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Getting To My First Print

2013-04-22 21.28.56As I mentioned previously I had already flashed my Arduino with the Marlin firmware, before I did this, I had to calculate the steps per millimeter for each axis,  Once I had an idea, I then was able to modify the configuration.h file which is included with the firmware.  I also updated line items such as the type of thermistors I had and what was connected to the outputs like heated bed and my extruder fan.

Once this was done and the board was flashed, I used an application called Pronterface (aka Printrun) to connect to the controller.  I then tested each of the end stop switches and sent a request to move each axis by 10mm at a time in each direction.  Finally I measured the movements to ensure that my calculations for steps per millimeter were indeed correct.

Next I hesitantly turned on the heated bed and waited as the temperature slowly rose through 100 degrees and finally turned off at the set point of 110 degrees Celsius.  Perfect!  Now the hot end… which is well, let’s just say HOT!  First I set it at 110 degrees Celsius and turned it on.  Everything seemed to go well so I incrementally increased the temperature set point to 225.  Cool or should I say HOT stuff.  After threading some ABS plastic into the extruder and pressing Extrude a few times I finally had my first whiff of melting plastic.  Usually this is a bad smell, but for this particular project it was a welcomely unpleasant smell.  LOL

Once everything was at temperature I started to calibrate the home position for each axis and then I leveled the bed.  It is important to do this step while everything is hot because of expansion when things heat up.  The rule of thumb I have been going by is to level the printer head approximately one paper thickness off of the print bed.  This really helps ensure your print sticks to the print bed and doesn’t pull up mid print.  Of course the bed has to be perfectly flat for this.  That’s why I ordered a sheet of purpose built glass from Voxel Factory.  The surface of the glass has a much flatter surface than any sheet of wood and this is a big improvement if you don’t want to fight your prints falling off.  Of course, there are a few other tricks up peoples sleeves.  One of which is to use Blue Scotch Painters tape on the print bed when printing in PLA.  Another common method is to use Kapton tape which works good for both ABS and PLA to a lesser extent.

So after applying my tape, I was finally ready for my first print.  To make things easy I sliced a simple belt clamp for the Prusa Mendel i2 and pressed the print button.  Everything went off without a hitch!  I guess it pays to do your research.  The result actually looked somewhat like it was supposed to.  The only issue I found was that because the print was so small the ABS didn’t have time to cool before each layer was printed on top of the last.  This resulted in a somewhat mushroom shaped print that looked mushy as it was printed.

After playing for a while I started to have my doubts about Pronterface and started to check out Repetier which has a much nicer interface.  I am much happier with it now.

All in all not a bad few days! (No April Fools joke either!)

dave

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