Need Help!- Machine code file size needs reducing

[billlaws]

Hi,
My university dissertation is to machine some turbine blades using a 30 year old CNC machine which has very limited memory (absolute maximum of only 75kb) The blades are 400mm long and will need an ok(ish) finnish. At the moment I'm going to be machining each side of the blade in 3 stages, 2 rough cuts and finnish.

I have already played about with:

tolerances,
machining angle
stepover and stepdown %'s
cutter size
is there any other factor that i really should look into?


I have tried a few different roughing tool paths, mainly the Surface High speed area and rough pocket.

Does anyone know of any toolpaths that normally give small nc files?

the finnish cut is not such a problem at the moment.

any help would be greatly appreciated.
thanks
will

[John@CRDM]

You could make containment boundaries and split the toolpath into lots of smaller ones or you could just copy the same toolpath several times and change the z limits each time then run them seperately.

[Matt Berube]

Usually when a machine has insufficient memory we "drip-feed" the program to the machine.

Are you using RS232 communications ? Is the machine capable of running on a "drip-feed" program ?

[Andre' B]

In my experience that is a boat load of memory for a machine that old.
Times like this it really is too bad CAM programs do not take advantage of Macro B and G65 sub calls. Assuming the control does macros.

I really would look at drip feeding, its not as good as having gigabytes of memory but it is better then splitting up programs.

[billlaws]

I've spent a good bit of time looking into drip feeding, in theory it solves the problem but in practice is too unreliable. i've had a good chat with my supervisor about it and we've had to axe it due to the unreliability of it.

thanks for the replies though guys.

[Matt Berube]

Not sure why it would be unreliable for you....

We use it here extremely often and there is never a problem. I have run an .nc file that was over 500MB and took 6 days running 24 hours per day to complete.

Good luck anyway and I hope you find something that works out.