1. Acrylic: |
Properties
Acrylic is a clear plastic that resembles glass, but has properties that make it superior to glass in many ways. It comes in an array of various colours and transparencies and also thicknesses. It is easily accessible and usable with the laser cutter
Acrylic is used to make various products, the advantages are:
§ It is many times stronger than glass, making it much more impact resistant and therefore safer.
§ Acrylic also insulates better than glass, potentially saving on heating bills.
§ Acrylic is only half as heavy as glass. This makes working with acrylic much easier.
§ It can also be sawed, whereas glass must be scored.
§ Adding to this favorable array of properties, a transparency rate of 93% makes acrylic the clearest material known. Very thick glass will have a green tint, while acrylic remains clear.
§ A unique property of plastic is its ability to be shaped.
§ There are also no seams in acrylic structures, as chemical welding at the molecular level actually "melts" seams into one piece of solid material. Seams that are welded and polished are invisible.
§ Scratches can be easily buffed out of acrylic.
§ Can be used in a similar manner to fibre-optic cables
§ When cut with the laser cutter a smooth edge is achieved.
Two disadvantages of acrylic:
§ It is more expensive than glass
§ If exposed to a direct flame it will melt and eventually burn
§ A rough edge is made if sawn. However can be rectified using a flame or blowtorch
Possible ways of incorporating the laser cutter with acrylic
Light transfer- acrylic used as a medium to transfer light
Customized Stands- demonstrating ease of design application and materials strength
Customized Shapes- heat used to manipulate a cut shape
Customized Patterns- ease of laser to cut different patterns
How to bend acrylic
The first thing you need to bend acrylic is an acrylic bender. You can buy one for 200 dollars or you can build one. I suggest building one since it is a lot cheaper. I built mine using a heating element strapped to a board. All of which I purchased at a local supplier.
The element sits between two boards that are attached to a main board with a gap between. The element sits about 1/4" down from the top surface of these boards. This way you can heat the plastic without melting it to the element. I covered the boards in tin foil to help protect them from the heat and also to reflect the heat more toward the acrylic.
Two different kinds of Plastic Benders. Here is a fancy one that will work better but cost too much. This Heat Strip is the one I used. It comes with all the directions you would need to build the wooden base. You could also use a hairdryer, making certain you isolate the beam of heat.
What I am bending here is a MB stand for my Martini Mod. I used an old MB tray from another computer and I want it back to use. I also wanted to clean up the wires in the Martini. It has been suggested that they were a mess and I have to agree.
Here I have selected a 1/8" thick piece of acrylic. I made sure it was cut to the length of my MB and extra wide for the folding I would be doing. I gave it 3" on each side. I then took off the paper protection and drew on the acrylic where I was first going to bend with a wax pencil. I wanted to bend at a right angle so I also got a section of aluminum angle from the shop to use as my angle. You should also drill any holes you want to have at this time. It will be very difficult to do so after the piece has been bent. I did not do this and had to actually do this same project twice.
Below you see me put the piece on the bender. To get a straight bend you want to line up your wax line to the center of the element. Within a few minutes the acrylic should get soft and bendable. You then want to take it off and set it immediately into your mold or position you want it to set in. It takes only a few minutes for it to cool and become hard again. If you don't get it where you want it quickly you are basically stuck with it that way.
You basically see me going through the same steps for all the bends until I end up with the finished project. I suggest first starting with simple bends until you get used to it. Eventually you can bend as complex shape as your imagination limits you to.
tips
§ The laser cutter has a max cutting depth of around 10mm
§ The thinnest acrylic you can get is around 3mm any thinner and it is another form of plastic
§ Investigate which axis it is best to put stress on; in the way you design with the use of this material in your model i.e. it is stronger in different axis.
§ Can be expensive if doing large projects, try minimize your waste error
Visit www. http://blog.makezine.com/archive/2005/08/how_to_bend_acr.html for more information on bending acrylic |