Fab Academy 2014
Jeff Opichka


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                   Course Outline
Project Management
Project proposal
Computer-aided design
Computer-controlled cutting
Electronic production
3D scanning and printing
Electronics design
Computer-controlled machining
Embedded programming
Molding and casting
Input devices
Composites
Interface and application programming
Mechanical design & machine design
Output devices
Networking and communications
Applications and implications
Invention, intellectual property, & income
Project development
Project Presentation


Composites

To make my mold for the composite part I started by using XPS rigid foam insulation.  Not sure what to mold, I decided to make a bowl.  Using Mastercam I created my design and would mill the bowl using a 5/8 inch ball end mill.  The insulation was very easy to mill.  I tried to sand the milling marks but it actually ripped some of the insulation making the surface worse.  To eliminate the milling marks I would try to overlap the ball mill so milling marks would be closer together.  

To make my composite bowl I used fiberglass cloth and epoxy with hardener.  Two pieces of glass were cut slightly larger than the bowl and placed inside.  When mixing epoxy and hardener it is critical that each is mixed with the appropriate ratio or an inconsistent cure will result.  The pumps  controlled the amount of resin and hardener, so measuring appropriate amounts of each were not needed.  I mixed the resin and hardener in a cup and applied a liberal coat over the entire bowl.  When the glass looked saturated is a good indicator telling you you have applied enough resin.  I repeated this step with a second layer of fiberglass cloth.  When finished, I let the bowl sit overnight. 

I wasn't sure how the foam board insulation was going to hold up to the epoxy resin.  My initial thought was for the foam to melt as a result of the chemical reaction. To my surprise the XPS held up to the epoxy.  The struggle was getting the bowl out of the mold.  The epoxy securely fastened to the foam insulation.  The only way to detach the two was to cut off the insulation.  With a little sanding the bowl did turn out.  Below is the finished product.  I could have added more layers of fiberglass or thicker fiberglass to add strength.  The bowl is functional but a little loose.