Week 3

Week 3: Assignment

The assignment for this week is to design, make, and document a press-fit construction kit. It might be about small units that can be put together in different ways.

I started off by making a drawing in Inkscape of a piece that could slot together, just to check out the design process and do my first laser cutting:

This was not a success, as the fit was not tight, so I did the exercise again. The reason was that I had not calculated correctly the effect of loss of material that the laser burns away. For the press-fit to work, an offset on 0.1 mm is recommended, so in Inkscape a stroke of 0.2 mm needs to be made, to allow for the cut. My second attempt resulted in pieces that could make the trailing boxes from MDF, that I wanted to create, and they press-fitted tightly. The settings used for the lasercutting were: speed 16, power 100, frequency 500. Through this process I learned to measure more accurately and to design a good fit in Inkscape. The trailing boxes look like this:

I was also looking at various tools, methods and projects, that are made with this way of working. I decided to experiment with a form of a sphere and a press-fit construction kit that I found on the internet, just to see if it would get me into the process and what I could learn from it:

I created a sphere in Rhino and used the tool 123D Make to transform the shape into a slotted press-fit construction:

I then created an elipsoid in Rhino and used 123D Make to transform the shape into another slotted press-fit construction:

I downloaded other interesting programs, suchs as Stipplegen2 and Flatlab, that I would like to experiment with later. Stipplegen is a program that can generate stipple diagrams and “TSP path” art from images, using Adrian Secord’s algorithm of weighted Voronoi stippling. It’s a free tool for turning a photo into CNC-ready artwork. Flatlab is a software that helps you design and fabricate 3D objects. It works in such a way that you draw in 2D, but can also view the objects in 3D. These designs can be cut on a laser cutter and object are being created, using connected planar parts.

I also made a sticker, made from vynil. It was designed for my Mac from a photograph, in a form of a hand that could hold the apple on its lid:

The preparation of the drawing to print can be done in Photoshop and Illustrator, as well as in Inkscape. I worked on the image in Photoshop where it was resized and adjusted (Adjustment – Threshold) to create a black and white image. The image was tweaked a little further and saved as a .png. It was then imported into Illustrator, where I did a conversion on it, to change it into a vector drawing. Object – Image Trace – Make. Then the image was saved as a .pdf.

Before saving the .pdf it is wise to check that the vektor image does not have any outlines (Stroke) and just a fill for the areas that are to be cut out from the vynil sheet. The print settings were:

The cutting was done on the Roland CAMM-1 Servo machine (GX 24):

The vynil sheet had to be positioned under small weels, btween markers and over a lens that helped confirming the size of the vynil to cut and the cutting area. The weels can be moved with a lever at the back of the machine. On the control board the setting "edge" was chosen as I was printing on a piece of vynil, not a roll.

A printing command is given on the computer: File - Print - Roland GX24. In preferences - Get data from Machine. In properties the following settings were chosen:

The handling of the sticker and is described in the following images. The vynil which is not being used is peeled off and a sheet sandwiched on the reverse side in order to be able to transfer the sticer intact on the the surface it was intended.

The result looks like this: