like there's air inside the filament (boiling perhaps?). It seems pretty darn strong though, I had to twist it a lot harder than I thought before I got layer separation.
Buuuut, it's way too late and my brain is only half awake, will have to sleep on it. But here's some pictures (they are giant if you want to zoom in more closely).
Looks pretty nice for a first test.
One question about this. Do you still need to oil the filament a bit? I'm concerned about the mess it could cause in the system?
@Didier: I did not use any oil.
@cor3ys: The surface looks a little bit like a sponge, porous, rather than solid if that makes any sense? But it sounds like that is to be expected judging from your reactions.
@cor3ys and @IRobertI: You both test the Ninjaflex with an UM2, don't you?
Iroberti print above was also done on a UM2 using his feeder design.
Right now I'm printing out "MiniCalTest" pieces, trying out some temperature changes and retraction settings. 5 down and a few more to go I guess hehe So far changing retraction settings doesn't seem to change much in the actual print but I'm doing it incrementally so we'll see. I also have to try at thicker layers to see if that makes a difference.
Right, time to show what I've been playing around with for the past couple of days. Basically I've just been experimenting with temperature and retraction settings, and a couple of layer heights.
First of all, please try to ignore the exposure/whitebalance being all over the bloody place. I was using incandescents and flash in a nice little mix that makes everything look like poop, hopefully the details will show up decently though (the original images are very big so you can zoom in quite a bit for more detail).
It looks like going up in layer height helps with stringing more so than increasing retraction settings. Or maybe I didn't go high enough. Input is welcome.
So I've now logged about 24 hours of printing NinjaFlex with my new feeder. Seems to work decently so far. I wish the surface quality was better though but again, maybe that's just to be expected with this material.
Did you manage to solve the twisting of the filament somehow?
How many meters of print was the frog?
I think that it would be an interesting test to put the roll/spool directly in front/below the feeder instead of at a 90 degree angle (like the stock feeder) to see whether it has any effect.
"You can't eliminate ooze entirely with these filaments is the conclusion I came to, but there are strategies you can take that make a huge improvement to how they print. The first is to print at a completely constant velocity, for perimeters, infill, everything. Make it quite slow - around 30mm/s all round - don't use a slower first layer. The reason for this is that we want to print this stuff in as much of a steady state system as possible. Changes in velocity and extrude rate affect the output flow rate of the extrudate in a drastic way. Travel moves should be made as quickly as your machine can handle them. Retraction should be aggressive and quite long. I usually use 0.5mm for PLA/ABS, for all the flex prints shown I used 1.5mm. Lastly you should watch your temps, higher temps make extruding easier, but the extrudate is runnier and oozes more. Try and print at as low temp as you can get away with.
I did a 5 hour print of the octopus to compare it with sanjays print in his thread, i think it come out slightly better than his but i made the mistake of not putting the fan on and went to bed, so you can see where it started to over heat on top of the head.
Wow, impressed by the perseverance to get Ninjaflex working.
It prints Ninjaflex perfectly. Retraction and everything. I've mostly been printing flat things, so you can't really compare to the octopus.
Amazing that your feeder design works so well. I mean, it's kind of overcoming a lot to push that elastic filament through the bowden.
The Flexystruder from what I can tell is a modified Wade's extruder. Lulzbot has http://ohai-kit.alephobjects.com/project/flexystruder_assembly/ on making your own on their site.
It looks like the main mod is a ptfe tube that holds the filament so the extruder bolt can gently push it along.
The frog was just over 5 meters of filament. It took 8+ hours to print.
As for the settings, well, that's what the purpose of the test was, to try to get the stringing out of it. I increased both the retraction length and speed but in the end it seemed like going up in layer thickness had a bigger positive impact.
Temperature wise it was tricky. 210C was much too cold and 235C with 0.2mm layers and 20mm/s speed was also a bit too cold, I had to drop the speed to 20mm/s to get proper bonding and get rid of underextrusion.
@rhymeandreason: Thanks and yes, it's asking a lot considering how stretchy and soft this stuff is. There's a loot of bowden for it to move around in. Having the feeder/extruder as one unit like Lulzbot will work much better I'm sure. But it's nice to have the option to print this stuff even with a bowden setup.
BTW, what about Filaflex.... it seems a very good product. Anybody is using it?