[NewMatter]

I am running Bobcam V25 on a Bridgeport EZtrak SX. I am having problems with the machine wanting to run jerking through a program around arcs or anytime it changes direction. I take the Gcode program directly from Bobcam and save it to a floppy disk as a .txt file and run it in the machine. I have read about the g64 and g61 commands used in Mach3 however I do not have mach3. I have changed the Arc Slowdown and that seems to have no change on things. Has anyone else had this problem or know how to solve it? Any help is appreciated. I know very little about gcode but I have attached a program that may offer some help. Thanks

[jrmach]

"Jerky" can mean a whole lot of things.
Sure sounds like a machine problem.
I would post in the appropriate forum for your machine also.

[hughesbros]

Try adding a G9 at the start of the profile, I think it's a modal code so you should only need it once. If you need to turn it off use G8.

Mark.

[NewMatter]

Its not a machine problem. The feed rate will continually jump from 100% to a lower percentage in between moves. Thanks for the advice on the G9 command I will try it out later today.

[aldepoalo]

New Matter,

Is the machine stopping and starting at every move?

[NewMatter]

No it is not coming to a complete stop. It will go from 30 IPM to 10 IPM between each line of code.

[hub]

What controller do you have?

[dertsap]

are you running equidistant toolpaths ? Reason that I ask is equidistant in v25 creates short line segment codes even on arcs , and the short line segments will cause a lot of jerkiness . If not then it may be an accel/decel issue with you machine settings

[hughesbros]

If you've got the G9 code in the right place it should use constant contouring. One other thing, you have the SX so no hard drive so it could be a problem reading the file from the floppy fast enough.

Mark

[The Engine Guy]

No it is not coming to a complete stop. It will go from 30 IPM to 10 IPM between each line of code.

Looking at your code it shows every line with an F30 for feed rate so the change in feed would appear to not come from BobCAD.

If your controller has Auto slow down for direction changes then have a look at it`s settings (Might have to consult the Manual for that) and adjust as required.

One thing I did notice is that some of your moves don`t have the "N" for the line number, these appear to be all G01 Linear moves and all look to be very short distances so it is possible that the controller may not be able to read these lines without the "N", some machines won`t, if that`s the case then the machine will in effect be "skipping" those moves which would cause a very jerky movement.
For example these lines in your code :-

N28 G02 X1.1551 Y-3.4774 I0.5333 J-3.0002 F30.0000
29 G01 G90 X1.1560 Y-3.4785 Z-0.0750 F30.0000
N30 G03 X1.5915 Y-3.7207 I2.8983 J-0.8590 F30.0000

Line N28 is what I would expect to see for a CW arc, and line N30 is what I would expect to see for a CCW arc, however the line in between 29 has no "N" and may not be being "seen" and run by the controller, so what could be happening is the machine is jumping from a CW arc to a CCW arc without doing that very short G01 Linear move in between them which I would expect to be "jerky"

A shot in the dark maybe, but all I have for now

Regards
Rob
:rainfro: :rainfro: :rainfro:

[hughesbros]

I should get my eyes tested I missed the file attached to the first post compleatly. All you need to change is remove the G64 on the first line then add a g9 to line 4 and it will run fine.



Mark