Shopbot mini project

To learn how to use the Shopbot, we chose a "mini" project from ShopBot Tools. Our project was the coaster set, except that we only made the coasters. The whole project was a lengthy process because we were inexperienced and our board kept warping. However, we walked away with professional looking coasters after a weeks worth of work. The first thing we learned was that we needed to drill a hole through the board and into the "throw-away" board but NOT past the "throw-away" board. Then, we placed the screws in the pre-made holes and screwed them in. This helped the screws stay in better and made the board not warp so much.

Once we had our board secured we downloaded the v-carve file from the website (the files we used are in the google drive folder on the main CNC Machine tab). We set the job size to the length and width of our board (35.75 x 5.25). Next, we moved the coasters into the work space and moved the other part (i.e. the box to hold the coasters) out. By selecting the circles and clicking pocket cut, we created a tool path. There are a couple of things that need to be changed depending the project. First, we changed the depth to .25 in., which was almost 1/2 way through our board, and we renamed the tool path in order to not get confused. The rest we kept the same. If our pocket cut was deeper, we might have changed the number of passes to make it easier on the drill bit. After doing all of that, we pressed "calculate" at the bottom. If you want to see what the tool path is going to look like on your board, you can check "project toolpath onto 3D model". You can recalculate the tool path if you enlarge your vector or edit the tool path. For a profile cut, there is one more important setting to check. Tabs are used to make sure what you're cutting out doesn't move. You can change the thickness and length, but you want to make them as small as possible to save yourself some work later on.

After getting the computer graphics done, we had to zero the x,y, and z axes. One source of error that we encountered was having to re-zero the x and y axes. This was because the origin kept on getting moved by someone later in the day, and when we came back, it was different than what we had it before. This is also the time when you should change the bit. We used a 1/4'' down bit for both the pocket and profile cut, so we didn't have to change the bit after doing the pocket cut. Once we had our axes in the right position and we saved the tool paths, we ran a 3D offset. We kept an eye on the 3D offset routine to make sure the spindle wouldn't get close to the nails. Finally, we were ready to run the real thing. An important thing to note is: BEFORE cutting the real thing, make sure the spindle is spinning!

(3D previews)

The final step was to break the tabs and sand the coaster to make a smooth edge. To do this, we used the chisel and a mallet to break the tab and sandpaper to sand down the sides.