SCREWS & BARRELS | MACHINERY
extrusion and the desired output. “There is no one-size-fits-all solution,” said Alessandro Ruotolo, extrusion test manager at Bausano. For heat-sensitive polymers such as rigid PVC, a conical screw is often best. The screw geometry – with a decreasing diameter from the feed zone to the discharge zone – allows a progressive increase in pressure, with high torque even at low rotation speeds. This ensures good thermal stability, reduced wear of mechanical parts and greater compactness of the line. If higher hourly output is required, along with a wider plasticising area and more intensive material processing – such as for technical compounds, and filled or recycled materials – a parallel screw configuration is preferred. Here, the equal-diame- ter screws provide uniform cutting and mixing, along with more refined control of temperature and internal pressures.
Melt redesign Canadian company ReDeTec says it has “changed the way plastic is melted” by redesigning the traditional screw-based system.
In processes like extrusion, plastic is usually melted by the action of the turning screw. ReDe- Tec’s process, called MixFlow, is inspired by 3D printing – which is the company’s main focus – and melts the plastic before it reaches the screw. By separating the drive section from melt section with a thermal isolator – as in 3D printing – it says it can reduce energy consumption by up to 75% while improving throughput.
“Because MixFlow doesn’t need to churn a long
screw through the molten plastic – which takes significant energy – it’s more affordable to produce and lasts longer than competing technologies,” said the company. It adds that MixFlow uses “lower energy process-
es” that preserve plastic quality – reducing degrada- tion to 1% or less with each cycle. Though still restricted to 3D printing, the company says the technique could be applied to processes like extrusion and injection moulding.
CLICK ON THE LINKS FOR MORE INFORMATION: �
www.conextru.eu �
www.bausano.com �
https://redetec.com
sales@jwell.cn
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44
