illuminarti
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Posts posted by illuminarti
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Doesn't the lack of springs cause problems during printing if there's any variation in extrusion amount, resulting in possible blobs of plastic that can catch the print head (e.g., on a z-scar)?
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Well since you're mostly interested in what happens on the sides, I'd recommend turning off the top and bottom in Cura, and just printing the sides. Perhaps print a single layer bottom if you need to for bed adhesion. But jsut the walls should stick well enough I think, especially if you do a couple of passes. (Although it might be worth comparing the effect of 1 v 2 passes to see if it affects the appearance).
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Bear in mind that if you're printing a 20mm-per-side cube at 100mm/s, then you're looking at less than 1 second per layer for a single-pass wall, or 1.6 seconds for a 2-pass wall. That's almost certainly too fast for the plastic to cool between layers, and so will introduce problems of its own.
Even reducing the speed by half (an risking reducing the ringing effects that you're testing for), the times will still be pretty short. You really need to print something that's large enough that the plastic can cool properly during the print, while still maintaining a reasonable print speed.
(These sort of layer time v. speed v. size issues are particularly challenging when you're testing 350mm/s printing as I have been recently :-) )
Cool I will try that on sunday (don't have time before) and will post photos of result here. I know you can modify the acceleration and jerk with the unticontroller but I don't know if doing mid-print works. 3 inches seems kinda big, I can already see ringing on the 20 mm cube from thingiverse.
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Lars - I think we both want the same thing - reliable, good quality prints. :-)
In my experience, the print head movement system is already better than the extrusion system can fully support. We print slower than we might otherwise do, because the print head can't provide enough plastic at the right temperature when it should, and provides too much when it shouldn't. It sounds like your new head design addresses at least some of that, and if you can sustain 15mm³/s then that's also a step forward, so yay! As you say, reworking the extruder drive mechanism is also going to be a big part of a long term solution.
I'm interested in understanding what prevents consistent printing at, say, 300mm/s, however, because as far as I can tell, even then it's not the mechanics of the print head movement but there do seem to be some extrusion/temperature related problems that crop up at those head movement speeds that aren't directly related to throughput volume per se. If we can solve them to enable high speed printing, I think that can only help improve quality even further at lower speeds.
There's another issue that you touched on earlier that I think is worthy of further exploration, too. You talked about circular perimeters being particularly poor, in terms of the quality of both finish and head movement. I also saw this in some 300mm/s+ print tests I was doing. In a lot of ways, circles are the hardest thing for the UM to print, because they require the largest number of very short segments, while also providing the lowest velocity change at each junction - allowing for more speed to be carried through each transition. So they require the most segments to be printed in the least amount of time. While that could tax the mechanics of the printer, I think that in practice it's taxing the firmware more than anything - and, indeed, overtaxing it.
I tried printing a 130mm diameter high-res cyclinder at 350mm/s. It basically worked, but the movement was slower than requested, and the movement wasn't very smooth. Looking at the resulting gcode, and doing the math, the end result was the printer was going to have to process about 130 line segments a second. So, about 0.008s per segment.
I think the problem here is that the firmware simply can't plan line segments that fast. When the buffer starts to empty, Marlin slows down segments to take at least 20ms to print. If the buffer gets completely empty, then it pauses momentarily until it can refill. I suspect that that when printing circles fast, we're seeing those slow downs and pauses, resulting in erratic movement.
I'm planning on adding some instrumentation to Marlin, to see how long segment planning takes, and try to figure out if there's a better way to manage the buffer to make it degrade more gracefully. Perhaps a larger buffer and/or longer delays would give better results - or a more intelligent process that gears the timing of a segment to how long segments are currently taking to process (I presume the time goes up the buffer fills, due to the need to scan the buffer to keep all the segment entry and exit speeds consistent).
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Yes, I think that more layers of solid overlay will smooth this out. I've seen this before sometimes. Interestingly, I think it's not that it's sagging into the infill, but bubbling up above it. My theory was that the infill is making relatively airtight chambers under the top surface, and the addition of new layers heats the air, causing it to expand, bubbling the surface up. That's why a slightly lower temp might also help - but mostly I'd go for more layers. I generally go for a top/bottom thickness that is at least 4 to 6 times the layer height.
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I think that there should be a very simple clear statement, in easy-to-read English that outlines the main points of the warranty, and the time frames involved, and explains how users can help themselves get the best out of (E.g., 'Check that you have the motors, electronics, and the right laser cut sheets, with no bits missing, as soon as possible'). It can refer to the online legalese for full details.
I think it should be included as a separate document, that is clearly marked as important and useful, and invites attention, however, not included 'on the back of' anything. Provided the warranties are reasonable and customer-friendly, there's no reason to hide them. Far better to get everyone on the same page, so there are no surprises. If they are unreasonable, then they need to be changed, not hidden.
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The shifting late on in the print is probably due to one or other of the pulleys becoming slightly loose. Make sure all the pulleys are tight - including the ones on the motor shafts.
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Delete the .cura folder in your home directory. It's hidden in the finder, so you'll need to use terminal for that too.
cd
rm -r .cura
Removing that, and trashing the application itself (and emptying the trash) should remove all traces, as far as I know.
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At what point in the process the bend happening? (And presumably you took this out when the Bowden tube was off the hot end - i can't imagine it would slide through the tube like this). It looks like the filament is softening well above the hot heater, and then when the tube comes off it is able to flop over to one side, putting the bend in?
Are you keeping the hot end heated, with filament in for extended periods, e.g., between prints? That can cause problems like this, by allowing heat to spread up the filament as it sits.
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Two weeks is too short for a kit like this, given that it could quite easily take someone more than two weeks to put together from date of receipt. Heck, mine sat in a box for well over a month because I was waiting for some time off to assemble it. Furthermore, it's far from trivial to even identify and understand what's in the box. Quite a lot of users end up with parts left over, and aren't sure what they're for or why. It doesn't seem impossible that the reverse would be true - that bits would be missing without realizing, at the very least until you get to the point of needing that part.
At the same time, some sort of limit is definitely reasonable. (Except in cases where UM knows verifiably that they definitely screwed up). A year does seem like its a bit excessive, and unlikely as a scenario.
However, given the complexity of the kit, and need for some sort of policy on it, it only seems fair and reasonable for Ultimaker to make everyone explicitly aware up front what the conditions are, and help/encourage them to do the right thing, via a note on the box, and a card inside. You might especially want to draw people's attention to checking for major/expensive parts inside such as electronics and motors. If a few screws are missing, its not the end of the world to supply those later on. At the end of the day, it's the right thing to do for the customers, and therefore for Ultimaker.
There's no shame in admitting the possibility of mistakes. Indeed, until y'all do, you can't begin to take steps to reduce the likelihood of them happening.
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There may be something about your particular Bowden tube, or how it is installed that's making it pop loose. Some people have had problems - some lots. Personally, I've never seen this happen on mine.
If the cabling to the thermocouple pops off, don't keep printing. Not only will you get bad results, but you'll quite possibly damage your print head.
Something is causing you to generate high pressures within the Bowden tube - which basically means you're pushing the filament harder and faster than it can escape out of your nozzle.
A few things to consider:
1) You might want to check how your feeder drive is assembled, and in particular what the tension is on the spring on the back of the filament clamp. It should be roughly 11mm long - the spring shouldn't be totally compressed. Part of the problem might be that you're grabbing the filament so hard that even when pressure gets quite high, it doesn't slip at the extruder end, but instead has to break something else.
2) Check your filament diameter. Is it comfortably less than 3mm throughout? When the extruder drive is open, can you slide fresh filament into the Bowden tube easily by hand, with virtually no resistance? If the filament is too thick, it will get stuck in the tube, and the extruder may keep pushing until it pulls the tube out.
3) What temperature, layer height, skin thickness, and print speed are you printing at? If you try to print too fast, the nozzle won't be able to keep up, and pressure will build up on the filament.
4) If you heat the print head, lower the bed a bit, and turn the extruder drive gear wheel by hand, what does it feel like? You should feel a little bit of push-back if you turn the edge of wheel more than one or two mm per second. But you should see continuous extrusion from the nozzle, and shouldn't feel a solid barrier. And you shouldn't be able to pop the Bowden tube off by hand.
Now that the tube has started to come loose, the ends are probably damaged, so you may want to trim the last few mm, and resecure them - perhaps with some additional sort of clamp. But it would be good to know what is causing the frequent pop-offs. I have no extra clamps on mine, and have never had it happen.
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What makes you think the head is catching on the layer below? Can you post photos, and/or video. They gcode would be good, also.
What print speed, temp and layer height are you using?
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So, can you post up a video of your printer pushing 30mm^3/s with a decent surface finish?
Even with thick 0.15mm layers, 250mm/s printing is only 15mm^3/s. I was able to hit that with perfectly fine extrusion, but circular perimeters were terrible. It looked like a control issue; uneven jerky speeds. When using slower perimeters on the new Cura, it underextrudes the infill.
Maybe we just print with different expectations.
No, precisely because I can't melt 30mm³/sec. That's two or three times what the standard print head/extruder can extrude.
Having a large nozzle makes it easier to sustain in the 15-25mm³/s range, but that's about as far as I can reliably go with PLA. With a 0.65mm nozzle, and 0.2mm layer height, that's about 170mm/s linear speed. I don't have to even get close to 250mm/s to start bumping into the limits.
Which was the point I was making in the first place.
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Firstly, welcome!
Secondly, oh no!!
Thirdly.... this thread has some info about possible difficulties with ABS leading to nozzle clogs due to heat traveling up the filament, and causing it to deform where it shouldn't...
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George - you don't get an 'attach' option? I can't embed pictures in a post unless I stick them in the gallery first, but I do get an 'attach files' option. Do you not get that? Perhaps its because I am a moderator and/or was a beta tester...
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If you click 'more reply options' to bottom right of the reply window at the bottom of the thread, then you should get a different editor that includes the option to attach files.
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I'm awaiting a shipment of the LayBrick Beta also, and am looking forward to testing with it. I'll have some spares available to sell (3mm and 1.75mm) if anyone in the US is interested in trying it out. Just let me know.
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... Illuminarti uses tissue paper wrapped around the filament held with tape to keep the filament clean as it is pulled into the feeder. I have a much cleaner room and rarely (but sometimes) have trouble with dust.
Actually, no, I don't :-) I think it was Ultinoob who I first saw propose that idea. Although it's not a bad idea. Depending on the supplier, new filament can pick up a bunch of dirt in manufacture and handling, let alone in the environment that you're using it.
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The gcode looks fine to me... the print actually starts changing layer at the back of the print, and that gradually curls around to the side nearest x=0 as it follows the shape. I don't see any back tracking or oddities in the path.
I have three thoughts about what might be going on:
1) Positioning error - perhaps you're seeing some backlash or other positioning errors that cause variability in the alignment of the head when printing the mostly-in-the-x-direction lines towards the back of the bed? Does the base of the print show any alignment problems, or gaps between infill and the perimeter? Is there any extra friction when moving the head by hand in the x direction in that part of the bed?
2) Cooling problems - maybe it really is a failure to cool in time, allied to the position of the print relative to the fan. I think its unlikely as your minimum print time should be good enough.
3) Layer change ooze... maybe the layer changes are happening a little slower than they might, due to the combination of x,y and z motion, and the fact that there are some odd defaults and bugs in Marlin that can slow these things down. if there's some oozing that then gets dragged into the next section, that might cause a mess - but as I look at the pictures, I think the messy printing is happening just before the layer change, not after it. So that may not be it either.
I'd check that the mechanics are ok. Maybe try printing a similar sized square, first aligned to the axes, and then at 45 degrees rotation around z, to see how those walls line up. That at least would rule out the effects of the slowly rotating layer start point as a potential source of problems.
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Post a gcode file so we can take a look at your settings. Also, are you sure that the extruder drive is correctly assembled and locked into place?
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I'm going to refer back to my last post. You are trying to cross a bridge we haven't arrived at yet.
Until you run into a situation where (at the speed you are after) the motion quality of the print head is acceptable, but you can't extrude fast enough, the solution to faster printing is either in the slicer program and/or the UM's control system.
I find that my more or less stock, but well tuned, printer can definitely gracefully support higher throughput than the hot end can deliver, and in comparing my results with others, it seems that both my mechanics and my throughput are representative of many other users. If the limiting factor for you is the printer mechanics, then I'd definitely try and figure out what's different about your printer.
Getting sufficiently fast extrusion is a problem that I deal with on a daily basis. In my experience helping users on here, and offline, I'd say it's the single largest problem that trips up new users and leads to blocked heads and stripped filament. With the wrong settings, you can very easily exceed the throughput capacity of a standard nozzle at very mediocre linear speeds.
As Joergen noted, while you might want to print perimeters at more modest linear speeds, you can certainly print loops and infill at very high linear speeds, and all of them at high volumetric throughput, in order to reduce print time without impacting finished print quality or strength.
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Great! I'm glad it turned out good :-) I think that in general, most of us stay dramatically inside the printer's performance envelope most of the time. It's easy to get hung up on folklore and misperceptions, that the only good print is one that is done at 0.04mm layers, 40mm/s, 40% infill, tons of support, etc etc etc. :-)
I'd be the first to caution that all prints are different, and some tricky ones really are going to need really cautious print settings - but in general I think that prints can go much faster than people think.
If I hear about someone spending 20, 30, 40 hours on a print, I'm almost certain that they could print it far faster than that without sacrificing any noticeable quality. The aim always needs to be to get satisfactory quality in the minimum amount of print time - too fast and you get crap, yes - but too slow can cause its own problems, and at the very least, just wastes a lot of time. Probably better to go faster, do a test print, and then tweak the settings based on what you see, to really nail it, than do one print that takes longer than both of those two put together, and still probably could be better if you'd used different settings in the first place.
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Lars, I'm sure that your changes have made several aspects of the print head operating envelope more tightly defined, and among other things, it probably helps to reduce hot-end nozzle blockages due to heat transfer. And those are all good things, and I'm grateful for all the work you've put in, to advance the state of knowledge.
My personal interest is in being able push the quality/time envelope in favor of reduced print times while maintaining or improving overall quality. And while that requires control etc, over heating, above all else it requires actually being able to heat the plastic quickly.
While very high temperatures, all things being equal, do lead to excessively runny uncontrollable PLA, that's only true if the PLA is actually reaching those temperatures. When printing high volumes - e.g., to print multiple layers of infill fast, if not to actually print the finished surface at high speeds/volumes (although that works ok for me too in many circumstances) - then the PLA doesn't actually reach those temperatures - which is the point/problem. Setting the heater excessively high and then relying on high throughput to keep the plastic workable doesn't seem like a good solution, because you inevitably get to slower bits, and the plastic gets hotter than you really want, and quality suffers. So, a solution that allows you to reach an equilibrium with the plastic actually getting to the target temperature before it is extruded seems like the ideal model to aim for. I'm not sure that a short melt zone, in and of itself, is helpful in that regard.
Having a short, responsive hot zone might be all well and good, if what it's responding to is the temperature of the extruded plastic. But if you're just measuring the temperature of the heating block assembly, and the PLA isn't having enough time to reach the temperature of the rest of the block, then you don't really get control over the temperature of the extruded plastic, and my sense is that you are probably restricting the speeds at which you can get attractive and reliable prints.
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That print was done at 230ºC, 95mm/s, with the fan on full from layer 2. I've heard of people getting good results with just two loops of a standard nozzle, and indeed yesterday I reprinted the figure with just one 0.65mm loop at 150mm/s and 0.045mm layers, and got pretty good, but not perfect results; some of the overhangs didn't print.
I think two loops would usually be enough for sure... you just need to experiment. Minimum layer time is going to be critical in ensuring that there's enough cooling - although I find that with 0.045 to 0.06mm layers, 2.5s is long enough for it to cool, since there's such a low volume of hot plastic being added on each pass.
Bad customer service, missing part and refuse to reship
in Buying or selling your UltiMaker
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Alexander - In this context, I wasn't exactly suggesting that the intention of putting the terms on the invoice was an attempt to hide them necessarily... just that I don't think its the most obvious place to put them. The point of being open and upfront with customers about this stuff is to take the initiative to engage them openly.
While it's not unheard of for them to be on invoices in the UK or US (the places I have experience of), it's again more likely to be legalese, or stuff directly related to returning a package. It might be a place people look for contact info if there's a problem but not for must-read advice and instructions. I also think that invoice/payment paperwork is more likely to get immediately filed away separately - especially in any kind of business environment.
So I would definitely recommend an attractive, eye catching sheet on the very top of the package (and maybe the bottom too, in case people open the box upside down!) that is clearly marked 'Important - Please read'.