The Woodpecker Ep 163 - How i carve a 3d logo with a cnc

Hi, on The Woodpecker today, I show how I made my 3d logo. I use my CNC machine a lot. Most of the time, you see me carve the date of my project with it. But I’ve also done over one hundred small plaques that I give as presents. And, this is without counting, the half drawer filled with those with my 3D logos. Those are pretty similar to the ones, I did for this frame. So, for the rest of this episode, I’m going to show how I made this particular carving. First, here comes the short version. I stick a maple board on a scrap piece of masonite that I clamp to the CNC table. Then I let the CNC do its job. And this is a big job. It takes in all six and a half hours or so, to carve this in maple and only five and a half in pine. But eventually, it’s done and I can remove it from the table. And voilà! This is my 3D logo, but the edges are a bit rough; I need to sand them. After a light hand sanding, it’s all done. This was the short version. If you like action, a lot of different angles and something interesting, well the rest is not for you... To make this kind of 3D carving, I spend a lot of time in front of my computer, for the most part using Photoshop. Yes, this dome shape, the lettering and the woodpecker are done with Photoshop. You see, when the router bit is moving on the board and carving it, its height is given using shades of grey. So white is the highest spot and black is the deepest. And in between there are lot of shades of grey. So now, I can return to Photoshop. I use Photoshop because it’s included in the package I pay to edit my videos, but I guess you can do the same thing with other picture retouching software. So don’t expect to learn about Photoshop because I’m not good with it. The first thing I want to do, is the gradient oval shape. So after making a big enough canvas, I fill it with black. Then I make an oval selection that I fill with white. To simulate a gradient shape, I add a blur to the whole canvas. When I’m happy with the blur, I make a new layer and display the grid to help me select another oval; but with the grid it’s more accurate. Now, I don’t need the grid anymore. But I don’t want to select the inside of the oval, but the outside; so I invert my selection and fill my new layer with white. I also want a well defined black edge. To do so, I re-invert my selection and contract the selection by 30 pixels. Humm, 30 is not enough; I contract 10 more. Now that I have the right size, I need a new layer to drop the black onto. So I begin by making a new layer, re-invert the selection again and fill the outside of the oval with black. Now, If I put the layers in the right order, I have a well defined edge around the gradient oval shape. But the gradient is too dark; I don’t want it to be so close to the black because the sides would be a bit too thin. So I add an exposure filter and add some offset. And now, the difference between the black and the edge of the oval is well defined. If I move the cursor around, I can see the gradient value and it’s exactly what I want. But now, I need to make the lettering. To do so, I make a copy of the gradient layer and move the copy to the top. Then, I make another layer for the text and write it. To centre it into the oval, I hide the gradient copy. But the font is too small, I stretch it to the size I want and centre it. But I don’t want black letters; I want the letters to be proud not inside the dome. So I move the text under the new gradient layer and say that I want the gradient to use the text as a stencil. And now, I have my lettering on top. But it’s not that obvious; so I redo all the same things I did with the last gradient and add an offset to the letters. And now, just like magic, I have letters that have the same curve as the background. Now that I have my text, I need to put a woodpecker right here. For that, I open a saved outline of my woodpecker. But I have one small problem; the tracing is too large; I need it to be thinner. So I select all the lines by using the select colour range function and choose black. Here you can see what will be selected. And if I zoom into the picture, the selection becomes more obvious. But it’s still too large. I modify my selection by contracting the selection and I end up with a small line. To continue, I make a new layer and hide the original. Next, I fill the inside of my selection, black. To have a better look, I zoom a little. And now, I have a nice thin outline of my bird. This will be easier to work with. But to be on the safe side, I make a copy of this layer and hide the rest. Now, I can draw my bird. I’m sure you remember that white is the top. Since I want the shoulder to be at the high spot, I select white, but not true white; true white is for something else. Next, I select the shoulder and fill it with white. Now, I want this section to be a little lower. I select it, choose a darker white and fill the selection. I repeat the same for all the sections of my bird, with different shades of grey according to the relief I want to give to it. This takes a bit of time. But when this is done, I’m not finished yet. I have to erase all the traces of black, because as you know black will be the deepest cut. Some sections are easier to do than others. But I always do the same thing. I just select the black and paint inside with its adjacent colour. When it’s more complicated, like here, I begin by painting over the black, to isolate it from the rest. When the black is isolated, I just do like I did the last time; select it and fill it with the adjacent colour. I do this everywhere on the bird. When I’m done, it looks something like this. Now, I just need to copy this and paste it to what I did before. But since the bird is way too big, I have to shrink it, to put it in place. But it’s not that easy; I have to place it so there’s no black showing anywhere between the bird and the oval. But I manage to do it, and here’s the result. Now, I need to draw a black outline around the bird. For that, I make a new layer, move it under the woodpecker and just draw around it. When I’m done, I hide the bird and fill the inside white, with black. Then, I hide all the logo layers and merge all those layers together. And now, if I un-hide all the layers, my 3D logo is complete. But this will be the rough cut version; in fact it’s the first pass which removes the bulk of the wood. The design of the final pass is the same except that I keep less black around the perimeter. So, I do like I did several times before, I select the white, invert the selection, contract it, make a new layer and fill the outside white. And now, I have two slightly different drawings. But I’ll use both of them to make the final plaque. I just have to save the two versions. Now it’s time to switch program. To create a file that the CNC can understand, I use dmap2gcode. It’s a free open source Python program. And if you wish, you can do like I did and modify it a bit. Using it is not too complicated; I open the file that has a thin border. It’s easier to recognize when it’s full screen. Next, I can modify a few parameters. First, I set the height of my carving. Then, I make sure the depth is actually black. Remember that my drawing was done with the black as the deepest cut. Then, I can change the origin, but I leave it to the left bottom corner. Then, I can choose if I’m going to cut what’s white. Since I don’t want to cut the white, I leave this unchecked and choose what depth will not be cut. I keep this value pretty low. I don’t want my high spot to be mixed up with the pure white. Then, on the other side, I choose the bit size and its shape. Next, comes the choice about how the carriage will move. I like cutting in a right-left movement, so I leave this alone. Then, the cutting speed; the harder the wood, the slower the speed should be. Generally, when I cut pine, I can go much faster than this. Next the stepover. Here we can see, it was already set for ten percent of the size of the cutting bit, which means that I will have ten passes to cut one sixteenth. I can also choose the distance the bit will be above the piece for quick movement when it’s not cutting. I like to keep this value small because it speeds up the cutting process. And finally, the depth of cut. In my case, it’s the height between the black and the white. And when I’m done, I can create the Gcode file. This takes a long time; so to avoid wasting too much time, my computer can easily calculate the rough pass at the same time. So I start the same program and open the file that has the wide black edge. But now I open the rough pass window. This is pretty similar to what I just did, but this time I use a quarter inch bit. The two big differences are that, instead of having a ten percent stepover, it’s forty; and since it’s a roughing pass, I have to choose the maximum depth cut for each passes. When all is to my liking, I save the file and do something else because this can take a lot of time. But eventually, it’s done and I can use the Gcode files to cut my logo. But this is not a good idea, because knowing myself, I probably made tons of mistakes and I don’t want to have to wait six hours just to see them... So it’s time to use another program. Yes, CAMotics transforms a Gcode file into a 3D representation of what a CNC would do. So what I have to do, is open the rough Gcode file and have a look. I can watch an animation of what actually the machine will cut, but it’s mostly the final product that interests me. But the roughing pass doesn’t tell me if the final product will be viewable or not... So I open the final cutting pass. But since my last bit was the quarter inch one, it’s awful. To change the size of the bit, I load a tool table that I made with a one sixteenth inch bit and restart the calculations. This gives me a much better view of the final product; but I still need to make more changes to have the best result. And now, I can see what the plaque would look like. This is not that bad, but I can see several problems. First, I don’t like how the edges of my bird look like because they’re too sharp. I forgot to apply a blur on the bird in photoshop. But the worst is that I don’t have enough space in between some letters for the bit to pass. So instead of returning to photoshop to fix this; for the sake of demonstration, I’m going to open the actual file I used for my logo. And here we can see the edges of the bird are softer. I also modify all the letters so now they actually look like letters. Now that I’m satisfied with my simulation, it’s time to actually carve the darn thing. Before carving something like that, I like to prepare my wood because it’s easier. So after surfacing two faces, I cut a piece of the board a bit longer that the carving itself and clamp it to the CNC table. So after unplugging the router, I can chuck the quarter inch bit; the one that will make the roughing pass. I use the program Universal Gcode Sender to control the CNC movements. And the first thing I do, is to move the bit to the bottom left corner of the wood. When I’m near the surface, I send the command to start the router and I lower the bit into the wood to make a small indentation. Then I reset the XYZ position. And now I have a visual reference of the origin of the carving. So with that, I will know if the bit is at the right place for the second pass. But before thinking of the final pass, I have to cut the roughing pass. So I open the Gcode file. Then I click on the visualize button and I can see what the machine will cut. By checking this, I make sure I’m going to cut the right thing. I even can move the preview to have a better view of it. And when I’m satisfied, I press the send button. For something this big, the roughing pass is something around an hour and a half. When it’s done, I switch bit and chuck the sixteen inch one. Then, with my origin mark, I check if I’m OK. MMM, I can see I’m not. I move the bit in the centre of the hole and touch the surface. I re-plug the router and it’s a go for the final pass. Since I have around six hundred and fifty right to left movements to finish this carving, it will take around five hours to finish. But after that, I can remove it from the table. And it’s then that I notice that a piece of one letter broke. This happens sometime with pine. I’ve never seen that in maple. I just glue it in place. But I’m not satisfied with the surface; I should have made my final pass a bit deeper than what I did. If I check my other carvings, they’re perfect. But this plaque is not totally finished; I need to cut the excess wood around it. And it’s here that the deep cut helps a lot because it provides a nice reference to see where to cut. When it’s roughly cut, I sand the rest up to the carving. And this is a fully finished carved logo. Humm, I still have a bunch to finish... Well this was the way too long, long version of how I make my 3D CNC carvings. I hope I didn’t bored you to death too much, so you will, maybe come back for another episode of The Woodpecker.