1

Anet A8 - Auto level sensor and bed surface setup issues.

I am having issues getting this printer to actually print anything now. I have got this printer to print before, but the bed surface wasn’t smooth so the print quality wasn’t great.

A little backstory:

Part 1:
At some point the original masking tape on the heated bed got damaged and I decided to replace it. Also the masking tape wasn’t that smooth either. I replaced it with “Wilko Washi” masking tape. Prints didn’t want to stick to the bed so I added lots of glue stick glue, which didn’t make any difference. At this point I decided to replace the tape with a “Signstek Bed Surface”. I am not sure if this bed surface is any good, because I am unable to correctly level the printer; which leads to the next part of the backstory.

Part 2:
At some point I decided that the Z-axis microswitch was too fiddly to adjust, so I wanted to replace it with an Auto-level sensor. It was probably at the point when I ripped the original making tape on the hot bed. I purchased the sensor below. Also I downloaded the “Anet A8 Official” firmware that supports auto-level sensors.

I installed the sensor as per this (Anet A8 3D Printer Auto Bed Level Sensor - YouTube) video guide on Youtube. Also I downloaded and installed the firmware (with Auto Level Sensor support) from here. https://www.3dprintersbay.com/anet-a8-a6-firmwares-latest.

Also I found a tip on a video on Youtube which said to use the head of an M10 bolt on each of the corners in order get a basic level starting point before setting up the auto level sensor.

The current problem:

I can’t seem to setup the auto level sensor and hotbed so that the bed is level and the “nozzle” is at the correct height.

The result is that either the nozzle is too high, which results in the PLA not stick to the bed surface; or the nozzle hits the side of the hot bed and scrapes the bed surface.

SO, HOW DO I SETUP THIS PRINTER? so it prints first time every time and only needs minimal adjustment if the printer is moved to a different location.

Parts, etc:

  1. Auto Leveling Position Sensor for Anet A8 Prusa i3 3D Printer RepRap
    Auto Leveling Position Sensor for Anet A8 Prusa i3 3D Printer RepRap Sale - Banggood USA sold out-arrival notice-arrival notice

  2. Signstek 3PCS 3D Printer Bed Surface for 3D Printer Platform, 220mm x 220mm x 0.5mm (Black)
    https://www.amazon.co.uk/gp/product/B072BYSB2Y

  3. Wilko Washi Masking Tape Smooth 48mm x 20m
    https://www.wilko.com/en-uk/wilko-washi-masking-tape-smooth-48mm-x-20m/p/0454512

2

Hey @dfear, I have been on that road of trying to make those auto calibration sensor work and I did spent quite some time making them work and then finding out they are not so precise after all.

If you want an auto level sensor for the experience of doing it then I say go for it, but if you are looking for a reliable, easy, risk free and repeatable solution, I would suggest the following:

  1. Get rid of those bed springs and fix properly the bed to its base
  2. Get rid of the auto levelling sensor and use a simple global z switch
  3. Change the frame to a metal one or try to stiffen this piece of jello because machine accuracy will always be an issue on a flexible frame
  4. Use TH3D firmware with MANUAL_MESH_LEVELING which enables you to calibrate the bed on the lcd screen using a piece of paper

I personally use the following mesh leveling settings which have been proven quite good :
“configuration_backend.h” at line 1996:

#if ENABLED(MANUAL_MESH_LEVELING) && DISABLED(EZABL_ENABLE)
#define PROBE_MANUALLY
#define LCD_BED_LEVELING
#define MESH_BED_LEVELING
#define MBL_Z_STEP 0.05
#define LCD_PROBE_Z_RANGE 10
#define MESH_INSET 10
#define GRID_MAX_POINTS_X 3
#define GRID_MAX_POINTS_Y GRID_MAX_POINTS_X
#endif

“Configuration.h” @ line 580:

#define MANUAL_MESH_LEVELING
#define MANUAL_Z_HOME_POS -5
#define Z_HOMING_HEIGHT 10

Happy bed leveling!