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Trouble with warping - please help

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I am at a loss with a simple part I printed out four times, and always having trouble with warping. Who might help? This might help you for a diagnosis:

- object: 7 x 5cm lid, 2mm thick, with two 5x5mm blocks on the top running along each long side

- Software: Cura 12.11, all default printing settings, if not mentioned below

- filament: PLA 2.9mm

- wall thickness/bottom/top thickness: 0.4mm resp. 1.2mm for all (I tried both versions with no perceptible effect

- printing speed: 100% versus 200% (on the ultimaker controller). 200% helped somewhat with the warping, but the object structure was very rough, looking like a coral reef. Speed in cura a default (50mm/s)

- layer thickness: 0.2mm vs. 0.1mm 0.1mm made the object more accurate, but the warping even stronger

- fill density: 20% (in the case of wall thickness 0.4mm)

- raft: no (would ruin the surface structure of the lid)

- printing temperature: 220°

- advanced config: all settings as in default

- blue tape/z-axis: replacing the blue tape brougt no effect. The structure pulls off the blue tape from the printing bed, so that it is "in the air"

Any Idea how I could solve this?

 

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Put down fresh blue tape, and rub it down with isopropyl alcohol before you start printing. That should help with the adhesion of the print to the tape. The key is to get the tape stuck well enough to the bed, and the print stuck well enough to the tape, that it can resist the warping forces while it cools. You may find that the print ends up very well stuck to the tape, so the tape tears when you take it off. If that happens, soak the bottom of the print in a little more alcohol for 5-10 mins, and it will lift right off.

Also, I would try turning off the fans totally for the print.

 

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What illuminarti said. I thought he was full of it until I tried his technique the first time. Amazing. Your next problem will getting the damn parts off the bed. :D

Regarding "the coral look" - that sounds like underextrusion. If you are going to be printing that fast (which is a good goal!) you need to at least raise your printing temp to allow that plastic to flow! But you will likely have problems on parts with gaps in it (stringing) if the temp is too high.

Other things that help with warping/lifting is rounded corners - makes a huge difference. Or checking that box in Cura that says "add raft". Or get a heated bed but getting a heated bed to just make PLA stick better is a waste of money when isoproply alcohol works better and more cheaply.

 

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Yes, I use 91% isopropyl alcohol from the local drugstore. Dirt cheap. Used as a general purpose wound/surface cleaner and disinfectant. Typically here in the US at least, there are two primary types of 'rubbing alcohol' - based on ethanol or isopropanol. I haven't tried the first one - I use the latter. See also:

http://en.wikipedia.org/wiki/Rubbing_alcohol

That page may give more information on what it might be called in your neck of the woods.

You can print up to 240 or even higher with PLA... but I generally find that I get better results at around 230 - but it will depend on the calibration of your heating block what works for you. (I have no idea what the accuracy of UM hot ends is, but it occurs to me that we all talk about temp as if its the same for all of us, and maybe it isn't).

You'll definitely need hotter to go faster - but in order to minimize warping, I'd recommend printing with the fan off, and then you'll probably want to reasonably slow, to give the extruded plastic time to cool before you put the next layer down.

If you print too fast for a given layer height and nozzle width and temperature, you will overwhelm the head, and start to get under-extrusion.

 

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If things aren't sticking well - if even the skirt isn't sticking well, I check leveling again. It's usually because my bed needs re-leveling. I use a slip of paper and I expect to feel the paper stick under each 4 corners.

I like 240C for the first layer and then lower the temp to anything from 200 to 220 depending. 240C is just for good sticking the first layer. Also print very slow. If you have ulticontroller set to 50% or tell cura to do first layer at 20 or 30 mm/sec. But usually 40mm/sec is slow enough for smaller stuff (just first layer). Also I like thicker first layer (I think cura defaults to .3 which is great for me). Also have fan off for the first layer. Another cura setting.

The skirt is also important for me as I can use it to test stickiness. If the skirt isn't sticking even just in a few spots then I abort the print. Give the skirt 5 seconds to cool and try to lift with thumbnail. it should stick well. Maybe even move your bed enough to mess up your print if you aren't careful.

Rubbing alcohol is sold anywhere bandages are sold. Drugstores. In the USA, CVS, Walgreens.

 

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Printing temp is very important. If I use > 220 I get stringing because the plastic is like honey. If < 200 I get under-extrusion. If I'm printing a part with no jumps (like a gear) I will print at 240C and print 2X faster. Or if I don't care if it comes out ugly (strings/blobs).

If I'm printing something with e.g. pillars - with a hop on each layer or lots of hops each layer I print colder. Like 210 or 220.

Different speeds require different temps. Different colors and manufactures of PLA require different temps. Do an experiment. Set nozzle to 200C. Disengage Feeder and push filament manually with one hand holding feeder in place. Then stop the pressure. How quickly does extruding stop? How fast is the leakage? Repeat at 240C. Huge difference. Now you know what to look for so go back to 180C and repeat at every 10C interval. Do this every time you buy a new filament. Make notes. Try to notice how much pressure is required.

 

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Thank you both for your valuable hints :-P

I'd like to add some more I got from the FabLab Luzern:

- first clean the acrylic bed with IPA

- then put on the blue tape. Use a broader one that the one you (maybe) received together with your ultimaker kit. The one I got was 25mm broad, I now bought a 38mm

- then clean the surface of the blue tape with IPA

- printing with 200% is a good idea, but in case of underextrusion increase the flow rate via ulticontroller ("tune" menu).

IPA, btw, I managed to buy at a Conrad Electronics store (conrad.com)

I am still collecting hints, but will soon try out which solution works best and post it here.

 

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Ok, now I finished my print and got fairly good results with the following changed settings:

- 0.2mm layer, wall thickness 0.4, bottom/top 0.8, fill density 20, packing density 1, 230 C temperature, printing speed for the lower part 200%, for the upper 150%

- use of IPA to clean the bed (before adding the blue tape) and the blue tape

- extruder fan turned off completely

The object stuck so perfectly to the z stage, that I only could rip it off together with the blue tape, and soaking it afterwards to scratch it off slowly with a cutter ... but at the end of the day it worked. the object was slightly "coral-reef"-looking, but only on one edge, so that's acceptable.

 

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The coral reef look is probably under-extrusion. Either slow down or increase temp or tighten your feeder spring or increase flow. Slowing down is the most likely to fix it. If it weren't for stringing issues I would always print at 240C.

 

bject stuck so perfectly to the z stage, that I only could rip it off together with the blue tape

 

Ha Ha. Yes, blue tape with ipa is amazing! For smaller parts or more delicate parts, consider not cleaning with ipa.

 

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@gr5: You ditched a heated bed? Really? We have one on our crappy Prusa Mendel and we have 0 problems with warping and objects sticking to the bed. When the print is finished we turn off the heated bed, wait for a minute and then we can pop the object off the bed. And the bottom surface is smooth and shiny.

The very next upgrade for my Ultimaker will definitely be a heated bed. To be honest I don't understand why the Ultimaker folks decided to release a dual extrusion kit instead of a proper heated bed kit. I'd say that the nice to have things you gain from dual extrusion are not worth if you still have to fight with warping, layer adhesion and ugly surfaces... Stuff like soluble support material sounds so far removed from the real world problems of 3d printing that it feels wrong to tackle "top end issues" instead of everyday problems.

 

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Does anyone have any tips for removing large flat objects from the build plate without damaging anything? My prints of that kind stick almost too well; if i try to pull it off with the tape, the tape just rips. Trying to pry it off with a knife or another flat and sharp object only slightly damages the object. To put it another way, it sticks so much that it takes 20 min or so to remove from the bed after destroying all of the tape. Any ideas?

 

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I use a small paint knife.

painting-with-a-palette-knife.jpg

first one to the left. They're flat and have a rounded edge and also flexible so it doesn't damage the prints. Though it sometimes gets it self under the tape. Once you get started though, it makes the rest of it pretty easy depending on the shape.

 

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I sprinkle the bottom of the object with IPA from all sides, wait a minute or two, and then gently insert a carpet cutter between the object and the blue tape. Sometimes, the object comes off together with the tape (without ripping it), then while holding the object in the air with one hand, with the other I press down the tape back to the build plate.

Be sure to catch the right moment for that because when the PLA evaporated too much, the blue tape will stick again to the object.

If the tape rips, anyway, I remove as much as possible from the object as long as there is PLA around. The tape remainders I remove by soaking the object bottom in warm water for some minutes and scraping it clean with the carpet cutter. Maybe not the most simple method but generally resulting in a clean, undamaged object.

 

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I also always use a putty knife. A lot of the times the tape comes off, but that is easily replaced.

For me it is not a big issue if there are some remains of tape on the bottom, so i usually let them be.

Why we chose for Dual extrusion, is because a heated bed has been proven to have more technical challenges then might appear on first sight, for example the wooden frame, weight and the power it needs to run.

Of course a heated bed is easily put together, but we want to make it backwards compatible so it fits perfectly in

the wooden frame of the Ultimaker, without causing other difficulties or tons of other replacements.

We are working on it, don't worry.

Dual extrusion has been released now that Cura (although not yet fully>Dual material) offers a better support for it.

 

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I use needle-nose pliers to remove the object from the bed. I search for the thinnest part and carefuly start wiggling until I hear that the object tears free from the tape. I had to change the tape only two times up until now. Now I can remove most things without damaging the prints.

@SandervG: I can understand now why the dual extrusion kit is easier to engineer. You already have the hotends and the space to mount another on the print head. But I think that the heated bed is really useful and needed, that's why I wondered about setting priorities. I'd say that most people would be fine with replacing the z-stage entierly if they get a heated bed. It is a small price to pay for the huge advantages.

However I am glad you are working on it. Do you have a (even vaguely) timeframe? This year? Next summer? It would it make it easier to decide to wait or build my own.

Thanks

 

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I agree that it is a very welcome upgrade, and personally i would rather have it seen released yesterday then tomorrow if you know what i mean.

Hopefully, on a short notice (weeks) we will be able to reveal more information about this subject that will answer a lot of questions. Right now, that is all i can say. So i would like to ask a little bit more of your patience :)

 

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@nicolinux - I have the heated bed. It works. But I rarely use it. My bed is aluminum with kapton tape on top. For cold prints I add blue tape on top of the kapton tape. For heated bed prints I sometimes use blue tape and sometimes kapton tape.

Recently I printed my most difficult print - a "boat propellor". Even using the heated bed and covering sides and tops there was excessive warping. I had to push down the parts that warped upwards repeatedly with a putty knife to keep it from hitting the fan shroud. I had to add extra support in CAD also. Similar to this one (was also 5 blades, steep pitch, rounded blades):

http://www.the3dstudio.com/product_details.aspx?id_product=523162

So I have found that even a heated bed isn't enough when you have steep overhangs on long skinny objects. The warping lifts the ends and makes it a challenge.

 

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going to have to re-light this thread. no matter what i do, i get warping on this certain piece. i have tried fresh tape, made sure its really well rolled down with a roller, and then rubbed down the tape with rubbing alcohol, made sure exposed edges are not near the edge of the tape, and still it lifts.

now its nowhere near as bad as i had it before the isoproyl, and next time i will use some wide tape that i got. fingers crossed that will solve it

print speed 45mm/s, temperature 215, shell 1.2, layer height 0.1 and bottom/top 0.8

its frustrating as its 2 halves of a piece that have to glue together :/

 

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What does your part look like? You can often design shapes into your object to reduce the warping. Especially for pieces you glue together, you can cut shapes out of the bottom so that it's not a solid flat surface which is what causes warping.

Anti_warp-1024x576.jpg

This is the cap for Thor's Hammer I made: The Left keeps a nice flat surface, the right will peel the corners leaving an ugly gap. (This render is of the bottom surface of the part)

005-mjolnir.jpg

Cut in little pyrimids near the edges and it should solve your problem. If you're glueing you won't see it and it'll save you a bit of material, but take longer to print due to the excessive amount of outlines.

Let us know if that helps!

 

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Yes. Cura even has a checkbox "solid bottom" that you can uncheck to reduce warping effects if the bottom will be invisible. That is the main purpose of that feature - not filling the bottom of something that won't be visible for example a statue or something that sits on a table like a lamp, a piece of artwork, a stand, etc.

Why get wider tape? Is it the part that is peeling or the tape? If it's the tape, get wider tape.

Did you use brim? Brim helps a lot. Also it helps to make sure the first layer is squished a bit into the tape. Also it helps to do the first layer hotter (I do 240C if I'm worried about lifting) and slower (no faster than 40mm/sec) and then I lower the temp for the second layer.

Also I have even heated my bed/tape to 30C with a hair dryer as this often helps the plastic flow into the cracks of the tape. 30C is not particularly hot but it helps a little. But if you do 240C for the filament then 20C for the bed should be fine.

Show a photo please if you still have trouble.

 

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here are my two pieces

4drl.jpg

and them together

f5eg.jpg

its actually the tape peeling off of the acrylic. the tape is hard to remove from the printed piece.

i tried brim once, but i was probably printing too fast, as it too lifted up from the deck and started warping and twisting, but that was on a different print.

 

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I would wrap that sucker in 30 rubber bands and then dip it in boiling water (water that was boiling a few seconds ago 70C is hot enough 100C not necessary) for about 20-40 seconds and you should be all set. Keep the rubber bands firm but as loose as possible. Use the smallest - weakest bands you can find. Otherwise they will cause grooves.

Yes - use wider blue tape. I use 2 inch wide. Illuminarti has 6 inch wide I think.

@0235 - remind me - UM1 or UM2? Maybe you should put it in your profile description (e.g. lives in UK has UM1).

 

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