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Printing issues ...
Thanks for your input, Cefiar. I should spend some time reading your historical post and learn from them.
It would be even nicer if you could sum them up for me again =)
So instead of PTC, you prefer good-old-day fuses, right?
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sam0737
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Controllers
Wow. My google-fu must be not good enough, didn't find this page before! There are some philosophy differences between our designs, which is good - diversity is good. Good job.
Mine is trying to dump all the legacy 5V - actually it does, and not strive to keeping pin-out/physical compatibility with RAMPS, your does.
There are so many cheap ARM board out there - usually based on STM32, some are
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sam0737
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Controllers
I don't think anyone is working on a shield for Arduino Due yet. So I am making one - so far I made the schematic, and placed everything on a 4" * 3.2" board and started routing.
Schematic Here:
There are no big deals with RAMPS, minor but workaround-able issues:
[*] The transistor stands in the air, it runs too hot then I would like it to be.
[*] I suspects the connector couldn't handle 1
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sam0737
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Controllers
wades: Too high or too low? And what shows that? Non-water tight filling of the surface?
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sam0737
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Printing
If you are not using Polulu/Stepstick but some other drivers - especially those including OPTO, check the rise/fall time of the opto/driver. You might need to add delay accordingly, to both DIR and STEP output.
Always the 4th layer? of every STL? If it's a particular STL, might be a particular pattern is causing the problem. Try lowering the acceleration and jerk number, the stepper might be n
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sam0737
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Printing
Ballscrew thread pitch is 5mm.
print_screw: is a screw for printable PCB vise.
* The start/end point is messy. The picture is after the clean up, I filed some extruding bits.
My retraction settings is 0.8mm, J head 0.5mm nozzle. I print both of them at the same time, almost no string in between.
print_wade_block.jpg:
* Red Area: At every corner (where it decelerate), it's not a sharp corner a
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sam0737
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Printing
I am re-purposing a DIY mill to a Repstrap, so far it prints, but the quality is not as good as the pictures that I have seen.
The printed output has bad quality when a line starts and ends.
As my machine is ballscrew driven with a cheap stepper motor. The max speed (for not skipping steps) I could achieve is 30mm/sec, acceleration 100, jerk 10.
I am not sure if the slow printing speed and acce
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sam0737
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Printing
pete-theobald Wrote:
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> sam0737 Wrote:
> --------------------------------------------------
> -----
> > 1Mbps on UART is hard, I expect noise, clock
> > glitches may ruins the packets.
> >
> I'm a bit worried about that but most firmwares
> are running rs232 at 250Mbaud (except its a short
> hop from the ft
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sam0737
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Controllers
I am not following...I bet most others too.
Exactly what's the question that stucked you?
Couldn't get communication working? or an axis moving~?
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sam0737
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Controllers
Try with slower baudrate, like 57600. Then work your way up.
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sam0737
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Controllers
1Mbps on UART is hard, I expect noise, clock glitches may ruins the packets.
People want print on SD for 2 reasons,
1. they need not to keep the computer running the host, connecting to the USB. Especially when Diablo 3 (insert your favorite CPU intensive program) and printing host doesn't mix well.
2. Performs better on small arc/corner because of the processing latency.
Why it prints better
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sam0737
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Controllers
Make sure you change to the correct chip in the Arduino (Tools -> Board)
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sam0737
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RAMPS Electronics
And there is a big "but" if the position computation is moved to the host - you lose the print by SD function! Or you need a host on the printer Raspberry Pi?
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sam0737
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Controllers
If the TB6560 is mounted like this
http://item.taobao.com/item.htm?spm=a230r.1.10.53&id=14993177339
You could even stack them up.
I have one for my extruder, the heat sink is big enough and it barely gets warm.
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sam0737
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Controllers
Linux offering a high resolution timer doesn't mean you could have a thread sleep at precisely as much as you want, for that you will need a real-time kernel, in particular even if you could control your thread, you need to make sure the data sent to the hardware as fast as possible, for that you need real time drivers for the particular hardware.
That's exactly what EMC2 does when interfacing w
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sam0737
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Controllers
Repetier host sends binary GCode, but it's still GCode but not computed position.
EMC2 requires still relatively real-time operation for the position calculation, becasue EMC2 is not just designed for stepper but also servo motor, it is designed to compute the position every 1ms (or some other regular interval) and update the stepper driver.
The stepper driver could be an old day parallel port,
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sam0737
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Controllers
I found that the same thing is happening on X and Y too. A particular pattern will trigger a particular amount of shift. And the shift is quiet consistent. (printing the same thing will get the same distortion)
And I think found the root cause and nailed it.
The problem is the opto used, it's TLP521-2. The stated turn-on time is 2us, and stated turn-off time could be as long as 25us. (BTW the
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sam0737
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Printing
Frankly I don't even have a vase, and not exactly comfortable working with power tools - drilling aluminium would get me nervous already.
The room I am working with the reprap is also my bedroom so I don't exactly like having all the dust and bits flying around. =)
Okay, perhaps I should walk out my comfort zone a bit and try that out, but I am still pursuing a no-power-tool method. Leaving the
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sam0737
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Mechanics
I am looking to print a new extruder preferably geared one like those based on Wade's design instead of direct drive because I am printing 3mm ABS.
Most if not all requires a hobbed bolt or some what if I am not mistaken. My problem is I don't own a lathe, mill or dremel. Drill + HSS drill bits, hand tap, jigsaw, hammer is all the tool I have.
As I live in China, there is plenty cheap supply o
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sam0737
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Mechanics
I don't know if anyone has interested in .NET Micro Framework (running C# on ARM with no OS, could debug with Visual Studio). AFAIK it was ported to STM32 architecture recently. That said, developing C# on Linux/Mac might not be fun at all, I havn't try.
I would love to have my electronics run on Ethernet, even UDP. (After all you need those checksum and application level keepalive check even w
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sam0737
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Next Wave Electronics Working Group
nophead made a good point that the spring is not hard enough.
I put a M5 screw in the spring effective reducing 4mm or 25% space of the spring, it seems made it pushing force double.
I thought the motor won't be able to spin, but to my surprise it still spins =) And the output flow is much more consistent, and it doesn't slip at all now.
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sam0737
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Printing
I can't resolve this yet. It doesn't seem to be the signal noise though.
Well, it doesn't hurt much without retracting Z.
At least I got some working prints from it already - With a working slug fit dovetail joint I bet it could print a new extruder, and a Mendel 90 from it.
> What sort of electronic set up do you have?
I think I missed your question, nophead =) Mine is a Arduino Mega + han
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sam0737
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Printing
Ya-let me try to combine other axis in repeated-movement test.
I wonder would that be the blub of plastics that prevent the printhead from moving down?
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sam0737
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Printing
Comparison - Left with Z retract. Right: without.
After a week or two at least it's printing something functional - based on a few years of community's effort.
I have been following the reprap info early on. So much improvement since Darwin. Kudos everyone!
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sam0737
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Printing
The first layer height and width should be very similar, if not the same as with other layer, unless you have tuned otherwise.
So if you see the line being over flat and wide, and thin, or so thin that it's almost transparent - stop immediately, the Z is a few 0.1 mm too low.
Otherwise what Weedz said would happen. The extruder would need much higher pressure to grip the filament out when it's s
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sam0737
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Printing
The 1st layer height and width should be very similar if not the same as with other layer (unless you have tuned otherwise)
So if you see the line being over flat and wide, and thin, or so thin that it's almost transparent - stop immediately, the Z is a few 0.1 mm too low.
Otherwise what Weedz said would happen. The extruder would need much higher pressure to grip the filament out when it's so s
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sam0737
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Printing
Backslash is minimal and yes the overall height in my case does changed.
Printing without retraction is nice enough.
I did thing like
G91
G1 Z0.5 F9999
G1 Z-0.5 F9999
for hundreds time. Position is accurate.
No idea what went wrong yet.
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sam0737
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Printing
Ah no.
Not that it moves when it should be stationary, but when it does (like after Z-Lift), sometimes it doesn't go back to the original layer height X but a little bit higher (X + unknown delta).
Stepper skipping steps? It should sound obvious but I don't hear that happening.
I am adding re-check motor-shaft coupler, and double verify max speed / acceleration / jerk to my todo list.
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sam0737
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Printing
Mine is a repstrap but I think someone might have encounters this already too...
It is converted from a homemade CNC. The Z-axis assembly is mounted on the X-carriage with ballscrew / smooth rails.
My problem is - during printing, the Z-axis is getting higher and higher. Resulted in a object which is higher than specified, and poor print quality (gaps between layers)
I checked mm/steps settings,
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sam0737
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Printing