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Hi all,  im nearing the end of my retrofit build. I am wanting to use some keyboard shortcuts. Not for jogging! 

I want to be able to select individual axis for mpg jogging using a keyboard shortcut. Also select things like mpg reaolution. Is this possible? 

Thanks in advance 

LinuxCNC has two forms of safety. The first is to limit the maximum distance that the axis can travel, but this option only works if the home is started in the initial position, otherwise it will collide. The second form of safety is to have sensors for the start and end of the stroke and the initial position, with these three sensors it is ideal to guarantee safety. A third option is to configure the drives, some equipment has parameters to limit the current and thus not exceed the mechanical limits of the machine.

A simple (simplistic?) way would be to use the lincurve component to compensate for the non-linear rotational distance.  Your model also needs to incorporate a pivot at the ballscrew mount since the screw will swing as the B-axis travels.

I would also install a high resolution encoder directly on the B-axis so LCNC can use a PID to adjust for screw mapping and lincurve errors.

But yea, I'd also abandon this idea and use a direct drive motor or a roller cam gear - or even a harmonic with a brake.  Even more simple - a big gear with two pinions and two servos.  One of the servos is in position mode and the other is programmed in torque mode to oppose the position servo to take up backlash.

Now you have a THCAD 2 you can do more tests.
But normally, you would set the THCAD to use 1/32 frequency. This would alter your offsets etc accordingly. Make that change
Assuming a 10 volt range, apply a 9 volt battery to the THCAD  HV input. The flashing light should change frequency. Does it?
the voltage should be about  90% of your full volt range. Is it?
What are the calibration frequencies for your THCAD on the sticker?
Read the encoder velocity at 0 volt at rest and at 9 volts.
What are these readings?

Just a question ? Do you have those softwares at hand?
You might end up with five axis requirements and then looking at a hefty monthly suscription

Just get a new detector and use it, for what it was for . But... did it come with some sort of x-ray light source?
mmmh. Any lead west in the box?

How about a 3d scanner? Woud at least be more close to original function.

I see your point. I thought to use Autodesk CAM (Inventor or Fusion).

Also something like this was used by Centroid for their cylinder head porting and polishing machines. Except they used to turn the work piece rather than the spindle. In their newer design they claim that the b-axis is controlled by a ballscrew but it is not visible

I'll make some more tests with MDI and see how feasible it is.
Motion blending is a must have for us.

Hi

I am new to CNC and specifically LInuxCNC. I am trying to build something like this for my B axis except I use the ball screw to turn the spindle rather than turning the workpiece. So it is possible to write a math function to relate the linear motion to the angle of the axis. It is similar to the formula used to find the crankshaft angle when the piston has travelled x distance. Like this

But how do I enter this into LinuxCNC? I am ok with the math I need help on the implementation into LinuxCNC

If you read the QTplasmac docs, there is a link to a calculator to determine your settings.

I'm using the calculator from the PNCconf. 

SOS UPDATE:
Changed the THC to THCAD2 and change for a divided arc
Put the THCAD2 outside the plasma source in a plastic box.
Shielded only on THCAD2, in new cables. 

Made the changes that you recommend:
   

Results:
This worked a week, but it happens again. The arc voltage is on -45.

I can take more pictures, make video. If anyone can help.
 

@phillc54:
I really shouldnt post at midnight. You are right. Lines with R90 were added by me manually and should be commented out.

"The second N12760 should have a J value of -89.450, not -89.500"
- yes and no, really. From the CAM the precision is fixed to 0.1 so therefore it is "correct" in this case. I really just need to adjust tolerance in linuxcnc somehow, because no possibility to change presision in cam. 

The source G-code is originally generated for esab NCE290. ";File converted successfully;" Means, it went trough parser which converts it to linuxcnc readable code without unknown command confilct (values are not checked).

If you are interested, there is complete program from CAM.

 
just to show you, how the code looks before


 
after converting to Linuxcnc readable code

Hi, thanks for the reply. I don't understand how this would create play. I designed it this way specifically to reduce backlash. I only need a travel of 45 degrees both ways and it needs a lot of torque to the weight of the spindle and motor being offset from center. The linkages are designed to have press-fitted bearings with dowel pins inside so I feel there should be no play. Also, the position of the ball-screw and the length of the linkage were designed to make sure that within the desired travel there are no dead spots. Is there something I am missing which you feel could result in backlash? Thanks again

Don't do this design! Do it worm gearbox . Just to make the project a success. There should be no play in the spindle.

Moin Juergen

den gut gemeinten Rat nehme ich gern an. Im ersten Step kann ich ja mal den Stecker in der Steckdose umdrehen, dann ist ein Großteil bereits über den L-Leiter integriert

Das diese elektrotechnische Gepflogenheit allerdings das Problem löst, denke ich nicht. Ich werde aber berichten, sobald ich einen neuen Stand habe.

Hi Everyone. 

I am new to CNC and This is my first post here. I am trying to build a 4th Axis that is controlled via a ballscrew. In the image attached you can see the motor and bearing for this setup. You can also see the linkages to control the rotation of the axis with the turning of the ballscrew. I wanted to know how I can setup my LinuxCNC to control the axis via the stepper and compensate for the change in angle based on turning the stepper. Thank you for your help in advance, and I apologise if this topic is not covered here. I'm not sure what to search for to find my answer.