Machine Slow on Curves

[swisscheese]

You can make CamBam curve fit a polyline using the "edit/polyline/arc fit" menu option.

E.g.



You are prompted for the tolerance so you can choose the tradeoff between accuracy and minimising the number of curves.

CamBam has a very good forum for asking these sort of questions. It is also deceptively simple and it's worth (never thought I'd say this) reading the manual to find out all the things it can do.

Hi,

Its not that i don't have an arc in cambam that is the problem. I do. The problem is when cambam creates the gcode it turns the arc into a series of lots of small straight lines. Im then having a problem with linuxCNC not giving a smooth output to the machine.

What i find weird in cambam is, you go to the postprocessor for linuxcnc, you then go down to 'Arc Output' and there are three options to choose from
normal
convert to lines
Helix convert to lines

So i assume normal would mean it makes a curve using lots of small radius. This isnt the case though

[JAZZCNC]

So i assume normal would mean it makes a curve using lots of small radius. This isnt the case though

Well you know the Old saying about "ASSumeing".!!. . . . . . Stop and go ask over at the Cambam forum and I'm sure you'll get the correct answer.

Personally I feel your not going to get what you want because like as been said this is how 99% of Cam packages output there code for 3d surfaces. Obviously linux as a problem with this and CV or again you need to go ask the Linux technical guys over at there forum but again I don't think you'll have much "Simple" joy because I've heard complaints from several experienced CNC users that Linux is rubbish at CV.

I quote "simple" because like the post Ger linked to shows there is a Planner in progress that may solve this but then I think you'll be into messing with compiling machine code and programming etc which if your not into programming isn't simple. It's also IMO why Linux CNC gets labeled with the GEEK factor and what lets Linux CNC down because the answer all too often is you have to resort to DIY programming machine code to get something fixed or working like you want it.!! . . . . . Which you shouldn't have to do this and esp for such a basic function as CV to use a CNC machine.

[swisscheese]

Well you know the Old saying about "ASSumeing".!!. . . . . . Stop and go ask over at the Cambam forum and I'm sure you'll get the correct answer.

Personally I feel your not going to get what you want because like as been said this is how 99% of Cam packages output there code for 3d surfaces. Obviously linux as a problem with this and CV or again you need to go ask the Linux technical guys over at there forum but again I don't think you'll have much "Simple" joy because I've heard complaints from several experienced CNC users that Linux is rubbish at CV.

I quote "simple" because like the post Ger linked to shows there is a Planner in progress that may solve this but then I think you'll be into messing with compiling machine code and programming etc which if your not into programming isn't simple. It's also IMO why Linux CNC gets labeled with the GEEK factor and what lets Linux down because the answer all too often is you have to resort to DIY programming machine code to get something fixed or working like you want it.!! . . . . . Which you shouldn't have to do this and esp for such a basic function as CV to use a CNC machine.

Jazz, have asked on the LinuxCNC forum and again was pointed to the New Projectory Planner, which i have to somehow install myself, i don't know much about the linux system. I spose thats what you get for free

Had a look at mach3 and was cheaper than i thought

[Jonathan]

Have you tried changing the 'P' setting with the G64 command to something other than zero? For example, if you put G64 P0.02 that will allow deviation of up to 0.02mm from the programmed path. That will reduce the amount the machine has to slow down when changing direction, for a given acceleration.

Also, what have you set the acceleration to for all of your axes?