For this assignment we are supposed to use composites to make a 3D model. We are also required to design the 3D mould and produce it using CNC machining.
To design the object I used Fusion 360 and for the milling I used EasyWorker MasterPro 2513 machine.
Designing the object
-My Idea was to make a head of a robot based on the one called Dalek
-I started by drwaing a 2D sketch of the profile of my object. I decided to make it out of 2 parts and then combine them.
-I revolved one profile and extruded the other.
-I Placed them correctly and combined them into one object.
-Due to the limitations of the tool we have I had to slice the body into layers as the tool was not long enough. I used the split command to divide the body, I did the math and with our tool I had to split it in 3.
-This is how it looked like.
-I moved them away from each other and placed them on the same plan. Here are the settings I used for the setup.
-I choose the Adaptive clearing technique to do the milling. Usually this strategy is used for roughing but because for composites quality is not an issue as the material is not able to get all the details of the mould. Here are the parameters I used.
-Finally I simulated to make sure that there aren't any collisions.
How to use the CNC is already documented in detail in the page of CNC machining week.
-Here is how the first piece looked like during milling.
-This is how it looked after it was done
-Here is after the second one was done
-This is the third and final piece
-This is how the three of them looked like
-I used hot glue gun to fix the pieces together
-I coated the whole object with wood glue to protect the foam from the resin
-Here are the chemicals I used to make the epoxy resin. I used epoxidharz 3321 I read its datasheet and got all the information I needed for the example the hardener to be used, the mixing ratio, pot life and curing time.
Hardener: Hardener B1.
Mixing ratio: Parts by weight 100 resin to 30 hardener.
Potlife: 20 minutes At 20 degrees
Curing time: 6 hours at 70 degrees
-I used 2 layers of natural fabric with one layer of blue paper towel in between. I added layer by layer while applying the resin in between.
-When I was done I put the whole thing in the vacuum machine to keep everything in place until the resin cures totally.
-This is how it looked the next morning
-I was not able to get the mould out of the composite because of the resin although that I used a separating spray but It was not good enough so I figured out that I need a trhicker layer of a higher viscosity material