Re: [CAD_CAM_EDM_DRO] Re: Tapered Threads in TurboCNC

That absolutely won't work.

I've made code modifications to G33 in TCNC, so I've seen first hand
what it can and can't do. First of all, it will error if you put more
than one axis on the line, ie it won't take G33 X.75 Z-2. Secondly it
only does calculations for and loads and runs ONE axis to move in synch
with the spindle.

I've spoken with Dave and looked at the source and it will probably do a
2 axis synch move if I program it to. I'll probably work on this over
the weekend as I need it for next week.

Kim

On Fri, 2003-10-31 at 02:45, rotarysmp wrote:
> If you really need to, this might (I haven't tried it) work to
> produce a tapered thread in TurboCNC by taking advantage of a couple
> of it's quirks.
>
> TCNC 3.xx does not check for unique axis names, or for duplicate axis.
>
> Duplicate your normal .INI, i'll call it Taper.INI
>
> Add a third axis, also called Z, which addresses the X axis Step/dir
> pins. We'll refer to this axis as fake Z.
>
> You would have to figure out the distance/step you plug into the fake
> Z axis based on the angle of taper you want to cut.
>
> When you call the G33, TurboCNC will drive both axis, synced to the
> encoder.
>
> If you have to do multiple cuts, your G00 X retracts and advances
> will be as though on a parallel shaft.
>
> Example:
> Cutting a 1:10 tapered thread with a 1mm pitch, 1mm deep from Z20 to
> Z0 with in a 20mm dia shaft in four passes.
>
> The initial taper from Z20 X18 to Z0 X20 is previously machined with
> the normal.INI. Position to Z30 X18 before changing .INI's
>
> If your Normal.INI has an X axis distance per step of 0.01mm, then
> the Taper.INI would have the fake Z axis step to 0.001 for this taper.
>
>
> ;With threading tool point at Z30 X18 to start
> G00 X16.75 ;1st infeed
> G33 Z0 K1 ;This will take you to Z0 X 19.75 although X
> display will still be at X16.75
> G00 X17.75 ;1mm retract
> G00 Z30 ;This will take you to Z30 X17.75
> G00 X16.5 ;second infeed
> G33 Z0 K1 ;thread to Z0 X19.5
> G00 X 17.5 ;1mm retract
> G00 Z30 ;This will take you to Z30 X17.5
> G00 X16.25 ;third infeed
> G33 Z0 K1
> G00 X17.25
> G00 Z30
> G00 X16 ;fouth infeed
> G33 Z0 K1
> G00 X17
> G00 Z30
> G00 X16 ;5th pass to clean up thread
> G33 Z0 K1
> G00 X17
> G00 Z30 ;
> G00 X18 ;Don't coordinate this with the line above, or
> you would have two axis's trying to address the same pins at the same
> time.Returns you to your start position, so you are at the same point
> you left your normal.INI from.
>
> Not really pretty, but should work.
> Regards,
> Mark.
>
>
>
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