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The biggest wrong assumption here I think is the "all heat goes into the barrel" assumption. Much of the power is lost through convection/ conduction. Also, the heater isn't on all the time (wouldn't run at 40W). Both these things will make the temperature difference smaller. So the use of stainless is not a big problem assuming your calculations are correct.
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Greg Frost
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General
I tried all steel including the nozzle and felt the poor conductivity at the tip was limiting the speed that the hotend could be run. It was a pretty unscientific test though and there are a lot of things that can impact the nozzle performance like the length of the small hole which can be tricky to control with hand machining
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Greg Frost
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General
Aluminium is an extremely good conductor of heat. That makes it a terrible material for a thermal barrier.
by
Greg Frost
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General
it is academic anyway because belt stretch, machine rigidity and extrusion inconsistencies will swamp the errors from the theoretical resolution.
by
Greg Frost
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General
Does sprinter have a jerk setting like marlin? If so, you may wish to decrease it. That will probably have more impact than decreasing the acceleration.
by
Greg Frost
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Printing
Check for backlash. You can get unpredictable lash if your pulley set screw is not tight enough.
by
Greg Frost
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Printing
Have you checked you Hobbed bolt for clogging? Sometimes a small bit of plastic can break off and fill in the gap between teeth. When that happens it will extrude ok for most of the time, then when it hits the clog it will just slip on the filament and you will get a pause in extrusion. Looking at the pic you posted there are some periodic spots on your filament that Appear to be without teeth ma
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Greg Frost
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Printing
With pla you could heat it and bend the filament so it wouldn't have to be straight. That is a really good idea nophead!
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Greg Frost
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Printing
I have blown up half a pololu and it sounds like that. One of the failure modes is for the drive for only one of the coils to blow. When that happens the motor jumps around aggressively in no particular direction making a horrible noise.
by
Greg Frost
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General
Have you passed the stl through netfabb for repair. Sometimes that will enable openscad to import it. Sometimes unfortunately it won't though.
by
Greg Frost
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General
openscad can do this too and is especially good if you want something other than a straight cut. See this:
by
Greg Frost
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General
Is your hotend insulated? That helps a lot. It is basically essential if you have a fan blowing on it.
by
Greg Frost
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General
Measure the resistance of the thermistor using the leads that you use to connect it to your controller. At room temperature it should be near 100 k (assuming it is a 100 k thermistor). If it doesn't, you either still have a wiring problem or your thermistor is broken. if that is ok, I would expect a problem on your controller board.
by
Greg Frost
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General
That could happen if you get a bogus temperature reading but i think that you get a message in the printer face console when that occurs.
It sounds to me if you have wires running everywhere that you may be having ground bounce issues and that is causing your computer's USB interface to shut down. Make sure your ground wiring is as short as possible and uses good heavy duty wire.
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Greg Frost
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Reprappers
Kapton is a brand name. You might want to look for polyimide tape. you can get it cheap from deal extreme, but postage can take a while.
by
Greg Frost
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Reprappers
I think it is showing you the control to the heater MOSFET. Is it on solid while the heater is heating?
by
Greg Frost
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General
Sorry,but I was meaning % when I suggested #. # actually highlights the tree that follows rather than making it transparent. Another operator that is useful is * which makes things disappear alltogether. The wiki manual is quite concise and a good read.
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Greg Frost
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3D Design tools
The term Jerk is actually supposed to refer to the rate of change of acceleration. I donk know if it is implemented in firmware that way though.
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Greg Frost
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Reprappers
I would have said anything but clear. Clear is very difficult to see details of print quality which makes it problematic when tuning a printer. I would suggest an opaque filament but not black or white as these can be difficult to photograph if you want to pay a picture to get some help or feedback.
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Greg Frost
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General
Temporarily put a # in front of the outer object
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Greg Frost
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3D Design tools
I have been working on some firmware for an arduino based laser tag gun. Here is what I have so far on a duemilanove:
1. IR reception based off 50usec timer controlled interrupt.
2. IR transmission based off the same interrupt, the 38kHz IR modulation is implemented by another timer.
3. Some simple sounds for laser shot, killed and coming alive again using the Tone library.
4. Trigger debouncing
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Greg Frost
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Let's design something! (I've got an idea ...)
like in the pic on this thing:
by
Greg Frost
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General
I like rubber/silicone washers instead of springs.
by
Greg Frost
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General
MotoBarsteward Wrote:
-------------------------------------------------------
> Congratulations Greg.
>
> Greg, which version of slic3r were you using?
git avoid-crossing-perimeters-graph branch.
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Greg Frost
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Competitions
It Blows!
http://www.youtube.com/embed/nYncQyxPq8k
by
Greg Frost
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Competitions
That certainly is challenging. The blade is extremely thin in a few places. I have decided to try the cut it in half method and Im using the version of Slic3r that has comb. Given the extremely thin walls, I have told Slicer my nozzle size if 0.16mm and im using a layer height of 0.075. You can see how fine it makes the filaments in this picture (compared to a fingerprint) and that is on the bott
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Greg Frost
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Competitions
BTW, I think it is a shame that these threads have been moved to their own forum. Im sure there would be more participation if we regularly had a new thread in the General section instead.
by
Greg Frost
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Competitions