Find out about.......Plastics, Polymer Engineering and Leadership

Polymer Selection Funnel Example - Radar transparent plastics for Advanced Driver Assistance Systems (Radar and Lidar)

Literature:

[1] https://www.syensqo.com/en/brands/ryton-pps

[2] https://analyzing-testing.netzsch.com/de/produkte/dynamische-differenzkalorimetrie-dsc-differenz-thermoanalyse-dta

Friday, 7 February 2025

Polymer Selection Funnel Example - Base plate of a filter coffee machine (POMS-Funnel Method)

Hello and welcome to another polymer material selection example for which we use the POMS-Funnel Method (in detail explained here and in this video). Today’s mission is to select the optimal polymer for a base plate used in traditional filter coffee machines (Figure 1).

Figure 1: Polymer Selection Funnel Example - Base plate of a filter coffee machine using the POMS-Funnel Method.

You want to get quickly started with plastics selection - I created a practical guide which leads you fast in 5 steps through a selection journey (check it out here).

Also, my post on 10+ key considerations for selecting the optimal polymer material can help to kickstart your material selection journey.

Now, back to the selection example.

For a more detailed selection approach, as mentioned before, I created the Polymer Selection Funnel methodology (POMS-Funnel) which you can check out here and practical examples in the start here section.

Figure 2 presents the four different stages of the material selection funnel as well as the tools we can use to facilitate the selection. We can use this as a guideline throughout the selection journey.

Figure 2: Polymer Selection Funnel - overview of the four different funnel stages and tools.

Funnel stage 1: Material selection factors

In the first Funnel stage we focus on gathering and understanding all the requirements of the base plate for the filter coffee machine.

Following questions can help us with this assessment:

-What are the performance requirements (structural, etc.)?

-Do you want to combine multiple parts or functions?

-What will be the structural load of the part (static, dynamic, cycling, impact, etc.)?

-What will be the environmental impact on the part (chemical, temperature, time)?

-What is the expected lifetime of the product?

After answering the functionality questions, we continue with the, in my point of view, six essential questions on material selection factors (6 What's):

1. What is the service environment of your part?

2. What are the regulatory requirements?

3. What types of load at which service temperature and time need to be fulfilled?

4. What other things such as wear and friction, electrical properties such as CTI, electrical breakdown strength, aesthetics and colour (relevant for application with food contact, and toys), and more, need to be considered?

5. What is the processing and fabrication method?

6. What are the economic and commercial considerations?

A more detailed list can be found here (incl. download): Material Selection Requirements Checklist

I split the requirements in three different sections:

Functional requirements related to the part: the base plate serves as a housing for electrical components and needs to protect the electrical equipment against external mechanical impacts according to the IEC 62262 (needs to pass the “spring hammer test”). Therefore, design weaknesses need to be avoided and materials with high impact resistance are needed. To stand properly on the floor, good mechanical stability needs to be ensured. Achieving this stiffness can be done over ribs, however ribs may increase surface defects and increase tooling costs. Therefore, a polymer with high stiffness is preferred (high elastic modulus; engineering polymers). Keeping the coffee warm for a longer time, temperatures up to 110°C can be reached. Polymers with high continuous use temperatures, as well as long heat aging durability are preferred. Being used in a kitchen, the coffee machine is exposed to all kinds of fats, oils, soaps, cleaning agents, alcohols, fruit and vegetable acids. Additionally, water vapor and hot coffee will touch the base plate too and therefore hydrolytic resistance is needed. Surface finish and optical quality are a key requirement too. High gloss and scratch resistance surface are required, together with customer specific coloring of the parts.
Production/processing-related requirements: Since long screw bosses need to be used, polymers with good flow properties need to be used (including good ejection). In addition, there should be no shrinkage and warpage problems after the part was moulded.
Assembly-related requirement: In order to save costs in the assembling, snap fits should be used to easily connect parts with each other. Therefore a material is needed with high elongation at break and flexural strength. Additionally, some self-tapping screws need to be used and therefore more viscoelastic material is needed.

After we collected all requirements, we turned them into quantifiable data and added them to our requirement worksheet. The main criteria will be continuous use temperature (CUT), heat resistance and ageing stability, and optical surface quality. Heat ageing stability can be achieved by additives and therefore, CUT and optical properties are the main driver for the selection. High filled polymers achieve not the desired outcome (with expectation such as PARA) and only neat polymers will be considered.

Table 1: Overview of requirements for the coffee machine base plate using the requirement worksheet.

Funnel stage 2: Decision on thermoplastic or thermoset

Funnel step 2 leads us through a decision tree, starting with the first branch of taking the thermoplastic route or thermoset route. Reviewing the application requirements (impact, optical, processing), thermoplastics can fulfil the requirements in a better way. Next decision branch in the thermoplastic route is to select whether amorphous or semi-crystalline polymers are feasible. Both amorphous and semi-crystalline materials are feasible to fulfil the coffee base plate requirements.

Now we can screen the databases and material suppliers for suitable material candidates. There are reliable database such as Campus and Omnexus and I created dashboards to support this step too:

Dynamic Mechanical Analysis (DMA) Data of Engineering and High Performance Polymers
Plastics Pricing Dashboard
Chemical Resistance of Polymers
Plastics Environmental Sustainability Dashboard

All dashboards can be found here.

Among the amorphous polymers, unfilled Polycarbonate (PC) can match the requirements. However, due to long flow length combined with thin ribs and high viscosity, filling of the part is harder. Styrene acrylonitrile resin (SAN) can be considered too, however will not fulfil the high continuous use temperature of 110°C (SAN: 85°C). Polyamide 6.6 will fulfil the 110°C continuous use temperature requirement (PA 6.6: 120°C), however there are limitations of use due to easy coloring when in contact with food. For example, parts moulded in PA 6.6 easily take up the red spots when touched by red beet.

For our detailed discussion in Funnel step 3, Polybutylene terephthalate (PBT), Polypropylene (PP), and Polyketone (POK) are considered (Table 2):

Ultradur® B 4520 (PBT) - BASF
BH348MO - Borealis
POKETONE® M630 – Hyosung

Table 2: Pre-selected materials for Funnel step 3.

Funnel stage 3: Selection discussion with worksheet (qualitative matrix analysis)

Now we reached the core element in the whole material selection funnel: the qualitative matrix analysis. It is a detailed selection discussion with a worksheet. It ranks all of the pre-selected polymers on how good each fulfills the requirements. Additionally, the requirements are ranked according to their importance too. The decision matrix analysis consists of five steps (explained in detail here) and the calculation principle is a scoring of each of the pre-selected materials for each of the material selection factors. As a result, we obtain scores for each material. The materials with the highest score are most suitable for selection and will be further investigated in the fourth stage.

How to start the qualitative matrix analysis?

We can use my online tool in order to facilitate this step (Polymer Material Selector V1.1). As an alternative, you can reach out to me and I will provide you with an excel version of it. I only considered the must-have requirements and ISO test standards; Long-term and multi-point test data needs to be checked in Funnel step 4 too.

In Table 3 the outcome of the qualitative matrix analysis is presented. PBT scored the highest number of points (score: 182 points), followed by PP (score:180 points) and POK (score: 180 points). All three materials should be validated in the Funnel stage 4 since there are important tests. Also, assessing the commercial and processing situation of the materials is important.

Table 3: Outcome of the qualitative matrix analysis - PBT scored the highest points, followed by PP and POK.

Funnel stage 4: Testing, selection of material and vendor

In the previous steps, we exclude PA 6.6. due to the potential of being colored by kitchen foods and liquids. Also, Polycarbonate was excluded due to low flow and difficult part filling. Now, in Funnel step 4, PBT, PP, and POK will be tested. In this test series, simple ISO based tests are one part, however the major knowledge on the material performance comes by making prototype parts and assembling them into a part group.

Major tests include safety tests according to the IEC, and CEE, as well as long-term testing. Long term endurance testing is done in two phases and represents 10 years of life time. In phase one, prototypes of all parts with all three materials are done, including the base plate. Then, water in the tank is overheated and kept for 20 minutes at the high temperature. Then, in phase two, the device is allowed to cool down for 5 minutes and the tank is refilled. This is repeated 7.000 times. This long-term test allows access to things such as deformation, warpage, coloring, material change, and embrittlement of the material. As a result, PBT performed well. PP and POK performed well too, however the design of the part needs to be adapted to compensate for higher shrinkage and warpage. The design of the coffee machine gets more complex by using PP and POK, in order to have the same part quality as with PBT. It is challenging to achieve the same part performance with a material which has a lower overall performance profile. However, with good training in part design and part optimization, materials such as PP and POK are replacing more and more expensive engineering polymers.

Conclusion

In conclusion, PBT can be used for the premium segment of filter coffee machines, and PP, as well as POK can play an important role in the more mass market application with more price sensitivity.

More polymer material selection examples using the funnel approach can be found here and below:

Polymer Selection Funnel Example - Smartphone Front Bezel (Consumer Electronics Material Selection)

Polymer Material Selection Funnel Example - Baby Bottles (Consumer Packing Example)

I offer to select the optimal polymer for your project, doing the polymer material selection together with you, and also teaching polymer material selection as a training in a group - let me know how I can help you here.

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog - check out the start here section

🔥 There is a problem keeping you awake - My personal website for Polymer Consulting

Literature:

[1] https://kdfeddersen.com/de/produkte/polymere/polyketon#Eigenschaften

[2] https://www.campusplastics.com/campus/en/datasheet/Ultradur%C2%AE+B+4450+G5/BASF/20/401a0566

[3] https://www.borealisgroup.com/products/product-catalogue/bh348mo

[4] Bednarz J: Kunststoffe in der Elektrotechnik & Elektronik

Monday, 3 February 2025

Plastics Industry - How to Kickstart Innovation in 2025

Hello and welcome to a new post. Today we discuss how to kickstart innovation in the plastics industry. Why? Most of us find ourselves in the position that in the 1st quarter of the business year the management staff and executives will present to you some expectations regarding innovation, especially how innovation will drive further business growth.

This can look like:

-Five new product ideas

-Three new programs started

-Minimum one new innovation project as part of the bonus goals

-Several patent applications.

It is combined with sentences like: ‘This year we need a push from our technology division to drive business forward’.

Also, emerging global megatrends, the fear of recessions and losing of market share increases the uncertainty at management level. In other words: now we must innovate to keep the business afloat!

It is in our hands to fulfill these expectations

How to start? Review the 4 types of innovation

Greg Satell, author of Mapping Innovation created the 2x2 Innovation Matrix, which helps us to identify the right type of strategy to solve a problem. The Innovation Matrix is linked to two questions:

1) How well can the problem be defined?

2) Who in the organization is best placed to solve the problem?

Figure 1 shows the 2x2 Innovation Matrix which includes basic innovation, breakthrough innovation, sustaining innovation, and breakthrough innovation.

Figure 1: Kickstart innovation - start by reviewing the 4 types of innovation (2x2 Innovation Matrix) [1].

Basic Innovation:

Driven by fundamental research and the discovery of new phenomena.
Leads to new knowledge and fuels the creation of novel applications.
Accessible to small and medium sized enterprises (SMEs) through online resources and collaborations with scientists.

Breakthrough Innovation:

Solves complex problems by combining expertise from different fields.
Emphasizes cross-domain knowledge exchange and open innovation.
Example: Using the behavior of clams to inspire a novel sensor design.

Improvement Innovation:

Focuses on incremental enhancements to existing products.
Aims to increase profitability through higher prices and added features.

Disruptive Innovation:

Occurs when market shifts render established products obsolete.
Requires a fundamental shift in business models and operational approaches.

How to apply this to your organization

First step is to locate where you and your innovation challenges are situated in the Innovation Matrix. Once done, it is time to apply tools which are especially suitable for each of the innovations:

-Basic innovation:

• Dedicated research departments in large corporations

• Accessing highly specialized research through local universities

• Academic partnerships

-Breakthrough innovation:

• Open Innovation Method Framework designed by Roland Harwood [2] consisting of degree of

openness (Open inside; Outside in; Inside out) on the x-axis and stage of innovation (explore, extract,

exploit) on the y-axis.

-Improvement innovation:

• Strategic road mapping

• Traditional R&D labs

• Acquisitions allowing to bring new know-how and skill sets into the organization

• Design thinking methods

-Disruptive innovation:

• The Lean Start-Up method with its three key principles (hypotheses testing with a framework

called a business model canvas; listening to customers and incorporate their feedback, and agile

development which allows for short, iterative product development cycles)

• Value Proposition Canvas is a framework which helping you to ensure that your product/service is

positioned around what the customer values and needs.

Generally, businesses emphasize the efficiency and good enough type of innovation since one can gain fast results, which can be measured well too. This can be a good start for you too, however gradually focus should be put on the four major types of innovation to uncover the next game changer in your industry.

Ready to revolutionize innovation in your organization?

My new book, How to innovate when you must, is your guide. It contains 15 actionable strategies to ignite creativity, spark new ideas, and drive business growth. Additionally the included innovation readiness assessment will help you pinpoint your organization's current innovation maturity and guide you toward a more innovative future.

Thanks for reading & #findoutaboutplastics

Herwig Juster

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog - check out the start here section

My personal website for polymer consulting

Literature:

[1] https://www.amazon.co.uk/Mapping-Innovation-Playbook-Navigating-Disruptive/dp/1259862259

[2] https://theharwoodinstitute.org/approach

Monday, 13 January 2025

Injection Moulding of PolyArylAmides (PARA; PA - MXD6) - Avoid this important mistake with the mould and melt temperature

Hello and welcome to a new post. Today we discuss the crystallization behavior of PolyArylAmide (PARA; PA MXD6), a semi-crystalline high performance Polyamide. Learn the ABCs of PARA here and the differences between PA and PARA here.

PARA combines excellent surface finish with high glass fiber loadings, outstanding stiffness (over 38 GPa possible), outstanding strength (>300 MPa possible), low creep, excellent flow (thin walls), and a CLTE which is similar to that of metal.

Crystallinity is Key

PARA's performance heavily relies on the level of crystallinity achieved during processing. Higher crystallinity leads to improved physical properties, dimensional stability, and high-temperature performance.

Semi-crystalline materials like PARA require temperatures above their glass transition temperature (Tg = 85°C for PARA) to crystallize effectively. Mould temperature directly influences the material's temperature during solidification. Studies indicate that a mould temperature around 120°C is necessary, especially for thin-walled parts, to maximize crystallinity. Figure 1 shows the relative crystallinity of PARA (PA MXD6) as a function of mould temperature [1]. The measured part had a thickness of 3 mm and samples from the core and from the skin where checked for crystallinity.

Figure 1: Relative crystallinity of PARA (PA MXD6) as a function of mould temperature [1].

DSC analysis as an effective tool to check crystallinity of semi-crystalline polymers

Differential Scanning Calorimetry (DSC) can assess crystallinity in an effective way. An exothermic peak in the DSC curve around 80-120°C signifies incomplete crystallization during injection moulding. Figure 2 shows a DSC curve of a fully crystallized and incomplete crystallized PARA. In the area of the Tg (85°C), an exothermal peak is visible, indicating that the tool temperature during moulding was too low. Sometimes lower tool temperatures are applied to decrease cycle time or to decrease shrinkage and warpage effects. However, this comes at the cost that the part which uses a high performance polymer, will not perform like a high performance polymer.

Figure 2: Comparing a DSC curve of a fully crystallized and incomplete crystallized PARA [1].

The maximum crystallinity of PARA can vary depending on factors like processing conditions, specific grade of PARA, and additives. PARA typically exhibits crystallinity levels ranging from 40% to 60%.

What are factors influencing crystallinity in general?

Moulding temperature: As discussed, high mould temperatures (> 120°C) are crucial for achieving higher crystallinity.
Cooling rate: Slower cooling rates generally allow for more complete crystallization.
Nucleating agents: Adding nucleating agents can significantly enhance crystallinity rates.

What are the consequences of low mould temperature with PARA?

There are five issues related with low mould temperature which I come across over and over again when moulding PARA:

Increased water absorption: Higher amorphous content leads to increased water absorption, affecting dimensional stability.
Post-Crystallization and distortion: Incomplete crystallization can lead to post-crystallization after moulding, causing part distortion.
Higher creep: Parts moulded at lower temperatures exhibit increased creep behavior.
Poor surface finish: Irregular surfaces and fiber appearance can result from insufficient mold temperature.
Ejection issues: Very low mould temperatures can lead to extremely low shrinkage, hindering part ejection.

How to measure the tool surface temperature best?

A practical option to measure the surface tool temperature is to use a non-contact IR temperature measurement device. They cover a temperature range from -50°C up to 600°C and can be fast applied to many surfaces.

Melt temperature and residence time are important too

Apart from applying the correct mould temperature with PARA, checking the melt temperature and residence time is important too. Too high melt temperatures (>285°C) in combination with long residence time can lead to thermo-degradation. This is not only affecting the base polymer, in our case PA-MXD6), but also the processing additives and other additives. Aim for a residence time of 5 minutes, with a maximum residence time of PARA of 10 minutes.

If you are not sure about the residence time, you can easily estimate it with this calculator.

The upper DSC curve in Figure 3 shows again a fully crystallized PARA with two melting peaks. The first, larger melting peak belongs to the PARA base resin and the second smaller belongs to an additive which is used in the formulation (most probably a processing aid). The lower DSC curve shows PARA when exposed to high melt temperatures (>285°C), combined with too long residence times (>10 minutes). The second smaller melting peak disappeared indicating that termo-degradation did take place. This in turn has an influence on the final mechanical properties of the moulded PARA part. Also, it can happen that the additive melting peak is overlapping with the main melting peak of the PARA, making it harder to detect it.

Figure 3: Thermo-degradation of additives in the PARA compound formulation caused by too high melt temperature and residence time.

Conclusion

High mould temperatures (>120°C) are crucial for processing PARA (PA MXD6) compounds. They ensure optimal crystallinity, leading to superior mechanical properties, dimensional stability, and overall part performance. Also, check from time to time the mould surface tempature to ensure that there is a match between set temperature vs. real temperature.

I hope this blog article has been helpful. If you have any questions, please feel free to leave me a message.

Thanks for reading & #findoutaboutplastics

Herwig Juster

Interested in my monthly blog posts – then subscribe here and receive my high performance polymers knowledge matrix.

New to my Find Out About Plastics Blog - check out the start here section

My personal website for polymer consulting