[a_j_p]

Hey Tom,

Thanks again... I gotta say your constant responses are very appreciated - also gotta say that now that I'm starting to figure out what I am doing writing in C I love this Kflop device and KmotionCNC software - definitely frustrating in the beginning but now that I'm getting past that it's amazing to be able to have full control of the machine and how it behaves to any/all situations.

Thanks homie,
-Andrew

[jossa]

holly crap!

i think i have found a bug in my setup.



in the step response window in kmotion.exe, i have not input any velocity, acceleration or jerk and it is set to 40000, 400000 and 4e+006 as default

we have earlier found out that in my case there is: 3200/5=640 steps/mm


could this be what is causing my mill to test cut outside of the dimensions in the cad file? (also the z axis is almost always higher then it should be)
i have been working on the premise that it was something wrong in my CAM program.

i have been writing a how to and while writing that i started looking at old post, and then i found this and started thinking.


if not here, where should the pitch and such be factored into the program?

[TomKerekes]

Hi jossa,

The values in the KMotion Step Response Screen are not necessarily in use unless you have downloaded the Screens to KFLOP by pushing "Download" or by performing a "Move" on the Step Response Screen. Please see this Flash Video to see if it helps:
http://www.dynomotion.com/Help/Flash...ers/index.html

You should have already used the Step Response Screen to find good working values of Velocity, Acceleration, and Jerk. These values should the be Exported to your Initialization C Program so the same values are used regardless of whether you use the KMotion Screens or the C Program.

However these values are only used when performing Rapids (G0). Not when cutting with G1, G2, G3 type of coordinated motion. For Coordinated Motion the parameters in KMotionCNC | Tool Setup | Trajectory Planner are used.

Note also that when cutting (G1 G2 G3) infinite Jerk is used. So you should experiment using the KMotion Step Response Screen with infinite Jerk (1000X Acceleration) to test how well your system performs with no Jerk limit. Often lower levels of Acceleration and Velocity are required when there is no Jerk limit.

HTH
Regards

[jossa]

i have not figured out any values.. i had forgot that part when moving to a new computer... so they are left to the default value..
and it works really fine, no resonance and no lost steps that i can see at any speed, and they can move lightning fast!


could this explain why i am having problems with my accuracy and dimensions?


i remember you explained to me the relationship between 16X microsteping and my 5mm pitched ball screws..
where is this relationship accounted for?

[TomKerekes]

Hi jossa,

If you haven't configured KMotionCNC for the resolution of your system that could certainly throw off your scale completely.

The microstepping resolution is entered into KMotionCNC | Tool Setup | Trajectory Planner | Axis Parameters | Cnts/inch

The units are counts (or steps) per inch. So if your resolution is 640 steps/mm enter:

640 steps/mm x 25.4mm/inch = 16256 steps/inch

Regards

[jossa]

I see!

I have not done that and the values are set to the default 10 000 counts/inch, thus explaining the odd behavior of my mill..
i will try updating that tomorrow and retry the same file and see what happens.

Thanks tom!

And referring to the other tread, you don't owe me anything, the "how to" i am writing is a way of repaying the approximate $10 000 worth of education and support you have given me after buying your product. (i have really learnt allot from it and you, and i am grateful for that)
And this gives me an opportunity to see if what i have done is right, or if it could be improved in any way.

i really like the kflop, and i want to do what i can to lower the threshold and allow other novices like myself a chance at using it..