They are not as closely connected as most processors think. Here’s why.
Because of roll deflection, sheet stacks made for PS don’t work nearly as well with PP. One solution is to try a top roll that bends in the opposite direction.
First, remember there is no universal cooling-roll stack. And be sure to take into account the specific heat of the polymer you are processing.
There are still companies that compound glass fibers on single screws. The process is considered an “art,” but can be made more predictable with attention to screw design, speed and length, as well the choice of mixer.
Calculating polymer flow is fairly straightforward when designing a die for a simple round profile, but as the shapes get more complicated these calculations can get extremely challenging. Here’s what you need to consider.
You run the risk of wasting time and money by not understanding what’s causing your screws to wear.
CO2 can be used as a totally “green” solvent to remove many kinds of contamination in recycled plastics without the need for toxic solvents.
This usually crops up when the two stages are not matched in output. The best solution is to install a pressure-adjusting valve at the discharge end of the extruder.
Every processor should get hold of the viscosity curves for the polymers they use or contemplate using in their operations, and learn how to read them.
Since many plastic products are made of a combination of materials with very different melting points, careful consideration must be given to designing screws when it comes time to recycle these products.
Coronavirus pandemic has made extrusion processors curious about entering the face-mask market. But melt-blown fiber is very different from most other extrusion processes and requires specialized equipment.
Tweaking the temperature settings of the first barrel zones may not yield the desired result. In fact, they may yield the opposite. Here’s why.
Very small screws have become more common with the growth of additive manufacturing. Designing such screws requires balancing their output requirements with their torque strength.
The more you know about what happens in a screw, the more you’ll be able to work with your supplier to optimize design.
You might be able to reduce purging times and save money by scheduling processing jobs in order of the increasing material viscosity. But to get started, you'll need shear rate/viscosity curves for your polymers.
Key considerations range from determining the right extruder sizes to tooling, matching material viscosities, and lots more. Take a look.
The other half? Aligning and supporting downstream equipment. Here are best practices.
Both the power-law coefficient and the consistency index must be considered to calculate viscosity.