Computer-Controlled Cutting

The laser cutter its a machine that wants to catch on fire, if every thing is working it wont, but if there is a failure and the laser stays in the same place or if the air assist stops working there is a hight risk of fire, for this reason never leave the laser untended.

Laser Radiation

The laser beam can blind you or burn your skin in nano seconds for this reason never operate it with the lid open, aways wear the safety glasses for the type of laser you are using.

CO2 laser cutter are typically 10600nm wavelength, in our lab this is the correct glasses.

Diode laser cutters are typically in the range of 200-550nm wavelength, in our lab this is the correct glasses.

Introduction

On this assignment I was going to be using a 3dprinter I designed and made and then I upgraded it with a 2 watts diode laser. But I ended up designing and making a co2 laser cutter as I did not want to finish this course without such machine in my lab. I am really happy with my machine. It is showing amazing results even as a DIY machine.

I will be testing its capabilities and testing it to its limits in other to have a better understand of its capabilities and limitations.

On the Vinyl side of the assignment I will be using a Silhouette Cameo and document its results.

3D printer I designed and made with a carbon fiber milled body

the printer now with a 2 watts diode laser head attached to it

Laser cutter I design and made in Computer Controlled Cutting

Group Assignment

Go to for the group assignment page for other assignments, this weeks group assignment I am doing by myself as I am alone in the lab.

Characterization of my laser cutter

Work area: 400 x 290mm

Height: 150mm

Laser power: 50W

focus and Kerf

image extracted from Laser Cutter Focus video from makestuffnow!

The lens I use in my laser is a 20mm diameter lens with 50.8mm focal length. This means I should keep the hight from the lens around that measurement.

It would be a challenge to measure the the focal distance every time for this reason I design the ramp bellow. This will allow the laser to trace a line from the highest point of the ramp (0mm from the tip of the laser) to the lowest point from of the ramp.

Design files for focus ramp here

The result from the test is the that I should use the distance of 5 to 7 mm from the material top to the tip of the laser head.

laser cut result from focus test

With the trace done I started measuring with a caliper and a square the most focused area of the trace.

The result is a range from 5 to 7mm.

to easily measure the encountered optimal distance I designed a small steps of 1mm starting from 3mm ending on 8mm

I then laser cut it.

Placing the nozzle on top of the desired hight gives a consistent measurement across the surface of the material.

Measuring the kerf was simple. I used the previous template and the hole left by the cut. The difference is the kerf or the thickness of the removed material by the laser beam.

The inside measurement was 8.1mm

The outside measurement was 7.9 this means the kerf is 0.2mm/2= 0.1mm

I really like the fact the fit perfectelly!

power and speed

original svg used here

The power test above was done with a speed of 5000mm/min on a 2.7mm plywood. The power I chose as most suitable for this speed is 50%.

The speed test above was done on a 2.7mm plywood, with power set at 60%, even with the low power the laser were able to cut on almost all speeds tested. To be on the safe side I wold chose to cut at 5000mm/min with the power at 60% this thickness of plywood.

Press fit construction kit

For this assignment I will use 2d design from Solidworks. This is done within the sketches. Solidworks is a parametric design tool able to dynamically change its features with a change of a variable.

I started by creating a sketch. I then draw a triangle.

Next I started creating global variables. While adding dimensions I simply typed "equal" and then named the variables. Next I confirmed the creation of the global variable.

I kept drawing more features to the sketch adding parameters to each measurement.

Next I created a pattern with the desired feature that will be the connection of the piece.

In this panel I am able to edit each variable changing it and dynamically changing the model.

I added a little fillet here to allow an smooth coupling of the parts.

I proceed then to create formulas this will allow me to change the opening by changing one variable and it will take into account the kerf size.

Next I prepared the kit for exporting as an dxf file

In Solidworks, in orther to export a sketch keep it open then click in save as and do not rebuild, then chose the format, in my case, DXF and finish the export process.

In Laserweb, add document. Next drag the added document to the gray area bellow.

After draging the file a dialog with configurations will open. The software sometimes won't prevent you from creating inviable gcode. This means if some parameters are filled up it will not warn about.

For this job sice its a cut used one of my presets with the speed 4000mm/min, power 80%, and segment 0.1.

Next I positioned the object using either the arrows or the coordinates.

Here I show that I ended up multiplied the triangles in Solidworks and then reopened the file.

In this picture is also possible to see the middle top the web camera that is positioned on top of the laser so I don't need to keep my eyes on it. Even I wear protective glasses still I prefer not to look at the laser while it is still without a cover.

I then remove it from the machine and pile it to start inspecting and assembly.

Just a pile.

I then start assembly and it fits perfectly.

Vinyl Cutting

The Vinyl cutter we have in the Lab is the Silhouette Cameo 3. It's a nice affordable easy to use Vinyl Cutter.

Lab's Silhouette Cameo 3

It comes with the software Silhouette Studio.

Print from the first screen when you open Silhouette Studio

Learning outcomes:

Identify and explain processes involved in using this machine.

Creating the file

Selecting a file from Library

As a warm up and because we are near the Halloween I decided to cut something my kids could use

image of Studio Library

I chose the bat from the library.

outline of the bat chosen from the Studio's library

Once clicking twice the bat gets inserted in the middle of the work area.

Then using ctrl+c Ctrl+v I copied and pasted the bat several times.

I then select all the pasted bats.

With the selected drawings is possible to align the drawings uniformly.

I then selected the vinyl size.

I then paste again some more bats and start setting up the job. This machine is capable of automatically set the thickness of the material but the option autoblade must be selected.

I then align the vinyl. And lift the roll that drags the material.

Using the Screen I feed the material a little bit.

At this point I could either connect an USB directly to the machine or use the USB.

I press start and in minutes the bats are cut.

For a project simple as that it is sufficient to just peal the adhesive out of the protective paper and stick it everywhere!