A Framework for Extrusion Screw Design
(2026) MMKM05 20261Innovation
- Abstract
- This thesis presents the development of a structured framework for extrusion screw design based on geometrical parameters, with the aim of improving understanding and supporting design decisions in industrial extrusion processes. The work was carried out in collaboration with Tetra Pak and focuses on the extrusion system used in injection compression molding of Tetra Top lids.
An initial numerical simulation approach was explored, but due to limitations related to model stability and setup complexity, the study proceeded using an analytical modelling approach. The analytical models were used to describe the relationship between screw geometry and process performance, focusing on mass flow rate and power consumption in the metering... (More) - This thesis presents the development of a structured framework for extrusion screw design based on geometrical parameters, with the aim of improving understanding and supporting design decisions in industrial extrusion processes. The work was carried out in collaboration with Tetra Pak and focuses on the extrusion system used in injection compression molding of Tetra Top lids.
An initial numerical simulation approach was explored, but due to limitations related to model stability and setup complexity, the study proceeded using an analytical modelling approach. The analytical models were used to describe the relationship between screw geometry and process performance, focusing on mass flow rate and power consumption in the metering section. The models were evaluated and compared with existing experimental data, showing that they capture the overall behaviour of the process, although with some deviations in absolute values.
To systematically analyse the influence of geometrical parameters, a Design of Experiments approach was applied. Response surface models were developed to represent the relationships between input and output parameters, enabling further analysis of parameter trends, parameter influence and trade-offs. The results show that most geometrical parameters influence mass flow rate and power consumption in opposite directions, highlighting a clear trade-off between high throughput and low energy consumption. Additionally, only a few parameters dominate the overall behaviour, which is important for practical design decisions.
Based on these results, a structured framework for extrusion screw design was proposed. The framework provides a systematic approach for analysing parameter trends, evaluating their influence, and handling trade-offs between different design objectives. It can be applied to processes similar to the studied case and serves as a decision support tool for screw design.
Overall, the study demonstrates how a model-based approach can support extrusion screw design and improve understanding of the relationship between screw geometry and process performance. (Less) - Popular Abstract (Swedish)
- Små förändringar i en skruvs form kan göra stor skillnad för hur plast bearbetas. I detta examensarbete har en metod utvecklats för att designa effektivare skruvar som både ökar produktivitet och minskar energianvändningen.
I många tillverkningsprocesser används så kallade extruderskruvar för att smälta och transportera plast. Dessa finns i allt från förpackningsmaskiner till industriproduktion, och spelar en avgörande roll för både produktkvalitet, effektivitet och energiförbrukning. Trots detta är designen av skruvar ofta komplex och bygger i stor utsträckning på erfarenhet snarare än systematiska metoder.
Det här examensarbetet har haft som mål att skapa ett strukturerat sätt att designa extruderskruvar baserat på deras geometri.... (More) - Små förändringar i en skruvs form kan göra stor skillnad för hur plast bearbetas. I detta examensarbete har en metod utvecklats för att designa effektivare skruvar som både ökar produktivitet och minskar energianvändningen.
I många tillverkningsprocesser används så kallade extruderskruvar för att smälta och transportera plast. Dessa finns i allt från förpackningsmaskiner till industriproduktion, och spelar en avgörande roll för både produktkvalitet, effektivitet och energiförbrukning. Trots detta är designen av skruvar ofta komplex och bygger i stor utsträckning på erfarenhet snarare än systematiska metoder.
Det här examensarbetet har haft som mål att skapa ett strukturerat sätt att designa extruderskruvar baserat på deras geometri. Fokus har varit att öka plastflödet samtidigt som energiförbrukningen minimeras.
Genom att använda matematiska modeller har olika geometriska parametrar studerats, till exempel skruvens diameter, gänghöjd, gängbredd, kanalbredd och spel mot höljet. Resultaten visar tydligt att dessa parametrar påverkar både kapacitet och energibehov, men ofta i motsatt riktning. Det innebär att det inte finns en enkel lösning, utan att designen måste balansera flera mål samtidigt.
Arbetet resulterade i ett ramverk som gör det möjligt att analysera och optimera skruvdesign på ett mer systematiskt sätt. Istället för att enbart testa sig fram kan ingenjörer använda modellen för att förstå vilka förändringar som ger störst effekt, och hur olika designval påverkar både produktion och energiåtgång.
Metoden kan bidra till effektivare plastbearbetning, vilket är viktigt både ur ett kostnadsperspektiv och ur ett hållbarhetsperspektiv. Även små förbättringar i energianvändning kan ge stora effekter över tid i industriella processer. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/student-papers/record/9234879
- author
- Mile, Amanda LU and Frick, Emma
- supervisor
- organization
- course
- MMKM05 20261
- year
- 2026
- type
- H2 - Master's Degree (Two Years)
- subject
- keywords
- Injection compression molding, extrusion screw design, design of experiments, response surface, mass flow rate, power consumption
- language
- English
- id
- 9234879
- date added to LUP
- 2026-06-14 08:54:03
- date last changed
- 2026-06-14 08:54:03
@misc{9234879,
abstract = {{This thesis presents the development of a structured framework for extrusion screw design based on geometrical parameters, with the aim of improving understanding and supporting design decisions in industrial extrusion processes. The work was carried out in collaboration with Tetra Pak and focuses on the extrusion system used in injection compression molding of Tetra Top lids.
An initial numerical simulation approach was explored, but due to limitations related to model stability and setup complexity, the study proceeded using an analytical modelling approach. The analytical models were used to describe the relationship between screw geometry and process performance, focusing on mass flow rate and power consumption in the metering section. The models were evaluated and compared with existing experimental data, showing that they capture the overall behaviour of the process, although with some deviations in absolute values.
To systematically analyse the influence of geometrical parameters, a Design of Experiments approach was applied. Response surface models were developed to represent the relationships between input and output parameters, enabling further analysis of parameter trends, parameter influence and trade-offs. The results show that most geometrical parameters influence mass flow rate and power consumption in opposite directions, highlighting a clear trade-off between high throughput and low energy consumption. Additionally, only a few parameters dominate the overall behaviour, which is important for practical design decisions.
Based on these results, a structured framework for extrusion screw design was proposed. The framework provides a systematic approach for analysing parameter trends, evaluating their influence, and handling trade-offs between different design objectives. It can be applied to processes similar to the studied case and serves as a decision support tool for screw design.
Overall, the study demonstrates how a model-based approach can support extrusion screw design and improve understanding of the relationship between screw geometry and process performance.}},
author = {{Mile, Amanda and Frick, Emma}},
language = {{eng}},
note = {{Student Paper}},
title = {{A Framework for Extrusion Screw Design}},
year = {{2026}},
}