Step 1: Bed Leveling

The first step to good results for any print is bed leveling. This video explains the best way to get great results on the I3 Mega

This will show you other problems too. For example with a 0.6 nozzle I noticed the start of the infill, where the nozzle first starts after a retraction move, had less material than there should be. To solve this I had to add a “retraction prime amount” of 0.07 mm3.

EDIT: I recently installed Marlin for Anycubic i3 Mega on my printer, and it enables Mesh-Bed Leveling. It’s a game changer. If you want me to make an explanation, just comment and let me know!.

Step 2: Correct Material Settings

Every spool of filament is different, even if it’s the same brand and the same color. So before doing anything with it, you should do a temperature tower.

Cura has an easy way to do this (taken from this great guide):

My most favorite model is temperature tower by 3DMN (3D Makernoob), you can find it on this link. But how do I setup my slicer to change temperature every X layers?

Well, this clearly depends on your slicer. If you have Simplify3D for example, you can simply set different temperatures every X layer in „temperature“ tab. I personaly use Cura, so I’ll try to give you an idea how to setup Cura for temperature tower, but I guess that it’ll be similar in other slicers as well. First of all import your .stl model to Cura, then set your temperature, layer height, initial layer height, infill,… and slice your model. Then set your view mode to „layer view“ and adjust slider to find first place, where temperature should change for the first time. Write down number of this layer and continue this way all the way up to the end. When you have written down all numbers of layers, where temperature should change, go to Extensions -> Post processing -> Modify G-Code, then click „Add a script“ and click „ChangeAtZ“. Type here number of first layer, where temperature should change, then check „Change extruder 1 temp“ and set your first temperature here. Continue so with the rest. In the end, slice your model again and export G-Code and give it shot on your 3D printer! If you’ve done everything correctly, you should see how temperature chages on display during print. As a result you’ll get tower with multiple bridges, overhangs and other features where you should be able to see difference every temperature change. Stick to the temperature value you consider as the best one.

Don’t be scared to go lower than you think. Temperature is the most important part of getting no or nearly no stringing.

Step 3: Best Cura Settings

Funny enough, the standard “Fine” settings for the i3 Mega in Cura 3.5.1 / 4.4.1 are already pretty good. But you can optimize some settings. To understand why and how, watch this great video:

Before you go to the actual Cura settings: add a nozzle wipe to your G-Code.

In your “Machine Settings” of the Anycubic I3 Mega in Cura, you can add the following “Start G-code”:

G21 ;metric values

G90 ;absolute positioning

M82 ;set extruder to absolute mode

M107 ;start with the fan off

G28 X0 Y0 Z0 ;move X/Y to min endstops

G0 Z0.15

G92 E0 ;zero the extruded length

G1 X40 E25 F500 ; Extrude 25mm of filament in a 4cm line. Reduce speed (F) if you have a nozzle smaller than 0.4mm!

G92 E0 ;zero the extruded length again

G1 E-1 F500 ; Retract a little

G1 X80 F4000 ; Quickly wipe away from the filament line

M117 Printing…

G5

This “cleans” your nozzle before printing by wiping it and a bit of filament on the front of the plate.

Now to all of the settings:

Quality:

Keep the “Fine” (Cura 3.5.1 / 4.4.1) Standard settings.

Shell:

You can reduce Top/Bottom Thickness to 0.8. Minis don’t need thick heads or bases.

Disable “Compensate Wall Overlaps”. This can lead to problems.

Infill:

Infill Density: 50%

Infill Pattern: Grid

Infill Overlap Percentage: 10%

Material:

See Step 2 for Temperature!

Reduce flow a bit. I’m using 97%, but you might need more / less. Check for under / overextrusion!

Click on the grey circle next to “Retraction Minimum Travel”, this lets Cura calculate the travel distance (in Cura 4.4.1 this step is no longer neccessary, the setting isn’t available anymore)

Click the highlighted circle in Cura

Speed:

Decrease “Wall Speed” to 30 mm/s.

Increase “Top/Bottom Speed” to 30 mm/s.

Increase “Travel Speed” to 100 mm/s. (new in Cura 4.4.1)

Decrease “Skirt/Brim Speed” to 25 mm/s.Decrease “Print Acceleration”, “Initial Layer Acceleration” and “Skirt/Brim Acceleration” to 300 mm/s.

Keep “Travel Acceleration” and “Initial Layer Travel Acceleration” at 3'000 mm/s.

Decrease “Print Jerk”, “Initial Layer Jerk” and “Skirt/Brim Jerk” to 5 mm/s.

Keep “Travel Jerk” at 10 mm/s.

Travel:

Set “Combing Mode” to “Not in Skin”.

Disable “Z-Hop when retracted”.

Cooling:

Set “Regular Fan Speed at height” to 0.2 mm.

Experimental (new in Cura 4.4.1):

Enable “Coasting”

Keep all other settings as the Cura 3.5.1 / 4.4.1 “Fine” standard!

Step 4: Improve your Supports

Adhesion: I used to use rafts, but since following Step 1 and 5 in this guide, it’s not necessary. It works so well with a totally level bed. But don’t be scared to use a raft if you feel the need to.

Supports: For standing minis I use tree supports. For small additional parts I use normal supports.

Normal Support settings:

Standing Mini Tree Support Settings:

Yes, disable “Generate Support” if you use the experimental “Tree Support” settings, but keep the options for the Support Interface!

The support density you can have between 10–20, depending on how many and how wild overhangs your print has.

Step 5: Clean your bed!

Clean your bed using alcohol and then wipe it with water. I use 38% Ethanol to clean it, and it works perfectly.

Step 6: Print

Keep the room you are printing in with a steady temperature. Airflow like an open window can be bad to keep a steady temperature.

I use Octoprint. I don’t think it improves quality, but it lets you do nice things with the add-ons. But some add-ons, like OctoLaps, can reduce quality if not set up correctly!

Step 7: Post-Print Cleanup

Removing supports can be a pain in the ass. The smaller the nozzle you use, the easier they are to pull away.

I use the clipper that came with the printer to clip them off close to the mini and pliers to pull them away.