All axis only move in positive direction

[Peregrine]

to cazuroweste;
When I put my machine together, I had the same binding problem and fixed it by reaming the 2 holes on the top plates that the Z drive screws go through. The holes were tapered slightly causing the lead screws to bind. You don't want to go over the size they are supposed to be, just make them straight through. I used a 5/16" (.311) undersize reamer. Even a standard .312 reamer should be OK. You can test this condition by removing the top caps and trying to slide them down the lead screws by hand. If they are tight, the holes are probably tapered like mine were.
This doesn't address the issue of "positive motion only" however. I believe it does have something to do with the end stops since the only time mine actually worked for a short time was when I removed the end stop wires and re-seated them at the switch ends and the board ends. As soon as I stopped the machine and tried to actually run a program, the "positive only" condition returned. You might try something like that on your Z end stop.

[cazuroweste]

zhangxueyou wrote:
cazuroweste wrote:
I have the same board. My z axis only moves positive, the other 2 work properly. The extruder is not working as well.

Is the connection of z motors correct?
The extruder motor can not move unless the temperature is higher than 175 degrees.


The z axis is connected correctly. Whether i press up or down, it will only go up. Also, it seems the threaded rods for the z axis are not straight, as it wants to bind up.

1.Let the z axis up first. After it stops, let it down. See if it can go down.
2.You should make sure the theaded rods are well installed.

I double checked all wiring and connections and no problems there.
I updated the firmware with what you had sent, and double checked through to make sure it was correct.
The X & Y axis home properly and move properly, the Z only moved in a positive (up) direction. I changed the steppers with the X axis stepper, then with the Y axis stepper on the board, to see if the stepper was bad, but the results were the same.
I connected the Z motors individually with the X, then Y cables and disconnected the threaded rods to check rotation. They rotate both clockwise and counter clockwise properly. I then hooked the Z leads to the x motor, and it would only move positive. I hooked them back to the proper motors (with the threaded rods still disconnected) and they would only spin clockwise. I went into the firmware and reversed the Z direction and they still would only move clockwise.
I triggered the end stop for the z while it was moving, and it stopped the board correctly, but would still only do up moves, even when a down move was sent it would only still go up.
The latest steps I was sent was for the RAMPS 1.4 board, and I was provided with the Sanguinololu board. I still doublechecked all the connections, and am having the issue.
I am thinking that the sanguinololu board may be bad.

[cazuroweste]

https://youtu.be/rfx3EPDAIiI

Here is a video to better explain the issue.

[espo3020]

I am having the exact same problem, almost the exact same as you described, and my extruder doesn't work properly (when hooked up to a different axis it feeds). If you figure out the problem please post your results!!
Thanks,
-Josh

[zhangxueyou]

https://youtu.be/rfx3EPDAIiI

Here is a video to better explain the issue.

Yes, from the video, z axis moves up even you give a moving down command. So when you let z home, or let all the axes autohome, what direction is z axis moving?

[cazuroweste]

It only moves up, no matter what you do.

[zhangxueyou]

It only moves up, no matter what you do.

Please check your email. I send you a firmware, which I had tested and my printer works perfect.

[Peregrine]

I finally got my machine to work correctly but only after completely disconnecting all stop switches and then crimping the connectors to make sure all wires to the switches and the board had solid contact. I don't know exactly why this worked but I was able to run a complete program and finish my first part. Good luck with yours, it definitely has to do with the stop switches so focus on them.

[zhangxueyou]

I finally got my machine to work correctly but only after completely disconnecting all stop switches and then crimping the connectors to make sure all wires to the switches and the board had solid contact. I don't know exactly why this worked but I was able to run a complete program and finish my first part. Good luck with yours, it definitely has to do with the stop switches so focus on them.

Thank you for your suggestions, we will mark it.

[cazuroweste]

It does appear that my z axis endstop is bad. that being said, I have replaced it with the one from the x axis, and I am still getting the same results. The only difference is that if I hit the endstop, the movement stops, but it will not go down in z at all. I really think the board is the problem, as I have swapped motors, endstops, and connections, and it only has an issue with what is hooked to the z axis portion of the board.