Dim3nsioneer
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Posts posted by Dim3nsioneer
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Looks to me as you would have to improve some Slic3r settings.
Illuminarti wrote a very nice blog about this topic: http://www.extrudable.me/2013/11/03/slic3r-strange-defaults-causing-qu-bd-woes/
Hope this helps you solve the issue!
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I remember someone from Ultimaker (I can't remember if it was Daid or Sander) having written here in the forum that if they bring a heated bed for the UM Original it has to be an upgrade kit with parts that extend or even replace existing parts. So they have to design new parts, manufacture them and test them. This takes some time.
When I asked Ultimaker support about the time of the release (last autumn) they told me second quarter of this year. I could imagine there is even a delay as they were quite busy with improving the UM2.
Of course there is an alternative for impatient people (like me... :wink: ): Build your own heated bed...
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Another possibility to drive a UM1 into the wrong z direction during homing is a customized firmware (self compiled or downloaded from marlinbuilder.robotfuzz.com) with the wrong settings at 'invert z axis'. Forget it if you have the default firmware installed.
EDIT: My last phrase was maybe misleading. The meaning was: If the default firmware is present then there should not be a problem with the firmware. In this case, nothing has to be changed.
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Chopmeister is right about Misumi not delivering to individuals. Fortunately there are ways around that restriction. However, they also claim not to sell to resellers which might make things complicated.
And thank you also from my side, mastory!
@JonnyBischof: I saw the GT2 belts and pulleys as well. :smile: However, the smallest pulley has 20mm diameter which is 3mm more than the original Ultimaker pulleys. :eek: But maybe it will work. Btw: I haven't heard anything from two of the three companies I asked for offering precision rods. The third company just sent me an offering but their axis deviation can be up to 0.3mm per meter.
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Don't these feelers cost a fortune?
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No, just about 2 Swiss Francs per piece. E.g. here. Nothing compared to a spare nozzle from Ultimaker for €15. :wink:
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To be a special case is not necessarily a bad thing... :wink:
A relatively easy way to test it might be to slice it with Slic3r which allows for a different outermost perimeter speed if I remember correctly. Setting a very conservative value for the perimeter speed might be close to the effect the suggested extension might have.
Personally, I like that outermost layer speed feature of Slic3r. It gives the print a very nice and smooth look without slowing down the print too much. Maybe a minimum perimeter time would lead to a similar effect?
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How did you measure your banana rod error?
The only thing I can do is roll it on the table which will probably tell me more about the flatness of the table than the straightness of the rod..
First estimation was exactly that way on a work bench and a table at different locations. That was actually sufficient to see it is a banana. In addition I compared it with the original rods from Ultimaker (of which one also had a very slight bend, but not as much it has to be called after a fruit...)
But for the real measurement I put the rod into the Ultimaker through the sliding block and put an indicating caliper gauge on top of the sliding block while turning the rod and looking for the highest and the lowest point. It's certainly not precise up to the micrometer but it gives an idea in which range (below or above 0.1mm) the deviation is.
Another idea might be to put the rod on a very flat surface (such as the Basalt bed from QU-BD which I think is quite familiar to you) and to check with feelers how large the maximum gap is.
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It might work if you buy it from Conrad. But you have to cut it. With the cutting you might deform the rod and it will not fit anymore into the bearings.
Another important factor is the maximum deviation of the axis. Precision rods have something like 0.05mm which is fine. Standard rods, even with h6 toleranz have higher deviations. The company I bought my 'banana' from (@JonnyBischof: die waren von Pestalozzi in Dietikon) told me afterwards that the axis can deviate up to 1mm per meter. I had a deviation of 0.4mm in one of the rods which is not suitable for such a fine machine like an Ultimaker (imagine your print head going up and down by several tenths of mm). If no maximum axis deviation is specified I guess you have to accept such a banana. But maybe other people are luckier than I am usually... :wacko:
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I'd be happy to hear about any kind of instructions / installation material about direct drive! I'll definetly do direct drive, but haven't decided yet which solution to use. As this will be an external mod, there is one more challenge to it: I don't want it to ruin the clean appearance of the UM, so style also matters here! Nick Foley's approach is very appealing.
If you put design as first priority you probably shouldn't realise Calum's approach or any derivative... they definitively put function over design. But at least for me it works fine (well, 50% of it...I'm still waiting for some offerings of straight rods).
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I agree, but I've seen people simply just dip the bolt into blue loctite and then insert; you don't need much. The extra step adds a few seconds which at most would accumulate to a couple of minutes of additional built time in an ideal situation. I thinks it's kind of a grey area as to whether or not it is financially worth it in the long run to deal with the few who have problems as a function of loose bolts and set screws or to add a few extra minutes to each build.
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I agree with you. It's a trade-off between assembly costs and service costs. Another reason to apply it could be safety (some parts don't do any good if they get loose...).
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Just updated the Wiki page of the 'Tweak At Z' plugin with details about V2.0 and V3.0.1, especially links to all additional versions.
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In professional assembling one usually avoids using loctite due to the time it takes to apply it. It means additional assembly time which results in a higher price of the product.
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Hmm...the term I would use for such a relationship between PLA and the brass nozzle is rather adhesion, not cohesion. To my experience, a piece of PLA melts easily on the outside of the nozzle and distributes over the surface, i.e. shows classic adhesion. This is quite nasty if you print one color and still have some other color sticking on the nozzle. Then it begins slowly to crawl down and suddenly you have a spot in your print.
If there is such an effect as you describe it, then it should become better with an underextrusion or just smaller extrusion. I think to remember that this didn't change anything? Something else which should work against such an effect is to raise temperature as the PLA then becomes more fluid and less sticky (it certainly takes less time to get the PLA above glass temperature on nozzle contact). However, to my personal experience the curling effect becomes worse with higher temperatures.
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just doubled the value: the first time sitting and waiting for priming, the second time waiting for retraction.
of course... :rolleyes:
I didn't see the forest, there were too many trees... :wink:
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at 50 mm/s it's approx. 0,3 sec sitting, waiting and cooking the part and 0,3 sec printing ...
The 0.3s idle time seems quite long, but not impossible. Assuming you have to move the filament by the usual 4.5mm with 30mm/s, a quite conservative value, you would just need half of that time. Acceleration is set to 3000mm/s^2 on my Ultimaker, I think, so it takes 0.01s to reach the 30mm/s. So total time needed for priming might be something like 0.16s taking the distance driven during acceleration and deceleration into account. Is that compatible with whatever method you used to determine the approx. 0.3s? If not, where is the additional time lost?
Some things I rather like not to have 'al dente', e.g. already printed PLA... :shock:
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I think you might run into trouble with the exactness of the rod positioning if you weaken their mechanical support (meaning the mounting of the bearings). The standard solution with the bearings firmly in place inside the precision-cut frame walls is probably hard to match with printed parts that are somehow attached to the frame.
But please prove me wrong! I'd love to have a solution with the stock rods.
I know a Swiss metal trader (metall-laden.ch) who does have stainless steel rods with 5mm,8mm and more diameters. But I don't think these are precision "shaft" rods. I'll have to check though; will visit them when I have time.
I see some chances as my backplane has significantly too big holes for the bearings and I had to wrap Teflon tape (thickness 0.13mm I think) around to fix it. I never had a problem with that fix. But it's something to have a really close look onto.
Stainless steel might be an overkill for the rods (as long as you don't run it outdoor), Calum suggests C45 (1.0503 I think). Tolerance h6 is the crucial number.
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Direct drive:
As I maybe will have to work with the original rod for the second axis I'm currently thinking about a printed part for shifting the bearing. But it has to be shifted quite some distance for the Calum-solution. So you get in conflict with the crossing rod. The space in between them is kept as low as possible meaning the pulleys just don't touch each other. The pulleys have an outer diameter of 17mm. The bearing has an outer diameter of 16mm. That leaves you with a wall thickness of 0.5mm for an adaptor. Delicate but not impossible.
Vibrations:
I've put my Ultimaker on a stone slab and put some rubber feet underneath the slab. It's far from perfect but a great improvement. I did some very quick and dirty analysis with a mobile phone app analysing the sound spectrum. There are very view distinct lines at certain frequencies. Most of the noise is quite broad band... Air springs (or pressure springs) might be something to try, but they are quite expensive. There are also some elastomeres which should be suitable to put under my slab, but there more than expensive...
The main problem is that all the motors are hard-coupled to the wooden frame. I plan to design a de-coupling part for the extruders. Taking away a running extruder from the frame during printing shows how large the excitation is.
The very low frequencies mainly come from hard direction changes of the print head. You can eliminate them at least partially by reducing the xy-acceleration to 1000mm/s^2.
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Very nice video!
If I look at the video I see the main issue is that already printed layers are partially liquified again. When the nozzle moves away, this liquified part is picked up by cohesion of the plastic fluid...
Why does it happen just on the overhang side? Well it doesn't. The effect is just stronger. You get the same thing everywhere if you print small structures too fast (e.g. minimum layer time below 5s). But on the overhang side the amount of material to be heated up again is limited or smaller compared to the other side. So the material temperature after contact with the nozzle is higher on the overhang side.
It's quite difficult to distinguish cooling phases. I expect the temperature to drop on some kind of exponential curve starting at the very moment the material leaves the nozzle. Re-heating certainly changes that temperature slope (EDIT: and active cooling by a fan as well). I think the crucial point is that the printed plastic is below glass temperature and stays there when the next layer is printed.
Another thought:
You see the nozzle is sitting there, heating up the part and waiting for priming/retraction to be finished. This takes a considerable amount of time compared to the short printing time in-between. Faster retraction (higher speed and/or less distance) would be very helpful. Direct driven extruders should have an advantage here. As far as I remember, Meshmixer documentation somewhere mentions a very small support diameter as the Makerbot default (of course it will move and print slower as well).
What if at least part of the priming after rectraction is done during the travel move? The idle time contacting the printed material would at least be smaller... But the priming process would have to be split up between the travel move and the original priming. Both gcode commands would have to be altered. It might be possible to do this with a Cura plugin.
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Direct drive: There is an update of the original Calum bracket which is more stable. With this bracket it's also not a disadvantage to make the new rods about 2mm longer than defined in Calum's excellent description. And find a source which sells straight rods and not bananas...
Actually changing to a direct drive is relatively easy compare to the implementation of e.g. a heated bed...very few new parts are needed.
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You may consider a direct drive. I just switched one axis to direct drive (I would have changed both axis but the other new rod is a banana... :sad: ) and I must say it's much easier to get smooth results with the direct drive. However as the mass-to-vibration ration is changed, I got some additional sounds...
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As far as I know there is already a plugin doing this: The PauseAtZ... it's included in Cura right from the start. But to be honest, I never used it so far. If you want to pause on the fly, you anyway have to use the Ulticontroller. All plugins are 'only' post-processors up to now...
If you want to write your own plugins best thing to do is probably to analyse an existing plugin assuming you are a bit familiar with Python (otherwise you get familiar while analysing the plugin). For the header, there is some information http://wiki.ultimaker.com/How_to_write_a_Cura_plugin.
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Only the backlight or also the digits?
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That's funny, what a coincidence!
Today I thought about starting a topic on this, but didn't have the time: "The tiny leg issue" or "Meshmixer support worries"
My understanding so far:
- The extrusion process applies some pressure to the structure underneath
- slanted structures, if tiny enough, sooner or later will bend due to that pressure
- bending causes thicker extrusion, especialy on the most overhanging edges
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- if structures are rigid enough, backpressure increases and things even out by themselves
- if not, more bending, more thickened edges ... and finally the nozzle breaks down the structure or knocks it over
Therapy: I don't have a clue ...
Extrusion *has* to apply some pressure. Small structures *will* give in.
Thinner layers should increase the problem as there is less room for the extruded filament and less clearance for the print head.
I guess it's even worse: the backpressure pushes the printed part against the nozzle. It decreases the gap for the new layer even further and if print speed is slow enough the printed part is heated up again and expands...
If you have a retraction in addition creating a tiny tip then the knock-over is scheduled...
I have the curling effect quite strong on the UM1 when printing an Ultimaker robot at the right ear (face to front). I always get the buttom of that ear curled up. Not for the left ear which is strongly cooled by the stock fan. I hoped to get better results one day with a different fan setup.
So do you still have the same strong curling effect with the crossflow fan?
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(Sorry, I have to... :wink: ) UM1 or UM2?
I guess it's on the UM2... so this cancels out the direction of the air flow.
Maybe I didn't get it right, but your question is why it goes up? I guess it's really just the shrinking as you thought. Why shouldn't it go up with this print? The top of the new layer cools first becoming a tiny bit smaller than the bottom of the new layer. So the direction of the curl is up... and that's why you see an influence without fan...still you have an air-flow (e.g. from the heated bed). Don't underestimate thermally induced air flows; they are very strong actually...
Maybe some additional air flow below the overhang might change the situation. If you do tests, you could also play around with the bed temperature...
printing very flexible
in Third party products & modifications
Posted
It looks to me as if the material is thicker than 3.00mm which is the absolute maximum thickness with an Ultimaker. If the material is thinner, there are some ways to get also a flexible material to slip through the Bowden tube.
Maybe you have a look at this thread: http://umforum.ultimaker.com/index.php?/topic/3440-advice-for-flexible-material/