Design Log #1: Cardboard Robot Parts

A project log for Laser Cut Cardboard Robot Construction Kit

Laser cut cardboard and wooden pieces for making animatronic robots. Open source templates and activity guides for educators.

simonsimon 06/04/2018 at 07:070 Comments

Hi, I’m Simon Lynch. I work as a designer, digital manufacturer, and occasional instructor for STEAMLabs, and I’m responsible for the design of the cardboard parts that make up our robot construction kits. Our next three blog posts will deal with design features we’ve developed for our kits over the past month and how they help facilitate robotics activities.

This first post will deal with the design of the physical parts that make up our kits.

Cardboard Parts

Clockwise from bottom left: chassis box, partially assembled with ends, head box, and prototype head box with integrated ends.

The central component of the cardboard construction kit is what we call the “chassis box.” It consists of a four rectangular faces connected side-to-side on their foldable edges. The chassis features parallel pegboard-like holes to hold axles (usually chopsticks), a pair of long vertical slots on one face to facilitate moving levers, and partially cut silhouettes of common electronic components. Each face also features small horizontal slots along the top and bottom into which two “end” pieces can snap to provide the box with a shape around which to fold.

A series of other designs support these central parts: a “head box” (a truncated chassis), three smaller parts with interlocking slots and a small number of holes (called “bodies”, “arms”, and “squares”), wheels, a pair of wooden gears matched to the dimensions of the chassis pegboard, and wooden levers with chopstick-shaped holes on one side and M3 bolt holes along the other. We previously featured a larger number of other parts, but these have been discontinued or integrated elsewhere as we’ve streamlined our designs.

people building

Science Centre visitors building with early versions of the cardboard robot parts. Crowds like this provide daily feedback on our designs.
We’ve been using our cardboard kits extensively in our own teaching programs over the past month, and our designs have undergone continual refinement as we’ve received input from everyone who interacts with them.

This group of collaborators includes (but is not limited to) our instructors and regular students, teachers from several school boards who have demoed the parts, Ontario Science Centre staff and visitors, our staff members assigned to cut parts at STEAMLabs, and the person who packages them for shipping. Their observations and experiences have led to changes in everything from the part names to their size, shape, variety, and fit. As we continue to expand our use of the cardboard kits, further improvements are underway.

chassis sheet

File for a sheet of sixteen chassis boxes.

To maximize cutting speed and material use, we use vector files that allow large quantities of parts to be cut on single sheets. The designs in these files are overlapped, so that the final cutting line of one part doubles as the first cutting line of the next. Gaps of ~0.5 mm are left in the lines between parts and on the edges of internal slots and axle holes. These provide tiny cardboard threads allow whole sheets of parts to be lifted at once, allowing the laser cutter to start cutting another sheet of parts immediately, but are fragile enough that they can be easily disassembled into individual pieces.

Certain parts, like the end squares, are arranged in their files to be cut diagonally, so that none of their lines are cut along the bias of the cardboard. This ensures that these structural parts don’t deform easily and provide strong joints.

These designs can be found above in our “Files” section.