Bad stepper driver

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Lioric
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Bad stepper driver

Post by Lioric »

Finally received the package, went two days in assembling the printer (around 16 hours) but sadly a stepper driver is bad.

Initially there was not any movement (or sometimes just a burst of movement of a stepper) but after long minutes of fine tunning and tracing the for the cause, I have all of the steppers working correctly (all of the steppers needed fine tunning of the trim pots) but the X axis

Tested switching the motor connector in another axis, works
Tested switching opto sensors, works
Tested switching another stepper driver, motor works

So the issue is the stepper driver, tried to adjust the trim pot but there is no evident change, sometimes just a small movement of less than a second but nothing more.

Will continue by testing all of the stepper pads and looking for their values

In the mean time, I will order a replace from a USA dealer (another 50 - 100 bucks to this project), I can't stand the idea of waiting more weeks just for this

Anyway, I have changed the bad stepper of the X axis with the extruder, and after calibrating I can at least see the printer "act as if is were printing" while watching the movements and trying to imagine what the printer part would look like (if the extruder were working).

So in the mean time my printer is a Virtual 3D printer (you have to imagine what each layer would be if there were plastic out of the extuder)

Another thing is that the X axis opto sensor is not working correctly, but will open a new thread for that

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gfeliksdal
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Post by gfeliksdal »

Can't believe another stepper driver broken, too many DOA's lately. Will have a good talk with the supplier...Have you already ordered the stepper driver? Please send me the invoice and I'll refund you the money.

Hope you get it fixed soon.

Kind regards,

Guillaume.

Kjetilei
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Post by Kjetilei »

That is soo frustrating!

If you use Repetier-Host you can run a print and take a screen shot of the finished print. It is "almost" as good as the real thing ;) (Sorry I just could not resist that bad joke - I feel for you)

US-source: http://ultimachine.com/content/pololu-a ... atsink-kit (the first I found in stock when Googling)

Guillaume: maybe you should ask your supplier to test the drivers or maybe you should do it yourself (although it sucks that you might be forced to do it because of bad product quality)?

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gfeliksdal
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Post by gfeliksdal »

Pretty bad joke :)...I already let the supplier test it before he sends it out to the production facility. I've just send him a mail to explain to me his way of testing...Maybe the culprit is the production facility, will investigate it further...

Lioric
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Post by Lioric »

Yes, I already have ordered via ebay, seems to be out of stock everywhere else

Thanks gfeliksdal, I will forward you the invoice later (when this all is fixed and printer is printing ;) ). One of the reasons that I purchased the printer was your prompt reply to my emails (I'm Andres), this shows that your customer support is top notch

And, seriously pretty bad joke :)

I almost forgot, if the printing quality is similar as the printed parts that came with the kit, just one thing: IT IS AMAZING (seriously, part of those 16 hours needed to assemble was just sitting there looking at the plastic parts)

Kjetilei
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Post by Kjetilei »

Sorry for the bad joke! :)

You'll get there in the end and I'm certain your prints will be just as good as the printer parts you received from Guillaume :)

Hang in there!

PS: I too took much longer too build then necessary just by staring at the parts and being amazed at the "beauty" :) I was especially blown away by the air duct that I still wonder how Guillaume can print so nicely with only one (or two) layers. I sure would like to see a video of that part printing.

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gfeliksdal
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Post by gfeliksdal »

I was just thinking about the extruder problem. Did you turn up the temperature when you wanted to extrude? Don't know if you already knew it, but the temp of the hot-end has to be above 170 degC. This is a protection mechanism to prevent cold extrusions.

I'm glad you find the print quality amazing :) and also like the customer service! My goal is to have everyone get most out of the printer.
The airduct is printed on its side by the way, I used the "production, raft and exterior support" for it ...See screenshot below...
2012-09-14_130830.png

Kjetilei
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Post by Kjetilei »

Guillaume: Thanks for the screen shot :) I had figured out that it had to have been printed sideways but I hadn't noticed any traces of support material. Hence my face resembling a big question mark when I admired it. You fooled me :)

Lioric
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Post by Lioric »

gfeliksdal wrote:I was just thinking about the extruder problem. Did you turn up the temperature when you wanted to extrude? Don't know if you already knew it, but the temp of the hot-end has to be above 170 degC. This is a protection mechanism to prevent cold extrusions.
Yes, thanks. I already know of the hot end protection (I saw it while browsing the firmware)

The bad stepper was in the X axis, the extruder stepper was working (after the tune). I changed them so at least the printer can move in all axis to perform a "dry run"

I have commented out the PREVENT_DANGEROUS_EXTRUDE define in the firmware so I can easily test the stepper that was switched over the extruder motor (and avoid waiting for the hot end to heat up). As there are not filament inserted, there are no risk in activation of the extruder without the hot end heated up

Cause I don't like the idea of waiting weeks for the new part to arrive before getting any results, I have manually wired a stepper driver that I have in the IC bits drawer, a A3967 driver and now it is extruding plastic. Sadly it seems that the extruder motor needs around 600 to 700mA per coil to rotate, and this part is rated at 700mA tops so it is getting hot rather fast and seem it is quickly going into the thermal protection mode. The other issue is that it is a 1/8 microstep and the A4988 (used by RAMPS) is 1/16 microstep in the default mode.

Well, will continue to play with this ;)

Lioric
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Joined: Wed Aug 15, 2012 1:13 am

Post by Lioric »

ok, I have measured the current used by motor coils and it was 1A, the voltage reference of the stepper drivers that works better for each axis is at 400mA (that is why it is suggested the 25% clockwise turn of the trim pot), 400mA x 2.5 = 1A (sense resistors are 0.05ohm). Sadly the replacement stepper driver (A3967) that I'm using in the mean time tops at 750mA so it is not extruding consistently, but at least I managed to print a single layer by issuing 50 or so gcodes manually while helping the extruder by hand pushing the filament

Hopefully the replacement stepper board is delivered asap

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