What is needed; is printer connected to Repetier-Host and working (working in you can control the printer in the movement of the x,y and z axes. Heat the hot end, manually extruded filament, retrieve printer firmware logs and set printer firmware settings etc.), Blue tape added to the printing bed. Sharpie, 2.5mm hex wrench, #2 Phillips Screwdriver, pencil, ruler and calipers or micrometer and maybe a calculator.
The Printrbot suggested printer software is Repetier-Host (Note that the Mac OSX Version uses different labels and terms on its UI than Linux and Windows versions do). However there other software you can use. I start calibration with leveling the printer bed. Some of the newer Printrbots use a auto bed leveling sensor witch allows you to skip this step or do things differently. However leveling a print bed is not hard it just takes some patiences.
My Printrbot simple has N-Stops including one for the Z axes. The end stop will need to be adjusted along with the 4 spring loaded screws on the bed plate. A index card works as a good paper weight to test if the bed is level. The paper or card should slide under the nozzle and the bed with slight friction in all four corners and dead center of the print bed to be level. This step takes about (10 to 45 minutes the first time) and 5 to 10 minutes (in future times). I notice that between every 15 to 20 prints the bed may need to be re-leveled, or after transportation. There many videos on youtube on bed leveling with many different kind of printers. The technique is nearly the same for every printer (just note if you have a N-Stop for the Z-Axes you need to adjust the screw for it here).
Extruder Feed calibration.
This might be one of the most important ones to do first, because if it is way off (and being this was a kit, it will be way off) you will not be able to even print the calibration cube because it may clog your nozzle first if it uses to much filament.)
You need to heat the hot-end (extruder) to 196 Temperature and wait till it gets to 196 before you feed. (note the picture is not up to temp yet)
Now while your waiting you can check some settings on the firmware. To do so while within the print-panel tab(on Mac) this is called something different on Windows and Linux versions of the software. But the steps are the same.
Type M501 into the G-Code field and hit send. This will get the current firmware settings for the printrbot. which will be displayed in the console logs at the bottom of the software window.
The line of text your looking for starts with M92 locate this line of text and take note of the last item of that line mine reads out E590.00 This could be different for you. This is the current firmware the printer is set to extrude at. The E stands for extrude. write down this value it will be needed with our calculation of calibrating the E value or the extruder feed rate.
It looks something like this:
< 1:07:38 PM: echo: M92 X63.36 Y63.36 Z2272.72 E590.00
The Blue value above is the E Value.
Once your up to heat if you have not add the PLA filament to the extruder and manually feed 10mm. If that spit out some hot plastic then your working. (If it did not you need to trouble shoot the issue. Make sure your heated to temp and also make sure the filament is pushed into the hot end and the tension spring is tighten, keep trying until you can get your color filament to show coming out of the bottom of the print nozzle.You may have to heat up the extruder a bit, but do not go over 205 for the printrbot simple with PLA. Printrbot itself suggest 195-205 Celsius.)
Once your ready to go, Get a ruler and a sharpie (Some use tape but I tell you when I first did this test on this kit, I extruded over the mark. and if I used tape I would had tape jammed in the hot end. and that would have been a major problem, That why I suggest a sharpie.)
You need to measure 100mm up from the from the top of where the filament comes out of the extruder and mark the plastic with the sharpie at 100mm, (Note 50mm can be used if you did not build a kit however Its very likely that with the kit it will extruded over 50mm the first time out, when you tell it to extruded 10mm) (also make sure this is tighter than the image below, A one handed photo with my cell phone did not show the correct way, but you should get the idea.)
Ok once you have your mark and you noted where you measured at, like I measures from the top of the extruder motor. This is important because you remeasures this in a second. Now on the Print Panel of Repeatier host Extruded 10mm of filament. Now measure the amount it actually extruded this value is used in the calculation to do the calibration.
The Calculation is as follows :
(Old firmware value * Software move) / Actual hardware move = New Firmware value
I use my values as an example but your will likely be different
my old firmware value was 590.0
my Software move was 10 mm
and my actual hardware move was 59.5mm
(590*10)/59.5=99.16
My new firmware value would be 99.16 your likely will be different.
Once you calculate your value out and have your new firmware value, we can now save it to the printer. To do this Type M92 E (Your value) like my example M92 E99.16 in the same g-code sender. and hit sent. Then type M500 to save this value to the firmware. You can then type M501 again to verify that it saved to the value.
The Calculation
(Old firmware value * Software move) / Actual hardware move = New Firmware value)
is used also for the X, Y and Z calibration. However I will not go over the Z calibration because I find the best way to test this is by actually printing out the calibration. cube.
For the Y and X calibration you need the blue painters tape, a pencil and a ruler. I first home all axis then move the z axles up from the bed about 30mm or enough room to fit your ruler under it standing on its side.
For the Y mark where the nozzle is at the home mark. and measure 50mm back from the front of the print bed. and mark a line. And for the X axis measure right from the home nozzle mark 50mm and make another mark.
Now you can home the extruder again and move the extruder back 50mm on the y axis. Now measures the how much it moved. This will be the actual hardware move.
Now type M501 back into the software to receive the M92 firmware settings for the X and Y axis. This is the same as what you did to get the extruder setting. However you need the Y value for the Y calculation and the X value for the X calculation.
I use my settings again just as a example you want to to your own measurements because all printers are different.
(Old firmware value * Software move) / Actual hardware move = New Firmware value)
my old firmware value was 63.63
my Software move was 50 mm
and my actual hardware move was 36mm
(63.63*50)/36=88
My new firmware value would be 88 your likely will be different. Before you save this setting do your x setting now. home the nozzle again and move the printhead over 50mm mark its location now calculate the difference.
I once again use my value as example only (yours will be different most likely)
(Old firmware value * Software move) / Actual hardware move = New Firmware value)
my old firmware value was 63.63
my Software move was 50 mm
and my actual hardware move was 39mm
(63.63*50)/39=81.23
Now you want to save these two new settings to your printers firmware so this time type
M92 X(your value) Y(your value) like my example( M92 X81.23 Y88 ) and hit send, then follow by M500 to save this to the firmware. Now you can type M501 and check the M92 has all your calibrated steps. If so you can now go and print out a calibration cube to check them and see if the Z axes needs adjusting. If it does you can use the same steps.
M501 to get current firmware values
M92 the line with the firmware value to get and set. X, Y, Z, E values are part of M92.
M500 to save a setting to the firmware.
These settings should save to the printer even when it is off and unplugged. If its not you may need a new battery on the printer board.
Below is the 5mm Calibration Cube step print I printed out after doing the Manual Calibration. I can report that my z axis actual did not need any calibration and the print was in prefect tolerance just after doing the manuel calibration above, Not bad for a first print ( a month ago) . This might not be the same case for you if not use the same steps to fine tune the setting to the printed cube (as mine pictured below)
5mm Calibration Cube Steps
Download at Thingiverse for free: http://www.thingiverse.com/thing:24238
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