Archive for the ‘CNC’ Category.

Saturday eggbotting

Eggbotting “Open Space Aarhus”

I measured the egg using the probe.

Create the path in in inkscape using gcodetools.

In a postprocess i first split the path in to short segments, then I linearly interpolate based on the measured data to follow the surface.

In this eggsperiment I used G64 to allow the machine some tolerance in following the path to gain a better feedrate. The result were at significantly different sound from the steppers, it sounds more ‘sick’. But it worked

See the video @ vimeo :

The next step is to try to make TSP art on the eggs, Nikolai Tesla made from a single line , Evil Mad scientists have nice guide:

Eggciting data

These data were made with a ‘FrakenProbe’ they represent the surface height, X(length) and A(rotational)axis.

The experience with the first test run proved that even though the penholder does have some play in the z direction, the plot could be better if the pen were to follow the surface of the egg exactly.  Now its possible to probe the surface and the next step is to interpolate the movements based on the data.

A video of the frakenprobe in action on vimeo :

The gcode to probe the data were my first experience with writing loops in gcode and making extensive use of parameters. I must admit that it not pretty, this is the main part with a nested loop:

(PROBEOPEN data.txt)
G0 Z[#<SAFEZ>]
#<J> = 0
o200 DO
G0 A[#<J> * #<ASTEP>] Z[#<SAFEZ> + <#PZ>]
#<I> = 0
o100 DO
G0 X[#<I> * #<XSTEP>] Z[#<SAFEZ> + <#PZ>]
G38.2 Z[#<PZ]
#<PZ> = [#5063]
#<I> = [#<I> + 1]
o100 WHILE [[#<I> * #<XSTEP>] lt #<W>]
#<J> = [#<J> + 1]
o200 WHILE [[#<J> * #<ASTEP>] lt 360]

Did i mention that it is really really nice to have a hackerpace, with tools, parts, club mate and geeks who can help out when you are stuck.

Eggbot first print

A penholder was made, its basis is the insides from a CD-ROM drive the pen is molded into place using Shapelock.

An Egg was mounted and some quick test pattern were made in Inkscape.

We step back and observe the magic.

Unfortunately i dropped the first real image, the first test run were spirals and a hardboiled egg.

There are still issues to work out, but all in all we are quite satisfied with the first test.