Friday, 24 June 2011

Pop, bang, fizzle

OK, I got new stepper motor controllers.

I have working extruder and hot end and hot bed now, so ABS should work.

Sadly still not right. I did find one of the issues is that the hot bed was gently sliding about as I only stuck it down with velcro pads, and they become slippery at 115C! That explains some of the leaning TARDIS of pisa issue. But even with that fixed and things printing a lot better the X axis was "missing" still, and causing steps and problems. Annoying as this has all been fine for a long time with the PLA.

So replaced the X controller again, and this time, well, it caught fire. In fact three controllers in a row caught fire on various axis.

I think (hope) it is down to powering up in the wrong sequence, connecting the 24V supply with the controller active perhaps. If that is the case I can just be more careful and all will be well.

So plan is to get yet more controllers (they are like £8 each) and try being very very careful on power up... So a few more days to wait, sod it.

3 comments:

  1. sorry,but i'd confused about the dns64 nat64 server 2001:8b0:6464::1 .does it don't work any more? I never heard the news before,but it can't ping well. Thanks you!

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  2. Err, that seems an odd thing to say on a post about 3D printers going bang!

    I just checked and the TOTD and NAT64 gateway seems to be working.

    e.g. http:[2001:8b0:6464:0:666:616:d43a:f65a]

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  3. These controllers sound a bit fragile! Are the motors two-phase (I forget the correct term - I mean they can have current flowing either way in any winding)?
    If so, the cause of driver transistors going Bang is often that both sides are turned on at once, putting the drivers as a dead short across the power supply. Or by going too fast the second driver turning on "sees" the field-collapse current from the previous one and can't handle trying to overcome it.

    The solution is to increase the lag between turning one current- direction off and the other on so that the collapsing magnetic field has dissipated before the next turn on (slows things down but it's necessary). It may be as simple as reducing the step-rate, or as complex as redesigning the circuit - sorry! :-)

    Cheers, Howard

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