Machsupport Forum

Mach Discussion => Mach4 General Discussion => Topic started by: RecceDG on August 04, 2021, 02:41:33 PM

Title: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 04, 2021, 02:41:33 PM
Firstly - has anybody beaten me to it?

Secondly, the behavior of G02/03 - is this legal?

G3 X.5081 Z-5.5497 I.1025

There's an I, but no K....

Thirdly, G28 - that moves back to the home switches, right? Is there a way to programmatically set a user-defined home position?

The generic FANUC post does this:

G28 U0. W0.
G50 X1. Z-5.

To move to X1.0, Z-0.5, but in the lathe manual G50 only sets min/max spindle speeds; passing it X and Z I don't think is legal.
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: gabedrummin on August 04, 2021, 03:18:26 PM
So I use a Fanuc post forMach4 lathe .With lots of issues , when threading I have to change all the E to F .I delete the lines with G28 , Mach dose some weird stuff when it see's that depending where the machine is I have had it run the tool into the spindle and some times it goes to the home switch position . I have had huge problems with I & K for G02 & G03 So much that I only use R value's when programing circles . It would be great to have a working post .Maybe when you fix it you wouldn't mind sharing ?
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 04, 2021, 09:03:29 PM
So it turns out you can force radius mode for arcs in the Control Definition - see image.
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: gabedrummin on August 04, 2021, 09:16:30 PM
Yes I know.
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 05, 2021, 08:02:53 AM
So this is proceeding. Someone at Mastercam is helping me and I'm going to chip away at this for the next couple of days.

Here's the current work list:

1. Append M6 to all tool changes

2. Eliminate spurious tool number at end of file

3. Make default "move to home position" a G0 move, not a G28 - this relies on setting a home position in the toolpath

4. Prepending the recommended Mach "safe start block" to the start of a file

Does anybody have any other changes they want?

Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: gabedrummin on August 05, 2021, 10:37:38 AM
If your changing stuff please change the G76 cycle when the code gets posted for threading Mastercam post E for the feed amount and Mach wants to see an F  .That will save some edit time.
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 05, 2021, 10:39:02 AM
Is that the only change to the thread cycle? E for F?
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 06, 2021, 07:41:17 AM
OK, I have those changes made.

To get rid of the G28 move to home, you need to set Misc Integer 1 to "1" in the control definition.

I also patched in the E for F in G76. There is a switch inside the post ("old style" or "new style") that on my copy was set to produce the F - so the patch shouldn't be needed if the switch is set right - but Mach never wants the E and this is (now) a Mach Lathe specific post, so I hacked that change in.

I'm now discussing how to get the post added to mastercam.com
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: Cbyrdtopper on August 06, 2021, 08:28:09 AM

Thirdly, G28 - that moves back to the home switches, right? Is there a way to programmatically set a user-defined home position?


You can use G30 instead of G28.  Populate the System VARS#  5181-5183 (5181 = X 5182 = Y 5183 = Z).  You put in the Machine Position you want it to go to into these variables. 
It is best to have homing on your machine since this is where it will go every time. 
It won't go to the home position unless you leave the #VARS 0.00
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 06, 2021, 08:59:02 AM

You can use G30 instead of G28.  Populate the System VARS#  5181-5183 (5181 = X 5182 = Y 5183 = Z).  You put in the Machine Position you want it to go to into these variables. 
It is best to have homing on your machine since this is where it will go every time. 
It won't go to the home position unless you leave the #VARS 0.00

We're having that discussion here: https://www.machsupport.com/forum/index.php?topic=45115.0
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: RecceDG on August 09, 2021, 07:49:50 PM
Discovered that I had fat-fingered the safe start line, putting in G17 instead of G18. That fixed the arc being missing, but revealed that the postprocessor is using G3 when it should use G2 and vice versa.

I *think* I have that fixed, but I'm going to have to design a part with a bunch of different profiles and make sure all the arcs are in the right direction to be sure. The part of the post that controls this bit is crazy complex.
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: gabedrummin on September 05, 2021, 10:52:06 PM
Great work thank you for trying to fix the post . Sure would like to use I & K instead of R .Only been using because I ,k gave me code that the ars were all messed up .?
Title: Re: Working on Mach 4 Lathe Postprocessor for Mastercam
Post by: smurph on September 07, 2021, 04:19:31 PM
Discovered that I had fat-fingered the safe start line, putting in G17 instead of G18. That fixed the arc being missing, but revealed that the postprocessor is using G3 when it should use G2 and vice versa.

I *think* I have that fixed, but I'm going to have to design a part with a bunch of different profiles and make sure all the arcs are in the right direction to be sure. The part of the post that controls this bit is crazy complex.

See "Newfangled Lathe Turret Standard.pdf" for an explanation tool post position affecting G02/G03 direction.  Depending on your lathe configuration, you may have to define your tool as being secondary direction.

Steve