3D Printing

We recently acquired and constructed a Kossel Mini 3D printer from BuildA3DPrinter.eu at the Floorplanner office in Rotterdam. So now we have it ready what does it do and how do we print with it?

SAFETY!!!

Before using the printer, it is important to realize that this printer is sold as a home build printer without any official safety regulations and that the heater element of the printer can reach temperatures of over 200 degrees Celcius. So use caution when handling the printer and never keep the power on the printer when not directly monitoring it. (So no overnight print jobs when you’re at home). These devices certainly can catch fire when they malfunction unattended.

How does it work

A 3d printer creates its result by creating a lot of 2D images and printing them on top of each other. In the case of our Kossel Mini printer, it makes slices of 0.2mm in height.

Printing is done by heating up plastic to around 210 degrees Celcius and pushing it out of the print nozzle. Once in place, the plastic quickly cools off to a safe temperature.

Because of this printing in layers, it is not always possible to print every shape without some preparation. Large overhanging parts will cause trouble and details that are too small will be lost. Sometimes it’s easy to work around these problems. A table can be printed upside down for example. In other cases, however, it is needed to add extra support to the printed models.

How to print a model

Now we got all the safety and theories out of the way it is time to start printing. The first thing we need of course is a 3d model to print. A website that contains a lot of 3d models for 3d printing is Thingiverse.

Slicing

To create a file that can be used by the printer to print a model we need a tool called a slicer. I am currently using KISSlicer for this. Get an adequately configured version for OS X here.

KISSlicer

 

In KISSlicer click the Open button in the top right to open a .stl 3d model and then click the Slice button next to it to let KISSlicer prepare the model for printing. Finally, click the Save button and store the .gcode file to the SD card that is found in the 3D printer.

Preparing the printer

Now we can prepare the printer for printing. First, check if there is any excess plastic hanging from the nozzle and cut it off if necessary. Next, clean the glass print plate with a bit of Glassex and a paper towel. Be careful not to use too much as the electronics below the glass plate doesn’t like this stuff. Make sure there is enough plastic available on the spool for printing and finally check if any objects could obstruct the movement of the printer head.

Printing

Now that the file is ready for printing and the printer is ready it is time to turn it on by plugging in the power. The printer will turn on and shows it’s status on the LCD screen.

Kossel-status

To control the printer using the knob next to the screen. Press the knob to open the main menu and turn the knob to select Print from SD from the menu. Press the knob again to show the files on the SD Card and select the file you want to print.

LCD-OpenFile

Now the printer will start warming up and after that will start printing. Depending on the model this might take several hours to complete. After printing is done wait for the headbed to cool down a bit before removing the model from the printer. Otherwise, you might damage the model.

After printing

After you are done with the printer wait for the nozzle to cool down to a normal level before turning off the power as the device will actively cool the nozzle while it is powered on. After it is cooled down unplug the device from the power connector for safety.

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