[cobrakai]

Attachment 253522

I have the same marks in mine, I just ran these this evening, it depends how the light shines on them for looks, they feel smooth to the touch. I think its related to the steppers as the mark spacings vary as to the feedrate.
These profiles are done with a .25 carbide 4 flute ball mill .005 woc 20 ipm finish pass.

Personally I think your part looks good.

I am using a 1 flute .125 engraver for the chamfer and it looks a bit rough as I dont have enough rpm for them at 20 ipm.

Those do look cool.

Hmm... I have dreams of a perfectly smooth finish on the side. Do you have a Series 1, 2, or 3? I have a series 2 and after watching videos online, the series 3 motors are significantly smoother and faster.

[popspipes]

Mine is a series 3, I balanced the spindle and drive parts soon after I got the machine, the main problem was the motor fan impeller which they have now corrected, that put a herring bone type wave in the finish at times.

Steppers start and stop, they are not a smooth rotation, and I think that may be what causes it or at least part of it.

My parts are small so I take the finish pass full depth less than .500 that blends in the rough passes.

[cobrakai]

Mine is a series 3, I balanced the spindle and drive parts soon after I got the machine, the main problem was the motor fan impeller which they have now corrected, that put a herring bone type wave in the finish at times.

Steppers start and stop, they are not a smooth rotation, and I think that may be what causes it or at least part of it.

My parts are small so I take the finish pass full depth less than .500 that blends in the rough passes.

Funny you mention that cause I work with steppers in my career quite often. I use microstepping drives with a resolution of 51,200 steps per revolution. Tuned properly, I can eliminate any perception of steps entirely. They are as smooth as servos and a lot cheaper. I wonder why Tormach didn't do that.

[popspipes]

Probably cost I would imagine. I would like to see them offer a dedicated machine controller, the personal computer and Mach 3 are not as problem free as I would like. I really dont trust it to let it run unattended.

Its a good machine for the price though, I am happy with mine. Mine is a retirement thing, I always wanted to learn cnc machining, so I bought it to mainly learn the trade and make a few parts, I must say I havent regretted it at all........

[mountaindew]

Mine is a series 3, I balanced the spindle and drive parts soon after I got the machine, the main problem was the motor fan impeller which they have now corrected, that put a herring bone type wave in the finish at times.

.

I have never come across this information other then the 770 spindles are balanced for high speed.
Please provide more detail on how this is measured and done. I like to keep my mill tuned and in top running order and this sounds like something to schedule and look at .
Thanks in advance for any information or tricks.
md

[Don Clement]

More information is really needed to find the cause of the periodic ripples. I would suggest using a dynamic analyzer during the machining process or a static FFT analysis of the periodic ripples so as to compare the periodic contributions from various rotating machine parts i.e. stepper motors, ball bearing races, spindle motor imbalances,cutter flexure, etc.

Don Clement

[popspipes]

I have never come across this information other then the 770 spindles are balanced for high speed.
Please provide more detail on how this is measured and done. I like to keep my mill tuned and in top running order and this sounds like something to schedule and look at .
Thanks in advance for any information or tricks.
md

MD,

The thread is "I love my Tormach but", kind of lengthy but all the details are there. I will say in my case anyway, it made quite a difference in the finish of the parts.