Dim3nsioneer
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Posts posted by Dim3nsioneer
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Did you see http://umforum.ultimaker.com/index.php?/topic/3406-experiments-on-bridging/?
From my tests I think yours are definitively more on the sunny side already... :wink:
What material did you use?
There might be some tricks like changing the acceleration for the bridge layer to avoid single strings from ripping but the sticking together of multiple strings is very difficult to avoid.
Maybe foehnsturm can say something about the effect of the crossflow fan onto bridging? Any difference concerning the sticking together?
EDIT: If you printed it oriented as shown in the first picture (x direction) and if you use the stock fan or any other fan duct blowing from the left only try to rotate it by 90° and print it in y direction.
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The key is a laminar airflow with some cm height which covers the entire printbed. You could achieve that with an axial fan and ducts as well, I assume. But I had less than encouraging experiences when I tried to produce that kind of airflow with axial fans and ducts (heavy airflow in the middle section and nothing at the sides) . It's a matter of how much static pressure the fan can handle as well. My choice was the crossflow fan because it is used in similar situations (ovens etc.) and the "output" is exactly as I need it.
A turbulent airflow results in a higher heat transfer from solid to air (the coefficient called 'alpha') but is also more likely to produce a spot with no airflow at all.
Crossflow fans are the 'weakest' of all fan types, having a quite low ration between pressure increase and flow, then comes axial fans, diagonal fans and finally radial fans which are used when a lot of pressure is needed and not very much flow (just for the case someone didn't know... :wink: ) But acutally one can run any type of fan in a more or less pure laminar flow range. However for applications where a large flow and a low pressure drop is needed, the crossflow fan is absolutely the right type to work with.
It might be interesting to compute some Reynold's numbers for different setups, giving a more quantified image of the topic... anybody tried that so far?
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[...]
What is potentially more of an issue is homing the z-axis before heating the head; you really do want any plastic attached to the head to be molten before you ram it into the print bed. Because of the springs, it's probably not a huge deal either way, but I always make sure to heat the head before homing the z-axis.
That's true!
I was assuming a clean head....
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I do the same work-around for some months. And sometimes I miss the right time to grab the outflow with tweezers (better for the fingers).
Actually, it should be possible to solve the problem as all the involved actions are in the start.gcode.
So this order might solve the problem:
- heat up the bed (if a heated bed is present)
- zero the z axis
- lower the bed by something like 10-15mm
- heat up the hotend
- move it a small amount in x or y direction
- zero it again (in case you change the height manually)
- and from there it goes...
- heat up the bed (if a heated bed is present)
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I just put it on the floor. Putting it on something that rotates easily (like a "Lazy Susan") helps to avoid tangles. If you just leave it on the floor like me you have to keep an eye on it. As the filament is dragged into the machine the coils get tighter and tighter and eventually wrap around themselves and make tangles that look like old telephone cords.
There's also tons and tons of designs on thingiverse if you want to print out holders for it to put on the printer.
Did you check my age before writing about the telephone cords...? :wink:
Thanks for confirming the twisting-issue. As I need my eyes elsewhere I will soon visit the next IKEA and by a 'SNUDDA'... (doesn't sound any better actually than 'lazy susan'; in Switzerland, these things do not have a special name (proving the Swiss are boring?)).
I'm actually in the post-holder area. Any specific Ultimaker holder I have seen so far was not very suitable for use with a dual extruder. So I built my own one which is standing on the table close to the Ultimaker and works perfect, even with the most brittle PLA.
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@Nick: If you say 'remaining', what were the other ones? You reported about the vibrations in the Bowden tube and the lubricating of the z thread. Was there something else?
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I also just received my first faberdashery material two days ago and was thinking about how to handle it.
Does one risk the filament to break when just lying beneath the printer? Can it be twisted and blocked? Is it an advantage to put it on some kind of rotary disk so there is a uniform tension on the filament?
I was also thinking about spools but the curvature of the faberdashery filament is rather different than it would have on the spool. After experiences with other, very brittle, PLA I'm just careful.
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I'm just printing a two-piece-model, one piece after the other, using a 15 lines brim. The first brim was printed 'normal' beginning with the outermost line working itself to the center.
The brim of the second object however was printed in a strange way. First the three or four innermost lines of the brim were printed, then the outer lines working from the inside to the outside.
I can't remember having seen this before (maybe I was just blind up to now). Can anybody else confirm this effect? I would prefer to have any brim printed from the outside to the inside due to priming the hotend.
I'm using Cura 13.12.
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One of the things I would really like to see, is an infill that automatically adjust so that it is less dense at the bottom and increases in density over height to support the top layer. Something where you would tell the computer the maximum unsupported span and maximum angle of an overhang and it would calculate a suitable branching infill pattern.
That would be a very nice feature, indeed!
I remember Daid writing recently here in the forum that slicer engines like Cura can't do any jobs which involve more than one layer. But maybe Meshmixer goes into that direction. At least it already has a function to determine the ideal orientation of the model for printing and support generation. Maybe they could implement such a feature...
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I used calipers and measured the distance between the edge of the top opening and the top of the hot end. It is a very nice set of certified calipers that were given to me as a graduation gift, so I am inclined to trust their stated precision and accuracy.
Process:
0) After homing, lower the bead out of the way move the print head to 90 mm along the x-axis.
1) Run the head out to 100 mm from left to right and measured the distance.
2) sent the head out to 110 mm, then back to 100 mm and measured again.
3) repeated about 5 times
4) repeat process around 50 mm
5) repeat steps 0 through 4 with y axis
From the results I computed backlash as well as steps/mm.
I was happy to at least find that the measurements were very repeatable (all within +/- 0.02 mm ); the backlash measurements at 50 mm and 100 mm gave very close to the same results; and the computed steps per/mm were essentially the same for both the y and x axis.
I hope you will not get me wrong, I don't mean to offend you.
But if you really can measure a distance of around 10cm with a (calibrated?) set of calipers between two wodden parts at an repeatability of 0.02mm, then I really have to congratulate you. :wink:
You should be aware that with repeated measurements you may reduce the statistical error but the systematic error of your measurement device stays the same. If you compare two measurements then it is even worse: no matter if you add or subtract values, the errors of the two measurements are correlated. So you have to add the individual errors which means in this case to double the error.
Realistic accuracy of a caliper measurement lies somewhere in the range of the backlash you actually measured. To my opinion, most people overestimate the accuracy of calipers. Having a number of digits on the display doesn't mean the tool measures with the accuracy of the last digit.
To get a real feeling about how large the backlash is, one has to compare it with the spacing of the MXL belts wich is to my knowledge about 2.03mm. So you have a backlash of around ten percent of the spacing. I think this is a bit larger than normal even when considering you have the play of two belts in series. You may try to tighten the long belts a bit. BUT:
... If you tighten the long belts too much you will increase friction so much that you will start to increase backlash again (bizarre but true!). So as you are tightening the belts, push the head around to make sure the friction doesn't increase drastically.
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@gr5: Where do you know that from...? :rolleyes:
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[...] I plan to tighten the belts some, but don't want to over do it.
[...]
Smart! :wink:
How did you measure it?
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I am not. The last couple things I made were just 1 mm. What do you consider large?
Let's say larger than 5cm... 1mm is definitively not large... :wink:
I have the same effect as Ian. Interestingly (and fortunately!) the shift is always uniform over the whole bed size.
A possible solution would be to put the z top end switch somewhere, where the leveled bed and not the z stage triggers it.
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Are you doing prints with a large z dimension?
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The curve is an interesting question. I like the idea of having longer segments in touch with the perimeter and peaks facing inwards, like bracings. However the peaks should be printable without any risk due to the sharp corners.
Some narrow Gaussian might do the job. Practically it would be rather a convolution of a Rectangle with a Gaussian. The smooth tip should lead to shorter print times compared to a sharp peak.
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I like the idea. The calculation should not be a problem as long as the layer-to-layer-shape-change is somehow continous. Then it's just a question of curve parametrisation. But three questions popped up:
- Is one layer enough to make it stable?
- Is it visible on the outside of the print (there is such an effect with injection moulding)?
- What is the most suitable type of oscillating curve?
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I think posting your designs on multiple platforms is ok as long as the platforms stay open-sourced and independent of the printer model you use. If one of them closes to the users of a certain printer, one might have to change. Actually Ultimaker is already going further into that direction by adding the 'send to 3d printer' button (I guess it's only possible with an Ultimaker, or am I wrong?).
If you want to make money with your prints you anyway have to use neither Youmagine nor Thingiverse.
Edit: To be honest, I usually first have a look on Thingiverse as the chances to find a suitable design is much bigger there. They have the advantage of having started earlier.
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@Ian: Did Xeno's hint work for your church print?
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It might be a bit off-topic, but Ultimaker https://www.ultimaker.com/pages/our-printers/ultimaker-2 (with the green checks) of which the last one is 'low cost material'.
Maybe it's because I'm Swiss and we are used to high-quality products in Switzerland, but for me this point would be rather a reason not to buy this product.
What do you think about that phrase (with the view of a customer who want's a nice and shiny machine, as discussed above)?
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Leider bekommt man aktuell noch nicht einmal Gerätespezifische Ersatzteile für die Maschine.
Auch nicht auf direkte Anfrage per trouble ticket?
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Ich habe bisher noch auf keinem UM2-Foto ein Teil entdeckt, das ich von meinem UM Original her kenne.
Soweit ich mich erinnere, hat jemand von Ultimaker, ich glaube, es war Sander, im Forum geschrieben, dass die Pläne zum UM2 irgendwann 2014 folgen würden. Im Prinzip könnte man die Daten jetzt aufschalten. Denn inzwischen wird wohl jeder Konkurrent, der einen UM2 auseinander nehmen und analysieren will, einen in seinem Entwicklungslabor stehen haben.
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This might be legally possible, but wouldn't that be somehow bad style?
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You can do with it as you please but not a partner. He would be bound to the NC term, wouldn't he?
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I guess this is the main reason why people buy a 3D printer: because they cannot handle ordinary tools...
In this regard: Hi, my name is Dim3nsioneer and I have an Ultimaker... :wink:
EDIT: Seriously, I see it as one big advantage of the 3D printer technology: People with not too much mechanical skills can create solid things... no offense to any of you!
The crossflow fan approach
in Third party products & modifications
Posted
Saw that one too. Might be a useful gadget (depends on the price). But be aware it shows only surface temperatures not the air temperature... some ntc measurement in parallel might not be the worst idea.
Cool that the iphone users will pay the engineering costs once more and the Android users will have the cheaper version... :wink: (I belong to the Androids...)