Even what, at first glance, seems like a complex sign element is easily broken down into simple shapes that can easily be routed and then glued together to form much more than simple pieces. Before I started building the reliefs I had done a simple sketch of the top view. It showed how the excavator would be created as vertical slices or layers.
The vector file I created last time was then separated into elements which will form each layer when I route it from 1" thick 30 lb Precision Board. The sign faces with the lettering would be routed from 1.5" thick HDU.
First up was the tracks. The elements were all created separately, with the background being 1/4" thick. The inside mechanical bits were done from 1/2" - 3/4" thick. The cleats of the tracks were 1" thick reliefs. Then I merged them together on a zero thickness background. I had done a tank some time ago in a similar fashion and discovered the tapered 1/8" bit created a wonderful effect when I routed the file. I'm hoping for the same effect this time around - only on purpose. Then I copied the file and flipped it for the back side. Then I created a rectangular block and merged it to the back side of the track. This will be used to glue things together after it is routed.
The cab was done as two pieces which will be glued up back to back. Only the windows and door handle were recessed. The third piece in this section was for the motor cover on the opposite side of the cab.
The boom proved to be a relatively simple piece to execute. Simple reliefs of various depths were created in EnRoute and then merged onto a zero height relief. The file was then copied and flipped for the back side of the boom. The pieces will be glued up with a piece of steel laminated into the middle. The bucket will be made up of four layers of 1" thick Precision Board.
Then it was on to the sign. One again I guilt each element as a separate piece adding some texture to the background of the sign using one of my bitmaps called 'splotches'. The lettering was beveled and raised from the outlines which surround them. These outlines were also raised slightly from the background to make them easier to paint. Once I had everything at the right height I merged everything together, then created a second copy for the back side of the sign.
For the middle of the sign I will laminate five 1" thick pieces of Precision Board. The center three laminations needed to be hollowed out to accommodate the welded steel frame which will hold up the sign. Using the precision input center I created the rectangles to form a 3" wide 'T' shaped hole in the boards. This was centered and then using the jigsaw tool I pulled out the vector I would use to cut the shapes.
With all the files done is was time to nest the pieces and then tool path them for the router.The files that appear yellow are reliefs which will be carved using a 3/8" ball nose bit to rough them and a 1/8" bit to do the final pass. The rest of the files are simple offset cuts, done as a separate pass.
The sign faces were nested in a separate file and tool-pathed for 1.5" stock. I'll route them tomorrow. I'll be starting to piece together the excavator and then glue it up then too.
Stay tuned...
-dan
