Unresolved Changing Vmax and Amax Z affects X and Y

Weird issue when I was trying to tweak some settings per Marquis Johnson's tweaks.

Whenever I modify the Vmax Z and Vmax A settings, it also changes the X and Y axis (speed wise, not numerical). This is causing the X axis to skip/grind during homing.

Anyone else run into this?

 

Beuller...Beuller...where is @Marquis Johnson these days?

 

Josh

Do you have a link to the video you were watching to get this advice?

 

From the Forums:
http://community.robo3d.com/index.php?threads/amazon-sain-smart-lead-screws.7077/#post-80760


From his YouTube video here:

He briefly speaks of it at timestamp 15:15, but explains it in the comments

Code:

Novice Expert9 months ago
+John New  (Configuration.h) #define DEFAULT_AXIS_STEPS_PER_UNIT {X, Y, 405, E} //405 is Z #define DEFAULT_MAX_FEEDRATE {X, Y, 25, E} //25 is Z #define HOMING_FEEDRATE {X, Y, 20*60, E} //20*60 is Z (Configuration_adv.h) #define MANUAL_FEEDRATE {X, Y, 25*60, E} //25*60 is Z
2

Novice Expert9 months ago
+John New WheresWaldo gave me the actual calculation for Z-Steps/mm. I used a proportion calculation, he actually figured out what screw pitch they actually were. So.... #define DEFAULT_AXIS_STEPS_PER_UNIT {X, Y, 400, E} //400 is Z

Maybe @WheresWaldo was involved as well?

 

I should have mentioned in the beginning, I have the SainSmart leadscrews. But I doubt that makes a difference as Z should not affect X or Y

 

These are the changes that affect it:

Code:

(Configuration.h)
#define DEFAULT_MAX_FEEDRATE {X, Y, 25, E} //25 is Z
#define HOMING_FEEDRATE {X, Y, 20*60, E} //20*60 is Z
(Configuration_adv.h)
#define MANUAL_FEEDRATE {X, Y, 25*60, E} //25*60 is Z

So, they are split up, but for some reason Z is affecting X and Y as well.
The DEFAULT_MAX_FEEDRATE coorelates directly to the Vmax Z on the LCD in Control-->Motion

After further testing, just the DEFAULT_MAX_FEEDRATE causes the issue.
Seems like when I change Vmax Z to 25 (from 5), it also affects X and Y (not sure about E, I didnt test as it was skipping on my X)

 

I think it was modified due to the SainSmart leadscrews being slower to raise/lower vs the 8MM threaded rods. This change does increase the speed, but is also affected the other axes (<-- plural of axis? axises? axiss? not enough coffee yet)

 

I will try 10 vs the stock 5 and see if it speed it up a bit. The wait time during homing after a 120+mm tall print is excruciating. Still weird that it affects the other axis. And I never thought about changing the math to direct numbers. That makes sense.

 

I did do some of his tweaks to get my ABL a bit faster but had to back down on his numbers. It put things way too fast for long time use.

 

what version? I better check my sketch when I get home.

 

I bet! That would be good to know, but also like WW said it is better practice not to use the match when you know all the values. Just use the result.

 

Necroposting, but this is an old printer and this thread is unresolved and exactly the issue I am having. I upgraded to lead screws, I want to speed up the z axis but changing DEFAULT_MAX_FEEDRATE from 5 to something higher produced skipping on the X or Y when hopping. It tries to go to the center for platform very fast, before lowing the Z and homing it.

Did anyone ever figure this out?