Re: [CAD_CAM_EDM_DRO] Re: Motors too weak or bad ball screws or software issues?? pictures of odd cuts

Mike Mueller wrote:

> 1/2" cutter(s)..4 flute HSS, US/Iseral made, I changed to a new
> cutter after the middle part came out like that.
>
> .05" depth cut per profile cycle (counter clockwise)

OK, if you go around the part's exterior in a counterclockwise
direction, that is conventional milling. You might try
programming it the opposite direction, taking a light cut in the
Z depth, and see how it does.

>
> for the middle part, I didn't set the tool hieght correctly for the
> last pass to remove all the material (moot point being that the part
> was ruined before the last Z command)
>
> not a ball end mill, strange reflection (bad picture)

What about the wrecked part?

>
> even with a .005" backlash, the "steps" are way more than .005"
>
> material otherwise cuts very easily (bandsaw, drill and tapping)
>
> all parts from the same raw stock.
>
> How should I approach this problem? Are there some tests or sample
> parts to run to see what is possibly causing the trouble? Perhaps
> try cutting in conventional direction?
>

You are going around in conventional direction. You should be
able to do more than .05" Z depth per pass, a good value is 1/2
cutter diameter. Did you chew this part out of a big block, or
pre-shape it on the bandsaw, so you were only trimming the
outside dimensions? If you are plowing the cutter full-width
through the material, it GREATLY increases heat, recutting of
chips, and all the bad things.

I honestly don't know what to tell you. If I had been there at
the time, I probably could have told you what was wrong just
from the sound. After running my Bridgeport for years manually,
I have developed an "ear" for what you CAN, and CAN'T do on it.

> I ended up changing the design and went with 6061T6 alum I had on
> hand (no fancy radius cuts, just plain rectangle part for now :( )

Much easier to cut aluminum with steel than steel with only
slightly harder steel.

Jon