By Aad van de Wijngaart

“I don’t think I would want one in my bedroom”, declares a female attender of the demo in the Library. Well… the attractions of a printer aren’t endless. But most of the visitors show themselves more than interested in the battery of Leapfrog machines arrayed in the lounge corner of the main hall.

Mischa Moritz and Pieter de Lange work the machines and provide explanations. They are still students, but they own a small business ( where fellow-students can have their models and prototypes printed. “That’s faster than manual crafting and looks more realistic”, says Mischa. “And in the meantime you can go and do something that’s more fun.”

A schoolclass arrives. The girls stand looking from a distance, giggling but obviously intrigued, while the boys bravely walk down to the machines and pick up the printed models. Who knows what effect this technology will have in their lives…

In the afternoon it’s workshop time. This will be my first attempt at 3D printing. What will come out of it?

The workshop, too, is run by Mischa and Pieter. They start off with an introduction into the technology, and into Leapfrog, with which they themselves are also involved. This Dutch company sold its first printer in May of 2012, but has already opened a subsidiary in America.

In view of the limited time we are advised to choose an existing design for our printing experiment. There’s plenty of choice: websites like and offer a wide range of models. Doorknobs, key rings, sold out IKEA parts – you can’t imagine anything that hasn’t been turned into STL file by someone and put online for other users. And if you think you can better the design, you add your new version too. “Nowadays everything is about sharing”, says Pieter philosophically.

Even complete printers can be downloaded as ‘open source’ and library workers have done just that. In the offices there are now two machines working busily. They have been assembled with lasered board material and printed mechanisms. At a price of some 450 euros each, the engineers of the Library now have their own little factories.

For now, I take a slower approach. After a few minutes of clicking at, I opt for a dice. The zipped STL file is only 21 kB. I share the printer with Beatriz, a PhD student from Spain. She first selects a panther head, but it turns out it’s too big and will take forever to print. OK, she goes instead for a key ring in the shape of a female figure. But first we’ll try the little dice.

The tension rises when we’re given the sign to load our printers with filament: the plastic wire that will soon be heated to 220 degrees inside the printhead. I break off the tip and push the hard filament into the opening. Fortunately, it’s wide enough.

Next I bend the protuding end into a more or less straight shape, after which Pieter cuts off the top with a little knife, as if it were the stem of a rose. The steel bolts of the printer do double duty as miniature cutting boards.

We enter the print settings into the Leapfrog software: material, filling percentage, temperature, quality… The computer start crunching and soon announces that it has succesfully parsed a model with exactly 1,460 triangles into printer commands.

The printing will take three quarters. Too much, deems Mischa. He reduces the size and now it’s half an hour.

The machines goes to work with gusto. The desk is vibrating. After seven minutes or so, the software tells us that the dice is 23% finished. The profile is coming out clearly. It looks fine! With each new layer, the printhead draws a wider outline and then speedily zigzags matrix lines for the filling.

I go and see how the neighbours are doing. They’ve already finished a lifelike Ford key ring: ten cm in size. The student behind me, in turn, has printed a sturdy, smooth bottle opener. All that’s left to make it work is inserting a cent into a small slot. Clever!

Unfortunately, my own little dice turnes out less than perfect: the top and bottom offer little glimpses into the hollow interior. “A fault in the design”, deems Mischa. It can be corrected through the print software by adding some extra layers, but there’s no time for a second run.

Half an hour later, Beatriz’ key ring is finished. It’s nice and smooth! Finally happy, I leave the scene of my first printing adventure.