illuminarti
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Posts posted by illuminarti
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It looks like your head position is slipping - depending on the orientation of how you printed that, probably in the Y direction. Check that the pulleys for that axis are all secured tightly, including the one on the motor shaft.
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For the longest time I never had any hot end plugs, then after a few months I started to get them - not sure if it was due to wear in the hot end/bowden, or was when I started using new filaments with, perhaps, different properties. But the combination of the v2 hotend and the new extruder upgrade (and v3 extruder bolt) have pretty much totally eliminated them. The new bolt with better teeth, and the spring loaded pressure plate help to ensure consistent feeding of the filament without too much deformation, even if the filament diameter changes a little.
I like the Owen's Fan Duct (
http://www.thingiverse.com/thing:32491
) - or his earlier version perhaps if you don't upgrade to the v2 hotend. I started to go with the fan duct you printed, but I saw some suggestions online that it might not be the most effective design a) because it gets in the way of cleaning/maintaining the head and b) the output opening is too small relative to the fan input - the stock fan design can't really generate much pressure (as I understand it) so having a small output opening is counter productive.
After about half a year of letting my Ultimaker collect dust, I decided to revive it to do some projects that I've been wanting to do for a while now. I was of course very excited to see how much Cura has been improved (thanks Daid!), but I'm also wondering about the hardware changes. Can anybody give advice on what to-
[*:1zwgsdzx]Fan duct - I replaced the standard fan duct with a fan from thingiverse (
[*:1zwgsdzx]Hotend v2 - I never had any plugs at all, so I wonder whether this upgrade has any added value (does it make a difference for retraction?).
[*:1zwgsdzx]Extruder drive v2 - looks worth the investment... As far as print quality goes, is this doing more than simply adding the Quick Connect Shim?Any other things that I missed? Cheap/easy heated beds?
Thanks!
still confused about the status of this 'official' forum versus the google groups (which is where most of the officials hang out?) btw!
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Have you tried different models? I had this happen with some stl files before now, although in general it works fine. If its just certain ones, then perhaps trying to repair the stl file in Netfabb might help?
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I think the correct syntax is M92 E865.888 - the M92 command allows you to specify values for any of X, Y, Z and E. Without the E specified, the value just gets ignored.
The code I have been using is:
M92 865.888
G91
G1 E100 F300
G90
I was changing the M92 xxx.xxx to adjust E steps per mm.
BTW, there has been a discussion over on the Google group (
https://groups.google.com/d/topic/ultim ... discussion
), that the current correct value for the steps-per-e (assuming a Bertho (spring) extruder tensioner and a v3 bolt, is somewhere round about 832.
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I don't usually use Cura to print any more - I use an ulticontroller and print from SD card. So, I'm not entirely sure about Cura's print interface. But in testing just now, it does seem that when I load a model, Cura loads and can display the associated gcode file. And so should then be able to print it...
I would assume though, that the gcode file has to still be in the same directory, and have the same file name as the model (apart from the extension), in order for Cura to know which it is.
Perhaps you could post some screen shots showing what you are clicking and/or seeing on screen, so that we can better guide you.
Also, once Cura has created it, the gcode file is a totally separate thing that you can then use with other programs. Cura is a pretty good slicer in most cases, for preparing the gcode files - but once you have that you could use another program such as printrun, Repetier Host, etc to transfer the files to the printer.
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Yes... the extruder bolt will chew into the pla if it keeps turning and, for whatever reason, the filament doesn't move. This could be due to blockage at the hot end, or something about the extruder drive mechanics. PLA is pretty soft really... I'd be interested to see this damage to the wood of the extruder mechanism.
Removing the nozzle is pretty straightforward - it's just screwed into place. You just need to be sure to heat it up to soften any plastic in it or on its threads. And then unscrew the nozzle carefully. It's just a metal tube with a hole in the end, so its fairly simple to remove and replace. I'd be inclined to heat it up to 250º or 260º to try and flush through any PLA before you start, and then once you take it off you will be able to so whether there is anything blocking the nozzle chamber.
Right.i will be posting pictures later.
The extruder cross hatched sectionis chewing the PLA.
The chewed PLA has worn down the extruder housing causing LUMPS of the wood to break off.
I can only assume a lump of wood has traveled down into the nozzle because at 260* i have struggling to force the PLA through manually.
This is my mind is a design flaw for the material used for the extruder.
how easy is it to remove the nozzle and clean it out?
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Sorry to hear about your problems... Here's a few things to check:
1) it could be a problem at the hot end that is making the extruder work too hard. What temperature are you printing at? When grinding occurs, can you manually push the filament through the tube fairly easily?
2) have you checked the diameter of your filament? Does it slide trough the tube easily when pushed by hand.
3) could you post some photos of your extruder, open and closed so folks can see if anything looks wrong?
After all that if you're still interested in selling, I might be interested... :-)
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Arch1tect - I'd definitely check that your belts are tight, and also that all the pulleys are done up tightly, and aren't slipping. As Daid noted - when the printer is powered off, can you move the head in x and y directions fairly easily, by pressing gently on the sliding blocks?
The video was a bit hard to see the detailed print quality, but I noticed that even the base layers where it was printing 'right' looked rather scrappy, and the left and right extremities of your object were getting turned into flats (I presume they are supposed to be curved). That also sounds like it could be a belt tightness issue to me.
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Here are some thoughts, based on my experiences with an Ultimaker for the 6 months or so....
- I am adjusting the platform to a point where I can slide a piece of paper between the nozzle and the blue tape with a little resistance by pulling with two fingers, is this right?That's basically what I do - put the head near the screw, and then tighten the screw until the paper slides freely. Then loosen the screw until the head just starts to catch on the paper. Then I loosen the screw a further 1/8 turn to compensate for hte thickness of the paper. Then move on and repeat at each corner, before repeating at least the first one again, to make sure that everything is still right. Make sure that the screws are in a 'middle' position so that there is still play in the springs, while keeping the screwhead in contact with the bed when the bed is at rest. Also, remember to preheat the head before leveling, so that any thermal expansion is accounted for, and any plastic on the head is softened so that it doesn't get in the way.
- When you guys say the printers is overextruding or underextruding, how do I change that? should I use the flow control in the tune menu of the ulticontrollerIf everything is set up right, then the extrusion should, by definition be perfect. Large variations in extrusion amount are typically due to either filament grinding or head blockages (causing major under extrusion) or big variations in filament diameter (causing under or over-extrusion). Cura calculates the amount of plastic needed for each head move, in terms of the length of raw filament needing to be fed in. So make sure that you have calibrated your steps-per-e setting correctly (so that the machine gets the length of filament it is asking for) and also measure your filament, and make sure that you set the diameter correctly in Cura (so that each mm of filament fed in is providing the total volume of plastic that Cura is expecting).
If your filament is highly variable in diameter, then you are going to get poor and erratic results - and some filaments can even be so far off spec that they are fat enough to block the bowden tube. So always go with good quality, consistent diameter filament. Once you have things calibrated correctly, then you can use the flow setting on the controller to adjust the amount of plastic requested in percentage terms, to adjsut for differences between filaments, or the specific needs of each print.
Note: make sure that you have a recent firmware that displays the flow adjustment in percent - defaulting to 100%. Older firmwares (before about December 2012?) had the display and adjustment screwed up, and displayed a number around 240-something as the default, iirc. That was harder to work with, so I recommend getting newer firmware. The ulticontroller display and functionality is also better in newer ones.
- Temperature for PLA (supplied by Ultimaker: I am using 210ºC, What are the advantages/disadvantages of going hotter or colder?
PLA can typically be printed between about 180 and 240 degrees or thereabouts. I typically print at 220 or 230. The higher the temp, the higher the gloss on the finished print, and the easier the plastic flows. This can allow for faster printing, but may come at the expense of blobbing and poorer overhangs if the plastic is too liquid to be controlled adequately in less forgiving situations.
Try printing the same piece at different temperatures, and see what works for you. Exact behavior can vary between colors and manufacturers, depending on the underlying plastic blends and additives and their effect on the plasticity of the material.
- Should I print the first layer of large flat objects warmer (220?) to help avoiding warping?I often find that it helps to print the first layer warmer (esp when using a slicer like Kisslicer that easily supports a hotter first layer temp). Mostly I avoid warping by printing hotter onto a single layer of blue tape that has been wiped down with isopropyl alcohol before printing. (I prefer 6" wide tape for ease of application, and to minimize seams that mark prints and provide an easy edge to start to pull off the bed). I generally turn the fan on as late as possible (if at all) when printing large/flat items that I expect to have warping problems.
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"Enable Retraction": should this option alway be used in Cura for good quality without stringing?Yes, pretty much. Although if you have small fiddly prints you might want to turn it off or reduce the amount to avoid the risk of filament grinding from all the back-and-forth.
- "Wall thickness": this just affects the strength of the print, right?Basically. This sets the target solid 'shell' amount on the outside of each layer. You want to make your wall thickness an exact multiple of the nozzle width (0.4mm by default) to make sure that you get an exact number of solid loops of plastic making up the outer wall. I typically use 0.4 for small fiddly parts, 0.8 for larger prints.
- "Bottom/Top thickness" : does this affect the smoothness of the first and last layer, or just the strength of the print? what is a good value?This is like the wall thickness, but for the bottom and top of the print. It should be an exact multiple of the layer height. A higher value will cause more solid layers to be put on the bottom and top of the print, which can help give a better finished surface on the outside (as it means more layers to fill in any little gaps or overhangs).
- "Initial layer thickness": what's the difference between the initial layer and the bottom layer? or is it the same? does this value override the "Bottom/Top thickness"? What's a good value?This is the height of the very first layer that prints. If you are printing with, say, a 0.1mm layer height, then the first layer will also try to print at that height, assuming that your initial layer thickness is set to 0. Having a thicker first layer will give more plastic for good adhesion, and also to overcome any slight variability in the flatness or leveling of the bed. I often use a first layer height of 0.2 or even 0.3mm if I have any concerns about a piece staying stuck.
- Any tips for smooth base and top finish?A thicker bottom/top will give more layers of solid print to even out any defects. Correctly calibrating the flow and filament diameter will ensure sufficient plastic to give a smooth layer. Printing hotter will probably also help with the flow and gloss of the top and bottom layers.
A heated bed is the best way to get a smooth bottom, as you can then print directly on glass/polyimide tape without the blue tape. This will give a mirror-like smooth finish on the bottom. For relatively flat parts I successfully print PLA directly onto a polyimide-covered bed even without a heater.
- When should I turn on the fan? Is its good or bad regarding warping? should I print the first layer without fan and the turn it on? which speed by Ulticontroler?Having the fan running all the time can cause excessive cooling, and so lead to warping. I generally avoid using the fan at all if I can when printing larger parts. Kisslicer has the option to turn the fan on only for the loops and perimeters (the outer shell) and off for the infill - I find this helps with warping also. Having the fan on whilst printing the outside surface can help improve print quality, especially on overhangs and bridges.
In cura you can set the height at which the fan turns on. If I'm going to be using the fan, I usually have it turn on a few mm into the print. And I just run it at full speed - I'm not convinced that lower speeds are useful. When you want it on, you generally want it as much as possible. And when you don't you just want it off.
Calibrated steps/mm and filament diameter set correctly causes Ultimaker to over-extrude.
in UltiMaker 3D printers
Posted
When you calibrate the steps per e in Repetier, does that store the value in the controller's memory? Or do you have to set it every time in your gcode. (And if you are then slicing with Cura, have you also set the correct steps-per-e value in Cura's preferences).
If we assume that the steps-per-e is correct, and the filament diameter is correct, then the only other variable on the input side would be the extrusion multiplier/packing density. That should be at 1, or very close. If it is, then by definition (and your verification that a 100mm extrusion command moves the filament 100mm, and the filament really is the diameter it says), then amount of plastic being fed into the system is 'correct'.
So that leaves the Bowden and the output end of things as the problem...
Even with the 15% over-extrusion you calculate, it surprises me that things are failing quite as catastrophically as you mentioned merely as a result of that. I could see prints maybe being a bit blobby with that much over-extrusion, but I wouldn't expect it would be too hard for the excess plastic to ooze out of the way, unless maybe you're printing something large and solid. What material are you printing, and at what temp?
Incidentally, this doesn't really explain the over extrusion/scraping aspect, but it sounds like you're putting a lot of pressure on the feeder end of things... when you talk about shearing off the filament, do you mean that it's snapping the filament? Filament is typically pretty soft, and i could see it slipping or chewing up the filament.. but shearing it off seems a bit unlikely in the normal course of things. In some ways, I think that slipping/grinding is a preferable failure mode to something that is going to put enough pressure into your feed system to shear the filament or pop a well-secured Bowden tube. This makes me think that the pressure plate on the feeder mechanism must be very tight - in which case it is probably deforming the filament pretty severely - is that enough to cause it to get stuck in the tube, or at the point where it enters the head? When you aren't having catastrophic problems, what does the filament in the tube look like? It should have some teeth marks from your bolt, but still be basically round, and not chewed up, flat-spotted, etc.
The other thing to consider is the physical capability of the head. What speed are you printing at, and what layer height. The standard 0.4mm nozzle is limited to depositing about 10 cubic mm per second... which corresponds to 125mm/s at 0.2mm layers. If you try to go faster than that volume per second, then you will get a pressure build up that can cause clogs, and in turn pop the Bowden. This could happen at lower speeds too, if the nozzle is partially blocked. But none of that wouldn't really explain your 'scraping' scenario.
So, next I'd verify that the bed is properly level, and homed? If the home position is off, so that the head is jammed down into the bed when you start printing, then that's going to cause scraping of course, and make it hard for even the right amount of plastic to escape.
Finally, is there a problem with the x/y or - most likely Z - calibration or mechanism? In particular, is the problem really that you are over-extruding, or could it be that the extrusion is right, and the head isn't moving as much as it should on each layer change, so that it drags through what it just extruded, rather than making full space for the next layer? Have you tried moving the bed up and down a set distance at the move speed you have set in your slicer, to confirm that it moves reliably? While you're at it, have you checked that your X and Y dimensions are coming out correct?
Finally, if it really is the over-extrusion that is causing the problems, you might want to look at the gcode to see if you're getting sensible values in there. Look to see what steps-per-e value is set in the start of the gcode (M92 Ennn). Also try slicing a simple shape like a 100 x 100 x 10mm block, and a) see if it prints ok, and b) look at the gcode for each of the edges of the block, and see if the amount of plastic being fed in matches what you would expect given your filament diameter.