45 degree worm M2.5

[ArtF]

Phil:
 
  I was speaking of the rooting. Raising the rooting would have had the effect of stopping it from
touching the tooth profile. But yes, I did also lower the tangent point. Or to bne more specific , I stopped it from calculating the tangent height each pass, and locked it to  the base circle height.

  Really, other than stopping the rooting from going outside the balnk I did nothing else, yet
you went from a fairly good cut to a very very bad one. Im still analysing, but Im still confused.
Take that last spur cut, its asymetrical..that should be impossible unless the Y wasnt zeroed dead straight up form the center. I havent suggested that because I doubt you did that. So Im still plotting
the toolpath to see where it hits..so far, it doesnt, but the plotting isnt automated so it takes me awhile, Ill find it yet..

Art

[ArtF]

Phil:

  Im away most of today, but I have uploaded a new version. It relabels the depth and thickness overrides, and when you press the GetFromObject button you go back to the actual design thickness
and such of the gear. There is a new checkbox that turns off the cleanup section of the rooting,
this may have caused trouble with any undercuts.

  I still cannot find what is causing the variations, but it is warming fast here so it wont be long. So far each tool simulation I do shows no collision, but I have decided after all this to make a simulation
on screen so I can watch the damn thing cut in real time.. :)

Art

[philbur]

The spur was very small, 15mm OD, and I used the largest possible end mill 3mm, as this was the size I used for the helicals (for comparison). Maybe the cutter size and the relatively small number of root passes is the cause of the ugly spur?

Phil :)

[ArtF]

Phil:

  Could be.. when you make anything small errors get magnified considerably.
Hurts me head either way. I really need to write a true simulator so we could watch it
work and see where it fails..

Art

[philbur]

Art. having a square ended tool dancing around in a confined space trying to produce what should be a convex profile was always going to be tough ask. Surely a bullnose cutter would stand a much better chance and at the same time be able to do the tan shaving and have the potential to minimise tool markers. Basically this is effectively 3D milling, which is bullnose territory.

Phil :)

[ArtF]

Hi Phil:

  There should be absolutely no difference. One couldnt use the ball section as its not the right shape,
so youd end up having the ball interfering in the root by th etime you lowered the tool enough
to get the flat section to touch the tangent..  :)
Art

[philbur]

I see that now. On my low tooth count gears the base circle is well above the root diameter, so aI guss a bullnose might work. Whereas for larger tooth counts the base circle can even be above the root diameter, so as you say not enough room for the bullnose. But can you not use a bullnose and allow the root diameter to lay where it falls?

Phil :)

[ArtF]

Well you could.. but it depends again on the toothcount.. if the root is above the base
then youd create trochoids below the root.. might be nasty in some instances..

I do in some things put the bit where I have to and if the root bottom gets gouged..so be it..
but I hate to push that theory too far.

Art

[philbur]

I have decided after all this to make a simulation
on screen so I can watch the damn thing cut in real time.. :)

Hi Art, is this simulation going to be made available to Gearotic users,..........pretty please. I did think about finding me a 3D simulator that I coud use but it would be very nice all in one package.

Phil :)

[ArtF]

Phil:

  Hard to promise anything there, simulators for things like this are very hard which is why they tend to be very expensive. If the hardness doesnt kill me then yes, Ill include it..otherwise Ill end up using it internally for verification.

Art