3D printing 101

The following is a handout for a class designed to help people go from knowing nothing about 3d printing to being able to start a print and design simple objects for printing.

What is 3D printing? 3D printing has a lot in common with 2D printing. Imagine that your 2d printer made thin pieces of plastic in any shape instead of ink in any shape. Now imagine that you could move up and put multiple layers of thin plastic on top of each other. The technology for 3d printing has been around since the 70s but recently cheap microprocessors made it possible to sell 3d printers for $400 or less.

What are you going to 3d print? Printers that fuse filaments of plastic together can make objects of virtually any shape. The printed object might not be as smooth or high resolution as you would like and it might require support material to ‘defy gravity’ but all of those limitations change if you go away from Fused Filament Fabrication and try one of the more expensive printing technologies. What is the plastic object of your dreams?

Download a file from Thingiverse.com a large, user friendly database of printable files. Nature doesn’t reinvent ‘the wheel’ very often, why should 3d modelers? STL files are some of the most universal 3d models but OBJ files will work too.

Repetier is one of several software options for turning digital .stl files into physical objects. Repetier is not the most user friendly but its complexity allows experts to control more aspects of the printing process

Click the “load file” button. Once the computer has processed the file you will see the object displayed inside of a digital box that shows the limitations of your print bed. You can load several STL files at once and drag them around the print bed however you like. Some files need to be rotated so that a large area will be in contact with the print bed. If an object is not strongly attached to the print bed the next layers of plastic will end up in the wrong place.


Click the “slice with slic3r” button. Slic3r is taking STL files that you arranged in repetier and generating the instructions that the printer will read to print each thin layer of plastic. These instructions are called Gcode. Gcode is not easy to modify and run on other machines because it often has coefficients that have been calibrated to a specific machine. IMG_2271

I wish I could say just click the “start print” button but our printers are still a little quirky.

  • The Velleman K8200 doesn’t turn on its extruder heat when you click the “start print” button so it will sit there waiting for the extruder to heat up. If you click the manual control tab before starting a print then you can turn on the extruder heat

Screen Shot 2015-11-04 at 10.55.18 PM

  • The Prusa i3 doesn’t have a sensor to tell it what height its print bed is located at and it assumes that its print bed is located at whatever height the extruder was at when it turned on. The way to work around this is to always lower the extruder back to the print bed before turning the machine off after you have finished with your print.


Changing Filament color:

  1. Open the manual control tab in repetier.
  2. Heat up the extruder.
  3. After the extruder is around 190º C, pull up on the filament while clicking the retract filament manual command.
  4. The extruder gears should spin in reverse and eventually the filament will come loose and allow you to push in the desired color.
  5. Insert the new filament and push the extrude filament manual command. The extruder gears should grab the filament and pull it in.
  6. Keep extruding until the desired color is coming out of the extruder nozzle.

TinkerCAD is the most user friendly 3d design software that I have found. It is free just go to www.TinkerCAD.com and log in.

Drag objects onto the work plane

drag objects

Resize objects


Change the location of the work plane

Change Workplane

Make holes

Make Holes

Download your design

download design

I do the majority of my 3d modeling in Blender, a free animation software. I will be hosting a class on modeling with Blender on December 3rd.

My Company, Pintstein L.L.C. is a startup 3d printing and education company or as I like to call it, a “Mad Scientist Toy Company”. Pintstein will print things out for you, teach you how to design your custom object and, hopefully some day, Pintstein will be able to send a technician out to your house to fix/recalibrate your 3d printer. 3d printing is resource cheap but time expensive. Children are the most time rich members of society so Pintstein wants to get kids access to 3d printers by making it easier for schools and libraries to keep their printer in good working order. www.PintsteinPro.com

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