What is laser cutting?
Laser cutting is a technique in which sheet material is cut with laser light. You can cut wood, plexi, cardboard or other materials.
The laser cutter can be used to make your own toys such as robots, puzzles, gripper arms, catapults, ...
It can also be used to cut out textiles for, clothing or bags. Another application is to make architectural models with it. It is possible to make wood pliable by working with certain incisions (this is called living hinges).
Laser cutting is used in finished products - for example the first version of the Ultimaker (a 3D printer) - or the packaging industry.
Laser cutting is a useful tool to make prototypes, the first version of a certain product.
From drawing to cut out figure
The different steps
In order to be able to do something with the laser cutter, we need a 2D computer drawing, this drawing must be a vector (more info about vector drawings can be found in our Inkscape tutorial ). We use Inkscape, but you could use other programs such as Illustrator. Export the 2D-drawing to the software of the laser cutter, and then cut the file with the laser cutter.
How does laser cutting work?
The Laser cutter
The laser cutter cuts by means of burning away material with a laser beam. In case of a C02 laser cutter, the laser beam is created in the glass tube at the backside of the laser cutter. This tube is filled with a gas that is brought under high voltage, thus creating a laser beam. This laser beam is sent to the laser head with the aid of mirrors. In the laser head there is a lens that focuses the laser light on the surface of our cutting material, thus burning away (or evaporating) material. The head can move from left to right and from front to back by motors. The 2D drawing that is made on the computer will describe the path that the laser head will follow during cutting. The laser cutter is equipped with all kinds of peripheral equipment such as the water cooler, the air filter and the air pump for safe cutting.
The water cooler ensures that water flows through the glass tube in order to cool the laser tube. This is necessary to ensure that our laser does not overheat.
The air filter ensures that the smoke, which is released when the material is burnt away, is filtered so that this air can return without soot particles.
The air pump blows air under the cutting head while cutting. The air pump ensures that the smoke that is released during cutting is blown away. As a result, the lens in the cutting head will remain clean for a longer period. Also, thanks to the air we get a cleaner cut.
Make your own drawing
There are several ways to draw something in 2D. We recommend Inkscape to make a 2D drawing, because this is a free and open source program. However, Inkscape requires some learning time, here you will find a tutorial to learn how to draw with Inkscape. It is possible to use Illustrator instead of Inkscape, in fact any design program that can generate .svg vector files (scalable vector graphics) will do the job. It is even possible to generate 2D cut drawings from 3D print software (for example: in Tinkercad).
Download laser cutting example
Here is a good example to practice laser cutting before you learn to draw something yourself. Download it or use your own drawing to follow the next steps. Inkscape raster, engrave and cut example
What specs should your drawing meet?
The drawing must be a vector drawing, this means that if you open the drawing with a vector program (eg with Inkscape) you can adjust the points. You can use a photo, but the laser cutter can only raster the image and therefore not cut or engrave it.
Use of color for cutting
The lines to be cut out must have a red line color. Set the line color to R: 255 G: 0 B: 0. Make sure that the filling is off. Check that the alpha (A, transparency) is 255. Also check that fade is at 0% and the opacity is at 100%. More information can be found here
Color use for engraving
The lines that need to be engraved (half-cut) must have a blue line color. Set the line color to R: 0 G: 0 B: 255. Make sure that the filling is off. Check that the alpha (A, transparency) is 255. Also check that fade is at 0% and the opacity is at 100%.
Use of color for rasterizing
The lines that need to be rasterized (surfaces "colored in/burned" with the laser) must have a black fill. So turn off the line color. Set the filling to R: 0 G: 0 B: 0. Check that the alpha (A, transparency) is 255. Also check that fade is at 0% and the opacity is at 100%. More information can be found here .
Set the line thickness to 0.1 mm, so you avoid the laser cutter cutting twice the same line.
Using the laser cutter for the first time.
Download software for Windows
Once you have downloaded the RetinaEngrave software, go to your downloads and double click on the file. Now follow the steps to install the software.
Turning on the machine
Turn on the air pump
The air pump looks like the picture on the right. Place a thin rubber hose over the metal connector and connect the other end of the rubber hose in the laser cutter under the 'air inlet' sticker. Insert the air pump power cable. Put your hand on the air pump to check if it is on, if you feel it vibrate it is on.
Turn on the air filter
Turn the air filter on, this is the big iron box you see. Place the plastic tube over the air filter and place the end of it in the laser cutter. Insert the power cable, turn on the front and rear buttons. Make sure you see the light on, the air filter also makes noise. Check if you hear the filter.
Turn on the water cooling
The water cooler is the low beige bin. Place a flexible hose over the outlet of the water cooler. Connect this to the inlet of the laser cutter. Connect the inlet of the water cooler to the outlet of the laser cutter. plug the power cable and check that the light is on.
Turn on the laser cutter
Make sure the power cable is plugged in. Then switch on the button at the back of the machine. Check that the emergency button isn't pressed.
No PVC or vinyl
NEVER cut or engrave PVC or vinyl. These materials (together with some other materials containing chlorine or chloride) produce a dangerous gas that is toxic to humans and corrosive for the machine.
Never leave the laser cutter alone
The laser cutter can catch fire, don't leave the laser cutter alone.
Do not cut out corrugated board or multiple materials at the same time
Be careful with material that contains air ducts, these materials are extra combustible. NEVER laser corrugated cardboard. Do not put multiple boards together to cut out.
Effectively cut out with the laser cutter
Prepare laser cutter
Is the laser cutter on?
Double check that the laser cutter is on. Is the water cooling on? Is the air filter on? Is the air pump on? Make sure all these devices are switched on.
Connect your computer directly to the laser cutter via an ethernet cross-cable. If the network interface card of the computer is active, the lasercutter will get an IP address that could look like "169.254.86.94" and will be displayed on the laser cutter screen. Write down this number, you need it for the configuration! If the IP address is 000.000.000.000 something went wrong, check whether the network interface card of the computer is active and if the ethernet cable is plugged in (restart the laser cutter if necessary).
Set static IP address on computer (Windows)
Provide your computer with a static IP address (as opposed to dynamic addresses via DHCP) that also starts with 169.254.
The next 2 numbers can be chosen randomly, as long as 1 of both numbers differs from the one of the laser cutter.
Start> All Programs> Control Panel> Network and Internet, select Change adapter settings, and then Internet Protocol Version 4 (TCP/IPv4). Enter your own static IP address here. We choose 169.254.0.1 as the IP address and subnet mask 255.255.0.0.
Interface laser cutter
The touchscreen you use to control the laser cutter has an LCD display and different pushbuttons. Below we explain some functions that we will use. If you would like more information in detail you can find the userguide here.
Click on the F/S button to change the working mode. We only need the FX mode, so make sure that the mode is put on FX.
The home symbol ensures that the laser head will travel back to the default home-position, so that it is completely referenced again. When the laser cutter starts up, it will always home itself first.
Focus the laser head
In the laser head there is a lens to focus the laser beams into a focal point (or burning point). The focal distance is the distance between the lens and the focal point, so we have to adjust the height of the laser head so that the lens focuses on the surface that we want to cut. The standard lens included with the H20x12 lasercutter has a focal distance of 2" - which is about 50.8mm.
Set the laser height
The distance between the upper surface of the material that we want to cut and the laser head must be adjusted corresponding the focal length of the lens being used. For this, we make use of a spacer disk. This spacer disc that corresponds to the default lens (2") is 7 mm high.
Loosen the screw of the laser head slightly. Place the spacer disc between the laser head and the surface to be cut. Re-tighten the laser head with the adjustment screw.
Send a drawing to lasercut software
Lasercut software, RetinaEngrave
Open the RetinaEngrave software. It is important that this software is running before sending your 2D drawing to the laser cutter. You can find the status in the left corner at the bottom. Click Hobby 20x12 > specify IP-adres for connection. Input the IP address of the lasercutter. Here you will find a link to the RetinaEngrave reference guide.
Open your drawing program (Inkscape)
Open the drawing program in which you made your 2D drawing. If you have not created a drawing yourself, open the "raster, engraving and cutting example" that you downloaded at the beginning of this tutorial.
Print the file
Just as you would normally print a file, go to File > print. If you now open RetinaEngrave, you will see that the file is loaded into it.
Raster Engrave, Vector Cut and Design View
There are three tabs:
Raster Engrave: visualises the filled surfaces, to be rasterised (the surfaces the laser cutter will "color in/burn").
Vector Cut: visualises the vectors (lines) of your drawing, to be cutted or engraved.
Design View: this is a simple 2D drawing program.
Open the Vector Cut tab, note that the colors on the right match the colors of your drawing. You can adjust the power and speed of the laser cutter per color. The red lines are cut out, we let the laser slowly pass over here and put the power at 100. So set the values for the red color at speed: 20 and power: 100 (for plywood of 3 mm). We want to engrave the blue lines, we do not want the laser cutter to completely cut through the material. Let the laser cutter cut across the surface with a low power. Set the values in blue to speed 100 and power 20 (for plywood of 3 mm). We do not want to cut out the black lines, we just want them to be engraved. Set the number of passes from black to 0. The passes indicate how many times the laser cutter will cut across the same line.
Go to the engraving tab. Here you see everything that the laser cutter will rasterise. Note that he will still cut out the lines that correspond to the red and blue color. With the black and white treshold you can play with the light and dark ratio that the laser will cut out. We set this value to 25 so that the laser only rasters the darkest colors (the colors we have made black on our 2D drawing).
Raster then vector mode
Choose "raster then vector mode". This way the laser cutter will first rasterize everything and then cut out the necessary lines.
Homing and positioning the laserhead
When you click home, the laser head travels to its default origin (the top right). Move the laser head with the arrows to the position where you want to start cutting your material. Pay attention: the laser always cuts everything from right-under the head. Position your head top left of where you want to cut your material. You can home and move the laser head in the software or on the machine itself.
Show the position of the cut out
With the button "run job perimeter" you can see how big and where your laser cut will be on your material. There is a run job perimeter button on the laser cutter itself. You can view this both on the computer and on the laser.
Start, Pause, Stop
Click on the play button to run the laser job. You can always pause or stop with the two buttons next to it.
When I cut, I’ve dubble cutouts, unsharp cutouts, in overall bad quality cut outs
Either the mirrors of the lasercutter are dirty or they are misalligned. You can clean the mirrors with nail polish remover and q-tips. On page 28 - 38 of this manual you’ll find the steps how to allign the mirrors in your lasercutter.
I lost the focus billet ofthe laser cutter
No worries, download the stl-files here