Students

Fab Lab Facens

• Laura Massaglia

Mechanical Design / Machine Building

The group made the machine in 2017 rond. First they decided the different tasks:

Laura and Carla was responsible for setting the end effector and redraw the motors box to use MDF instead of cardboard. They where also resposible for assemble each axis.

Paulo worked with Siron to set the necessary parts to make the axis works, using the Gestalt Nodes, and programing it.

Software used

- Fusion 360

- Solidworks

- IDLE (Python GUI)

- GIMP

Machine Used

- G-weike 1290 Laser cutter

- Roland MDX-40

The group decided to build a 2 axis drawing machine. This machine will simply draw following the lines of a G-code that could be generated by the FabModules.

We first started by redrawing the cardboard layout for the motorr, in order to use 3mm MDF instead.

We redraw it using CorelDraw. Basically we measured and understood the original drawing, and we made a press-fit construction kit with 3mm MDF. Our laser cutter cuts using DXF files. So we provide de source file.here.

After few tryings we got it to work and assembled it. As aways we had to make some adjustments on the kerf to get a good press fit construction.

While assembling it, we realized that some of the parts needs to be assembled before close the central box, where the screws go.

Another problem that we faced it that the guide tubes sometimes slip while the motor rotate. So we had to fix it by making a new central box and gluing the guide tubes on the sides.

We defined that the end effector was going to be a marker pen fixed in one of the axis.

The way we wanted to position each axis, we needeed to design a wheel on the y axis. The Y axis would be mounted on the X axis, and as it is too heavy, we need a wheel to support it other side. We fast designed a solution for this using 6mm MDF and the laser cutter and a bearing.

Paulo was responsible for study and set the programming part. You can check his documentation here

Paulo basically got to understand how to connect the computer to the gestalt nodes.

He firs started by testing a single node using one of the files found on Nadya's page. We got some time to understand what each part of the programming means, but it was easy to put it move, just by changins the coordinates.

We found the programs from Nadya's git, we had to try understand what each part means. There was a lot of different files and folders and at the end, with some help from Siron I got the correct files. We found the file xy_plotter but he adivesed me that the file cannot start the name with 'x' because of a weird "windows" problem. So we changed it to axy_plotter.

Studying the code , some important functions that we found was:

portName = 'name-of-your-port' - You need to know in which port on your computer the Fabnet is conected. In Windows you can find it at Device Manager

elements.leadscrew.forward(#) - Sets how much the motor rotate for each command. use 8 to ride 1 mm when you send a command that changes in 1 from the previous command.

stage.xNode.setVelocityRequest(10) - Sets the speed of the axis. Be careful because after 15 the motors start to go to fast and makes some bad noises.

We first started testing just one node, using the file single_node.py available in Nadia's git. We got it to work using the existing FTDI cable and Fabnet to connect int he gestalts.

Siron explained us a way to use Fab Modules to the MTM. We could use files generated for the Vynil cutter and change its parameters to work in our machine.

To our machine, to travel 10 mm our commmands range in 10. In the vynil cutter to travel 10mm the code changes in around 398. So all we have to do is to divide the coordinates from the Fab Modules per 39.8, and we will get a good coordinates for our machine.

Having some programming set, we made a example file with a star to load and make the machine move.