Z height trouble (too short)

having problems guys need some help.

Iv noticed i have a problem with my Z Axis.

im running a prusa I3 (wooded box) with M5 threaded rod.

I was using 4000 steps per mm but was suggested to try 3657.10 (IRC)

still got the problem

if i print a 10mm cube it is only 8mm heigh (x and y is okay and measure 10mm in cube print)

any ideas what i can try ?

my current marlin settings are

#define NUM_AXIS 4 // The axis order in all axis related arrays is X, Y, Z, E
#define HOMING_FEEDRATE {50*60, 50*60, 1*60, 0}  // set the homing speeds (mm/min)

#define DEFAULT_AXIS_STEPS_PER_UNIT   {80, 80, 3657.14 ,390.6}  // default steps per unit for ultimaker 
#define DEFAULT_MAX_FEEDRATE          {500, 500, 5, 45}    // (mm/sec)    
#define DEFAULT_MAX_ACCELERATION      {9000,9000,100,10000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION          3000    // X, Y, Z and E max acceleration in mm/s^2 for printing moves 
#define DEFAULT_RETRACT_ACCELERATION  3000   // X, Y, Z and E max acceleration in mm/s^2 for r retracts

// 
#define DEFAULT_XYJERK                20.0    // (mm/sec)
#define DEFAULT_ZJERK                 0.4     // (mm/sec)
#define DEFAULT_EJERK                 5.0    // (mm/sec)

Edited 1 time(s). Last edit at 01/18/2013 09:14AM by Enlightx.

5 mm/sec for the Z axis seems awfully high.
Try 1 mm/sec and see if that fixes your problem.
In any case, loosing steps on the z axis could be the cause of your problem.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Yes 4000 is correct but you probably can't get 5mm/s with an M5 screw.

---

[www.hydraraptor.blogspot.com]

changed the feed rate to 1mm/sec still getting problems

any ideas what is suggested to join the M5 rod to the steppers iv been using silicon tubing 4mm

just thinking if this is the problem

just cannot understand why i have no problem when moving the axis with pronterface i say move 10mm it moves 10mm okay

any other ideas?

is your axis set to be enabled when it is not used? for some reason my newer prusa requires the z axis always to be enabled. I think it is because i run it beyond 60mm/s, and the vibrations cause the z axis threaded rods to move down slightly, because of the weight on the axis.

i changed it to be disabled when not used so i could alter height if needed while printing.

Ill enable it and see if it fixes the problem

And to isolate the problem in a process of eliminaton fashion:

Start with your z Homed, and get a measurment. Move your z up (at different speeds) in various amounts, and measure again making sure your z is moving how far it's supposed to and not slipping.

If you don't rule out slipping/missed steps you can play with firmware all day long and it's not going to help.

jamesdanielv you solved it problem was that i had Z disabled when not in use.

why this was causing a problem i have no idea

thanks guys

Enlightx Wrote:
-------------------------------------------------------
> jamesdanielv you solved it problem was that i had
> Z disabled when not in use.
>
> why this was causing a problem i have no idea
>
> thanks guys


hi enlightx,

what did you do to solve your problem?
Did you decrease the feedrate?
How did you change the firmware to always enable your z axis?

Hi Flow

my problem was solved by settings disable Z when not used to disbaled. This is the default so if you havnt changed it you shouldnt have a problem.

But if you having a Z height issue its probs your Z speed. With my I3 printer i use a speed of 3 i tend to have no trouble with this.

to changed Z Speed edit this line

#define DEFAULT_MAX_FEEDRATE          {500, 500, 5, 45}    // (mm/sec)

settings to X Y Z E

So you need to change 5 to 3 then re flash

Take into account if your using eeprom settings on a LCD panel type device you will need to change the settings via M commands and then save the settings to the eeprom.(i use pronterface to enter commands)

Thank you,
that was a quick reply.
Can we compare our settings, I also have a Prusa i3 (LC frame and also M5 threaded rods for Z axis)?
These are mine:

#define DEFAULT_AXIS_STEPS_PER_UNIT   {80, 80, 4000, 915}
#define DEFAULT_MAX_FEEDRATE          {500, 500, 3, 45}    // (mm/sec)
#define DEFAULT_MAX_ACCELERATION      {9000,9000,100,300}  

Enlightx Wrote:
-------------------------------------------------------
> jamesdanielv you solved it problem was that i had
> Z disabled when not in use.
>
> why this was causing a problem i have no idea
>
> thanks guys


Where is this setting? In Marlin's configuration.h? or Ponterface?

Nevermind, I found it right in front of face

// Disables axis when it's not being used.
#define DISABLE_X false
#define DISABLE_Y false
#define DISABLE_Z false
#define DISABLE_E false // For all extruders

Hi,
this is in Configuration.h, it would be nice to compare our settings.
BTW, I figured Out my problem, it was a Heat problem with my z axis driver.

you are doing it wrong...
why 4000 steps?


if you will good setup do the full step, thats 250 steps per mm.


you ask why?
on z axis you have 2 stepper motors. if they are running on full step they are sync.



on microstep, everything is ok when first setup.
then you ran print, no problem, you shut printer off. when you turn printer next time on, motors are still on some microstep position, and its possibilitiy that one goes to one side, and second to another "step" side when they are powered..

i would share settings but as i use an LCD panel with eeprom the settings in config.g mean nothing

ok i used 5 and my motor thumped turned it down to 3 noise went away i have not had any problems with z and 4000 is correct for m5 and im using 4mm id tubing check blog out with the print i did yesterday

---

Check my rubbish blog for my prusa i3

up and running
[3dimetech.blogspot.co.uk]

chriss33 is right, 4000 is ok for z steps for a Prusa i3. After solving my problem by myself I just wanted to compare my settings.

why?


why do you need step resolution of 0.00025 mm??


by so much steps on Z you just messing up with machine, firmware and have bigger chance that somethings goes wrong.

@ full step you have resolution of 0.004 mm, when considered that normal layer height is 0.2-0.3 mm thats enough.




there is a simple test.

home your z axis, and put some mark on both Z couplers, on same place. after few days of printing check if they are still in same place when homed..

thats eod from me

Edited 1 time(s). Last edit at 08/03/2013 12:35AM by woo.

hi all,
i have the same problem i think.
I finish to build my prusa i3 and i start to make some tests. I print 0.5mm-thin-wall.stl that it's 10 mm tall but the final height is an half (5mm). I change configuration.h with no luck

my current config is:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80,80,4000,1792} // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE {500, 500, 3, 45} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {9000,9000,100,10000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for skeinforge 40+, for older versions raise them a lot.

#define DEFAULT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for printing moves
#define DEFAULT_RETRACT_ACCELERATION 3000 // X, Y, Z and E max acceleration in mm/s^2 for retracts

The motors power is ok and I don't lost them. If i manually move of 1 cm up and down it goes right

Ideas?

Thx

not using epprom are you and not changing epprom steps ? (seperate to hard settings in marlin)

normally using eprom if using a display device

Please post a picture of your printer ...

i have the display but for now i'm using firmware configuation.

I remake the checks tonight after changing a polulo (now i put a drv8825 version) and i see that if i send the command to go up of 1 cm it goes for 5 mm, the same for down. I'm using M5 rod.
If i put a normal polulo it goes 1 cm. Do i need to change jumper under polulo slot? (now all are closed)

Edited 1 time(s). Last edit at 01/23/2014 04:44PM by thebus.

i set Z parameter to 8000 and now it move of 1 cm up and down. Now i make print test

only thing i can think is your running in 1/32 instead of 1/16 on the jumpers?

4000 is correct at 1/16 steps

and 8000 would be correct at 1/32 steps

have you checked your X and Y ?

X e Y use "normal" polulo. I use drv for Z and extruder due I broke the original polulo and i migrate to drv.
Now the print is quiete ok, the only problem is the 1st layer but i think is a temperature problem.

I solved setting Z to 8000.

Thanks to all