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Author Topic: Taig CNC loud/not smooth steppers  (Read 3469 times)

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Taig CNC loud/not smooth steppers
« on: November 05, 2016, 12:20:45 AM »
new to the forum, my name is Michael and I am new to CNC

this is my first CNC a Taig mill.
running microproto taig control box and steppers.
I am running pokeys usb to parallel to connect to my windows 7 professional desktop (I will confirm windows 7)

at 100 and 95% jog the steppers sound smooth, when I lower the jog they start sounding grindy and angry.  not a consistent sound either but the motion looks consistent.
just recently I noticed the z stalling while jogging up.
the steppers are at about 105F for temp.

perhaps this is all just normal?

anymore information to help solve this I can provide, I am just unsure what might be needed.
Re: Taig CNC loud/not smooth steppers
« Reply #1 on: December 01, 2016, 12:47:46 AM »
not familiar with your machine but have a few questions which might push you in the right direction.

First can you post the manual for the controller?
The reason I ask is to know/estimate if microstepping is being used. The principle advantage of microstepping
aside from the theoretical increase in resolution is that it smooths the motion of two phase steppers.
If full stepping is used, and it is possible, then you can expect resonance issues at certain speeds.

One test you might try is to MDI a move

G01 X100 F300 say
and then while moving alter the speedrate override slider, if the noise comes and goes at different speeds
then resonance is the likely culprit. Can also cause overheating.

It might be possible to calculate if microstepping is employed if you know the pitch of the lead screws and any reduction
gearing in the stepper-to-screw drive and comparing that to the 'steps/unit' value on the motor tuning page. Sort of doing
a steps/per calibration but backwards.

Another useful piece of information is current reduction. A lot of stepper drivers, certainly all the good ones have the means
to adjust the current delivered to the motor. Sometimes a modest reduction in current will result in much cooler running
without a huge loss of torque. Another common feature is current reduction at idle, so if the current when running is 3A say,
the current will reduce to about half if the motor is stopped. It will reduce the holding torque but unless the steppers are
undersize usually not a problem but a significant reduction in heat produced.

The stalling and/or loss of steps of the Z axis is concerning. No useful machining can be done while that is the case. It seems
unlikely to me that such a well recognised brand would use too small a stepper for the job. Would pay to check that the axis
is not binding up as it moves.

Let us know how you get on, and by the way welcome to the forum, you can tell CNCers from ordainary humans because
of the lumps of missing hair on their heads as a result of frustration!

My wife left with my best friend...
     and I miss him!