What's new
What's new

How close do you rapid?

johnrobholmes

Aluminum
Joined
Jul 9, 2006
Location
missouri
I was once told by a machinist (while changing the machine parameters and overriding some safety functions to make a part) that 0.005" of clearance might as well be a mile. He always ran rapids to 0.005" clearance and didn't seem to have problems. I did the same on the Mazak and never had issues. But it was also a brand new machine.

How close do you cut it?
 
On lathes I rapid to within .1" on X and .05 on Z.
On mills, I rapid Z down to within .250" with a jump height of 2" to clear clamps and whatnot.
You can crash a lathe all day long, but crashing a mill will cost you big $$$
 
I was once told by a machinist (while changing the machine parameters and overriding some safety functions to make a part) that 0.005" of clearance might as well be a mile. He always ran rapids to 0.005" clearance and didn't seem to have problems. I did the same on the Mazak and never had issues. But it was also a brand new machine.

How close do you cut it?
Terrifying. Literally.
I've been running NC since the 70s, and that is just the scariest thing to do.
I rapid to within .1" except on castings/forgings and certain tools where it's .25"
All you need is an offset out of whack and *KABOOM* - if you're rapid-ing to within .005.
No thanks.
With .1 or greater, you at least have a chance to react, as I always prove out in single block with the rapid down.
 
For me, 5x machine. First start point, block center 2" above piece, then all rapids and skims are .025" radially, .070" axially, collision checking .001" shank clearance, .020" holder clearance, .70" machine clearance.
 
Both on a Machining Centre and Lathe in Z, to 10mm in Rapid, followed by a very rapid Feed move to 1mm. When running the first part of a new program there is just that bit more control with G01 and a fast feed rate for the final move close to the work-piece. Then in production, the time difference for that last 9mm move between Rapid and the Fast Feed rate is infinitesimal.

Plus the rapid to Z10.0 (mm) doesn't scare the shit out of an operator like a rapid to Z1.0 off a new program.

Regards,

Bill
 
Mills… Solidcam puts out three planes. Start height is 3”, clearance height between chains is .50”, and safety distance to go to and switch from rapid to feed is .050”.

I usually change the clearance to .100” on jobs that are either higher volume or have a lot of holes, chains etc..

Lathes, usually .100” in X (.050 per side) and .050 in Z. On volume jobs I’ll set it down to .020”. Tool retract moves I usually start high and tweak it down at the machine if I have the chance, usually allowing at least 1/2” of clearance for toolchanges.
 








 
Back
Top