Help! Help with bed leveling

[kdobson83]

Ok, so i just got a Creality Ender 3 printer. Got it all built, was fairly easy. I go to level the bed, i hit home, and the nozzle goes to the home position. I then turn off the motors and level the bed using a piece of printer paper. I have all four corners perfect, just light resistance with the paper. when i print the test print, and it goes to start, it lowers the nozzle even more digging into the print bed, forcing me to shut off the printer. Looking around, it has smashed the vertical stop sensor all the way down, far more that it did when going to the home position. Almost like the vertical sensor isn't working when i start the test print.

Am i missing something here? The sensor reads that its vertical axis is at the bottom when i hit the home button, but when i start the print, it goes to far and digs into the print bed...

 

[kdobson83]

I have downloaded some bed leveling gcode, it rotates the bed around to all four corners to help you level stuff. But when starting the print, the vertical motor i believe is making a horrible vibrating noise, like its bottomed out and is trying to go further down. The extruder arm, the part that touches the vertical stop sensor is pushed all the way down on the sensor, so much so it looks like it has pressed the little metal arm of the sensor flat. Shouldn't hitting the home button bring the head to the proper printing height for leveling?

 

[DharanFlyer]

The Anet A8 has a Z offset from home that I have to tweak. It's under Controls menu for me. I know that this isn't helpful, but all I have to add.

 

[TheWW1FlyingAce]

When you homed the printer before leveling the bed, how far from the bed was the nozzle? Some printers end up with a "home position" where the nozzle is up to 10mm away from the bed and only lower the nozzle to the actual bed height when they're starting a print. Also, I would recommend not turning off the motors when leveling to ensure that any force you place on the nozzle to move it side to side doesn't also move it down by mistake.

What I would do in your position (assuming your printer uses a normal Z endstop switch):
- Lower the bed using the leveling knobs as low as it will go.
- Home the printer. Leave the motors on.
- Check the Z position on the LCD and if it isn't 0, use the controls on the LCD to lower the nozzle until Z is 0. If the Ender 3 uses Marlin (which I believe it does) it would be in Prepare->Move Axis.
- Use the LCD to move the nozzle to each corner and adjust using the piece of paper.

 

[kdobson83]

When you homed the printer before leveling the bed, how far from the bed was the nozzle? Some printers end up with a "home position" where the nozzle is up to 10mm away from the bed and only lower the nozzle to the actual bed height when they're starting a print. Also, I would recommend not turning off the motors when leveling to ensure that any force you place on the nozzle to move it side to side doesn't also move it down by mistake.

When i hit the home button it was a few milometers away from the bed. I adjusted the bed with piece of printer paper like the YouTube videos i watched, leveling all four corners over and over until it was right. I moved the bed numerous times and hit the home button numerous times and every time was the same and no measurements moved, it was holding the level that i did. But when i print, it goes farther down digging the nozzle into the bed. when it does this, it has pushed the metal arm on the sensor completely flat, way more that it does when i hit the home button, not to mention it makes horrible noises like its still trying to go even lower.
I will try what you said next, when i get some time. If it does it again ill take some pics/video and post it so you can see it. It has marred up the bed pretty bad. Which isn't too bad as i plan on putting some glass on it, but i wanted to get a few simple test prints done first.

 

[TheWW1FlyingAce]

After homing the printer, check the Z value displayed on the LCD. If it is not 0, you won't be able to successfully level the bed until you use the LCD to move Z so that it displays 0 on the LCD.

 

[kdobson83]

After homing the printer, check the Z value displayed on the LCD. If it is not 0, you won't be able to successfully level the bed until you use the LCD to move Z so that it displays 0 on the LCD.

Yup. It's zero. Here is a video of what it's doing. I tried my best to operate the phone and the printer at the same time.

Pay attention to when I start the test print. It's like it tries to raise up to move where it needs to go but is stuck for some reason. It makes nasty clicking noises and doesn't go up. It then moves to position and the goes down even further. I assume since it wasn't able to go up for what ever reason, once it moved it thought it still needed to go down and that's why it's digging in to the bed. What is that horrible clicking noise when it tries to go up as soon as I start the print? Everything is freed up, I can manually move the z axis up and down, I can also move it up and down with the dial. But when I hit print it has a spasm and messed up.
Anyone have any ideas?

 

[kdobson83]

As I was writing this it occurred to me that maybe the rollers we're binding up not letting the motor move the z axis up. I had checked before but it was never that low. Sure enough, it was getting stuck when I used the knob while it was that low. I adjusted the wheels and freed it up. It seems to be functioning properly now. Hopefully I can get it calibrated and printing. To bad my wife and kids have other ideas with my free time... Lol Thanks for your input!!

 

[TheWW1FlyingAce]

Glad you got it figured out. A mechanical issue never even crossed my mind (what can I say, I'm a software developer).