illuminarti
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Posts posted by illuminarti
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You could also use Repetier Host which is a front-end for Slicer, and also has a printer interface capability for sending the gcode to the printer, and also does a nice job of visualizing gcode for testing whether the gcode is doing what you expect it to.
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If you're really changing the number of steps/mm to do this test, I'm not sure that you're really testing the difference between micro-stepping and not microstepping. All you are changing is the number of steps that gets executed to move from A to B (and hence getting a shorter distance moved as you request ever-lower steps per e).
The firmware calculates the total number of steps needed to perform the requested move (based on steps per e), and then pulses the motor lines that many times. How far each of those pulses moves the motor depends on the configuration of the steppers. Off the top of my head, I don't remember how the microstepping is set up on the X/Y axes - but in any case, the printer is going to be using exactly the same microstepping in each of your test cases, just not moving as far. I'm afraid you may just be seeing the inaccuracy in your measuring tools as you try to measure smaller and smaller moves.
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Features that are smaller than your declared nozzle width are going to get filtered out during the slicing. You could try reducing your nozzle width setting a little - to perhaps 0.25mm or 0.3mm and see if that recovers the detail.
Note that you don't necessarily have to have a physically smaller nozzle - within limits you can declare the nozzle to be a little smaller than it actually is, although you'd get better results if the physical and declared nozzle sizes match.
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Almost certainly one or other pulleys for the y-axis is slipping. Check that they are all tight, includin the one on the motor itself. You might want to use a sharpie marker to put a mark on the pulley and shaft, and make sure that the marks don't move as you print.
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Even with retraction enabled you're going to get this kind of problem because the head does travel moves across the surface, damaging it. What you might want to try is enabling the 'hop on move' capability, so that it lifts off the surface during moves. But Cura's not very smart about that - you might get better results with the equivalent setting in Kisslicer. You should also take a look at my blog post about z move speeds, and consider tweaking things to get slightly faster z-moves...
http://www.extrudable.me/2013/04/02/the-myth-of-z-speed/
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Yes, as far as I know the M81 command is implemented in all the shipping versions of the Marlin firmware. It affects the state of pin 54 on the Arduino, which then needs to be hooked up appropriately to kill the power.
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Bear in mind that you'll probably need to slide the nuts in properly aligned/rotated - so that the two of the 6 flat surfaces line up with the sides of the slot in the wood, otherwise the diameter of the nut will be too wide to fit.
If that still fails then maybe you need to take a small file and open out the holes very slightly?
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No, as far as I'm aware, no slicers are that sophisticated. The given temp gets set early on in the preamble gcode, but then totally ignored otherwise.
In theory, changing the speed and flow via the ulticontroller should be the same as having set them that way in the initial gcode, with the only exception that all head moves get speeded up uniformly by changing the print speed multiplier. As a result, all movements (except pure retraction/advance moves) are affected, including travel moves, whereas in the slicer you can set travel moves separately, and in some slicers (not Cura) you can set loops, infill etc to have different speeds. From the ulticontroller, they all get affected by the same proportion, but you loose the ability to differentiate, or to NOT increase the speed of your travel moves, if they are already set to be fast.
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Netfabb for Ultimaker is paid software. You don't seem to think you've paid for it, so you may have had a time limited demo that has now expired?
The free version of netfabb is really hard to find on their site these days, but you can download it here:
http://www.netfabb.com/download.php
It doesn't do gcode generation, but it is very good for repairing broken STL files.
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Yes, I think that's almost certainly the issue. These problems crop up in various places at various times, and Daid tries to fix them, but it's probably still not perfect.
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Yes, I think George's explanation makes a lot of sense. New one on me too. Might also explain some of the things I've seen people post lately with weird blobby patterns on their first solid layers... or even ooze in short infill sections, as well. I guess there are really two choices... on the second pass along a line, the extra plastic can either push the lower layer out of the way (if there's room to), just sort of blob our randomly, or mostly get contained in the nozzle, increasing pressure. On starting layers, I would imagine you're mostly going to see either pent-up pressure or random blobbing when the pressure gets high enough to cause oozing out the side.
Well done guys, good detective work!!
On the retraction distance question, bear in mind that the retraction distance is as measured at the extruder gear input. It's very solid plastic at that point, so in theory if the retract and prime distances are the same (and especially if the distances are sufficiently short that the move keeps semi/un-melted plastic within the diameter-constrained hot end, to act as a piston) then you should be exactly back where you started after retracting and re-priming the head. This does ignore the potential for air to get trapped in the head etc. Which is not to say that there aren't valid use cases to have them not be equal to compensate for some other problem - most likely slipping in the extruder gear. I wonder if you weren't especially prone to that, especially during the backlash problems, because you were probably more likely to be getting a pressure build-up in the head, when every other line of plastic had nowhere to go.
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I still think you're missing something in your testing which is leading you to conclude that the gaps between passes in the solid layers are a result of backlash. I think something else must be going on. When it's correctly set up, the gcode is exactly enough to exactly fill the available space with nozzle-width strips of plastic. In an enclosed space, that plastic has to go somewhere. While backlash might cause some slight errors in the start and end points of the lines, overall it would have to smear the lines out over say a 50% greater area to create the sort of gaps you saw. And it isn't doing that. So I still think something else is going on. I'm just not sure what.
By definition you should never need the de-retract distance to be longer than the initial retraction, so this definitely indicates that something is going wrong at the extruder end of things. You were seeing this when printing with quite high volume per second, so it may well be that the back pressure that built up in the nozzle was able to shove the filament back extra far during the retraction moves.... as discussed in that article I linked to above.
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Solid walls only require that the bead of plastic is the right depth and, within reason, gravity and cohesion will make sure that the small vertical height of each layer is filled in.
Getting solid layers without gaps between the passes requires that the beads are the right width as well so that they touch one another.
However, it looks like you are getting everything sorted out, so I'm sure you'll soon have it all honed to perfection. Enjoy!!
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Bear in mind that what you're seeing could well be the notorious 'thin wall' problem in Cura, where certain parts of the walls don't get filled in properly.
If you haven't already, try slicing with a single loop around the outside - set your wall thickness equal to your nozzle width, and are if that makes any difference to the end result.
Hi - Is it possible to generate screenshots from Cura once the file has been 'prepared' for printing? I have had a bottle cap with thread designed for me but once it has been 'prepared' the walls have hollow sections in them - I need to show my designer
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Well... here's what I found looking at the gcode... KC is printing the object with 'duplicate outlines' enabled. This setting is a horrible hack that prints the identical outline twice for each layer. I'm not convinced that it helps much, and it definitely can cause problems - for instance, someone had some oddities a few weeks back that ended up being due to trying to combine Joris and duplicate outlines.
As a result of this setting, what is happening on this print is that right before starting the second layer, the printer does a long X/Y travel move during which time it is also raising the head by 0.1mm. Marlin isn't terribly happy about combining x,y and z moves, and I'm aware of at least one as-yet-unpatched bug related to how that works (but I don't think the bug should cause the behaviour that KC sees). But during my speed testing, I've definitely seen some problems with moving all three axes at the same time - speeds and accelerations that individually work fine can reduce the printer to a howling mess of skipped steps when combined.
When I tried to print the gcode file, it basically worked fine for me, but the printer sounded absolutely awful on those long moves. I can imagine that on a less-well-bedded-in printer, or with different speed and acceleration settings, problems might happen.
My recommendation to KC is to try reslicing it with duplicate outlines turned off, and indeed just to forswear the setting totally in future. :smile:
Meanwhile, I'll dig into the firmware a bit more, and see if I can figure out what is causing the problem.
PS... is it related to Calin's problem - I'm not sure. I agree with his assessment that it's probably not the firmware per se, but some sort of reduced tolerance for hardware problems. Maybe reloading the firmware is resetting some parameter that creates enough headroom for the problems to not become critical. I just don't know. I'll keep digging...
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Yes, as George said, there's very significant under-extrusion in your full size print, and also really bad backlash causing the infill to not touch the walls.
Under-extrusion just refers to outputting less plastic than needed. The effect can range from gaps between the passes in solid layers, all the way up to holes in vertical walls, or printing cotton-candy fluff - it all depends on the degree to which it happens. It happens for the reasons I explained in my earlier message.
Backlash is when the head doesn't move quite as far as it should before changing direction. It's the major cause of infill not touching walls. The usual reason for this is the short belts not being tight enough. I couldn't tell much from the video about your long belt tension, although I got the impression that they were very tight - tighter than mine, probably. But I'd really need to see the actual belts, rather than just listen to them, given the limitations of web video I think.
Measuring bed height with calipers is over-complicated, and probably difficult to do accurately given the springiness of the bed. Just do the piece of paper thing that I described. The most important thing is that the head is touching the bed, when z=0. That's all that matters. If it's the same height everywhere, that doesn't help you at all if that height doesn't put the nozzle in contact with the bed. Looking at your photo, it does look like the gap between nozzle and bed is slightly less when the head is in the middle. But maybe not enough of a difference to matter. (The difference could be due to the bed not being flat, or due to the 6mm cross rods or axes being slightly bent perhaps?) But what I do notice, as George said, is that the head isn't close enough to the bed at the edges. The first layer of plastic should be slightly squashed and flattened, so as to get good adhesion. In your test print, it looks like the bead of plastic is very round in cross section, and barely attached to the blue tape.
The rods can sometimes slap back and forth if they aren't exactly the right length. A little movement probably won't hurt - it's probably better than too much tension from the end-plates pressing onto them. You might want to try using something like this: http://www.thingiverse.com/thing:54075.
There's no particular formula for temperature vs speed - but in general you'll be able to sustain faster speeds with higher temperature (although may get other effects such as increased stringing).
Are you using the latest Cura? Earlier versions of Cura had a problem when the wall thickness wasn't an exact multiple of the nozzle width that could also cause your 'A v B' under-extrusion-like issues in some circumstances. Make sure your wall thickness setting is an exact multiple of nozzle size, and it won't be an issue either way. But I think that your problem is just that you aren't extruding enough.
You might check the tension in your feeder again... see the photo towards the end of this post for an example of what the teeth marks should look like.
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It seems it might be a firmware issue - what version of the firmware are you using? Is it one that came with Cura?
Please can you email me the gcode for a file that fails, so I can take a look at it, and try to troubleshoot? You can send it to gcode@fbrc8.com.
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Calin, I can totally understand where you're coming from - those sort of electronics problems can be really frustrating, and very hard for most users to diagnose.I certainly wouldn't know where to begin. I'm fortunate that I haven't had that sort of problem so far.
Perhaps the only difference between your experiences and what variador experienced is that in his case the print failed on the second layer, rather than as soon as the print started.
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Email me the problematic gcode file to gcode@fbrc8.com. Let me see if there's anything obviously wrong with it.
I do not have an ulticontroller. I saw the pause at height option in Cura, it is turned off.
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I think there are a lot of different issues here that are going to take a little while to isolate and work through. But here are some thoughts to consider:
1) You seem to be printing a lot of very small things. That is technically quite challenging, because you need to make sure that lower layers have enough time to cool and solidify before you pile more heat on top. Otherwise, the lower layers will tend to droop and deform. The minimum layer time in Cura helps with this - I generally use a minimum layer time of 7 seconds for PLA which I print at about 220º normally. However, with very small things, slowing down can be counter productive because the head slows down so much that it transfers excess heat into the model anyway, just by lingering over each part. So be sure and set a minimum layer time, but also try printing some slightly bigger parts while you are calibrating things.
2) Circles can end up not round because of backlash in one or other axis, or due to poor layer adhesion resulting in the plastic getting pulled straight. Again, printing some larger parts to begin with will help avoid some of the noise of short, fast moves, head ooze etc, and give a clearer picture of what is really going on. Small prints tend to magnify the impact of small errors, and whats going on can get lost in the random variation of the print. Start by tweaking the printer to print large things well at a 0.2mm layer height, and then once you have that set up well, you can refine things to get equally good results with smaller prints and smaller layers.
3) I don't see any mention of what temperature you are printing at. I'd recommend try a fairly hot temperature - say 230º, and printing at 50mm/s, with 0.2mm layer height, and 0.8mm wall width to begin with. Trying to print too fast can definitely lead to extrusion problems, if you end up extruding too fast for the nozzle. The limit depends on the temperature of the plastic. Printing with those settings should put you in a fairly comfortable middle ground where you can rule out excess speed and insufficiently fluid plastic.
4) Regarding bed levelling. I'm not exactly sure how you are using 'a caliper' to level the bed. Your levelling print looks like the bed isn't level in all the corners, and is too far from the head in most, if not all, of them. The simplest thing to do is to just heat up the nozzle, autohome the z axis, and then manually move the head near to each of the 4 bed screws. Slip a sheet of paper between the nozzle and the bed, and adjust the screw tighter, until the paper can be slid easily back and forth without catching on the head. Then loosen the screw, until the nozzle just begins to catch on the paper. Then loosen the screw another 1/8 turn. Repeat in each corner. Make sure that the underside of each screw head ends up in contact with the bed when you're done. And also make sure that the washers on the springs aren't caught in the keyhole slots (I found it made a huge difference to add bigger washers under the bed).
5) It's possible (but not massively likely) that the bed really is bowed. But I'd follow the process in step 4 first. Then once all four are set, move the head to the middle, and see if you can just slip the paper back under the nozzle with the barest of downward presses on the bed.
6) You seem to be underextruding pretty much everywhere. This is what causes solid surfaces to not fill in properly. This can happen for a number of reasons, including:
a) Using a filament diameter that is less than the diameter stated in the slicer config
b) Printing too fast/thick for the temperature
c) Having your filament feed mechanism be improperly set up. You should have clear deep impressions in the filament as it passes into the bowden tube, but the plastic shouldn't be chewed up or deformed. You might want to try adjusting the tension on the feeder spring. The spring shouldn't be compressed all the way, nor should it be too loose.
d) incorrect steps-per-e setting
7) Slicers are far from perfect. Try different ones, and see what works best for different types of print.
8) Don't bother with the quickprint settings in Cura - go into the full user interface mode, so that you get a proper sense of all the settings that are available, and can begin to tweak things to improve things. The standard modes aren't bad for real-world prints, but are a bit crude for trying to evaluate difficult test prints.
9) Print real world things that you actually like and want - only worry about calibration and test pieces to the extent that they help you print real stuff better. Those test pieces are basically designed to fail at some point; don't worry too much that they do. The only problems that you need to solve are the ones that show up in real prints. :-)
10) Be sure and configure and use retraction. For PLA you will want a distance of 4.5mm, and a speed of around 30mm/s if you have built your own firmware recently, or 40mm/s if you are using the stock firmware from any of the recent Curas. (There is a bug in older firmwares which means that retraction speeds are broken. With fixed firmware you need a speed around 25-35. With the older ones you need a speed of about 40 (which is really 20)). IIRC, the standard profiles in Cura don't use retraction at all, and you seem to be getting a lot of stringing.
11) The reality is that plastic does shrink as it cools, so dimensions are going to be slightly off, and some warping may well occur. With any large, flat, solid pieces that are especially prone to curling, you can minimize the effect of that by wiping down the blue tape with isopropyl alcohol before you start printing. That will stick the base very solidly to the tape, and the tape to the bed. That can't totally avoid warping higher in the print, but it should keep the base firmly stuck.
So, some recommendations....
- Re-level the bed as described above
- Change to the full settings in Cura, and print at the mid-range settings I mentioned... get things sorted out at those settings before pushing the envelope by going faster/thinner.
- Check your filament diameter, and extruder tension to try to fix the under-extrusion issues.
- Focus on printing larger objects that you want to print for their own sake. Ultimately the art of 3D printing lies in figuring out how to adjust the settings to best print any given object. To do that, you need to build up experience printing stuff. Calibration prints can drive you nuts. :-)
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Do you have an ulticontroller? The behavior sounds a bit like the 'Pause at Height' plugin for Cura has been triggered. Have you been using that setting?
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You can just download a previous version of Cura, and run the install firmware option from that. The firmware hex files live inside the Cura application folder structure - you might want to find the hex files and copy them separately onto your hard disk somewhere, and that way you will always have them handy. Then you can just use the 'Install Custom Firmware' option in Cura, and point it at whichever hex file you want to load, if you want to go back to an older version that you have saved.
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That's really weird, variador. And pretty frustrating sounding. But the differences between the recent versions of the firmware shipped with Cura are not that great, and I'd be very surprised if they changed anything significantly about your printer. I suppose its possible that there might be a slightly different default setting in an earlier version of the firmware, and that is showing up some mechanical issue with the printer, but in general not a lot has changed recently.
I think it's also unlikely that firmware 'corruption' in and of itself would cause the printer to print out of alignment on the second layer... so far as the firmware is concerned, even the concept of layers is a bit meaningless - it just deals with individual axis movements, one set at a time. If any of them work (e.g., to print the first layer) then there's no particular reason that they all won't work, so far as the firmware is concerned.
If I had to guess, I'd say that you possibly experienced some skipped steps during a 'fast travel move' as the printer was moving into position to start the second layer. You might want to check your speed and acceleration settings, and perhaps lower the travel move speed a bit. It might be that the earlier firmware had lower maximum speeds compiled in, and that might have slowed the troublesome moves to the point that they were no longer causing problems.
I've never had problems uploading firmware to the printer, and I do it a lot. And I'm not aware of any reason why you shouldn't be able to move back and forth between versions at will. There's nothing that ties together Cura and particular firmware versions - Cura creates standard gcode, and the firmware understands it. Pretty much any version of Cura should talk to any version of the firmware.
It sounds more like some sort of USB issue - which could be on the printer end, but equally could be on the computer side, or perhaps the cable. I'd be inclined to try different ports and cable just to try and narrow that down. And I'd also be sure to power cycle the printer when switching between client programs, just to be sure that you're starting from a known-good state.
It's an odd problem, and it shouldn't be that hard to upload firmware and connect. Let us know if you're able to narrow down the problem any.
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It sounds like it may be, yes. I'd recommend opening a ticket with UM support. They can probably walk you through more testing, and/or adjusting the stepper driver current.
Solid parts
in UltiMaker Cura
Posted
The 'perimeter' is the outermost exposed lines of plastic that forms the surface of the print. This will be on the outside for sure, but may also be on the inside of your print, depending on your object. Eg, a cup which is modeled as an STL with a thin wall and a hollow space inside has one perimeter around the outside of the cup, and another around the inside of the cup.
If you specify a wall thickness that is a multiple of your nozzle size >=2 (e.g., a 0.8mm wall thickness, with a 0.4mm nozzle) then the extra passes that the head does around the boundary of the layer are 'loops'.
Once the perimeter and loops have been drawn, any other solid parts on the layer get filled in with diagonal hatching (solid infill). Cura has a problem where sometimes it doesn't fully fill in small spaces with diagonal hatching. This is called the 'thin wall' problem, and may be improved by just having a single perimeter (setting wall thickness = nozzle size).
You can also get gaps between the infill and and perimeter/loop due to backlash - caused by your belts being too loose, and causing the head to not quite travel as far as it needs to when changing direction at the end of the infill passes.
Posting photos will help us diagnose the problems better.