This week's summary
This week's exercise was to "Make Something Big" using the
Shopbot or equivalent computer controlled machining. My project is
inspired by the mess in my home office which bothers me every week
during Neil's lecture. The goal is to make a storage cabinet for
printers and other equipment in my office.
Tools and References
Inkscape was the primary tool used for the design.
VCarve Pro Trial Edition 7.0 was downloaded (free) and was used to
simulate the design. Files cannot be migrated from the trial
edition to the version at the Shopbot machine, but the simulation
capability was invaluable in debugging the design.
Design Notes
The design consists of 2 sides, 3 shelves, a
support bar and a front door.
Dimensions are approx 40 inches high by 35 inches wide by 24
inches deep.
Design is press fit. Front door has pocket design with Celtic
image.
The image was downloaded as a bitmap file from the web and
converted in Inkscape using the Trace Bitmap command
Side, shelf, support, door (left to right)
Design Simulation
VCarve Pro Trial Edition 7.0 is an excellent tool
to simulate the design.
Several iterations were required to get a good bitmap image. It
is important to get a source file with the image. Much time was
wasted with poor quality images.
VCarve Pro provides an excellent view of the simulated cut.
View of VCarve Pro Simulation
Fabrication Notes
The board was fabricated using the Shopbot milling
machine.
The material was 8 feet x 4feet x 0.75 inch Maple plywood.
The material was clamped in 3 positions around the edge and also
screwed down in 3 positions.
Care must be taken to ensure the cutting profile does not overlap
with the screws or clamps.
X, Y and Z origins must be set to zero.
The pocket was cut at 0.2 inches deep. The profile was cut at the
material measured thickness plus 0.05 inches to ensure cutting all
the way through.
Excellent tutorials are available at http://shopbottools.com/
Shopbot in action
The Outcome
The job ran well (appropriately on Saint Patrick's Day) and the
outcome was very good. Some sanding was required but it worked
nicely. The entire cabinet was sealed and the front door recessed
design was painted. A handle and hinges were added.
Finished cabinet installed
Learnings
A piece of furniture is a lot of work, even for a
relatively simple design.
Last minute modifications of Inkscape line widths can impact
overall dimensions.
Door design: if you do not leave clearance to floor then feet will
be required. Also, large doors are heavy, 2 smaller doors may have
been a better design.
Hinge design: should be considered up front, not as an
afterthought. Many hinges require cutouts. If you do not plan for
these then hinge selection is limited.
Press fit design at this level works well, but lead-ins and
chamfers are critical.