Cutting 4" NPT on lathe

ecs

ECS
Hi Guys,

I'm not sure what i'm doing wrong but i've drawn a product in fusion and ran some tool paths to cut a 4" NPT taper thread on some pvc pipe.

Everything works in the simulation. I load the file into masso and it show everything correct with the taper in the display. But when it cuts it doesn't follow the taper. When threading it just goes across in a straight line. The x axis doesn't move to suit the taper.

Attached is the file.

In the profile section it turns the taper no problem just not in the threading section. I also have "fade thread end" turned on which doesn't work (but the z axis is doing something funny at the end of the thread so i think the z axis is actually doing the the fade out instead of the x axis.

Cheers,
Josh
 

Attachments

  • 1002.nc
    1.3 KB · Views: 14

ecs

ECS
@masso-support - well that makes sense haha!

I read it needs a G76 command.
You guys mentioned you were going to add the G76 command on another post a year and a bit ago. Is this still going to happen?
 

al

AL
you should be able to put a x value in the G32 to cut a taper thread ( if masso allows it ) that is standard for the G32 check the link for explanation

N40 X22.026 (start x value )
N50 G32 X49.562 Z-71.5 F3.0 ( larger x to cut taper , the x axis moves while the z is traveling)
N60 G00 X90.0

 

ecs

ECS
@al I can confirm this doesn't work. If you look at my attached 1002.nc file. It doesn't work on the masso and has the code the same as above. It cuts the thread straight even tho the code for the taper is there.

From all my research tonight it looks like the G76 is the best option. The Helman website has some great information about all he codes and example code. Thanks!
 

masso-support

MASSO Support
Staff member
Quote from ECS on August 13, 2019, 5:20 am

@masso-support - well that makes sense haha!

I read it needs a G76 command.
You guys mentioned you were going to add the G76 command on another post a year and a bit ago. Is this still going to happen?

all feature requests are prioritized depending on how many users request a feature. This was only requested by a few users and the development was stopped.
 

evermech

evermech
@ecs

if you think you can cut that thread in one pass you might think about regenerating the code with one pass then substitute a G01 on the line that creates the taper ( remove the G76 or G32 whichever you are using )

unfortunately you won't be able to cut that thread again because there is no relation to spindle datum

Uh I'd air cut this first just in case it's not happy I hate crashes

Guy
 

machinedude

machinedude
Quote from evermech on August 14, 2019, 1:38 am

@ecs

if you think you can cut that thread in one pass you might think about regenerating the code with one pass then substitute a G01 on the line that creates the taper ( remove the G76 or G32 whichever you are using )

unfortunately you won't be able to cut that thread again because there is no relation to spindle datum

Uh I'd air cut this first just in case it's not happy I hate crashes

Guy

cutting plastic i would bet the plastic pipe would go before anything else maybe the tool tip but i would be surprised if anything else bad went wrong before that. look at it this way it's good practice for the butt hole pucker switch reaction time :)
 

ecs

ECS
@testyourdesign - So i had a further look into this and while the code isn't using any G32 it has no way of tracking the thread. Its different for a mill as the stock never moves!

@machinedude - I did have a crack at this and it didn't go well..... I would have recorded it but trying to hold a phone while hovering over the estop just wasn't an option. The PVC just flew out of the chuck.

I'm just going to request the feature and see if we can get enough people on board to have this looked at.
 
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