Ville Klar
Doctoral Candidate
Aalto University, School of Engineering
Department of Engineering Design and Production
2.0
Machine Design in DWOC2.0Production machine design for new
cellulose-based products
Why filaments?
• Strong form
• Building block for other shapes and structures
• Many established processes
• Filaments or fibre yarn
3
Raw materials
Machine elements
Applications
Process parameters
Raw materials
• New processes required in spinning from fibre suspensions
– Development of sections of the spinning line required
• Established solution spinning technologies not directly applicable
– Multiphase fibre suspension different rheological properties
– Forming (drawing) and axial alignment of fibres
– Drying & dewatering
Raw materials
• Fibre properties
• Stiffness comparable to Kevlar [1]
• Tenacity comparable to glass fibres [2]
• Fibre properties and yarn properties
not directly comparable (fibre network)
• Native wood cellulose structure
• Cellulose I structure is 50 % stiffer than the
Cellulose II structure [1]
• Cost and raw material efficient processes
• Development required in production of raw materials
Helicoidal structure[3]
[1] Sakurada, Ichiro, Yasuhiko Nukushina, and Taisuke Ito. "Experimental determination of the elastic modulus of
crystalline regions in oriented polymers." Journal of Polymer Science 57.165 (1962): 651-660.’
[2] Saito, Tsuguyuki, et al. "An ultrastrong nanofibrillar biomaterial: the strength of single cellulose nanofibrils revealed via
sonication-induced fragmentation." Biomacromolecules 14.1 (2012): 248-253.
[3] Emons, Anne Mie C., and Bela M. Mulder. "How the deposition of cellulose microfibrils builds cell wall architecture."
Trends in plant science 5.1 (2000): 35-40.
Machine elements
Dry spinning [4]
[4] Dry spinning, http://www.tikp.co.uk/knowledge/technology/fibre-and-filament-production/dry-spinning/
[5] Introduction to solution spinning, http://nptel.ac.in/courses/116102010/18
Wet spinning [5]
Dry-jet wet spinning [5]
Machine elements
Pump Spinneret Bath Forming Drying Spooling
Rheology of the
suspension Filament geometry
Efficiency
Wet strength
Axial alignment of fibres
Drawing
Machine elements: Spinneret
• ”Headbox” of spinning
• Iterative prototyping
• Phenomenological study of a coaxial spinneret
Process parameters
Pump Spinneret Bath Forming Drying Spooling
Flow rates (ml/min)
Agitation of suspension
(thermal, ultrasound, mechanical)
Spinneret diameter (mm)
Air gap (mm)
Spinneret geometry / type
(cylindrical, conical, double
conical, hyperbolical, etc.)
Bath liquid
Bath temperature
Drawing ratio
Drawing sequence
Compression / twisting
Roll / godet geometry, surface, configuration
Conductive/convective/radiation
Air flow / pressure
Drying time
Drying temperatures
Plying
Coating
Post-treatment
Process parameters
Raw material properties
Suspension parameters
Spinneret geometry
Timescales
Forming parameters
Drying parameters
Filament properties
Production rates
Analysis of the effect of spinning parameters
Process parameters
• Prototype coaxial spinning line
• Different parameters measured and controlled
• Efficient testing of different spinning parameters in a fume hood with sufficient
production rates
Applications
Textiles
Composites
NonwovensFilaments Design
Applications
Applications
Weft-knitted sample
Sufficient production capability
Sufficient filament properties
Sufficient lengths of filaments
Applications
• Filaments are the first step…
• Additive manufacturing
• Combined processes
• New processes based on native wood fibres can be greatly improved by developing new machinery
• Effects of spinning parameters can be efficiently studied through automation and control
• Scalability can be studied through prototype spinning lines
• Development of spinning leads to different processes for new applications
Conclusions
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