Hello folks, It's been awfully quite on the boards.....hope all is well
Anyway...I wanted to give you folks an update on my Mikini. I have finally been able to finish my first set of brackets for a throttle system that i have developed. It has only taken close to a year, thanks to this mill ..... but, I finally did it. But, it wasn't without it's Mikini problems.
Ever since Mikini sent back my motor and boards, the machine ran, but, it just didn't sound right. For instance, at 3000 rpm there would be a slight change in speed...like it's skipping a beat. When i was machining the brackets, I had a couple alarms from overloading. The cuts were with a 5/16" rougher carbide end mill, at 3000 rpm, 020" depth of cut, 25 ipm, in 6061 aluminum.
I didn't want to touch anything and try to make any adjustments...since these machines are so delicate..So, I waited till I completed my first job.
Tonight, I decided to adjust the Hall sensor ring, in hopes of improving the torque and speed issues.
Here is what I found....
http://www.youtube.com/watch?v=cCTaZ0SsVnY]P1300002 - YouTube
Since the ring was loose, I had to figure out were the sweet spot is with the Hall commutation and set it. In my motor repair days, we use to set armature brushes by adjusting them while the motor was running.
So, i decided to do the same in this situation. I brought the spindle up to 3000 rpm and slowly turned the sensor ring clockwise till I went into alarm. I marked the location of a Hall sensor (that I will use as a reference point). I moved the ring back a little bit and started the spindle again and this time I moved the sensor slowly counter clockwise..till I went into alarm. Again I marked the location of the same hall sensor. Now i have two marks..then I just moved the Hall sensor that I used for reference, in the middle of the two marks....
I ran the spindle at 3000 rpm and made a very slight adjustment ...clockwise. This time I didn't hear any of the dips in motor speed. Here's were Mikini will probably flip...I designed my own dynamometer.....I kinda wedged a long 2x4 against the spindle, actually the top of the draw bar ( I did have it screwed into a collet) to see if i could cause an overload situation....I cut a nice half round shape into the 2x4 with the drawbar nut....and it didn't go into alarm
I know my sensor ring adjustment technique will probably make the hairs on the back of the Mikini folks stand on end, but, I don't care. My goal is to have a running mill...and I will take unorthodox methods to get it to that point.