Das Band - Polyethylene Extruder
| Das Band - Polyethylene Extruder Release status: stable [box doku] | |
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| Description | A Band making machine. |
| Author(s) | A.B. (Bilex) |
| Platform | Sophistication |
Information
Das Band is a multicolored LD-PE ribbon. It is flexible but durable, has a nice smooth surface and can be cut into pieces easily. This assures high adaptability in many thousand applications. It was manufactured within two weeks in line with the Big Banana factory.
Dimensions: 1,5mm x 15mm x ~250.000mm
Material: Riblene® MV10
Processing
The Extruder is the machine creating das Band. It works similar to those machines known from industrial production of plastic pipes, sheets and profiles. A turning screw (here: ordinary 20mm drill bit) takes plastic pellets from a feed hopper and squeeze them through a die. While in industrial machines the energy is provided by shear strain and high pressure, this machine works with an heating area where the pellets start to melt. After inserting energy into the material, it needs to be cooled down after leaving the die immediately to bring it into shape. (This loss of energy is a general problem during the extrusion process, even in industrial processing.) Several rotating rolls work as a shaping unit.
The Machine
Motor & Gear
First tests were made with a low-budget gearmotor found on ebay. Those are advertised with high torque rates. A closer look at the data sheet shows that sometimes these numbers are the stall values. That means: No rotation at given load. The required torque for proper operation was not known before and there was no clue how to calculate it. The motor not only needs to press the material through the pipe and the die, sometimes the drill needs to cut pellets on their way from the hopper inside the heating pipe. That means that the required power depends on the used material. The first test-material was a gift from the plastic labotory of the University Duisburg Essen. They gave us a whole 25kg bag for testing purpose. Unfortunately the material was not suitable for processing it in a selfmade-extruder due to its low MFI (Melt-flow-index) value.
CNC-Milled housing & bearings
Gears
Screw without hopper
Heating Unit
First test
25V / 8,37A
Die
Shaping Unit
Distribution
Video
Video on Youtube