Hi, everyone. For this CNC assignment, I got this picture from http://thenounproject.com (pic 1), which is a scenery in desert. I like this image and decided to mill out portions of it at different heights with some texture in certain areas to make it into almost a 3D postcard with a night view on it.
Pic 1
As shown in pic 2, here’s the first toolpath I created in Carbide Create. In this toolpath, I have the sun and cactus both as pockets and a contour to create all the outlines. Then a texture toolpath would go over the entire piece to create the parallel lines that symbolize the stars flying by. However, when I actually started milling this piece out during training on Shapeoko Pro, it seems that the toolpath I had for texture was too deep into the wood that it took almost three times the original estimated amount of time required. Also, the drill bit it self had a hard time to drill through.
Pic 2
As you can see in pic 3, at first, per suggestions from others, I only used two pairs of clamps on the wood piece, since it is not supposed to move too much with the double-sided tapes between the bottom of wood piece and the stage. However, since, as mentioned above, the drill bit took too much more time than expected and the resistance was very high, I had to add many more clamps to keep the piece from moving on the stage (pic 4). However, the piece still got pushed around slightly over the course of time and left me with a very crude finish (pic 5). It was obvious that the pockets for sun and cactus have been largely misaligned and the texture cuts are too deep to be called texture.
Pic 3
Pic 4
Pic 5
Therefore, for the second trial, I decided to remake the entire toolpath design. As shown in pic 6, I decided to only have the entire sky as a pocket so that I can have different visual depth in different areas to create an almost 3D representation of the views. Also, I’ll have textures only in the mountains behind the cactus so that they can be differentiated from the ground at front where the cactus is located at. This time I used Nomad 3 to cut and applied a much tighter clamping setup so that the wood piece didn’t move that much this time (pic 7). This time, there’s no misalignment of the piece in the end result, but the drill bit didn’t reach all the way through, probably due to slightly uneven surface of the material (pic 8). However, since the thickness of the last layer that didn’t go through was only about 1 mm, it was very easy to process (pic 9).
Pic 6
Pic 7
Pic 8
Pic 9
Essentially, I used a hand saw to manually remove the scenery out of the rest of the material (pic 10). Then, I used the sanding machine to quickly polish off all the splinters and rough edges so that it’s very smooth a touch on all sides. Also, to polish off some of the damaged corners from the raw material itself and to add a smoother feeling when touching it, I added chamfers on all edges on the bottom side (vid 1). After the initial processing of the wood pieces, I applied grey primer on the top surface first so that I can paint them sooner (pic 11). I chose grey, since I believe that it will be a better combination with other deeper color I will apply later.
Pic 10
Vid 1
Pic 11
After the grey primer is dried on top surface, I proceeded to paint all the scenery with acrylic. As you can see in pic 12, I use a very deep blue to represent the sky and deep red for the sun to bring out the feeling of dawn. Also, I took a long time to fine tune the color of mountains in the back so that it would look more like a wasteland. Furthermore, I’ve chosen a dark green for the cactus and bright orange for the ground so that they can have a unique contract that almost resembles the desert. Finally, I’ve chosen a bright yellow for the line between sky and mountains and around the surface of cactus and a bright light blue to separate the cactus from the sand. More specifically, the former is to have a subtle representation of a starry night (light from the star shining on top of the mountains and cactus). The bright light blue is to bring a little bit presence of water in the scene.
Pic 12
After the acrylic paint is dried, I used some blue tapes to wrap around the two wood pieces so that the acrylic paint can be preserved while I paint the bottom side with grey primer (pic 13). As shown in pic 14 and 15 are how the two pieces are flipped and how the grey primer is applied on the bottom side. After the grey primer on bottom is also dried, I applied much clear coating on top so that the whole scenery can have a very shiny look (pic 16).
Pic 13
Pic 14
Pic 15
Pic 16
Cost analysis table is shown here:
| Cost Type | Cost | Price | Source | Quantity | Total |
| Materials | |||||
| Wood piece (X2) | $3.75/board foot | Country concepts | 6”X3.5”X0.76” | ~$20 | |
| Acrylic Paint | $21.74/400 mL | Amazon | 10 mL | $0.54 | |
| Gray Filler Primer Spray Paint | $8.99/can | RUST-OLEUM | ¼ of a can | $2.25 | |
| Clear Coat Spray | $8.99 / 12 oz | Summit racing | ~1 oz | $0.75 | |
| Labor | Prototyping Engineer | $25.91 / hour | indeed | 6 hr | $155.46 |
| Overhead | Utility Cost (considering both the cost of facility and electricity) | ~$5.13/ hour | TexAgs | 4 hr | $20.52 |
| Depreciation of Assets (CNC machines and tools versus their typical life spans) | ~$3/hour | MDCplus | 2 hr | $6 | |
| Design | Engineering and Development | $44.34 / hour | ZipRecruiter | 1 hr | $44.34 |
| Iterations (a continuation of the previous category) | $44.34 / hour | ZipRecruiter | 0.5 hr | $22.17 | |
| Misc. | Waste and Scrap | ~$49.5/L | UltiMaker | 0.3L | $14.85 |
Total=$286.88
Here are cleaned-up two CNC machines and tabletop.
