This calibration involves tweaking the firmware of the printer. This calibration should be done when changing to a new filament or if it seems too much/too little plastic is being extruded.
The firmware of the boards (RAMPS or RAMBO) tells the extruder stepper motor how many steps it takes to extrude a certain amount of material. This changes depending on multiple factors and it is a good idea to do the calibration regularly.
What You Need: Current value of extruder steps per mm(found in firmware) Marker Waste material 100mm in length
Step 1. Raise the print head manually using Pronterface and heat the hotend to the temperature it normally prints at.
Step 2. While the printer is heating up, find something that can be cut to 100mm in lenth. A straw works perfectly in this situation as it can be cut to 100mm and then sliced down the middle so that it can be wrapped around the filament.
Step 3. Using whatever was measured to 100mm, place the bottom of the object at the top of the extruder(where the filament enters). Now using a sharpie or anything that can make a visible mark, make a mark at the other end of the 100mm object on the filament.
Step 4. Manually extrude 100mm. Once the filament has stopped moving, measure the difference from the top of the extruder to the mark. If the step setting in the firmware is 100% correct then this distance should be 0. Otherwise this setting needs to be changed via gcode command M92 E<newsteps>
Example: Say our initial steps/mm value is 515. When this calibration is done, only 90 mm of filament has been extruded instead of the expected 100mm. Using the equation (new steps/mm) = (original steps/mm)*[(expected length)/(actual length)] or (new steps/mm) = 515steps/mm *[(100mm)/(90mm)] = 572.22steps/mm
So our new steps/mm value should be 572.22. To apply this enter M92 E572.22 into the gcode command box of pronterface.
This is another calibration that should be done when switching filaments. This calibration makes sure slicer is calculating the correct amount of plastic that should come out of the hotend.
What You Need: Slic3r Calipers
Step 1. Download a single walled cube from thingiverse. Make sure infill is set to 0 in slic3r settings. Also uncheck "Generate extra perimeters when needed". Under the advanced tab set Default extrusion width to (layer height * 1.4). So for a .3mm layer height you would set this parameter to .42. Under Filament Tab set extrusion multiplier to 1.
Step 2. Print the cube. Once completed use calipers to measure thickness of wall. If printer is calibrated this should be .42mm(if using .3mm layer height). If not the extrusion multiplier needs to be changed.
Step 3. Using the equation (expected thickness)/(actual thickness) * 1 = extrusion multiplier setting.
Example. Say we got .51mm instead of .42mm. (.42mm/.51mm) * 1 = .82
Therefore we set the Extrusion Multiplier setting under the filament tab to .82 and save the setting. The flow rate is now calibrated.
This will calibrate the hotend so that temperatures are more stable instead of oscillating.
Step 1. Enter gcode command M303 S<temp used for printing> C5
This will cycle the hotend at that temp for 5 cycles. then it will output values for Kp, Ki, and Kd.
Step 2. Enter gcode command M301 P<Kp value> I<Ki value> D<Kd value>
Step 3. Enter gcode command M500
to save these values to the printer