<p>I have 3 printers, all Anet A8 with RAMPS 1.4 boards running identical firmware. One printer, however, has a Bowden extruder setup and RepRap 3 pin limit switches. Otherwise identical to the other 2 printers. </p>

<p>I'm mass-printing face shields, and I sliced the STL with 2 brackets at 180&deg; angles and offset like so:</p>

<p><a href="https://i.sstatic.net/J4kAg.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/J4kAg.png" alt="enter image description here"></a></p>

<p>I'm trying to print this same G-code on all 3 printers. Same dimensions, same filament, etc. All 3 printers are on OctoPrint (separate Raspberry Pi devices)</p>

<p>However, on my 3rd printer, it's doing weird things. It will print the first layer of the frame facing the back. But when it goes to print the 2nd one (that's facing the front) it prints it right on top of the first one instead of offsetting it. </p>

<p>I noticed that the printer was starting off about 20&nbsp;mm to the right. My initial thought was the X-axis was going past it's limit to the right, skipping the belt causing the 2nd piece to offset to the left. I corrected that by adjusting the <code>#define X_MIN_POS</code> to compensate (the only change in firmware between the 3 printers). Now it is printing centered as it should, but still trying to print both pieces on top of one another. I watched the printer until it hit this failure and can say for absolutely certain it's not going past its limit. It didn't even try to move over and print the 2nd piece properly.</p>

<p>I also tried printing another file and it would randomly offset toward the front on the Y-axis. </p>

<p>I have also checked to ensure my belts are snug and not skipping. </p>

<p>It sounds wrong to me, but it's almost like the machine is receiving the proper G-code but not processing it properly. Either that or something in OctoPrint is out of whack. </p>

<p>I've also attached the output from the terminal window in OctoPrint. I understand the commands, but darned if I can find where the error is occurring. I stopped the print right after it started to print the 2nd piece on top of the 1st.</p>

<p>Edit:
I forgot to include in my initial post the terminal output: pastebin.com/iEA8bNH9</p>

<p>Edit 2:
Adding image of behavior
<a href="https://i.sstatic.net/4ekhv.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/4ekhv.jpg" alt="enter image description here"></a></p>

CC BY-SA 4.0
2020-05-01T09:38:07.103Z
The default X offset from home position for the Anet A8 is: `#define X_MIN_POS -33`. See also [How to center my prints on the build platform? (Re-calibrate homing offset)](/q/6375).
0scar
CC BY-SA 4.0
2020-05-01T11:04:41.410Z
or look at an ender-3 specific one that has some more explanation... https://3dprinting.stackexchange.com/questions/6399
Trish
CC BY-SA 4.0
2020-05-02T20:32:22.543Z
The print is now centered by adjusting the firmware. However, it is still overlapping both pieces.
rtuite
CC BY-SA 4.0
2020-05-04T14:44:30.820Z
Can you add an image of what is happening?
0scar
CC BY-SA 4.0
2020-05-06T21:09:55.340Z
@0scar - Added picture. This time, it is randomly offsetting in both X and Y...
rtuite
CC BY-SA 4.0
2020-05-06T21:19:44.560Z
This looks a lot like layer shifting, could be a mechanical issue.
0scar
<marlin><ramps>
Printer not processing G-code properly?
rtuite
# Printer not processing G-code properly?

(Asked by: username_0 on 2020-04-29)

I have 3 printers, all Anet A8 with RAMPS 1.4 boards running identical firmware. One printer, however, has a Bowden extruder setup and RepRap 3 pin limit switches. Otherwise identical to the other 2 printers.

I'm mass-printing face shields, and I sliced the STL with 2 brackets at 180° angles and offset like so:

[![enter image description here](https://i.sstatic.net/J4kAg.png)](https://i.sstatic.net/J4kAg.png)

I'm trying to print this same G-code on all 3 printers. Same dimensions, same filament, etc. All 3 printers are on OctoPrint (separate Raspberry Pi devices)

However, on my 3rd printer, it's doing weird things. It will print the first layer of the frame facing the back. But when it goes to print the 2nd one (that's facing the front) it prints it right on top of the first one instead of offsetting it.

I noticed that the printer was starting off about 20 mm to the right. My initial thought was the X-axis was going past it's limit to the right, skipping the belt causing the 2nd piece to offset to the left. I corrected that by adjusting the `#define X_MIN_POS` to compensate (the only change in firmware between the 3 printers). Now it is printing centered as it should, but still trying to print both pieces on top of one another. I watched the printer until it hit this failure and can say for absolutely certain it's not going past its limit. It didn't even try to move over and print the 2nd piece properly.

I also tried printing another file and it would randomly offset toward the front on the Y-axis.

I have also checked to ensure my belts are snug and not skipping.

It sounds wrong to me, but it's almost like the machine is receiving the proper G-code but not processing it properly. Either that or something in OctoPrint is out of whack.

I've also attached the output from the terminal window in OctoPrint. I understand the commands, but darned if I can find where the error is occurring. I stopped the print right after it started to print the 2nd piece on top of the 1st.

Edit:
I forgot to include in my initial post the terminal output: pastebin.com/iEA8bNH9

Edit 2:
Adding image of behavior
[![enter image description here](https://i.sstatic.net/4ekhv.jpg)](https://i.sstatic.net/4ekhv.jpg)

**Tags:** marlin, ramps

> **Comments:**
> **username_1**: The default X offset from home position for the Anet A8 is: `#define X_MIN_POS -33`. See also [How to center my prints on the build platform? (Re-calibrate homing offset)](/q/6375).  
> **username_2**: or look at an ender-3 specific one that has some more explanation... https://3dprinting.stackexchange.com/questions/6399  
> **username_0**: The print is now centered by adjusting the firmware. However, it is still overlapping both pieces.  
> **username_1**: Can you add an image of what is happening?  
> **username_0**: @username_1 - Added picture. This time, it is randomly offsetting in both X and Y...  
> **username_1**: This looks a lot like layer shifting, could be a mechanical issue.  

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## 0 answers

