c axis toolpath scallops on finished part

[Zoffen]

hey all,

 

I'm running some parts today on our Mazak QT350M with a 640T control.

 

I am cutting a rectangular pocket when i finish i'm getting small evenly spaced scallops on the finished edge and i think its because im not feeding the machine enough code to do it smoothly. Right now there is a line of C&X axis movement every 2ish degrees.

I'm thinking that if i could get that down to .1ish degrees then the toolpath would be very smooth.

 

I'm using Milling toolpaths with axis substitution.

 

Anyone have any thoughts or ideas?

Any help is MUCH appreciated!

 

thanks!

[Philcott]

Are you cutting on the face of the part or on the O.D.?

 

I would try using polar notching (G112 or G12.1) if your machine supports it. It will give much better results.

[Zoffen]

It is a pocket cut through the center of the part.

 

This machine doesn't have polar machining....our new QT350 Does tho.....

 

Any way to force mastercam to spit out more code....?

[Dtm]

It is a pocket cut through the center of the part.

 

This machine doesn't have polar machining....our new QT350 Does tho.....

 

Any way to force mastercam to spit out more code....?

 

If you are using splines rather than lines you will get a finish you are describing. Did you create curves from a model or draw it yourself?

[Zoffen]

the geo is arcs and lines...

[Chris Rizzo]

im not feeding the machine enough code to do it smoothly

 

A straight line would need just a few lines of code? right? Are the walls just evenly faceted? sounds like your getting point to point, vs. tangent line and arcs.

 

Turn you filter on in the toolpath.

Take a look at nc size.

Regen.

See if size went up or down.

[Zoffen]

ok so i might have figured it out....

 

Would being in M200 Milling point to point mode make it happen? Instead of being in M201 Line machining mode....

 

Seems logical to me......

 

now just need to wait till the cycles done to test out...

[Zoffen]

NOPE!

 

Finished looked the same....just need to force more code down that b*tches CPU!

 

I'm using a generic 4x lathe post that i customized. I read that this doens't read the Machine Def by default.

In the machine def there is a break rotory motion in the rotary axis compent properties page. How would i link this up to the post to get the desired output i'm lookin for?

or what could i put in my post to break rotary motion in .1ish increments?

 

Thanks for the help!

[andate caga]

Have you tried filtering?

[K2csq7]

If your tool is following a chain, edit, trim break, break many pcs. and break it as many times as you see fit.

If your tool is cutting a pocket, filtering the toolpath is the way to go.

(If you are doing some pocketing, a last resort would be to backplot, save as geo, then break that geo into many pcs.)

Also check your machine definition, double click the rotary axis, you will see a box for "break rotary motion" enter the desired max rotary move in degrees. Not sure if this actually changes anything (a lot of the MD's & CD's seem to be fluff), but it sounds right!

You may have a similar setting in your post if that doesn't have any effect.

[Zoffen]

this is for the finish pass only. The roughing seems to do fine.

 

I will try breaking the lines and arcs into many pieces and see what it does.

 

Yea....that setting in the MD does nothing and i don't see an obvious break c axis moves variable in my post.

 

Could someone share some post logic to make the break rotary motion in my Machine def actually do something?

I know i need to read it into a variable but then how would i apply logic in the post to actually break the motion.

thanks!

[Dtm]

ok so i might have figured it out....

 

Would being in M200 Milling point to point mode make it happen? Instead of being in M201 Line machining mode....

 

Seems logical to me......

 

now just need to wait till the cycles done to test out...

 

I use M200 on all of my programs and do not use the filter and my parts look good, not sure.