This week was to desing and produce something through digital fabrication process,Here In our week week have different options like composites, textiles, biotechnology,cooking... to go forward with "COMPOSITES".This week seems very friendly to me because I am from a chemistry background and happy to do the practical that I studied .
COMPOSITES - are made through adding two constituent materials with different properties after finishing we will get material with different properties from the individual ones in the finishing structure the individual components remains different. The individuals componenets are like fibers and epoxy ,there are many fibers that are differ in there strength and quality"c arbon fiber ,fiber glass, jute "are some example of fibers. Composites are gained high popularity in the product level "aircrafts parts,marine parts,and so are now mainly using the coposite insted of some metals " the low weight , high withstand and zero corrosion will attracts the composite into high product level productions .
As a part of group assignment we also did a test run on various combination of composites because we want to know the strength
We took 3 layers of Jute and 2 layers of Linen to combine with Easy Cast Epoxy mixed in the ratio 100:5 of part A and B
.The different combinations we took are;
Two layer of Linen having an angle 90 degree and middle layer of Jute having 45 degree and other two layer with 90 degree
Two layer of Linen having an angle 90 degree and 3 layer of Jute having 45 degree
Two layer of Linen having an angle 90 degree and 3 layer of Jute having 90 degree
Then we equally pored the epoxy to all the layers and applied peroforated relase film and bagging film, ratio of epoxy mixture is 10:.5
After 24 hr we got the test coupon for taking the strenght
RESULT: Two layer of Linen having an angle 90 degree and 3 layer of Jute having 45 degrees has more strength among the three.
Here I decided to make a "Skate board " sakteboard with composite will give more strength than wood and less weight also ,here I drew my model in fusion 360 this 3D CAD software is very much femilar to me and also I go forward with that,
Here you can download the 3Dfile of my skate board
Here you can download the "STL" of my skate board
Making of 3D mold
Here I faced some problems for making the 3D mold of my skate board, In first I decided to make a negative of my skate on plywood on shopbot but we didn't have the bit that can go to the depth in the sides it will cause collet will hit on the sides ,it stops me from making the mold on shopbot but I am very attach to make the Skateboard through composite
At that time I got the help from the early fab students Rahul Rajan and
Ganadev Prajapathy who were doing fellowship in fablab ,They made a 4AxisFoamCutter
machine for there projects That I can decide to make the 3D mold Using foam
This machine cuts the foam using hot wire ,A hot wire cutter is the most efficient way to cut foam. So they made this hot wire as a CNC arraignment through this we can cut out any parts in foam smoothly by taking less time It can save our time.Here they used Jedicut for making the Gcode for operting the system Here you get more discription about 4AxisFoamCutter
I just changed the 3D design as 2D for making the out cut of saketboard For that In first we tried a small cut of the angled positon of the skateboard
It was successful so I decided to go with this cut ,I opend Jedicut software for making the settings uploded the x & y part and add the distance and feedrate
I Selected a 50mm foam for cutting the 3D mold here the phenomenon is place the foam in the bed the the hot wire cut the part by moving in x and y direction Here they made this for another purpose so the machine is not too much develope in eyes but the working is more effective thats why it can give smooth cut.
After completing the foam cut exact like skate board I got a +ve and -ve parts were I can make my composite fixing in between them .Is the epoxy can cause any damege to foam? in that thought I just rolled bagging film around
Here I first I gave the cellotape coat and the bagging film rolled around it. Because it will not cause any damage to foam and also after drying we can remove the parts easly.I didn't think going with the vaccum bag here I attached Two plywood above and below so I can give aximum copression than any other processes and also I avoided peroforated release film.
After that I cut out 3 pieces of sack an 2 pieces of linen cloth ,my purpose
was using sack give the strenght and I decided to go with linen cloth above and below surface for giving a perfect finish.
The I used plastic resin as epoxyA and Hardner as B I already work with this in the moulding week so I know about the ratio of A & B as 10:6 I had so many sack and linen pieces so that I want more solution Here I taken 300 g of plastic resin and 180 g of hardner as equals with ratio
Then I pored the mixture on the sack pieces I did this with somuch patience because it takes too much time for giving the epoxy in all area of sack,I just try to dip each pices into the epoxy that will make sure the epoxy can spread in all areas after that I spread each layer one by one in above each
After that I put the upper portion also the insted of vaccum bag I completily tried another method I placed this in between two plywood pieces the I fixed "clamp" in each corner Then I gave equal pressure from each corner by measuring the gap between plywood using veriner scale this helps me to give high compression to my composite
I know it takes 24 Hrs to take for the settle down of the composite so I put that into for settle down after 24 hrs I just take out the composite very carefully with the help my Instructor Yadu with out any damage
I take my composite out and I just polished the edges and making it seems like skateboard that give me a lot of happiness beacause of completing my idea in a proper way
Problem That Fixed
I faced somany problems at the starts of this week after completing the 3D design I didnt get the bit for making
the mold in shopbot , My design having too much depth than the bit length thats why I made it through 44AxisFoamCutter.
The second one when Resin is mixing to the sack pieces I took more time because I cant spread it all the parts through dipping into the miture
The skateboard doesn't have too much strenght as I execpt,I dont know thats why may It because I used plastic resin for making my composite