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Maybe an electronic 'copy' device to build up a library of lobe shapes?

I'm thinking of a motorized fixture to rotate the cam, with a high-res rotary encoder and a roller follower with a high-res linear encoder.  Rotate the cam and you can now plot the toolpath based on the follower location to rotational position (and follower wheel diameter)

Once in CAM, the plot should allow reverse engineering the lobe max lift and duration @0 or 0.050" lift since it should be obvious when the follower is riding on the cylindrical portion of the cam.

If the fixture were built with the follower on a track that's aligned with the camshaft long axis, it'd be easy to just work your way down each lobe without much setup time.

As for generating toolpaths, this looks like a good use of LCNC's external offsets.  Like everything, the details are probably fussy... but I think you could essentially load the plot back in to an external offset table and the 'X" axis would follow the rotary axis's rotation.  Multiple step-downs, of course, and I'm not sure how to avoid air cutting during the roughing phase.

Cool project.  Can't wait to see how it works out.

Thanks PCW, yes restarting LinuxCNC= all good.


irrelevant here, but ,i fixed links permissions on sl bob pdf i've posted .

Hi

Background. Taig 3 axis mill with stepper motors. Been running for about 10 years. Was PC based but PC failed.
I had  Pi5 to hand so bought HAT from byte2bot and a breakout board.
I used the HAL file and ini file from byte2bot modifying with information from the old PC ini file and setting pin allocations to match Pi.
just starting setup sorting out home and limit switches. X axis works perfectly but when I try Y axis I am getting a following error fault.
I understand the basics of following error on a servo machine. How can you get a following error on a stepper drive and what do I need to do to solve the issue? FERROR set to 1.
 Are there any other sample Pi5 HAL files available to download?

Regards

Ian


 

Yes, it went well. Both your card, COFHAL, and SOLD's system were able to start and are now working.

Background: I have been making a few EtherCAT client cards, just to see how it can be done, to learn about EtherCAT and eventually use a card in my plasma cutter which is slowly being built. If all goes well.

I publish the project on github.com/MetalMusings/MyOwnEtherCATDevice and I made a series of Youtube video as I learned things along the way.

The card we were working on was the EaserCAT 3000

Yes, when you stop LinuxCNC, the 7I92 watchdog will bite.
The red '/INIT' LED indicates that the watchdog has bitten.
The RED LEDl will go off when you restart LinuxCNC.

thank you. i did everything like you mentioned and it works. setting steplen to 1 and stepsace to 0 along with pin reset 1 increases the total rpm i can acheive with my motor. ( now it rotates much faster than it did with scale at 6400)

what doesnt work (or is counter intuitive) is when i set the spindle scale to 800 (as my servo is set to 800 pulses/rev) the spindle turns very slowly.
when i put it to 6400, it turns much faster.
and when i put it to 64000 it turns even faster.

but as it works for me, ill leave it at that. thanks again!

Should i specify , as i showed interest in arm64 , I'm on a pc , fresh official debian 12 linuxcnc install ,all up to date to latest ,not messing arround with orange pi 5/rt preempt until i got some success with the x64 .

I am slowly getting back to it ,into mesa first test 2 years ago , where i got very basic success fiddling with the 5abob firmware/linuxcnc 2.8 and some kind of communication with the sl bob relays , that was it .
Now , got pncconf discovery magic to recognise 7i92_slpc2x2d firmware & generate a configuration that , hmm , at least load in linuxcnc . Still a lot do , first will be , charge pump , something is wrong , and or missing.
Learning curve is steep ,i most admit ,the n00b is studying .

Closing linuxcnc get the 7i92 to lock ,red light , reload needed , is that normal ?

One option, maybe the best, is to switch to an EtherCAT stepper motor driver.

Hi NTULINUX, thank you for your efforts to make LinuxCNC faster on Gentoo. Could you share with us what performance gains you got with this, especially when it comes to latency? It may be interesting for other distros too.

timo post=315275 userid=29371What I saw in hobby forums are mostly "copy" machines using a master(template)cam and some mechanical system to follow the template. (this boils down to 2d operation.

What do you mean by scale? Does it matter what size the parts are?

lobe shapes/profiles are not directly related to the base circle. That is to say that, the size of a lobe is correlated to the base diameter of the camshaft journal, but not always. I can upload some 3d models of camshafts and screen shots to illustrate this. 

PCW wrote:

This should be close:



 

Added a scope widget. Maybe add cool widgets. Have seen flight simulator widgets 

thanks for reply .but laser has just x and y but my machine is special sewing and has 4 axies xyza and spindle works as needle punch that speed must be dynamicly related to speed of x axies y axies or xy movment speed.

Achtung jetzt kommt gefährliches Halbwissen:

Manche Encoder laufen mit Differnzsignal, manche gegen GND.
Auf der Mesa Karte sind soweit ich mich erinnere Jumper, wo man die Sorte auswählen muss.
Jumper W2 entscheided, ob TB3 extra 5V benötigt, oder ob 5V von der anderen Verbindung kommt.
Zitat:

"The 7I76s high speed encoder input can be programmed for differential or single
ended mode operation. W4, W5 and W6 set the encoder input mode. When W4,W5,and
W6 are in the right hand position, the encoder input is mode is differential. When W4,W5,
and W6 are in the left hand position, the encoder input mode is single ended or "TTL"."

Da würde ich mal gucken ob W4, W5, und W6 zum Encoder passend gesteckt sind.

Hoffe das hilft

Grüße Timo