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livingfractal

Under extrusion while printing on Ultimaker 3

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print temp is supposed to be 250.  That's the default.  That's what I print CPE at.  I mean there are like 3 or 4 printing temperatures but that's the main one.

 

Infill by default is printed much faster than walls so that is probably why infill looks like crap.  I would probably set all my printing speeds to around 30mm/sec.

 

Defaults are 60/45/35 (infill/outer wall/ inner wall).  I like 30/30/30.

 

Basically either print hotter, or slower, or both.  I have only done a few dozen CPE prints (although several recently) so I just left the printing temps to the defaults and slowed it down a bit.  Have you ever printed glowfill or carbon fill with this printer?

 

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Yeah, I reviewed the spec sheet from Ultimaker and saw that it listed  The temp range as 235 to 250. 

 

The settings I used were just what the lab supervisor tells everyone to use as the default. Also, I’ve only used copolyester and I assume that’s all that’s been used, but it is a bank of 30 odd printers at a large public university. 

 

I think im going to drop the layer height to .15mm, slow the speed down to 30mmps and raise the temp to 250C. 

 

Im curious if there is a better infill than trianglular or grid. Grid is what the wiki project recommends, but I plan on using these parts for assembling another 3D printer, so I want things like gear drives to have good structural integrity (I’ll obviously use higher infill percents for those as well).

 

This is the project I’m working on: http://reprap.org/wiki/Snappy_3

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The volume of filament you're putting out can be calculated by nozzle width (mm) X layer height (mm) X print speed. There's a certain amount of room for play by increasing temperature (for example with PLA at 230 a well calibrated printer with a .4mm nozzle can get 8-10mm^3/s extruded although I never recommend printing that way). Increasing the PLA temperature up to 230 from the default 200-210 can make it work. That you're printing at full speed with low temperature on the CPE is probably making it struggle.

 

 

Because the volume of filament you're trying to extrude matters, Cura does change the infill speeds depending on your layer height (.2 layer height CPE profile has a 60mm/s infill speed, whereas .1 layer height CPE profile has a 70mm/s infill speed), to try to make sure that the total volume isn't too high.

 

That said, I'd go with what gr5 says. Take the temperature up and/or slow the speed down. Cura defaults to faster speeds for infill, but you can also manually set the speeds and you might be better off setting a constant speed for infill and walls. If you don't see the infill speed setting, click the gear in any of the header menus on the custom side and it will pop up with all the possible settings.

 

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I dropped the speed to 30/30/20 (speed, infill, wall) and up the temp to 250C.

 

I don't want to exceed the temp range that ultimaker has recommended, because I don't want to piss of the university's workspace supervisor :)

 

I'll update tomorrow (labs close before the print will finish).

Edited by livingfractal
grammar is hard

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Like @gr5 said crappy looking infill is quite normal with the stock cura profiles as the speeds are way to fast. The walls are normally printed way slower and you shouldn't see any under extrusion in the walls like on your photos.

Therefore you may also want to check the feeder. Sometimes filament gets stuck and blocks the movement arm and therefore results in feeding issues. (Guide: https://ultimaker.com/en/resources/50688-clean-the-feeder

 

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I'm thinking that on some of these heavily used printers something is making it feed worse than normal - maybe someone printed with CF (carbon fill) filament and the feeder knurled sleeve isn't as sharp as it is supposed to be - but printing a bit slower - .15mm layers - like you decided to try will make the feeder have to work not as hard and should help a lot.

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37 minutes ago, cjs said:

Like @gr5 said crappy looking infill is quite normal with the stock cura profiles as the speeds are way to fast. The walls are normally printed way slower and you shouldn't see any under extrusion in the walls like on your photos.

Therefore you may also want to check the feeder. Sometimes filament gets stuck and blocks the movement arm and therefore results in feeding issues. (Guide: https://ultimaker.com/en/resources/50688-clean-the-feeder

 

Considering it’s ran by students who couldn’t figure out how to read a spec sheet...

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I am so glad I have my own printers for when I start college this fall. There is no way I would want to rely on lab printers. Having taught college classes and seen the level of workmanship and care on the printers themselves, I feel for you. Greatly. I had one guy who prepped the files tell me he did not know what slicer they were using......sigh......I do wish you luck.

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For structural integrity, I think it is best to do a test print: make a ruler of 10mm x 10mm x 200mm or so, and print it with various infill-levels: 50%, 70%, 80%...

 

I do understand the desire for low temperatures by your supervisor. Otherwise students are going to dial temps up all the way, to get a faster flow. And then he has to spend all his day cleaning out burnt plastic and blocked nozzles...  :)

 

If I had to run a huge lab with printers, probably I would assign materials to each printer: this printer only for PLA, this printer only for PET, this only for abrasive stuff, this for messy things and experiments, etc... And I would interrogate all students before starting to print, on all aspects of it; like sort of an exam, to get a "printing license". Only students who would pass with +90% would be allowed to print. The others would first have to restudy the manuals, and redo the test until they pass.

 

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7 minutes ago, geert_2 said:

If I had to run a huge lab with printers, probably I would assign materials to each printer: this printer only for PLA, this printer only for PET, this only for abrasive stuff, this for messy things and experiments, etc... And I would interrogate all students before starting to print, on all aspects of it; like sort of an exam, to get a "printing license". Only students who would pass with +90% would be allowed to print. The others would first have to restudy the manuals, and redo the test until they pass.

 

Having worked in the college system, I do not see that happening.......My experience, is that is what the lab monitors are for; to ensure proper processing. I do agree with the first part as it makes sense other than, again, in my experience, they limit the type of materials available to just one or two. Me old job felt that specialty stuff was for output bureaus. They have enough keeping up with basic ops as students just overwhelm the system by sheer numbers. It is literally the McDonalds of output services.....fast in and fast out in the most consistent manner possible.

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Update:

 

Settings:

30/30/20 mmps speed

250C print temp

80C plate temp

.15mm height

30% infill

grid

 

I really should have came and paused the print in the middle to see if the infill printed better... things to do next time, but for now - DESTRUCTIVE TESTING!.

 

Anywho, walls are much more solid - meaning they are actually solid!

 

Though, I am now seeing some minor warping in the sides.

So, any suggestions to fix that.

 

Also, does anyone know what a "slope calibrator" is used for? Printing this thing over and over is really helping teach me how to manipulate the settings, but I have no idea what this part is supposed to show!

 

This is all I know, and I don't really understand it:

https://github.com/revarbat/snappy-reprap/wiki/v3.0-BOM

http://forums.reprap.org/read.php?2,556724

 

PS: Added cat tax; she's sophisticated.

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The slop calibrator is to see how much smaller a peg has to be to fit in a hole.  If you make the peg and the whole both exactly 1cm it might not fit so this print has the holes bigger and bigger with a wider margin all around to determine what will fit.

 

There is a feature called "horizontal expansion" that can be set to negative numbers (for either pegs *or* holes) to give you a little more "slop" or "play".  For example you could set horizontal expansion to -0.1 and it would make everything smaller in X,Y by 0.1mm -- vertical holes would be larger by .1 and outer dimensions smaller by .1.

 

I'm not sure though how you take there results of the calibrator

Quote

You will need the following tools to assemble this printer.

Qty Description
1 Multimeter for checking wiring.
1 Soldering iron.
1 Small rubber mallet to help convince some parts to join.

"help convince some parts..." -- LOL!! :'D

 

I would write to the author of this design and tell him/her the result of your slop test and ask if that means you should try to increase or decrease the parts based on your result or if that's the same result the designer expected and no adjustments necessary.

 

Let's see - the warping.  That small part has a bowed in side.  I assume you mean that?  What happens is that liquid CPE sticks to itself and acts like a liquid rubber band as it comes out of the nozzle.  Like snot.  The tension is high-ish (not loose) because it shrinks a bit in milliseconds and is already pulling gently against itself.  As you go around an outer corner or curving wall (or inner hole) it gets pulled inward.  Particularly at corners.  Each successive layer is pulled in further and further until you get far enough from the toasty heated bed and the lower layers are more solid and it slowly corrects itself until it is back to nominal dimensions.

 

You can "fix" this by lowering the build plate temp which is fine for tiny parts but for large parts is a hugely bad idea.  The main reason for keeping the bed at 80C is because this is slightly above the softening temp of CPE such that it can flex slightly.  This helps to prevent corners from lifting off the bed.  If you are printing multiple parts you are less likely to get this "warping" anyway because there's more time for the lower layers to cool.  If you are just printing one small part then go ahead and lower bed temp to 60C.  Or better yet - never print just one small part.  Here is a visual guide to this very issue under "cave in":

http://support.3dverkstan.se/article/23-a-visual-ultimaker-troubleshooting-guide#wallcavein

 

So... how strong was your part?  Did it break on layer lines or randomly?  If it broke on layer lines then your fan may be too high and layers might not be bonding (melting the layer below as they go down).  One fix is to lower fan to about 1%.  This is never a problem for PLA but for higher temp materials like ABS is a common issue.  Note that fan at 10% is the same as 100% for UM3 so you need to go down to 3% or less for ABS.  Not sure about CPE - I always just left things at default.  CPE is much easier to print than ABS but harder than PLA.

 

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ROUND 3.

GO.

 

Adjusted the build plate down to 70C, and the first couple layers at 80C.

 

Added a brim - just in case.

 

Lowered infill back down 20% - I'm kind of green.

 

Turned fan to 1% - I assume there is a fan...

 

Adjusted the horizontal expansion to -.25 (that's the hole the little knub fit into the most snug without taking a mallet to it. I was using the same printer for consistency, but apparently I can't use the force to convince the other thousand qualified students from using it :(

 

Update with photos & results tomorrow.

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I was basing the decision off this: https://ultimaker.com/en/resources/22229-how-to-print-with-ultimaker-cpe

 

I also used a brim. 

 

Since I'm going to try to fit all this parts together with dynamic movement I’m really just trying learn how to prevent both. 

 

We also use wolfbite - which is supposed to make better adhesion than just stick glue. 

 

Either way, they take my student fees no matter how much I use. 

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Okay. They came out great!

 

no warping. No caving. Perfect extrusion. 

 

Ill add photos after some exams. I’m leaving them in the lab for other students to look at (I know they probably won’t). 

 

I think ill I’ll need to lower the horizontal expansion to around -.20

 

what factors affect horizontal expansion?

Edited by livingfractal

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