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mold making Mach3mill scaling
« on: April 20, 2012, 01:43:27 PM »
1) If i have code generated for a cavity in a mold thats programed 1:1 with no shrink allowance for when the plastic cools down ,can I use the "scale" next to the DRO to add .010 by typing "1.010" into the xyz scale boxes and will that make my cavity .010 larger in all axis  for the shrink I need ??? VERY COOL IF IT DOES !!!!!
 2) Also if I'm using a .500 diameter end mill cutting out a pocket and I want to be on the safe side of material removal, will putting .990 in the scale boxes make it cut the pocket under size, then after measuring it , set scaling back to 1.000 ,would it make a clean up pass to my end dimensions.
3) I'm thinking the "scaling" feature would be a very easy way of cutter comp without actually having to have it in the program.  And just do EVERTHING 1:1
4) Is that what the "Scaling" feature is for or is it for something else?
I be a knoob with all this so use small words and short sentences please.  ;D Thanks, rj

Offline BR549

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Re: mold making Mach3mill scaling
« Reply #1 on: April 20, 2012, 02:43:51 PM »
First NOONE creates molds that would not account for part shrinkage IF it mattered. (;-)

Scaling will work BUT you have to be aware of WHERE the reference point of the scaling takes place IF you are going to repeat the process at a different scale.  You really would need to be at teh exact center of the part for the scaling origin and that may be almost impossible to do in 3d space.

A one shot scale is fairly easy IF the resulting final part position does not need to be exact. BUT if you are needing to repeat it at a different scale at teh exact same position THAT is a toughy

It is NOT an easy process to master(;-)

Just a thought, (;-)
« Last Edit: April 20, 2012, 02:46:15 PM by BR549 »
Re: mold making Mach3mill scaling
« Reply #2 on: April 20, 2012, 03:09:08 PM »
Good thoughts BR549 I hadn't thought of the reference point.  
  To simplify my question. If someone sends me a 3d part file and its 1:1 scale. I bring it into my cam system BobCad v24, let it make the code, import code into Mach3. Run it and rough it out as is, then scale it up on the Mach3 "Scale" by my shrink factor, rerun to make a finish pass making it ever so lovely.
Figuring out where the reference point origin is may be like trying to pull a rabbit out of the hat.
So how/what for is the "Scale" feature used in real life applications? thanks rj

Offline BR549

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Re: mold making Mach3mill scaling
« Reply #3 on: April 20, 2012, 04:10:44 PM »
YOU would normaly  DO the RESCALE to the cad drawing BEFORE you Cammed it out(;-)

Scaling can be very useful for a one shot rescale.  We use it all the time in plasma cutting where it is a simple2d process. AND re can recut at a rescaled value BUT you have to know exactly where the ref point is going to be and plan accordingly for the Coord shift to get it lined back up.

YOU CAN set the scale reference point WHEN you call the rescale. From the screen just move to the position you want it to be BEFORE you input the scaling factor. FROM gcode include the move to a ref point before the G50 call

G0 X1Y1
G50 X2.0Y2.0

Move to the ref point
Apply the scaling factor of 2.0 to X and Y

Just don't forget to cancel the scaling when done with the G51 .

AND it IS possible to calculate the REF point offsetting when scalling. But that is way above my simple brain.

HECK give it a try with a simple shape like a cube (;-) you may end up being good at it. YA NEVER KNOW  untill you try it.

(;-) TP
« Last Edit: April 20, 2012, 04:18:47 PM by BR549 »

Offline BR549

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Re: mold making Mach3mill scaling
« Reply #4 on: April 20, 2012, 04:39:07 PM »
Something along these lines MAY work. It offset the second cut to account for the ref shift. It uses 1/2 the scale amount for the offset.

DON't go by the toolpath display it does funny things with offsetting displays.

F100
G0 X0 Y0
G1 X10 Y0
X10Y10
Y10X0
X0Y0

G0 X-.5Y-.5
G92 X0 Y0

G51 X1.1 Y1.1
G0 X0 Y0
G1 X10 Y0
X10Y10
Y10X0
X0Y0

G50
M30