Jump to content
Ultimaker Community of 3D Printing Experts
  • Sign Up

eriksw

Member
  • Content Count

    30
  • Joined

  • Last visited

Everything posted by eriksw

  1. That looks weird. Something is going wrong with the slicing here, so you can rule out printer problems for now. Never seen this happen in Cura (nor in Repetier, but I don't use that a lot). You could download Cura from the Ultimaker site (it's free), and see if the same thing happens when you load the model in Cura.
  2. If these bits are caused by the slicer then you would definitely see it in Cura's layer view. If you don't see anything like that there, it is not caused by Cura or a "faulty" model. In that case the problem is in the printer, mechanical or firmware. Or perhaps it is caused by cheapo Chinese PLA, but then I would expect to see a lot of other shit in other parts of the model as well. Still, don't use that stuff. Always get good quality PLA if you want good quality prints. Another tip for delta printers: accuracy of those is worse in the centre of the platform, and better towards the edges...
  3. Never seen anything like that on Ultimaker with Cura, so I doubt this is bad slicing. Good to know, and PERHAPS this might be causing it: a model of a thin walled cylinder is never 100 % round. The cylinder has sides and although it might seem round when there are many sides (120 or more for instance), it actually isn't. Curves don't really exist in a digital system, they are always "steps".... As a result, the thickness of the wall is never exactly the same all over. This is always the case in all curved walls. So if you have a straight wall that is exactly 0.4 mm thick, when you put a curve in it there will be areas where the wall thickness will be less than 0.4 mm, which usually results in Cura "skipping" these areas. When this happens, an easy way to solve it is to scale up the model just a tiny bit. 0.5-1% is usually enough. Or you can change the setting for the nozzle size a bit, that also works. In your case it might be the other way around (so that some bits are just OVER a certain wall thickness) in which case it might help to scale the model DOWN just a bit. And you only need to scale in x and y direction, no need to scale the height as well. Again, I doubt whether this is the cause, never seen defects like that, but it can't hurt to try scaling to see if it helps.
  4. PS I just noticed that gr5 already mentioned that this could be the cause, back in june. See page 1 of this thread, I quote: "Another solution (maybe) is to use a copy of Marlin that uses "slow fan PWM". You can do that by unchecking the 4th checkbox from the bottom here. This won't eliminate the problem but it will cause less frequent spikes in the voltage so that hopefully you get less frequent "bad temperature" readings. http://marlinbuilder.robotfuzz.com/ " (It's the 5th box from below actually, if you want to try it out.) Somehow I missed this first time around - too busy replacing all the parts I suspected, I guess....or perhaps I did read it but did not feel like messing with firmware (yet), which is tricky... and you can damage the printer if you don't know what you are doing, just so you know.
  5. Quite a while since last I posted on this thread, but here's an update. I FINALLY found out that the temperature swing is caused by a firmware setting called "fast PWM". This setting causes much more PWM noise when you print with any fan speed other than 0 or 100. This noise interferes with the thermocouple signal. I made a version of the firmware with the "fast PWM" switched off, and now I only get very moderate swings in the temperature reading (2 or 3 degrees max) and (more important) the actual nozzle temperature actually stays in the neighbourhood of the temperature reading, instead of dropping some 10-20 degrees below it. (You can check this by first printing with reduced fan speed, then set the fan speed to 100 on the controller, and then quickly go back to the info page to check the temperature reading.) But HEY - I installed the new default firmware with Cura 15.2 and it looks like that also solves the problem ! I'll do some more checks later, but it seems like it is back to normal now. So perhaps the "fast PWM" has been switched off in this version again, or perhaps something else was altered, but I'm not a firmware expert so I'll leave that to those who are.
  6. In case you're wondering: the smoke accident happened when I was tinkering with the print head, and I did a test print without clamping down the plug of the thermocouple (and probably didn't plug it in properly). Plug came loose, the electronics were getting no temperature reading, and that caused the heater to stay on. By the time I stopped it and stuck that plug back in, the temperature was 320 degrees...and that took a while, so it got hotter than that. Big PLA smoke cloud in my shop. So this is not bound to happen very often, however I understand that the connecting wires can break sometimes, and that could happen to anyone, even without tinkering. Has not happened here yet though - which is quite amazing, been printing almost 24/7 for 1,5 years on UM1. That's a WHOLE lot of shaking going on...
  7. Agreed, all electronics can cause fire. But this machine also has an electric heater that is melting plastic, quite different from most other equipment I would say... People WILL be leaving their printer unattended. Or am I supposed to sit and watch the machine when it is doing a 24 hour print ? I can watch it for hours (printer meditation...) but I need some sleep as well. And I did not suggest building a smoke alarm into the UM3. The system I described above would hardly add to the cost of the printer (if at all), and would definitely make it MORE safe. 100% safety was not what I asked for. By the way: I doubt that the hot end would catch fire in case the heater stays on continuously (anyone ever tested this ?), but this WILL produce quite impressive clouds of smoke, I can tell from my own experience. Fortunately that time I was there to switch it off within a minute or so, but it would be great if the machine would do that for me, in case this ever happens again. The last thing the industry needs is press reports about houses burning down due to a printer catching fire. And the last thing I need is my shop burning down. So ANYTHING that can help minimize this risk would be a GREAT advantage, I would say, especially if it can be added without extra costs. To me 70 dollars seems reasonable for this Kickstarter Smoke Signal (if only to prevent my shop filling up with smoke), but of course 20 dollars would be better...let's hope it gets picked up by some Chinese manufacturer.
  8. That's the one. So printers CAN burn your house down.... I wonder how often this happens, looks like chances are very low, but still... some people win the lottery as well. All the more reason to add the function as described above to ALL printers from now on. It should be simple. In the meantime I'll be waiting for that Smoke Signal to arrive... thanks for the link.
  9. PS Google only comes up with some patents for "smoke detector power cut-off systems", but apparently there's trouble from insurance companies. Can't find any such thing on the market...
  10. Still very happy with the UM1... what a great machine, and many ways to make it work even better, which seems a lot harder with the UM2. I really like the ability to manually move the feeder wheel (while starting prints, changing filament...), which you can't do on the UM2. Would be nice if that was possible on the UM3. Or else some dedicated buttons to do this. Could do with another 2 buttons to quickly lower/raise the platform. For safety it would be great if there was something built into the electronics to check the behaviour of the power going to the heater. It is possible to get a malfunction of the temperature measurement (in any part in that chain, but mainly broken wires due to metal fatigue from vibrations are my concern) causing the heater to stay on continuously, leading to excessively high nozzle temperature, causing clouds of smoke (had that once) or perhaps even fire (although I never heard of that happening, fortunately...). And this of course ruins the insulator if you're not there to switch it off immediately. Normally the heater switches on and off several times per minute, except during heat-up (or when the temperature gets changed by a tweak). So it should be possible to have some monitor system that would "notice" that the heater is on for (let's say) more than 30 seconds, even though the printer is not heating up for printing or due to a tweak. In that case it could either switch off the printer directly, or give out some alarm sound first for a while (to prevent any "false alarms" ruining a print) before switching off the printer. As the UM1 does not have such a system, I have been thinking about building a smoke alarm that can switch off the power to the printer when it is triggered. Anybody know if this exists already ?
  11. @UltiArjan: nice thread about that exchangable nozzle. Very interesting, but not very accesible to most users yet, I guess...A good one for the "what do you want on the UM3" request ? And yes, 120% flow can be good for watertightness. However I have noticed that when the flow gets too high this actually makes the bottom leaky again, as the upward ridges between the print lines become too high, creating more pores again. Also, very high flow can make the outer edge of the bottom layer look ugly, so I often set the TweakAtZ plugin to increase the flow gradually during the first few layers. Another thing that has not been mentioned yet: print temperature should be quite high to get stuff waterproof. You need nice "runny" PLA to "seal" the bottom, for good layer adhesion in the wall, and it also helps to make increased flow happen more easily.
  12. @UltiArjan: Nothing wrong with a big nozzle, but I assume the majority of UM users don't want to be bothered with changing nozzles (and releveling the bed) for each print... @Kirash4: please read my reply again: you can have the bottom as thick as you like (up to 20 cm ) but when you set the shell to 1 mm (using "spiralized") while using a 0.4 nozzle this means that your infill lines will be 1 mm apart, and there is no way you can extrude enough PLA through that 0.4 mm nozzle to get that bottom watertight, no matter how thick it is. Apparently you can file down the nozzle to create a larger "shoulder" so the above MIGHT become possible, but I haven't tried that yet as it seems a bit crude. Cups/vases with only 0.4 - 0.5 mm shell will be pretty strong already, by the way. But if you don't mind changing nozzles then UltiArjan is right, go for a bigger nozzle. And of course you could print without "spiralized". Then you can print your wall any thickness you like, because it does not have to be a "single line wall" anymore - but you will get a small vertical seam at the spot where the platform moves down.... however if there is some 3D pattern in the wall (as opposed to a smooth cone or cylinder) this seam is often hardly noticeable, so perhaps that's a better way to go for your print.
  13. eriksw

    inside brim

    That's funny... I tried that trick some time ago, but it did not work then. I have checked, and indeed it does not work in 14.01 (which I have used for most part of last year) as that one also produces "inside skirts" (pretty annoying...) but it DOES work in later versions. Never noticed those inside skirts had disappeared, as I had set all my skirts at quite some distance around all objects with cutouts since then, because that removed the inside ones. So now I can put those skirts back to 1-2 mm again, which is nice. Thanks. Still, would be nice to have a checkbox for "inside brim", so we don't have to use this workaround, which is not obvious to many users I guess...
  14. Using the "spiralize" function, the wall of your cup will always be a single layer, because the spiral starts at the bottom and then spirals up on top of itself, like a coil/spring. So you should usually set the shell to the same size as your nozzle (standard is 0.4 mm) when printing spiralized. You CAN increase the wall thickness by using a higher setting for the shell when using "spiralized". That way there will be more extrusion, so although it is still a single layer, the extra extrusion will be forced out of the nozzle and will be spread out sideways by the "shoulder" of the nozzle (= the flat part of the tip around the hole). This works fine with shell set at 0.5 or 0.6, but 1 mm is way too much to get a good quality print. HOWEVER: with the shell setting a bit higher than the nozzle size as described here, Cura will increase the distance between the lines of the infill. This is what causes the gaps between the extrusion lines as you mentioned (mainly because you are bound to get some under-extrusion when printing this way, definitely with shell at 1 mm). With shell set to 0.5 or 0.6 the gaps will be smaller (or non-existent), and you can close them up by increasing the flow a bit (try around 105-110%). That way the wall of your cup will be a little bit thicker as well. OR you can set the shell to the same size as your nozzle, and then use the TweakAtZ plugin to increase the flow at the height where the wall starts, so 3 mm in your case. Keep in mind that this increased flow will remain in your printer's settings after it has been changed this way, so either switch your printer off-on before the next print or set the flow back to 100 with the controller (but you can only do this AFTER you start the next print, unfortunately, as you need the TUNE menu to do this, which only appears while printing...) So if you really want your cup to have a wall thickness of 1 mm, there are 2 options: either switch off the spiralize function (watch your print time double or triple...) or use a much bigger nozzle, which is not a very sweet option. One more thing: the fact that you did not get the gaps between the lines in the first and second layer probably indicates that your nozzle is a bit too close to the platform.
  15. Check whether you have set the right setting for "combing" in Cura 15, as it doesn't properly copy the settings from ini files made with earlier versions. Not sure whether it is causing this problem (probably not) but it's worth checking anyway... My intuition tells me it makes more sense to do the shell before the infill, as there are bound to be small imperfections at the starting points of the infill lines (blobs). These will be in the way when the shell is built, and the shell will be pushed outward at these points. When you put down the shell first, these blobs will be stuck against the inside of the shell and will therefore not affect the shape of the shell. Or a lot less, at least, I would assume. I'll check to see if I have the same trouble, haven't used v15 a lot yet - it's great to get all the improved versions, but often there are new troubles appearing, so for production I usually stick to a version that has proven to work well. It's becoming quite a skill to know what version of Cura works best for each print, it seems...
  16. I use the "spiralized" function a lot (earrings, vases, etc). It was working fine up to version 14.07, but since then there are strange travels that happen here and there in many of the objects, which ruin the print. For instance I get vases which have a couple of wires across the inside, caused by a travel that interrupted the spiral. Would be great if this could be fixed, as I have to keep using 14.7 for spiralized printing at the moment. Thanks ! Erik Swetter Printed In Space Amsterdam
  17. eriksw

    inside brim

    With Cura (up to) version 13.10 I could print objects which have cutouts in the bottom using a brim, and the cutouts would come out clean. In all later versions there is an "inside brim" which (partially) fills up those cutouts. As I print LOTS of objects with cutouts (logo etc.) I still have to revert to using 13.10 for those, which is a pity because Cura has really advanced in many ways since then... So if possible, could you please make this inside brim optional in the next version ? Thanks !!! Erik Swetter Printed In Space Amsterdam
  18. When I load a profile made with earlier versions into Cura 15.2, with "enable combing" checked, it is translated to "combing OFF", which causes zillions of retractions.... Took a little bit of cursing to find the problem. Please change it so that when in old profile "enable combing" is checked this translates to "combing ALL", that solves it. These retractions happen mainly in the extra "zigzag" that is added to the inside of sloping walls. It would be nice if this "zigzag" was optional, as it is not always necessary and can ruin prints in transparent PLA because it is added for walls which have more slope but not for walls that are (almost) vertical. With "spiralized" printing this zigzag is never there, which causes much nicer transparent prints, but of course many objects can not be printed spiralized so I would like to be able to switch off those zigzags in some cases. On the up side: some great new options in 15.2, thanks ! Erik Swetter Printed In Space Amsterdam
  19. Correction: where I said it started spinning at 51%, this was actually at VALUE 51 (out of 255) on the controller, which is 20%. And that tin foil was a feeble attempt, I admit. I did "earth" it by holding it, but let's forget about that. As said, I want it to work as it did before, so without shielded cables. It should not be necessary to change them... Holding the fan was a good idea. Here's the test results: I set the print temp to 200, and the fan speed at value 91. While holding the fan, the temp readings were slightly longer apart, ranging between 198 and 202, with no steps larger than 2 degrees. On releasing the fan, the readings were faster (slightly less than a second apart), ranging between 194 and 207, with steps averaging about 3 degrees, with some jumps of 8 degrees. So definitely more interference when it is turning. I have a gut feeling the PWM noise will normally be worse when you hold the fan ?
  20. Thanks for all that info. I'm not in a rush, as I can use it with fan at 100. So I'll take the time to replace some parts until the problem is solved. I don't have an oscilloscope so I'll need to find one I can borrow. Replacing the wires with shielded ones seems like a solution that is not really dealing with the cause of the problem, as it used to print fine with the normal wires. As a test, I have wrapped aluminium foil around all the wires, but I did not notice any improvement. If, as you said, chances are that an aged darlington will only emit LESS noise, I'll leave that one until I have no other options to try. I could switch the main board from my other printer to see if that solves it, I'll try that some time this week. But I think my first bet would be to change the fan. It seems to me that this is the one element that is most likely to be worn out after such extensive use. I noticed today that it did not start to move when I set the speed to 51 %, it only started after I gave it a little push... So perhaps it is the fan itself that is emitting more radio noise during PWM, due to aging ? Or is that not possible ?
  21. GR5, could you tell me where to find that darlington and how to check it ?
  22. Daid, thanks for joining in. For the record: I'm not a "newbie", but I forgot my forum login details so I made a new account. I have been printing practically 24/7 since last august. I run Printed In Space, the Amsterdam 3D print shop. My printer was doing fine (at all fan speeds), now I have trouble with PWM interference, but haven't been able (yet) to find the source of the problem...
  23. Helpful info, thanks again. As you say I can use the printer with fan at 100, which I also do normally, but there's 3 problems with that: 1. The gradual start of the fan over the first few layers is very nice, for the reason you mentioned. But now this is only causing more trouble... 2. The printer is right next to a single pane window and a shop door that is letting in cold gusts of wind regularly, so I found that during the cold winter period it was better to use the fan at 40-50%, else it was cooling too much (even though I closed off the printer with pvc windows and a beautiful self-made harmonica roof). 3. It bugs me. I want to know the cause of the problem, for mine and hopefully other people's sake. Where is that darlington transistor hiding ? Is it on that little circuit board ?
  24. UPDATE Measured the resistance of the probe: 1,5 Ohm, so no problem there. 99% sure no wires got damaged while changing nozzle... I also twisted the wires of the probe before reconnecting them. Alas, no fix. So that leaves the fan and the amplifier circuit board, I think. I'm tempted to change the whole lot in one go, but then I would not find out what is causing this problem, so I'll be patient and work it out one by one. Another clue that leaves me clueless: I just tried printing a vase with fan speed at 40 % to see what would happen. Temp reading started jumping about again, but I left it to see if it would settle. It didn't. When I noticed that the print had been failing for quite a few layers (got distracted, I have a shop to run...) I saw that the temperature reading was on average about 230, while print temp was set to 240.... I would assume that the jumping of the probe readings around the set temperature would cause the actual nozzle temp to be roughly the same, close to the set temperature. If the probe reading is too low (as was the case just now) I would expect the heater to be on all the time, causing actual nozzle temp to be way too high. But I'm quite sure the failure was caused by the nozzle temperature being TOO LOW, causing under-extrusion. WTF ??
  25. Ok thanks, I'll check that. Might take until monday before I get a chance... I'll keep you posted.
×
×
  • Create New...