MakerGear Forum

Does anyone know what material the extruder drive block that comes with the M2 is printed from? I printed one out of ABS but I don't think the original is ABS. The holes and slots are very slightly undersized in my print, which can mostly be fixed by re-drilling them to the correct size but that slot for the press fit hot end is a lot harder to fix, and those hex shaped holes for the nuts are hard to enlarge post-print too. I'm guessing there is some setting in Simplify 3D I need to adjust to fix the tolerances, but haven't tried anything yet. I guess I just need to print a block with some known hole sizes in it and then play with parameters until it comes out accurate, then re-print the extruder drive piece. I find it easier to print this part on the opposite side as was used on the original, that way you don't have to clear out the support material around the counter sunk motor mount hole.

The originals are printed in ABS, and yes, what you're looking for is the extruder multiplier value. I don't know what it usually is for ABS, but for all the filaments I've used it has invariably landed in the ~0.88 range. You can do a full calibration test if you want, by getting one of the thin-wall calibration parts off of Thingiverse. However, if your extruder multiplier was set at 1.0, it's most likely that all the tolerance tightness will go away by setting it to 0.88.

The press fit on the stock model is super tight.

Try this model for a slightly less punishing fit: http://www.thingiverse.com/thing:433292
It has some extra modifications as well, most notably the filament guide tube and more cone on the hot end intake.

jsc wrote:The press fit on the stock model is super tight.

Try this model for a slightly less punishing fit: http://www.thingiverse.com/thing:433292
It has some extra modifications as well, most notably the filament guide tube and more cone on the hot end intake.

Would that one allow the use of Ninjaflex filament? I've read where the standard V3b won't work with Ninjaflex.

I don't have any personal experience with ninjaflex. The filament support tube should help, according to what I've read, but the hot zone may just be too long in the v3b to do a consistent job. Do a search on ninjaflex in this forum for more discussion.

pyronaught wrote:

jsc wrote:The press fit on the stock model is super tight.

Try this model for a slightly less punishing fit: http://www.thingiverse.com/thing:433292
It has some extra modifications as well, most notably the filament guide tube and more cone on the hot end intake.

Would that one allow the use of Ninjaflex filament? I've read where the standard V3b won't work with Ninjaflex.

Not sure where you read that...I used NinjaFlex on a V3B just fine. Go slow & hot (40mm/sec, 250C) and up your extrusion multiplier to about 120%. The PTFE tube likes to fall over but the plastic pulls through anyway.

insta wrote:

pyronaught wrote:
Would that one allow the use of Ninjaflex filament? I've read where the standard V3b won't work with Ninjaflex.

Not sure where you read that...I used NinjaFlex on a V3B just fine. Go slow & hot (40mm/sec, 250C) and up your extrusion multiplier to about 120%. The PTFE tube likes to fall over but the plastic pulls through anyway.

I read it on this forum somewhere after doing a search, but it could have been just one guy who could not figure out the proper settings.

Is ninjaflex anything like real rubber? I mean, would it be feasible to print your own functional O-rings and gaskets?

Tim wrote:The originals are printed in ABS, and yes, what you're looking for is the extruder multiplier value. I don't know what it usually is for ABS, but for all the filaments I've used it has invariably landed in the ~0.88 range. You can do a full calibration test if you want, by getting one of the thin-wall calibration parts off of Thingiverse. However, if your extruder multiplier was set at 1.0, it's most likely that all the tolerance tightness will go away by setting it to 0.88.

Thanks for the info, mine was set to .9 so I'll have to try again with .88 (or whatever finally gets things to be the right size). I guess this multiplier must compensate for how much a bead of extruded filament shrinks or expands after it has been laid down.

pyronaught wrote:

insta wrote:

pyronaught wrote:
Would that one allow the use of Ninjaflex filament? I've read where the standard V3b won't work with Ninjaflex.

Not sure where you read that...I used NinjaFlex on a V3B just fine. Go slow & hot (40mm/sec, 250C) and up your extrusion multiplier to about 120%. The PTFE tube likes to fall over but the plastic pulls through anyway.

I read it on this forum somewhere after doing a search, but it could have been just one guy who could not figure out the proper settings.

Is ninjaflex anything like real rubber? I mean, would it be feasible to print your own functional O-rings and gaskets?

Some gaskets, maybe. It's very spongy. The behavior of a wrench I printed (customer said "it should be flexible so I dont have to measure the size better" ) was that it could be crushed into a ball like a stress toy and it would sproing back into shape. It had absolutely zero rigidity for his purposes.

pyronaught wrote:this multiplier must compensate for how much a bead of extruded filament shrinks or expands after it has been laid down.

It's even simpler than that: the extrusion multiplier adjusts the ratio between the volume of filament going in and the volume of the extruded thread coming out.

You set the filament diameter to whatever you measure for a particular spool, which lets the slicer calculate the filament's actual cross-section area and, thus, it knows the plastic volume per millimeter of filament feed.

You set (or the slicer automagically controls) the extruded thread's width and thickness, which determines the thread's cross-section area and, thus, it knows the plastic volume per millimeter of nozzle motion. Note that the slicer doesn't know what's actually coming out of the nozzle: it's working with values you want to see.

In principle, the ratio of the filament area to the thread area tells the slicer exactly how much filament to crank into the extruder to make the actual thickness match the desired value for every millimeter of nozzle motion.

In practice, for all the usual reasons, that isn't the case.

So you set the extrusion multiplier to 1.0, print a single-wall test cube, measure its actual wall thickness, adjust the extrusion multiplier, and repeat until the actual wall thickness matches the desired thread width. Then you're set for that particular filament spool, as long as nothing else changes.

The multiplier crushes all the drive gear depth, filament hardness, printing speed, shrinkage, and other imponderables into a single number that works reasonably well.

Make sense?