Bill A's A8 Printer Build

We've got a winter storm warning and I've been battening down the hatches, getting fuel for the truck and bobcat, gas for the generator, piling up wood on the back patio. Almost done and then I'm going to take a nap. Sure wish Napcar was on.
 
You guys have been getting one round of nastiness after another out there. We're thankful for the rain we got from this system - 0.6" yesterday and 1.1" so far today - some wind but nothing twisty. At least we don't have the ice and snow down here!

NASCAR is almost close enough to sniff now! We'll have to get through a couple of weeks of football - maybe hope for some type of "malfunction" during halftime at the Super Bowl .....
 
You didn't make any kind of changes to z offset in the firmware or anything? Just grabbing at straws.

I haven't delved into firmware yet; guess I hadn't thought of it, yet ... duh on my part!

Am I correct in assuming that there's a configuration file on the SD card similar to what I've used on my CNC?
 
I don't remember if there are any settings on the stock firmware, but I do believe is uses eeprom to store things, not the SD card.

It just seems weird that the z axis would move fine when homing, but then not move when starting to print.
 
I don't remember if there are any settings on the stock firmware, but I do believe is uses eeprom to store things, not the SD card.

It just seems weird that the z axis would move fine when homing, but then not move when starting to print.


I took a few minutes between storm systems to attach to the main board using Arduino IDE. Got the connection OK; now to remember the steps to read the settings, etc.

The Z axis moves OK when the file starts running. It just lifts above the bed to make the move to the starting point of a print, then stays up rather than moving down to the 0.2mm or 0.1mm level it should be to attach the filament to the bed.
 
I took a few minutes between storm systems to attach to the main board using Arduino IDE. Got the connection OK; now to remember the steps to read the settings, etc.

The Z axis moves OK when the file starts running. It just lifts above the bed to make the move to the starting point of a print, then stays up rather than moving down to the 0.2mm or 0.1mm level it should be to attach the filament to the bed.
Is the lcd readout showing z is lowering when its supposed to be? Sound like its hitting a soft limit on the z axis somewhere.

Sent from my SM-G920P using Tapatalk
 
I was thinking about this tonight and my suspicion is that the z axis is binding either at the top of the threads in the holes or on one or both the nuts for the Z, perhaps the x axis rods are pushing them out a bit and may need tapped in a bit.

My thought is that when Homing Z, the steppers are going to keep pushing for z home since it won't stop until it hits the switch. However, when you're printing, it's going to just send x number of steps and that will be it. so when it goes up it's fine, but it's skipping steps trying to come back down.
 
Thanks for your suggestions, guys. I'm finally back online after a NOT fun weekend as you might read in my Off Topic post.

I don't get a sense that anything is binding; everything moves smoothly manually and it does exactly the same thing each time I've tried a print.

I'll try to get back on track today. I wanted to research a couple of things but didn't have online access. I did connect to the main board via the USB port and got a connection. What should I see after getting connected?
 
Thanks for your suggestions, guys. I'm finally back online after a NOT fun weekend as you might read in my Off Topic post.

I don't get a sense that anything is binding; everything moves smoothly manually and it does exactly the same thing each time I've tried a print.

I'll try to get back on track today. I wanted to research a couple of things but didn't have online access. I did connect to the main board via the USB port and got a connection. What should I see after getting connected?

Are you using Repetier? If so, usually you can click the manual controls and send gcodes from it (may have to click the "advanced" button, what ever it is called on the top tool bar). I think it may have the option to read any stored eeprom values as well, but that may only be with newer versions of marlin. But could try it to see if there is a stored "Z_OFFSET" option.

You might check in your menu to see if there is an autolevel option, which would mean it's a newer version of firmware than Brent and I had originally. I'm not sure the original had any indication of what version of firmware it was other than some menu options are different.
 
I've been using CURA, not Repetier. Should I change?

The only files I've tried are the gcodes that came on the SD card.

How do I read the EEPROM?
 
Yep, Hook it up to reptier, or octoprint, or S3d, or basically open a terminal and connect.

Then move the axis around and see how things work.
 
While I was without Internet yesterday, I built a torsion box to mount my printer on. I took it out of the clamps and set the printer on it this morning. After making a few measurements, I found a couple of discrepancies that I knew were right when I completed assembling the printer a few days ago. The bottom line is I found the bench where I assembled the printer was a little out of flat. On the torsion box, I re-aligned the printer, adjusted the table to the nozzle. In the process, I found the positions of the left and right Z axis lead screws had shifted; nothing appears to be binding, so I don't know what happened there unless the motors skipped for some reason.

I downloaded and installed Repetier - free version. I can control the axes and it reads the end and bed temps. When I attempt to load a gcode file to run from Repetier, I get a window that says I need PRO. So, I started the "Box" file from the LCD menu to see what happens. ...Film at 11...
 
Well, things are improving a bit. I'm not totally satisfied with the Z0 position yet, but I have to work on it a bit more. I'm using a piece of 3.2mm polycarbonate on the heat plate to simulate the glass and adjusting the table until I have contact. Moving the Z end stop is a pain since there's no fine adjustment; that will be fixed with one of the upgrades.

I started a print of the "Box" file from the SD card and below is what I got. When it started, the nozzle was almost touching the glass, although the LCD display showed Z0.02mm. I let it run for a while to see what happens. As you can see in the left photo, the PLA was getting deposited real splotchy. I read that can happen if the extruder isn't hot enough. I had it set to 200C, so I bumped it up to 210C through Repetier and it began to deposit better. Looks like I might need to go a bit hotter on the next trial.

100_1205.jpg100_1207.jpg
 
With the little bit of success from earlier, I decided to go for it an run Brent's calibration cube using Repetier.

100_1208.jpg100_1210.jpg100_1213.jpg

It turned out at about 2.05mm in both X and Y. Z measures about 1.95mm which confirms I still need to do some work on Z.

I'm not having any issues with the PLA sticking to clean glass at about 50C. It adheres well and is no problem to pop off when cooled.

Things are looking up! Next will be getting the RPi connected and see how bad I can mess that up!

Thanks for all your help guys!!!
 
Last edited:
Top