MaxNC cnc problems was Re: Recommendations

PJH,

The 145 oz. motors should have enough "oomph" for most "typical" CNC sherline use.

The inexpensive MaxNC Kit is an L/R type drive, and will only run the machine reliably VERY slowly. Are you familiar with the yahoo group for MaxNC users?

The type of action you describe is typical of steppers operating beyond their capabilities. Slow the feed down. Adjust the timing/ acceleration parameters in the MAX software. This will be a trial error thing and if you have an older version of the software, you should know that some versions were buggy in the way accel/timing issues were handled.

Realise that there may be interactions between the different parameters EVEN WHEN there "shouldn't" be any relation.
Been there, done that...

Hope this helps.

Ballendo

P.S. The post about some computer types giving "better" pulses is EXACTLY on the mark... But it may not be your problem.

> | Gentlemen,
> | First my position - I have the basics+ of ac/dc/electronics
> | knowledge. I am
> | a self-taught machinist. I am retired so have limited resources.
> |
> | My problem - I purchased a Sherline 2000 which I ran by hand for a while
> | then retrofitted with a Maxnc retrofit kit 145oz steppers and
> | w/4th axis as
> | I knew not of this list at that time. I use BobCad/Cam to draw
> | parts and as
> | I learn more it seems to handle my needs OK. In looking at
> | software I got a
> | demo copy of Flashcut which I now use to verify tool paths and edit cnc
> | programs created with BobCad. I have never been able to get reliable cuts
> | from the system. I loose or gain(?) steps randomly. Example; while
> | engraving a letter 'A' the horizontal bar was displaced to the right by
> | aprox 1/5 the bar length ( as a way to express the displacment as
> | it varies
> | with size). This has also happened on the y and z axis at times as well. I
> | have tried all the mechanical remedies I know and have seen here on the
> | list. Do I need more powerful steppers, should I change to servos and how
> | much of my present system would be usable in that case? I also seem to be
> | at a crossroad where the Sherline MIGHT be too small/frail and I
> | should look
> | at a bigger machine?
> | While I am willing to learn I do not wish to become an expert in
> | steppers/servos, more I would like to produce useful parts for my various
> | hobby projects
> | PJH