Should i have the calibration plugs under my plate?

[DidierKlein 729]

Hi all,

This week i went through the building manual of the UM2.

So today i had another case of my bed level being changed without doing anything causing the first layer to be very thin.

I noticed that the bed does a horrible noise while preparing to print. Also i pressed the bed against the bottom because i applied a little force on it to remove some stuff.

Then i wondered is this normal? So i went back to the manual and found this to be described:

Should i have these plugs still in place?

Because if i do i don't have them and i wonder if this could cause the sligh change of leveling that i believe to have

 

[illuminarti 18]

No, you shouldn't.

If you slide the bed up and down by hand, does the z-switch engage and disengage properly, clicking on and off? If you 'lower the bed' using the front panel controller, does it hit the limit switch, bounce off, and then resettle - all without making nasty noises?

 

[gr5 2,295]

I noticed that the bed does a horrible noise while preparing to print

 

Now you tell us? That's definitely the problem. It needs to hit the limit switch. There is a long screw at the bottom of the bed that goes up and down when the bed goes up and down. That long screw needs to hit the Z limit switch when it does it's homing procedure. You can hear the switch click if it is working. The switch could be loose or might need slight adjustment.

 

[gr5 2,295]

No, you shouldn't.

 

No he shouldn't move them? No he shouldn't have them?

 

[DidierKlein 729]

Can't test for the moment it's printing ^^

When the print is finished it seems to me that the plate goes down then up a little before stopping.

Thing is here that i can push it down until it touchs the bottom of the printer.

The odd noise happens at the start, sounds like something painfull.

Will check after this print if i have time, still didn't try pronterface could it help?

By the way, how do you slide the bed by hand?

 

[gr5 2,295]

Homing isn't done very often. Typically it's the first thing done when starting a print.

 

By the way, how do you slide the bed by hand?

 

The first time you try it, do it with power off. Just push down firmly with your hands as close to the rear of the platform as possible. Same with lifting, lift near the rear. Just push and pull hard enough until it starts moving.

Then later you can try it with power on. If the servo is powered (often it is not!) then the bed won't move.

 

[illuminarti 18]

(No you shouldn't) have those plastic bits in place.

 

[DidierKlein 729]

Okay thanks

So i just tested the plate with the menu.

Up and down no strange noise.

Start a print no noise.

I leave the print finish and i will test more (have to go anyway).

Thing is i guess it makes this noise only when the build plate is laying on the bottom and the i start a print.

After the up and down from the menu the build plate was a couple of mm higher than the bottom.

Should it be able to go all the way down? (by hand)

 

[gr5 2,295]

I'm worried that sometimes the build plate isn't triggering the Z limit switch, but sometimes it does. I'm worried that if the build plate moves .1mm farther it hits something. Ideally you want the bed to go down enough until you hear the "click" from the switch, and then can move another mm (minimum) before hitting something that stops the bed from going farther.

 

[illuminarti 18]

If you push it by hand, you can certainly push it further than the point at which the switch triggers. But when starting up in this position, the printer should realize that the switch is triggered, and move upwards only. Hmm. I wonder if it's possible to push the bed down further than the 'back-off/bounce' distance so that it never untriggers itself before the re-trigger...

* goes to test on his printer *

 

[illuminarti 18]

No, on mine... If I do 'lower buildplate', then turn power off and push bed all the way down, then turn it on, and do lower buildplate, it seems like it just moves up until the switch unclicks and then stops. Which seems like reasonable behavior.

 

[DidierKlein 729]

Really odd, just tried a couple of times and the noise doesn't reproduce. But i had it twice on the second print of the day...

This time tough, the plate went all way down after the end of the print. Next print started with no problem after that.

I have to find a way to reproduce this.

The other times cancelling and restarting the print seemed to resolve the issue.

I have to pay attention at that click sound as it isn't very clear to me how it should sound like.

Thanks anyway for your clear advices it's really helpful thumbs up just to say, this is the main reason i went to buy a UM2. The community is great :cool: :geek:

 

[gr5 2,295]

I have to pay attention at that click sound as it isn't very clear to me how it should sound like.

 

With power off, raise the bed.

Now take a toothpick or something small and push it through that hole under the bed and listen for the click when you push on the endstop. Note the screw sticking out under the bed that goes into that hole.

 

[DidierKlein 729]

Thanks i saw the screw, Not easy to see