M201 Crushing Z endstop with lead screws

[Menelaus]

I replaced the threaded rod with lead screws on my M201 as I got tired of the binding on the rods. I adjusted the steps per mm and verified the movement with a digital caliper for each of the speeds (10mm, 1mm, .1mm) and they were all spot on. Problem is that when I send the home command from the LCD, the z will do its touch-off and slow approach but won't stop when it hits the end stop and will continue an additional couple of mm. By bending the lever on the switch as well as adding about 1.5mm of rolled tape between the button and the lever (adding 4-5 mm of height to the lever where the screw contacts it) I was able to get it to stop before it tried to destroy the switch. Problem with that is that if the tape falls out or the Is there a setting in firmware that can be changed on the LCD or am I going to have to figure out some trick with a spring to keep it from making me have to stock up on end stops?


https://www.youtube.com/watch?v=WknxUhLt-uM
That's a video of it homing a second time with the tape and bend.(note that with the screw in that position, the nozzle used to be at the correct distance to the plate).

I haven't tried it tethered yet but I'll give that a shot in the next couple of days to see if it behaves the same over USB.



Speaking of firmware, any word on an update to support a bed level sensor? Pretty sure that would solve my problem, too.

[bang]

So did the motor stop moving when you push down the Z endstop manually(i mean when you "Auto Home")?
And it seems like your Z endstop is too low(the spring on it is too tight)?Sorry i can't take a close look at it...

[Menelaus]

If I push the endstop while it is still higher up, it will do the touch off and move as normal. The problem is that on it's slow approach, it seems to ignore the endstop and travel a preset distance since it goes past triggering the switch, if that makes any sense.

I have the screw a bit tighter because I've been using a print in z plate which adds a good 5mm or so. Edit: before bending the tab and adding the ball of tape to the endstop, the bed was calibrated, the distance you're seeing is the result of those changes minus a little because I started re-calibrating it but didn't finish because I ran out of time.

Thanks for the reply.

[Menelaus]

Here's a video of the auto home and I press the endstop after it starts coming back down after the touch-off and you can see it moves at least and extra 2 mm. https://www.youtube.com/watch?v=gNoPyUSMdaA
Is there a setting in the firmware that tells it how far to move after the endstop triggers?

Edit:
The homing is also very inconsistent. Sometimes it'll be kissing the bed, other times it'll be 1mm up. Sometimes when I tighten the z-stop screw (should stop the axis higher up) the homing goes lower. I have no idea whats going on. I have some replacement endstop switches on the way but I'd be surprised if that solves it.

Edit 2:
This video was done controlling the printer via Simplify3d.

[Menelaus]

Replaced the endstop with a new one and still happens. At this point I can only think that it's a fault with the firmware. It seems like they set it to travel x steps past the switch trigger rather than x mm so the steps per millimeter has no effect when homing

[William]

Hi，you can try re-install the lastest firmware in the post:http://www.geeetech.com/forum/viewtopic ... 20&t=17046 .If it still don't work,I think the board may have some problems.Could you take some photos of it with front and back side?

[Menelaus]

Thanks for the reply.

I tried reinstalling the firmware but it didn't change anything. (Rev B board)

Here are some pictures of the board:
Since the html doesn't seem to be working here's a link to the imgur album: http://imgur.com/a/Ewd4x?

2nWF6eJ.jpg (705.08 KiB) Viewed 12813 times

aI7zZno.jpg (653.77 KiB) Viewed 12813 times

[Menelaus]

Since re-flashing the Firmware didn't change anything, does that mean I'm going to need a new control board? If that is the case I would like to get the replacement set up as soon as possible so I can get the printer working again.

Thanks

[William]

Hi,before you get the replacement,I think you can resolder this place on the back board.There might be some bad weldings.

[William]

Here is the pictures.