lars86
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Posts posted by lars86
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I agree. The auto-regeneration makes the interface incredibly tedious.
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My biggest problem I need to resolve is I get a lot of quality issues from ringing. Even though all the belts are tight I just don't seem to be able to get rid of it unless printing really slow. Maybe direct drive will be my next mod.
Keep up the good work.
What are your max XY acceleration and jerk settings?
I have also had good luck supergluing a heavy steel weight to the front underside of the bed. I think the bed is more prone to ringing than the head, and this helps.
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Good question! I'd love to hear some opinions too.
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I just wanted to thank Markus again for organizing this pulley order, and Joergen for handling the US shipment. I haven't installed them just yet, but the quality and runout (lack of) are top notch!
Cheers!
Lars
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All I'm saying is that even though a dead center isn't perfect on a lathe, it is certainly more effective than just slamming a wooden block against the end of your workpiece - which is equivalent to the stock endcap solution of an Ultimaker.
The solution is to print end caps, and use m3 bolts to locate the shafts axially. No preload, no cutting tapered holes into the shafts. It's far more simple than you are trying to make it. Just concede.
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I'm not convinced by this argument - 1) though not as great as a live center, a dead center works fine on a lathe for most operations and I see no reason it wouldn't improve things here, and 2) If the bearings are adequately aligned by the laser-cut frame, I see no reason that the endcaps couldn't also be adequately aligned, particularly if they are a 3D printed part with a tighter fit than the laser cut caps.
This is definitely something I would do if I had easy access to a metal lathe. It's unclear if Daniel meant drilling an actual hole, or just an V- shaped indentation with the tip of a drillbit. Obviously a full hole won't work so well, but I think a V-profiled cut with an angle wider than the bevel angle of the pointed cap screw could only be an improvement.
Your argument doesn't make sense to me.
You claim "a dead center works fine on a lathe for most operations", like it proves that a dead center is better in this specific case we are looking at. The reason a dead center "works fine", is because a lathe has a torquey drive motor that can overcome the dead center's parasitic friction. We are trying to remove all possible friction throughout the carriage drive assembly, in search of better quality of motion. The bearings that the shafts ride on are not only low friction, but locate the rods well in the normal plane. Adding a dead center on top of them adds unnecessary friction, and can offer no help in the already located rods. At best, it can mirror the location, and at worst it could try to constrain the rods with a slight shift, inducing bind. Yes the cap mounting holes are laser cut, but an M3 bolt's fit in these holes is nowhere near the fit between the bearing and case (by design).
Take it as you will. I'm just a mechanical engineer that designs and programs machining strategies for a high-tech manufacturing firm (big CNC mill-turn rigs)... what do I know, hahaha
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I would not use the cap screws in an attempt to locate the rods. That's great on a lathe, when the live centers are perfectly coaxial, and supported by bearings. In this case, the screws are located by the end caps which can shift relative to the rod axis, and are fixed from turning. The rod bearings are located nicely by the laser cut frame. You stand to gain nothing, but could induce extra friction/bind.
On mine, I have printed end caps, with pointed screws. I run them set for just a slight bit of lash (no preload), and it is a great combo of low friction and good location.
I received my pulleys earlier this week and will try to install them today together with fresh belts (they are spare parts from UM; my current ones are two years old and a bit worn) and a new Thermocouple board also from UM (my old one is a bit off in temperature).
My question to those of you who has already upgraded to the new pulleys:
- How long time did it take and exactly whats steps are needed to do this?
I would guess that parts of the steps on the Ultimaker wiki assembly pages would need to be followed in reverse, but I also suspect that it might not be as simple as that?
I have an older (about two years) Ultimaker with the 8mm rods for the XY head cross, but I guess that doesn't really affect the pulley upgrade?
I'm also thinking about making (with my lathe) a small centering hole on the end of each steel rods, so that you could mount a modified screw in through the rod caps like described in the comments to this:
http://www.thingiverse.com/thing:54075
This way it would act like "turning between centers" in a metal lathe setup.
However, I'm not sure if it's worth all the work that this would entail, what do you think??
Cheers,
Daniel
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I was hoping that Daid would have some feedback.
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Thanks for the update Daid!
The triangle infill idea sounds cool. What if it laid down one set of parallel lines, followed by a set at 60* to those, then third third set. Whenever the print head gets to an intersection point (2nd and 3rd sets), it does a very short rapid across it to prevent an overextruded blob.
Thoughts so far on 13.05.1:
Outside quality is looking good
The new grid infill pattern end up being only a pattern of very narrow, free standing columns, where the lines cross. Works great as a low density inner support. But it is not a strong form.
In some areas of the print, it infill behavior is strange. It stays very near the perimeter and essentially vibrates. This causes the head to dwell too long near thin overhangs, heating them up. I think it is trying to produce an area of 100% infill, underneath a soon to be exposed layer. It just seems like adding more perimeter passes would accomplish this without so much dwell time and vibration.
https://dl.dropboxusercontent.com/u/60958586/VIDEO0052.avi
??
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The other option is to switch 2 flags in the marlin firmware
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Thoughts so far on 13.05.1:
Outside quality is looking good
The new grid infill pattern end up being only a pattern of very narrow, free standing columns, where the lines cross. Works great as a low density inner support. But it is not a strong form.
In some areas of the print, it infill behavior is strange. It stays very near the perimeter and essentially vibrates. This causes the head to dwell too long near thin overhangs, heating them up. I think it is trying to produce an area of 100% infill, underneath a soon to be exposed layer. It just seems like adding more perimeter passes would accomplish this without so much dwell time and vibration.
https://dl.dropboxusercontent.com/u/60958586/VIDEO0052.avi
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I've uploaded an 13.05.1 to http://software.ultimaker.com/Cura_closed_beta/
This fixes the SD card copy problem on MacOS. Puts the 'combing' paths more inside the model, removing the outside scaring of models. Removes one more problem with odd order of doing infill lines. Add the overhang view again. Solves the problem with the "spool part x3". Adds a 500ms delay before starting slicing so you don't see 10 restarts when changing settings (this was already intended and implemented, but the delay was wrong in 1ms instead of 500ms)
Fixed the GCode preview to look pretty again (rounded corners)
I've also looked at making triangle infills instead of square infills, which in theory would be stronger. But I haven't got the results I want yet.
Thanks for the update Daid!
The triangle infill idea sounds cool. What if it laid down one set of parallel lines, followed by a set at 60* to those, then third third set. Whenever the print head gets to an intersection point (2nd and 3rd sets), it does a very short rapid across it to prevent an overextruded blob.
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Looks good Dojan. you might check out my development work in the Google group:
https://groups.google.com/forum/#!topic/ultimaker/JJuCfGdg6M0[251-275-false]
https://groups.google.com/forum/#!topic/ultimaker/zdPsd-tfB54
At the moment, I am running a V2 hotend, with a stainless steel uptube (identical to stock brass). I welded up the hole in the aluminum plate and drilled/tapped for M6. The stainless tube is threaded directly into the plate with thermal grease, providing a more rigid mount, and turning the plate into a heat spreader. I've reversed the fan flow and ducted it to blow air across the plate and tube. I have the whole heater block/nozzle insulated with a few layers of alumina tape and capped with aluminum foil. It works great!
The next step is to replace the whole print head with a printed part I designed, and attach a proper heatsink to my stainless tube.
My suggestions:
- [*]Find a way to ditch the plastic parts all together. If you properly cool the stainless tube, you will be better off leaving some of the tube (near the top) exposed to further cool. I simply tapered the stainless tube, and countersunk the inside of the bowden tube to join them. Once that junction is well below the glass transition temp, it is not prone to plugging issues. I've run mine with the bowden tube separated from the stainless by 0.5", with the filament open air in between.
- [*]Bring the inside of the stainless tube to a nice polished surface
- [*]Go with aluminum for the heater/nozzle combo. I've crunched the numbers and see no reason at all to use brass. With that assembly well insulated, the heat loss into filament is something like 5W. The heat capacity you gain with brass is useless in my eyes, and you sacrifice thermal conductivity which IS usefull to us here.
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I will have a proper heatsink on there soon... for now I welded up the hole in the aluminum plate, replaced the brass up tube with stainless steel, and threaded it into the aluminum plate with thermal grease. I reversed the fan direction and ducted it to blow air across the plate. It works very well. I've run temps up to 240* with retracts, and still no plugging.
I'm not so sure that it will work as well with the brass though, as it is much more thermally conductive. With the stock V2 hot end, the whole thing is a melt zone, including the brass up-tube. If you try to actively cool it, I'd guess you will just end up with a large transition-zone (not fully melted or solid), and a bunch of extra friction.
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Thanks Markus!
Come on US guys, pay the man! I vote that the US order goes out Friday with or without em. Ya snooze, and ya pay separate shipping.
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For cutting stuff like this, it's hard to beat a composite blade. Bang for your buck --> 4.5" angle grinder with a composite blade.
I'm halfway through this conversion... one of the 2 shafts I ordered has too much runout. Luckily, I ordered through Amazon, so they are overnighting me a replacement. Between this and replacing all the pulleys with higher quality ones, this thing is gonna be smooth!
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I have never tried the 2nd coupler style, and have no experince of it.
Sorry, however it looks like is a bit better at giving vibration isolated coupling..perhaps it might
reduce the noise a bit. But I cannot make out from the pics if its a real bona-fide "zero backlash" coupling
or a not. The ones with the plastic rings and 4 little "bulbs" are really good for allowing for
misalignemnt and play of all kinds, but also pretty skeptical about their angular timing prescision.
I always liked the 1st style just because its always used on engine throttles, which have to maintain
perfect angular alignment. But no idea...perhaps the 2nd one is also good....
C.
Cool, thanks. I went with the spiral cut versions.
I've got an MK7 drive gear on the way too for a full, over the top extruder drive redesign.
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Im sure it probably "works", but I would still suggest its well worth doing another couple of hours
of "googleing" to find a pinchclamp design. The grub will put alot of eccentricity into the coupling
and its not designed to accomodate that - only angular misalignment.
Im just being a typical moaning engineer, so take that into account as well. But since the whole point
of this modification is to get the best possible performance from the drive system it seems
a shame to compromise one of the most important parts of it....
Im sorry I dont have good info on USA sources for this kind of stuff....
C.
https://www.tindie.com/products/diyourfaceoff/cnc-5x8mm-motor-shaft-coupler-5mm-to-8mm/
http://www.amazon.com/5x8mm-Coupler-Flexible-Couplings-26x26mm/dp/B00A2FVGVU
GOOGLE> "5x8mm flexible shaft coupling"
Thanks for the input Grouch. No deaf ears here... I'm an ME and CNC machinist. Eccentricity aggravates the hell out of me! hahaha. I'm pretty psyched to get X and Y direct driven, and sporting those upgraded pulleys!
I think that I'll design an anti-backlash Z nut to keep the platform repeatability up. My experiments of attaching weights to the underside of the platform and using rubber bands to preload it to the side have gone really well. I think a third linear bearing at the front would do really well. I'd wager a lot of the "ringing" that people see, is in the bed, not the head.
Between these two styles, do you have any input?
http://www.amazon.com/5x8mm-Coupler-Flexible-Couplings-26x35mm/dp/B00A1YT1ZU
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The original ebay link for the couplers has expired. Would these be a good option, or is there a better retention mechanism?
http://www.adafruit.com/products/1176
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I'm going to try switching over to the double-herring bone drive gears.
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Hahahahaha, okay problem solved.
I found the small extruder drive gear laying on my workbench! It was spit off right where my print halted, so neither Cura or the Ulticontroller are to blame!
I measured the print, deleted all layers before that height and it looks like it should finish up nicely.
Feel free to delete this thread since it doesn't really have anything to do with Cura
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With Cura 13.04, I had a strange issue. My print stopped a few mm short of completion and I can't explain it. I wasn't by the printer when it happened, but since the UC displayed the print time and the head was home, I think a power failure or sd card issue can be ruled out.
The layers look perfect inside of Cura:
But here is the print:
Any ideas?
I'd like to try salvaging this print by truncating the completed gcode and re-running it. The gcode file actually looks complete, so in hindsight, I guess this was a failure of the machine, not Cura.
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I would love to see separate velocity and acceleration overrides for perimeter vs infill moves.
Also, an extrusion rate multiplier for infill would be awesome.
The ability to chose the order of the perimeter/loops (ie inside to out, vice versa)
On the more "out there" side of things, I had an idea last night to try to mitigate the staircase effect on very shallow part angles. During slicing, you could assign a slope to each perimeter layer (based off the XY shift from the previous). If that slope was below a threshold, Cura could micro step the Z height for each perimeter pass. Example: layer height = 0.15; printing with 3 perimeter passes; Cura bumps the Z up 0.15 / 3 = 0.05 for the outer pass, 0.10 for the second, and finally hits the 0.15 layer height on the third. This would be for the supported case, as opposed to an overhang.
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I think the set of 8 will do it for me. I plan on converting to direct drive soon.
Lars
Looking for beta testers.
in UltiMaker Cura
Posted
I am using 13.05.2
The code it generated is really pretty nice in support and print quality.
I just don't see the upshot to using this auto-regen. Almost every time, I am making multiple changes to settings and it slows me way down. I do not see clicking a button when I'm ready to be a bad thing at all.