Post on 20-Jun-2018
Mark P Kearns
Moulding Research Manager
Polymer Processing Research Centre
Future Proofing the Rotational Moulding Process:
R&D Activities at The Polymer Processing Research
Centre
Queens University, Belfast is involved in a number of important ‘future-proofing’ R&D projects for the rotomoulding industry. ‘Future-Proofing’: “The process of trying to anticipate future developments, so that actions can be taken to seize opportunities and minimise negative consequences.”
Future Proofing the Rotomoulding
Industry
This is what Rotomoulders seem to do really well… • Mould a lot of large, hollow parts e.g. big tanks
• Mould different types of polyethylene
• Use relatively cheap moulds
• Build our own rotomoulding machines
• Make parts with nearly uniform walls
Current Technical Status of our Industry
This is what some Rotomoulders are learning (starting?) to do… • Monitor mould, material and oven temperatures
• Buy standardised rotomoulding machines
• Mould a few non-PE plastics e.g. PP / PA
• Build good quality tooling
• Decorate in the mould • Use robotic finishing techniques
Current Technical Status of our Industry
This is what most Rotomoulders are not really too good at… • Reducing cycle times - heating, cooling, material handling
• Moulding engineering plastics e.g. ABS, PC, PEEK
• Making efficient use of energy
• Using pressurised moulds
• Holding close tolerances
• Making quality foamed parts
Current Technical Status of our Industry
Current Technical Status of our Industry
Summary: 1. Rotomoulding competes well in design and overall dimensional
versatility
2. Rotomoulding lags in production, equipment and tooling
3. Rotomoulding lags in dimensional stability, material selection, ease of material/part handling
4. Rotomoulding lags in energy efficiency, cycle time, process monitoring/control
So what do we do? • Nothing
• Moan / complain about the competition
• Continue to ‘fiddle’ with the process without real technical input
• Play around with samples from material suppliers but never really ‘evaluate’
Current Technical Status of our Industry
So what should we do?
• Try to understand, monitor and eventually control the process better
• Adopt innovative technologies
• Consolidate and share technical advances for the sake of the industry
• Support major R&D / academic efforts to improve and advance the process
Current Technical Status of our Industry
• The Rotational moulding industry in Europe consists of some 350+ companies around 90% of which are SME’s. Representing almost 30% of the global rotomoulding community.
• The EU sector is affected by globalisation and increased competition. This is especially significant for rotomoulding, as it is currently a labour-intensive and relatively slow process. • Therefore, continual innovation and expansion into new areas and applications is necessary in order to keep the rotomoulding community at the forefront.
Future Proofing the Rotomoulding
Industry
• Achieved through access to cutting-edge technologies within Europe’s leading research institutions (RTD), and through collaboration with counterparts across Europe. • A ‘supply chain’ approach is essential where material suppliers, machinery manufacturers, mould makers, moulders, designers, and end-users collaborate. • Providing a step change in the sophistication of rotomoulding, leading to greatly more efficient processing and value-added products that cannot be produced with existing technologies.
Future Proofing the Rotomoulding
Industry
The EU Commission helps provide support aimed at SMEs or SME Associations in need of outsourcing research where.... R&D carried out by RTD’s on behalf of SMEs / Industrial Associations in order to expand their knowledge base and to improve their general standard of competitiveness.
European Commission Research For SMEs
1. ‘Intelligent Process Control for Rotational Moulding’ (Internal Cooling ~ €500k – Completed July 02)
2. ‘Development of innovative high performance anodised aluminium moulding
tools for the thermoplastic processing sector to achieve competitive advantage’ (Alamo ~ €600k – Completed Jan 06)
3. ‘Development of an efficient heating and cooling technology system for the reduction of cycle time, product cost and energy consumption’
(Rotofast ~ €2.66m – started Aug 10)
QUB Rotomoulding
European Funded R&D Projects
4. ‘Development of an automated process to extract natural fibres from waste food production for exploitation as a sustainable reinforcement in injection and rotomoulded products’ (Badana ~ €700k – started July 09)
5. ‘Innovative rotomoulding development to improve cycle times and process efficiency whilst facilitating greater flexibility in product design and integrity for the SME-rotomoulding sector’(Rotoflex ~ €1.23m – started Jan 09)
QUB Rotomoulding
European Funded R&D Projects
6. ‘The Development Of Advanced Retro-Fit Processing Technologies For
Rotational Moulding To Reduce Product Cost and Processing Time and Increase Surface Quality’ (Micromelt ~ €2.55m – Completed Aug 09 )
QUB Rotomoulding
European Funded R&D Projects
Multi-layer Applications
Courtesy of Total Petrochemicals: Made with BioTP SealTM Technology
Rotoflex – FP7 EU Rotomoulding
Project
‘Innovative rotomoulding development to improve cycle times and
process efficiency whilst facilitating greater flexibility in product design
and integrity for the SME-rotomoulding sector’
Start Date: 1st January 2009
Finish Date: 31st December 2011
Total Project Value €1.23m (www.rotoflex-eu.org)
Feed
Feed
Feed
N2 gas
Internal
cooling
Computer control
a) b)
c)
Overall Technical Strategy
Development of a ‘universal’ automatic feed system that can be attached to any mould, such that if required materials and fluids may be fed at any stage in the rotational moulding cycle.
The goal is that Rotoflex will facilitate the accurate, controlled delivery of resins, reinforcements, additives, inert gas, coolant media and mould pressurisation leading to the development of advanced polymer composites. The intention is to develop a system that can be configured to fit existing rotomoulding machines.
•Development of feed pipe end connection
•Development of connection mechanism
•Development of mould end connection
•Machine – control mechanism to position arm / mould
•Mould – positioning to accommodate connection and
mould filling / multi-shot moulding
Technical Strategy
Off-Line Test Rig
Prototype
Autopark Development
•The Autopark system was designed and installed on the rotomoulding machine to allow the positioning of the mould in the correct orientation in both the plate and arm direction
•This allows for correct alignment of the material delivery lance as it is lowered vertically from the roof through the oven. •The system operates by having two sensors, one on the arm which senses when the arm is on the horizontal axis.
Installation of Material Feed System
Test Mould with Profit Pins
Source : Maack Business Services
• 4 kg of Natural PE in mould from
start (No material added) normal
cycle carried out
Two Layer & Four Layer Mouldings
Material Feed System – Dissemination
Feed system has been validated to provide data for industrial trials which
involved substantial testing and rotomoulding trials using a range of
conventional and engineering polymer materials and fibres.
Trials were conducted to determine optimum process parameters to
produce a range of complex and innovative multi-layer mouldings e.g. skin-
foam-skin; multi-layer engineering polymer structures as well as fibre-
reinforced composites with multiple alternating layers of polymer and fibre.
• Fundamental understanding of the effect of water spray to cool molten polyethylene – spray nozzles, water characteristics, etc
• Experimental • Nozzle Type • DOE Study • Test mould analysis • Mechanical and Shrinkage Testing
• Industrial Water Cooling Trials
Internal Mould Water Spray
Cooling
Ambient Cooling
Polarised Microscopy - Magnification 500X
Nozzle B
1.5Bar Air 2Bar Water
Nozzle A
2.5Bar Air 2.5Bar Water
100m 100m
Water Mass Flow Rate ~ 0.34 kg/min
100m
sample thickness: 15 micron
3.4 deg C/min 26.9 deg C/min 31.3 deg C/min
Sturdy Mould - Ext. Air Cool Only
0
50
100
150
200
250
00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24
Time (min)
Tem
p.
(ºC
)
100% Air Cool Int. Air
100% Air Cool Melt
Sturdy Mould - Comparison of Int. Air at 180ºC
0
50
100
150
200
250
00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00
Time (min)
Tem
p.
(ºC
)
180ºC Ext Water Cool Int. Air
180ºC Ext + Int Water Int. Air
Sturdy Mould - Comparison of Int. Air at 120ºC
0
50
100
150
200
250
00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12
Time (min)
Tem
p.
(ºC
)
120ºC Ext Water Cool Int. Air
120ºC Ext + Int Water Int. Air
Steel Test Mould – Internal Air Ext. Water Cooling Vs. Ext. Water + Int. Water Cooling
• Steel Mould
• Shot weight = 8.4kg
• Wall thickness ~ 6mm
• Dim: 500 x 500 x 520mm
Sturdy Mould - Comparison of Ext. Water and Ext. Air
0
50
100
150
200
250
00:00:00 00:07:12 00:14:24 00:21:36 00:28:48 00:36:00 00:43:12 00:50:24
Time (min)
Tem
p.
(ºC
)
180ºC Ext Water Cool Int. Air
180ºC Ext Water Cool Melt
120ºC Ext Water Cool Melt
120ºC Ext Water Cool Int. Air
100% Air Cool Int. Air
100% Air Cool Melt
Steel Test Mould Ext. Water Cooling Vs. Ext. Water + Int. Water Cooling
Ext. Water Cooling Only
Ext.+ Int. Water Cooling
• Underground Septic Tank
• Wall thickness = 8-10 mm
• Steel tool
B almoral T rial S eptic 61
0
50
100
150
200
250
300
350
400
450
0 10 20 30 40 50 60 70 80 90 100
T ime (min)
Te
mp
era
ture
(ºC
)
Mould S eptic 61
O ven S eptic 61
Int. Air S eptic 61
Internal Water Cooling
Septic Tank
Internal Water Cooling
Underground Tank
K over T rial Normal C ooling Vs . Water C ooling
0
50
100
150
200
250
0 10 20 30 40 50 60 70 80 90 100
T ime (min)
Te
mp
era
ture
(ºC
)
Mould Water C ool
Int. Air Water C ool
Mould Air C ool
Int. Air Air C ool
• PE = 270kg
• 6500 litre
• Wall thickness = 8mm
• Steel tool
Internal Water Cooling
Industrial street cleaning product
Int. + Ext. Water Cool
External Air Cool
Internal Water Cooling
Industrial street cleaning product
• Average cycletime savings of 15 - 20% achievable with no effect on inside surface quality
• With further optimisation 25%+ possible combining external water cooling and applying internal water at higher internal air temperatures
Industrial Trials to date:
Dissemination Papers / Articles:
• The Development of Internal Water Cooling Techniques for the Rotational Moulding Process – ANTEC 2009 pp. 1961-1965
• The Effects of Water Droplet Size and Velocity on Spray Cooling of Polymers during Rotational Moulding – ANTEC 2009
pp.1951 - 1955
• Pan-European Rotomoulding Research: “The Micromelt Project ” Volume IV, Issue 6, November – December 2008
• Rotoworld Article, “The Use of Internal Mould Cooling in the Rotational Moulding Process” Volume V, Issue 3, May-June
2009
Collaboration = Results
Maus GmbH, mould makers, Germany and Queens University, Belfast
partner on the development of a self contained, automatic, internal water
cooling spray device -
Rotocooler©
Rotocooler©
• The Rotocooler device attaches and travels with the mould.
• At the appropriate temperature / time it accurately sprays a
controlled water jet into the centre of the rotating moulding.
• The effect of this is to internally cool the plastic part.
• There is no detrimental effect on part quality.
• There is no detrimental effect on mechanical properties.
• There is a reduction in cooling time.
• There is a reduction in warpage / shrinkage.
• Balanced internal / external cooling is achievable.
Rotocooler©
For further details on Rotocooler contact:
Oliver Wandres
Maus
Am Viehweg 9 - D-76229 Karlsruhe
Tel.: +49-(0)721-94874-0 Fax: -44
www.maus-gmbh.de
Research and Development
• R & D is a process intended to create new or improved technology that can provide a competitive advantage. • An R&D project to improve a product or service has a far higher chance of success than one aimed at creating a completely new product or service.
• While the rewards can be very high, the process of technological innovation is complex and risky. R&D always carries an element of risk • Returns from R&D can be considerably greater than for other investments - and could even ensure your business' future survival.
Thanks…
If your interested in taking part in EU Framework projects contact:
Mark Kearns Moulding Research Manager
Polymer Processing Research Centre Ashby Building
Stranmillis Road Belfast
N. Ireland BT9 5AH
T: +44 2890 974711 F: +44 2890 660631
M.Kearns@qub.ac.uk