Plastics & Sustainability - A Contradiction? Expert Interview Video Series with Dirk Moses - Technoform & Herwig Juster FindOutAboutPlastics.com (Part 1/3)

Expert interview with Dirk Moses from Technoform: Plastics & Sustainability - a contradiction?

Hello and welcome to this polymer expert interview series diving into the world of sustainable polymer solutions. It is a three part video series and today we start with our first video:

🌱 Plastics & sustainability - a contradiction? 🌱

I visited Technoform in Lohfelden, Germany to explore the link between plastics & sustainability. In this video I find out how Technoform has been researching sustainable solutions since 2015, from the use of renewable resources to the introduction of innovative separation technologies. Dirk Moses and his team are setting standards, from overcoming skepticism about bio-based materials to making effective use of production waste.

Since the Sustainable Development Goals were set in 2015, Technoform, solution provider for customized plastic profiles, has been exploring measures to enable sustainable plastic solutions. 

From the use of renewable resources to the introduction of innovative separation technologies along the value chain.

We learn how Technoform has tackled the challenges of the thermoplastic market, from initial scepticism towards bio-based materials to the effective use of production waste and the development of single-variety recycling methods. These strategies not only have an environmental impact, but also contribute to the quality of the products.

Dirk Moses and his team are committed to avoiding production waste and are working on solutions to save resources and reduce environmental impact. 

By utilizing post-industrial plastics and calculating the CO2 equivalents of their raw materials, they are leading the way in the industry and helping to shape a sustainable future.

Get an insight into the world of plastics innovation and discover how Technoform and companies can make an important contribution to conserving our resources while improving the quality of their products.

Watch the video now here:

Stay tuned for two more episodes:

- Sustainable plastics solutions for the automotive sector

- Prejudices about plastics - a brake on innovation?

Get in touch with Technoform here. 

Thanks for reading & watching!

Greetings, 

Herwig 

📚My Polymer Material Selection Book - Available Here

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Residence Time Calculation for Extrusion - Polymer Processing

Hello and welcome to a new blog post. In a previous post, I presented the residence time calculation in injection moulding. Today we will focus on the extrusion process.

Residence time in extrusion is referring to the time, which a polymer pellet, and as consequence, polymer melt needs to travel from the melting zone until the end of the metering zone.

The online calculation

For an approximate calculation of the residence time, building the quotient of the volume of the extruder filled with melt and the volume flow of the melt is possible (underlying basic laws of physics):

Equation 1 - extrusion residence time (average residence time): t=V/Q

V = volume of the extruder filled with melt

Q = flow rate of the melt

t = extrusion residence time

This is the background of the online calculation tool shown below:

Check out the new tool here

In literature, extruder output (flow rate; kg/h) can be calculated by the following equation [3]:

The leakage flow is calculated by addition of mass flow rate (drag) and pressure flow rate minus the extruder output.

2nd way to calculate the average residence time

average residence time t = V/Q= (2 * z) / (v_bz *(1-a)) = 

z =dz = unwound channel length = L / sin φ

φ = outer slope angle f.e. 30.72°

L = screw length f.e. 14*D

D = screw diameter (mm)

n = RPM (1/min)

h = groove depth

b = π*D*sin φ-e

e =  bridge width

dp = pressure drop f.e. 20 bar = 20*10^5 Pa

v_bz = circumferential speed in Z direction = n*π*D*cos φ 

a = throttle coefficient = ((b*h^3)/(12*η))*(dp/dz)* (2)/(v_bz*b*h)

Example with following extrusion screw and process data

D=45 mm

L=14*D

h=3 mm

e=4.7mm

n=60 1/min

φ=30.72°

η = 800 PAs

1. calculate b = 67.52 mm

2. calculate v_bz = 121.53 mm/s

3. calculate  z = 1233.26 mm

4. calculate a = 0.25

5. calculate t = 2*1233,26 / 121,53 (1-0,25) = 27,07 s

Also as a general rule, the higher the temperature, the lower should be the melt residence time. 

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

📚My Polymer Material Selection Book - Available Here

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Literature:

[1] https://www.findoutaboutplastics.com/2017/10/how-to-calculate-residence-time-in.html

[2] https://www.extrusion-training.de/extruder-dimensionierung/

[3] Rao, Natti S. - Design Formulas for Plastics Engineers

[3] N. Rao: Design formulas for plastics engineers