I've recently upgraded from the Ubuntu 10.04 ISO version which for both my Sherline 2000 and Chinese 6040 Router was very effective and completely trouble-free.
But alas, the need for swifter graphics in my system's HP Elite 8300 led to the purchase of a Nvidia Super 1650. There was no driver available for Ubuntu 10.04 for this card, so I installed the Ubuntu 18.04 RTAI kernel and the additional modules required to make it work and (Voila!) it did work.
But I now have a problem I didn't have before.
Among other things I use the router to etch Printed Circuit Boards. The G-code for the boards is generated by a Plug-In ULP named pcb-gcode which converts an Eagle file to the Gcode needed to drill holes in the boards, etch and isolate the traces and mill the perimeter so that the board will have uniform dimensions and fit the box it goes into.
This has worked flawlessly for years using LinxCNC 10.04.
The arrows point to where the isolation trench adjacent to the trace has been radiused. These are not in my G-Code
They do not show if I run the code in CAMotics - a nifty visualizer which shows what the G-Code will do. Clearly this is something which LinuxCNC is doing. And with no consistent pattern although most of these are inside radii.
They do show up in the visual screen when LinuxCNC runs the code and of course they get cut. Initially I thought this was really only a cosmetic problem and for sure no-one else would know about them, but it wasn't that simple. I found a place where the radius in trench was cutting an adjacent trace - cannot have that!
Where should I look for the source of this problem? I did have to do a new stepconf for the router because the old one wouldn't load- not compatible with Version2.8. Could I have screwed up my INI?
Should I add a G64 statement to each job?
I would rather find out how this is happening and fix LinuxCNC itself.
G64 is the way to go. By default Linuxcnc prioritises velocity when moving. By adding G64, it tells the system how far away from the planned trajectory it is allowed to go so it forces deceleration to keep to the path. Most of us have learnt this lesson. In my case it was tracing 1.0m x 1.0m square on my plasma table and it was almost a circle.
how wonderful that this could be so easily fixed. I can add this line to the default front end of every file output from pcb-gcode and hopefully not have to worry about it again.
a circle rather than a square and at that size. amazing.
It's nice to find I wasn't the only one to encounter this problem. Wouldn't you think how LinuxCNC prioritizes tracking should be a toggle somewhere.
