Z axis homing problem

Hi. I have done a Prusa model DIY 3d printer. I have a problem in Z axis Homing. I use Pronterface to control the movements of XYZ axis motor. when manual feeding is done, three stepper motors runs perfectly. But when homing is done XY motors runs perfectly but Z axis motors gets vibrated and then stops.

I have attached a video clip of it. In this first I moved all the axis for some distance and gave homing command using pronterface. During homing Z axis vibrates.
Video clip.

Please give me some suggestions.

Thanks in advance

with regards
Baalaji

I would say that the Z axis stepper current is low and needs to be adjusted.

Included is a video link

---

Computer Programmer / Electronics Technician

Z max feed rate is to high

in configuration.h find

#define DEFAULT_MAX_FEEDRATE { 300, 300, 5, 25 }

change to

#define DEFAULT_MAX_FEEDRATE { 300, 300, 2, 25 }

Okay thanks will check it.

with regards
Baalaji

In my Ramps LED 2 gets Lighted up continuously when connected with PSU. I replaced a new ramps and checked but no change.

And the hotend doesn't gets heated up when controlling using pronterface. But when I ran Ramps test code the Hotend got heated.

Thanks and regards
Baalaji

Edited 1 time(s). Last edit at 09/21/2018 06:50AM by Baalaji V.

What have you set the motherboard to in your firmware?

Z axis homing worked fine. Thanks sir.

The motherboard configuration is
#ifndef MOTHERBOARD
#define MOTHERBOARD BOARD_RAMPS_14_EFB
#endif

thanks and with regards
Baalaji

Edited 2 time(s). Last edit at 09/22/2018 01:15AM by Baalaji V.

Well motherboard is set fine, so firmware is using correct IO pins. (as long as you haven't edited the pins_ramps.h file)

the second possibility is dead mosfets on the ramps, but you say you replaced the ramps.

final possibility is that the mega has a fault. Dead IO pins. Sadly you have to replace the mega2560

I suggest you reinstall the ramps test firmware [reprap.org]

Check the 3 mosfet leds are turning on and off. If they dont, then definitely replace the mega

Edited 2 time(s). Last edit at 09/22/2018 02:29AM by Dust.

I reinstalled Ramps test code. It all worked fine. All the 4 leds blinked continuously(flickering) and all the motors worked perfectly.

And I uploaded new marlin 1.1.7 and still the same problem. Previously tried with I installed marlin 1.1.8, 1.1.9.

I checked voltage across hotbed connection while running ramps test code, it is about 11.4V. And when I checked after uploading Marlin in the same setup, it was about 0.04V.

And there is a very minute LED 3 blink.

Please give me a solution for this.

Thanks and regards
Baalaji

Edited 2 time(s). Last edit at 09/22/2018 03:29AM by Baalaji V.

That would indicate that its a firmware issue.

what version of arduino are you using?
1.8.6 is known to be buggy, please use 1.8.5 from [www.arduino.cc]

also please upload your configuration.h so I can check for other issues.

I have checked by using arduino 1.8.5 but the issue remained same. And I also tried with uploading using arduino 1.8.7 but no change.

I have attached my configuration.h file below.

[www.dropbox.com]

Thanks and regards
Baalaji

Edited 1 time(s). Last edit at 09/22/2018 05:51AM by Baalaji V.

Thanks for your suggestion @Dust. I solved the problem. The problem is in non working thermistor. I made it work.

Thanks and regards
Baalaji