Introduction: Engraving a Picture for a Loved One on Hardwood Using Free Software and a Lasercutter
A picture says more than a thousand words says the saying... Let's say you have some leftovers of a nice wood you used in a previous project and you certainly don't want to thrown it away and waste it. Or you just bought some wood with the intention of engraving it. This instructable will explain how you can combine the natural grain of the wood with a meaningful picture. The perfect gift for that one special person in your life. This method cost me nothing as I already had the supplies available from previous projects. Let's get started!
(scrap) Wood of choice, ruler, sanding paper, free software + computer (GIMP and Inkscape), lasercutter (or lasercutting service Free Service)
Step 1: Preparing the Picture for Lasercutting (GIMP)
You will need to prepare your pictures before they are suitable for lasercutting. First preparations are done in GIMP. You can make the preparation easiest by choosing simple pictures that are high in contrast. Here multiple small pictures can be combined into one big picture to increase interest. First GIMP is used in which the picture is prepared for further editing to be done in Inkscape.
Lasercutters usually work with simple fixed depths. Depending on the color from the picture, the lasercutter will use a certain moving method and speed (depth) setting. Lasercutters at FabLab Leuven use the following color code:
- Black: Engrave, unidirectional raster movement (horizontal lines), Surfaces
- Red: Cut, moves along vector, Lines
- Blue: Fast cut (marking lines), moves along vector, Lines
The depth is kept constant for each color throughout the job. Engraving usually being the fastest motion as it doesn't have to cut through the entire work piece. This step goes over the conversion of a picture to a black and white picture. Simply grey scale will not work since only black color will be engraved by the lasercutter, grays and any other color will simply be ignored by the machine. For this we need a threshold function which is available in GIMP. See the image to follow the following steps:
Open your picture with GIMP...
- Remove unwanted parts with a white bucket fill
- Choose threshold in the colors tab (change parameters as desired)
- Double check whether your unwanted parts are indeed white
- Export the image (.jpg or .png)
Your picture now exists of strictly black and white and is ready for opening in Inkscape! Almost ready for engraving!
Step 2: Preparing the Picture for Lasercutting (Inkscape)
If more than one picture is desired, multiple pictures can be opened in the same Inkscape-document. Such a picture is still what is called a "bitmap". A lasercutter works with vectors, therefore the bitmap needs to be converted to a vector representation of the bitmap. In Inkscape this can be done as follows:
Select the picture that you want to convert
Open the "paths" tab
Choose "trace bitmap" (a window with settings opens as shown in the image)
Select the setting "color measurement" and choose for colors "2"
Click on the preview. If everything went well, you should be able to see
a good representation of the selected black and white picture
The picture is now a vector representation and is ready for lasercutting! You can delete the bitmap version so you are left with the vector representation. Save the document in ".svg" format. If these steps didn't work, try to invert the colors in the settings and try again.
Make sure to check your document properties. Choose as document size the same size as the lasercutter's specifications. This makes positioning easier. For example the lasercutters from FabLab Leuven have the dimensions 600x300mm so your document size must be set to 600x300mm.
Tip to ensure a good start:
Nobody wants to cut/engrave besides their wood. Measure your wood blank and draw its outline in the document. That way you are one step closer to fitting all your engravings where they belong on the wood!
Tip on looks:
Add a blue outline to parts of the picture and add meaningful text, it will add a lot of extra interest to the piece and look good! See the second image as an example.
Tip on accuracy:
Use line thickness 0,1mm for all your lines (Ctrl + Shift + F). Ungroup all objects in Inkscape (Ctrl + Shift + G). Visit FabLab for more tips on Inkscape.
P.S.: I included my svg-file from this project so you can see how things are constructed which can help you in your own project.
Step 3: Preparing Your Wood
Lasercutters have a fixed focus which means a flat surface is a must. Usually plate and plank wood is flat enough to do the trick. After the engraving is finished, the engraved surface shouldn't be touched anymore as it will leave visible scratches. Therefore make sure you are happy with the condition of the wood's surface before you go to the next step. I usually sand the surface until it's smooth to the touch, then I wet the surface with water on a cloth to raise the grain of the wood. This locally releases tension between the fibers which will result in a rough texture. This can then be sanded off at last. The obtained smooth surface will stay stable in time.
Step 4: Ready for Lasercutting!
Your file is ready, your wood is ready, now it's time to do the lasercutting! Open your Inkscape file and look at the printer preferences. If you are not sure what you are doing, kindly ask for help! I did the same as I wasn't sure the first and second time. For American black walnut I used the same settings as for Oak wood, which worked just fine as you can see in the video. You have a lot of settings to choose from, choose one that fits your wood the best. Make sure the laser is focused correctly and check whether the laser's position corresponds correctly with the software's stated position. All of this is done? Close the safety lid and start engraving!
Place the grain of the wood horizontal with the sense of engraving for the best results.
Step 5: Give Your Finished Piece(s) a Special Place
You can present your creations in a creative way by making a live sized version and a mini version which you can place in a doll house or a maquette of your own house. That way you can give a double surprise to your loved one meaning double the fun! Good luck and happy engraving!