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### Author Topic: Z speed limiting xy speed  (Read 3370 times)

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#### Millone

• 10
##### Re: Z speed limiting xy speed
« Reply #10 on: February 19, 2018, 01:54:56 PM »
The machine is normally set as following (with the Z motor connected):
X and Y are set at 500 steps/mm, 20000 mm/min acceleration 500
Z is set at 500 steps/mm, 10000 mm/min acceleration 400
With the above setting I use the machine for normal operations

When I connect the laser instead of the Z motor, I change the Z settings as following:
250 steps/mm, 20000 mm/sec, acceleration 100000

In such configuration I do expect Z to be so reactive that XY are not affected by the Z changes which are from -0.3 to - 0.8 mm
Instead I clearly see the machine slowing down on the DRO for each Z change and I can clearly hear the ugly noise of a machine stepping all the tiime. You can get a feeling of the noise here:  https://www.youtube.com/watch?v=jUVU17ks89Y
I am trying to get the machine rastering smoothly but I cannot achieve it.
« Last Edit: February 19, 2018, 02:03:32 PM by Millone »

#### TPS

• 2,436
##### Re: Z speed limiting xy speed
« Reply #11 on: February 19, 2018, 02:10:44 PM »
ok let's do some basic's

F100
G1 X100 -> will Need 1 Minute because distance is 100mm

F100
G1 Y100 -> will Need 1 Minute because distance is 100mm

F100
G1 X100 Y100 -> will Need about 1 Minute 24 seconds because distance is about 141mm (SQR(X²+Y²))

i hope this example makes clear, that every Z axis movement will slow down XY, because
the real distance is allways longer, than a simple XY movement, because machine is allways
doing constant Speed based on real distance (in CV mode).

Thomas

anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.

#### TPS

• 2,436
##### Re: Z speed limiting xy speed
« Reply #12 on: February 19, 2018, 02:24:33 PM »
btw in your Video i have recognized that you are working on a laser Project.

here:

http://www.machsupport.com/forum/index.php/topic,12444.0.html

Tweakie has documented his hard laser road.

as far i got the Information out of this thread the "clue" is to regulate XY Speed instead of laser power.

'hopefully' Tweakie is jumping in here, because i think he has the Experience on laser.

Thomas
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.

#### Millone

• 10
##### Re: Z speed limiting xy speed
« Reply #13 on: February 19, 2018, 03:01:12 PM »
Thanks for the link. There is a lot to read there. Let me study it.....

#### Millone

• 10
##### Re: Z speed limiting xy speed
« Reply #14 on: February 19, 2018, 03:11:16 PM »
@TPS

I did look at the project you pointed me. Nice beautiful project but it is something completely different. In my project I modulate the laser power with the Z values obtaining something like a grayscale engraving.
In the project you have referred me the Z looks to be fixed, the laser power is adjusted manually. What I am trying to solve is to avoid that the Z variations slows down xy during the rastering.

#### TOTALLYRC

• 861
##### Re: Z speed limiting xy speed
« Reply #15 on: February 19, 2018, 09:07:52 PM »
I just took a look at your G-code and since you have the "Z" moves on separate line it will not do what you want. Try putting the "Z" move an the same line as the motion.

In other words you are saying, move the X stop, move the Z, Stop and so on. Most trajectory planners have a hell of a time with the short segment code that you are throwing at it.

I would also try not repeating the Z moves every other line if they don't change. It may allow the look ahead to be more effective since you will remove a lot of lines from the program.

Mike
We never have the time or money to do it right the first time, but we somehow manage to do it twice and then spend the money to get it right.

#### TPS

• 2,436
##### Re: Z speed limiting xy speed
« Reply #16 on: February 20, 2018, 01:46:28 AM »
an other idea might be to use spindlespeed for laserpower

M3 S100 F500
G1 X10  S200
G1 X20  S300
G1 X30  S400
M5

just brainstorming.
anything is possible, just try to do it.
if you find some mistakes, in my bad bavarian english,they are yours.