Tuning Anycubic 4Max Pro
Tuning the Anycubic 4Max Pro Printer.
8 minute read
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Introduction
This guide describes various techniques for tuning the Anycubic 4Max Pro printer for best performance.
This guide assumes the printer is running a Marlin 2.x firmware provided by Knutwurst. Upgrading the printer to this firmware is described in this guide.
Bed Levelling
This section details how to level the bed of the Anycubic 4Max Pro to ensure the first layer of a print is laid down accurately.
In this process the height of the hotend nozzle above the bed will be measured by slipping a piece of paper between the nozzle and the bed. The nozzle Z-height will be adjusted until the paper is just lightly gripped between the nozzle and the bed, but can still be easily slid around. I measured the thickness of the paper and it was 0.1 mm. Thus, when the paper is lightly gripped, the Z-height of the nozzle above the bed should be just under 0.1mm.
Check Z Endstop
The Z=0 height of the bed is set by a microswitch which triggers when the bed has been raised to the Z=0 position.
When my printer shipped this endstop was set to a position which meant that, when the Z-axis was homed, the nozzle brush beside the bed was too low. When the bed was levelled, this brush was at the height of the bed and thus not high enough to scrape filament off the end of the nozzle.
If this is the situation with the printer, the solution is to adjust the Z endstop up a little so that the levelled bed will be below the nozzle brush.
This adjustment is achieved by adjusting the vertical position of the Z endstop microswitch at the back of the printer, behind the raised bed.
- Loosen the two screws that fasten this microswitch.
- Adjust the position of the microswitch a few millimeters up or down.
- Refasten the two screws on the microswitch.
- Level the bed and check that the new nozzle brush position is ok.
Manually Level the Bed
When the printer has been homed in Z, the height of the bed below the nozzle is set by spring loaded screws at each corner of the bed. By rotating these screws, the height of the bed at that corner can be adjusted.
Before manually adjusting the height of the bed at each corner using these screws, warm up the printer close to operational temperature, to accomodate the thermal expansion of the nozzle and bed when the printer is printing.
- Set the bed temperature to about 60C.
- Set the nozzle temperature to 170C.
Ensure that the toolhead has no filament loaded and the nozzle is clean.
Step 1:
- Home the printer in X, Y and Z.
Step 2:
- Place the test paper on the bed at the near left side.
- Manually move the head until it is over the paper in this corner.
- Gently move the paper back and forth.
- If the paper is gripped strongly by the nozzle, adjust the bed levelling screw in that corner until the paper can move freely.
- If the paper moves without any sensation of it dragging on the nozzle, adjust the bed levelling screw in that corner until the paper is just starting to drag on the nozzle.
- Keep adjusting the bed levelling screw until there is a light sensation of friction on the paper from the nozzle pinching it to the bed.
Step 3:
- Repeat Step 2 but with the paper and toolhead at the near right side.
Step 4:
- Repeat Step 2 but with the paper and toolhead at the far right side.
Step 5:
- Repeat Step 2 but with the paper and toolhead at the far left side.
Step 6:
- Iterate through Steps 2 to 5 until the drag on the paper at each position feels equal.
Step 7:
- Place the paper and nozzle in the centre of the bed.
- Check the drag on the paper at this position feels the same as it did at each corner.
- Repeat the whole levelling process if all 5 points do not have the same paper drag feel.
Note
The adjustment of each corner can affect the other corners. Therefore it can take several iterations of this process until the paper drag is equal in all corners, without adjusting the height of any corner.Once all positions of the bed have the same light drag on the paper, the bed is manually leveled with the nozzle at the Z=0 position sitting the paper width above the bed (about 0.1 mm above in this example). In the slicer settings, setting a Z-Offset of -0.8 to 0.1 mm can be used to compensate for the thickness of this sheet of paper during levelling.
Mesh Bed Levelling
The Marlin 2.x firmware supports mesh bed levelling. The firmware allows the user to probe the Z-height of the bed at 20 locations across the bed. This can then be used in printing to adjust the Z-height of the hotend to accomodate any uneveness in the bed surface.
In this process, the printer touchscreen is used to move the toolhead to each of the 20 positions on the bed where the Z-height of the mesh are evaluated. At each of these 20 positions, the paper measuring tool is slipped between the nozzle and the bed. The Z-height at each of these positions is tweaked in the software to ensure a uniform Z-height above the bed at each location. These Z-heights in the mesh are then stored in the printer EEPROM to be recalled during a print and used to adjust the Z-height of the nozzle to compensate for the measured bed uneveness, thus ensuring a uniform first layer.
The first step of this process is to prepare the printer:
- Ensure no filament is loaded in the toolhead and that the nozzle is clean.
- Home the printer in X, Y and Z.
- Set the bed temperature to about 60C.
- Set the nozzle temperature to 170C.
- Wait until the printer is up to temperature.
The mesh bed levelling function can be found in the special menu of the printer’s touchscreen:
- Select the Print menu.
- Select the <Special Menu> option.
- Press <Refresh>.
In the following steps, after selecting a menu option, it is necessary to press the <Refresh> button to effect the selected option.
- Scroll through this menu and Select <Mesh Leveling> option.
- Press <Start Mesh Leveling> to start the mesh levelling process.
The printer will now move the toolhead to the first mesh position at the front left of the bed. Insert the measuring paper between the nozzle and the print bed and move the paper by hand feeling for the friction caused by dragging the paper between the nozzle and bed. The paper should slide easily with just a gentle sensation of friction. If the paper slides too easily, or is being grabbed by the nozzle, the Z-height of the nozzle needs to be adjusted. This can be performed by selecting menu options to adjust the nozzle height:
- Up in increments of 0.01, 0.02 or 0.1 mm.
- Down in increments of 0.01, 0.02 or 0.1 mm.
To adjust the Z-height of the nozzle select the desired Z up/down motion in the touchscreen menu and press Refresh. Keep adjusting the nozzle up or down until the paper is just barely dragging between the nozzle and bed.
Now that the Z-height has been set for this mesh point:
- Press the <Next Mesh Point> option.
The hotend will now move to the next point in the mesh. At this point put the measuring paper between the nozzle and the bed and adjust the Z-height via the touchscreen as above, until the paper is just being caught as in the previous measuring point.
Once this is mesh point is done select the <Next Mesh Point> option and repeat the previous step for each mesh point in turn.
After all 20 measurement points have been adjusted, the last pressing of <Next Mesh Point> will end the process, and the printer will emit a beep.
The final step in the process is to save the new mesh to the printer EEPROM.
- Press the <Save EEPROM> option.
To go back to the top-level special menu:
- Press the <End Mesh Levelling> option.
This Z-height mesh is not automatically used in a print. Instead it must be invoked in the start Gcode of the print through the command M420 S1. The following shows an example of the start Gcode.
G21 ;metric values
G90 ;absolute positioning
M82 ;set extruder to absolute mode
G28 X0 Y0 ;move X/Y to min endstops
G28 Z0 ;move Z to min endstops
; Get bed mesh
M501 ;Restore settings
M420 S1 ;Set auto-bed levelling values
PID Tuning
PID tuning adjusts the heater control algorithms for the hotend and bed to optimise the heating control of these systems.
PID Tuning of Hotend
This can be carried out via the printer touchscreen:
- Select the Print menu.
- Select the <Special Menu> option.
- Press <Refresh>
In the following steps, after selecting a menu option, it is necessary to press the <Refresh> button to effect the selected option.
- Scroll through this menu and Select <PID Tune Hotend> option.
The printer will carry out PID tuning of the hotend. This process can take several minutes. Once complete, the printer will emit a beep and move the toolhead to signify PID tuning is complete. At this point store the new configuration in the printer EEPROM by selecting the special menu item.
- Select <Save EEPROM>.
PID Tuning of Bed
This can be carried out via the printer touchscreen:
- Select the Print menu.
- Select the <Special Menu> option.
- Press <Refresh>
In the following steps, after selecting a menu option, it is necessary to press the <Refresh> button to effect the selected option.
- Scroll through this menu and Select <PID Tune Ultrabase> option.
The printer will carry out PID tuning of the bed. This process can take several minutes. Once complete, the printer will emit a beep and move the toolhead to signify PID tuning is complete. At this point store the new configuration in the printer EEPROM by selecting the special menu item.
- Select <Save EEPROM>.