gr5
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Posts posted by gr5
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In configuration.h in the marlin build you want the following commented or not commented as shown:
//#define PIDTEMPBED
//#define BED_LIMIT_SWITCHING
#define MAX_BED_POWER 255 // limits duty cycle to bed; 255=full current
If you haven't built your own Marlin yet, well, I recommend it. It's not too hard. You have to install the arduine IDE and you have to download the latest Marlin (which I'm pretty sure has some key bugs fixed that aren't in cura yet). There are instructions if you google about how to build marlin. Very detailed instructions. It ended up not being so hard.
To get help on what to comment in and out in configuration.h I read the comments in there and I also used daid's web page and looked at the configuration.h that came out of that.
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But, my extruder doesn't extrude... The last part of the wizard is to print a square, the head move like square, but no PLA is extrude. It's work if I disconnect the extruder clamp and push the PLA myself.
Look at the knurled bolt, make sure the sharpest part touches the filament. Put some filament inside the feeder. Does the spring compress when you close it? It should. Try turning the large gear by hand. If everything seems fine, heat up the hot end to 200C. Then try turning large gear by hand again.
But I don't find the way to monitoring the temp without use the wizard, and I don't find the menu to manually move the head, the bed etc...In Cura, the temperature is the first window, and x,y,z,extruder can be controlled in the next tab. But I prefer to use my hand for the turning the extruder/feeder.
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Probably be fine but kapton tape can handle the heat no problem (I think it can handle 600C maybe) so you could unwind your twisted pair where it will be touching the heated bed and use kapton tape to keep the two strands from touching. That way if the insulation ever melts it won't mater.
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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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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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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.
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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Did you use Cura to slice the robot? Did you go through the Cura wizard where you check limit switches (aka end stops)? Did Cura load the marlin firmware into the ultimaker? What version of Cura do you have?
Assuming you got through the above just fine...
Assuming you don't have an ulticontroller, and assuming you are using Cura connected through usb, click "print". Control the X axis and Y axis. positive values in X should move the print head to the right. POsitive Y values should move the head towards the back. Is the X motor backwards? Maybe the wires were soldered to the X motor backwards if it moves the wrong direction?
I believe if you wire the servos backwards they move the opposite direction. There's also a flip bit in Marlin somewhere to flip any of the steppers.
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Consider lowering your fan - did you change fan settings recently? Is the fan cooling the tip too much?
I print PLA at 240C all the time. I know I'm weird but it works well for me. Don't be afraid to do some test cubes or something at even higher temps.
Owen may be onto the actual problem - possibly some blockage.
Did you recently start printing faster? Faster speeds might need higher temps. Look at your fan shroud - did it break? Or get ripped open? Is the air suddenly on the tip? Did you recently change fan settings? Maybe your new filament just needs to print at 250C. Or at least 240C. Experiment. Maybe the new filament is larger than 3mm in diameter in spots and gets stuck in the tube (which is not much larger than 3mm and sometimes the filament can't fit through the bowden tube - especially when compressed by the feeder).
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This is a great example of where one would want variable thickness layers. I would want to double up my layers for these areas. This is referenced in that "paper" slicemeister posted about earlier in this thread.
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I didn't notice that! You need to move that fan soon or it will break on the z screw.
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Hmm. Try opening the latch on the extruder so the plastic filament can slide freely. With the hot end at 220C, try shoving the filament through the tube. Does anything leak out the nozzle? You can push pretty hard - say 5 pounds of force - plenty that you need to hold the feeder from flying up off the machine.
If that works, pull the feed out of the bowden tube a few inches, close it back up, and turn the big gear by hand - you should see the filament moving slowly. Can you see a pattern in the filament where the knurled bolt is cutting into the fillament? You should. Keep turning the gear until it enters the hot end and filament should come out.
You may have to rebuild your feeder - the knurled bolt may not have the best part touching the filament or 20 other possible things not assembled right.
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This problem isn't really that big of a deal. Some people had the switches backwards and did a home and were afraid of damage after their x axis did a "total slam" but their ultimaker survived (and they were annoyed but so what - deal with it - UM can handle it - so should you).
Maybe the new instructions are wrong and messed up twipwip? Twipwip - what month did you order your ultimaker or when did it arrive (roughly) and is the bottom of your ultimaker backwards like the picture? Or is the printing on the bottom of your ultimaker fixed now (I doubt it). If so I'll fix the instructions.
http://wiki.ultimaker.com/File:Endstops.png
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I assume you are just making fun, but just in case - I meant an hour to read instructions, install the compiler, download marlin, figure out what the instructions meant (where's the bloody open project and build project commands?), read every variable in configuration.h and all the comments and change a few things, and then build it and download onto ultimaker. The actual compile was trivially quick.
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By the way, there are tons of comments about how the kit was fixed, plus tons of more messages about how "nope, not fixed yet" months later. It would be nice to have a specific cutoff - something like:
"ultimakers shipped after Feb 27, 2013 have this 'reverse x limit switch' printing fixed".
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Well I got my kit just 4 months ago today and the wood was still printed wrong. However, the nice thing about the current instructions is that if you fix the printing on the wood, the instruction corrections will still be correct.
Have you taken a look at a recent laser-cut "bottom" piece to see if it's fixed? You can check it against the picture here:
http://wiki.ultimaker.com/File:Endstops.png
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You issues look more like you are printing too hot than too cold. I see no regions of under-extrusion. If I tried to print at 210C you would see lots of under-extrusion but I guess my thermocouple is off or something (maybe too much air from the fan hitting my tip).
Anyway, here are some samples of too low and too high temp (not my pic but it's very helpful):
http://umforum.ultimaker.com/index.php?/topic/1763-bad-surface-on-printed-parts/?p=12318
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Nice! Someone who actually knows how to use the MAC! This is why I don't use Macs - I know details like this for the PC but don't want to spend 5 years learning every little feature of the Mac's os.
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If you are a competent and experienced c coder - definitely look over the firmware. It's well written code for the most part and easy to read (the parts I've looked at).
Also don't be discouraged by all the steps to build your own Marlin. I was nervous it was going to be very complicated but google told me everything I needed to know and I think it took less than an hour. I found not one, but a few places that gave me step by step instructions for installing the compiler, getting the source, editing the config files and getting my own custom Marlin build. This was necessary anyway at the time because at least then (early january when I added my heated bed) Daid's page didn't work right for heated beds. Daids marlin builder page was *very* helpful in createing a configuration.h file - I was able to diff Daid's versus the default to see what I might want to mess with:
http://daid.eu/~daid/marlin_build/
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The instructions were finally corrected (by me) just a week ago (I took this picture last November):
http://wiki.ultimaker.com/File:Endstops.png
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The thing that makes this print the most difficult is just all the skips: Where the extruder is expected to stop down to zero and then instantly go back up to extruding again.
What happens is you often get stringing where it is extruding when it isn't supposed to be (the extruder doesn't stop fast enough) or you get under extrusion during printing the skin, or you get over extrusion when the head slows down.
These can cause the walls to be thicker or thinner at different layers.
XY belt play can also cause layers to shift so I thought possibly that should be elminated since you mentioned it. But if it's extruder issues...
Some people try to fix this by having the extruder reverse directoin by 2mm or even 4mm. This is called "retraction" it can help, but sometimes it just makes things worse because the head pauses during the retraction.
Another thing that helps is to have very fast travel speed and very slow print speed so there just isn't much time to make thick strings. Say 50mm/sec for print and 250mm/sec for travel.
Another thing that helps is to have a lower print temperature. This is so the plastic is more like paste than like honey. That also makes it so that the extruding stops faster when it needs to stop and starts faster when it needs to start back up.
The fan can also make a difference - possibly if you turn the fan off you can go to a lower printing temp. If you go too low with the temp, then the pressure gets too high and you can get underextrusion (not enough plastic all over) which looks kind of like lots of holes everywhere evenlyish spaced.
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Well if the belts seem even slightly loose to you maybe you should tighten and loose belts would definitely cause what you call "shifting":
http://www.thingiverse.com/thing:24336
http://www.thingiverse.com/thing:10082
http://www.thingiverse.com/thing:16449
Or read the ultimaker assembly instructions - somewhere in there is a great video showing how tight the belts should be and how to tighten them without needing any parts (there's a screw you can adjust).
Also tighten all the X,Y pulley screws (10 of them?). Make them verry tight - you-should-be-nervous-you-might-break-something tight, but not so tight that you break something, lol.
Another thing to try is printing even slower. I dont' think it's the slicer.
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I found the usb cable to be unreliable and only print using ulticontroller and SD card option now. However if you don't want to buy a UC then try to limit noise maybe? No AC fan's or microwaves ovens or hair dryers in the house while printing?
It often crashes right at the start or end of the print job (have to reconnect with cura when it crashes). Maybe something is causing a voltage spike then (turning on or off the heater causes noise spike?) so it makes sense to me this would happen part way through the print job but right at the end of a part (or start of the next).
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I think it would be great (and probably easyish) to have the "bottom" layer optional. This would help greatly with parts that don't need to look good on the bottom and that are large (have warping issues). With no bottom, the bottom layer would be able to compress a little when the upper layers are cooling and would be less likely to lift and also less likely to warp (almost the same thing).
Examples would be a "bust" where it is meant to sit on a flat surface and you don't see the bottom layer without picking it up. The infill would be visible from the bottom and would be a nice conversation starter on how 3d printers work.
Or architectural models or anything that is meant to sit on a flat surface. This should only affect the "bottom most" layer and not layers that are higher up in the model (for example the underside of a chin on a face).
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Oh! I get it -- I could easily use openScad to remove circular or square regions giving the bottom lots of large holes. This would greatly reduce the warping.
Heated Bed Tuning
in Third party products & modifications
Posted
Don't just trial and error your thermister. Presumably you bought it from somewhere and there are specs for it? These thermisters come with a formula. You can use the formula to generate your own table if there isn't one in the firmware already. There's a bunch in thermistertables.h.
Or if you have an accurate thermometer you could calibrate the thermister yourself at 10C intervals