The Path to Polymer Selection Mastery: A Jedi's Journey

Hello and welcome to this new post, today in the theme of Star Wars, together with polymer material selection. 

FindOutAboutPlastics.com presents: The Path to Polymer Selection Mastery - A Jedi's Journey.

The path to becoming a master of polymer material selection is a challenging one, requiring dedication, perseverance, and a deep understanding of the Force, or in this case, the properties of plastics. Just as a Padawan must undergo rigorous training and face numerous trials to become a Jedi Knight, so too must an aspiring polymer engineer navigate a series of challenges to master the art of material selection.

This journey begins with a thorough understanding of the fundamental principles of polymer science, including the various types of polymers, their structures, and their unique properties. It is akin to a Padawan learning the basics of lightsaber combat and the Force. From there, the aspiring engineer must delve into the intricate details of polymer behavior, exploring how different polymers react under various conditions, such as heat, stress, and chemical exposure. This is similar to a Padawan mastering the subtle nuances of the Force, understanding its power and limitations.

The next step involves applying this knowledge to real-world applications, selecting the most suitable polymer for a specific purpose. This is where the true test of skill lies, as the engineer must weigh various factors, such as cost, performance, and environmental impact, to make the optimal choice. This is analogous to a Jedi Knight facing a dangerous mission, where they must use their knowledge and skills to overcome obstacles and achieve their goal.

Finally, the journey culminates in mastery, where the engineer can seamlessly integrate their knowledge of polymer science with their understanding of engineering principles to create innovative and sustainable solutions. This is akin to a Jedi Master, who has achieved enlightenment and can use the Force for the greater good.

In essence, becoming a master of polymer material selection is a continuous learning process, requiring a combination of theoretical knowledge, practical experience, and a deep understanding of the challenges and opportunities that lie ahead. It is a journey that demands dedication, perseverance, and a willingness to embrace the unknown, just as it does for a Padawan seeking to become a Jedi Master.

The path to polymer mastery may be arduous, but the rewards are great. Those who persevere will gain the ability to shape the future, creating products that are not only functional but also sustainable and beneficial to society. So, embrace the challenge, hone your skills, and embark on your journey to polymer mastery.

Ready to begin your journey to Polymer Mastery? Take the Polymer Material Selection scorecard today and discover your POMS score!

Polymer Material Selection scorecard

Also, you can get familiar with the 6 essential polymer material selection skills here. 

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Interested in My Monthly Newsletter

Literature: 

[1] https://www.findoutaboutplastics.com/2025/03/become-master-in-polymer-material.html

More Than Just Profiles: Unlocking the Diverse Potential of Technoform's Flexible Pultrusion #insightsfromindustry

Hello and welcome to a new post in which we explore the new flexible pultrusion technology introduced by Technoform. I met with Dirk Moses, Head Of Market Development, at the KPA fair Ulm, Germany, discussing their new pultrusion technology. Watch the whole video here and check out our previous interview series here. 

Dirk Moses from Technoform (right in picture), together with Herwig Juster, discussing the new thermoplastic pultrusion technology at KPA Ulm, Germany.

Thermoplastic pultrusion: combining extreme strength with maximum cost-efficiency

Dirk explained to me their company's new thermoplastic pultrusion technology which was developed by Sindy Richter, Head of the Development Department at Technoform, and her team.

It is flexible in terms of material selection, allowing for the use of standard plastics such as polypropylene - PP, engineering plastics such as polyamides (PA6, PA66), and high-performance polymers. This positively impacts the properties of the pultruded profiles as well as their ability to connect to other plastic components. Furthermore, the fiber content can be varied depending on the specific application. The resulting products are characterized by a lower weight combined with high impact resistance and bending strength.

Thermoplastic pultrusion is an advancement of the classic pultrusion process, in which thermoplastics serve as the matrix material instead of thermosetting resins. In both processes, continuous fibers are impregnated with plastic to ensure optimal force transmission through the connection of adjacent fiber elements. A key challenge in thermoplastic pultrusion is the high viscosity of thermoplastics compared to the lower-viscosity thermosets, which makes fiber impregnation more difficult. To address this challenge, Technoform has developed a special process for thermoplastic melt pultrusion.

Potential applications 

Furthermore, Dirk highlighted significant potential in sectors prioritizing lightweight construction and recyclability, particularly the automotive industry for components like battery casings and structural reinforcements. Other promising applications include façade elements using recyclable thermoplastics and opportunities within the sports and furniture sectors where lightweight and flexible materials are advantageous.

Figure 1: Herwig and Dirk discussing profiles, façade elements, and automotive battery casings.

What about recycling of pultruded profiles? 

Dirk emphasizes the technology's benefits over thermosets or aluminum, citing recyclability, material adaptability, and the ability to reshape or weld thermoplastic products. Their approach enables customized material combinations to meet specific requirements more effectively than aluminum. Regarding recycling, he explains that their pultruded profiles can be shredded and reused as high-quality components, with the retention of long fibers enhancing the mechanical properties of the recycled material. 

Metal replacement

In terms of economic viability, Dirk asserts that their technology presents an attractive alternative, especially when replacing steel or aluminum parts with intelligent system solutions that incorporate integrated functions, lightweight design, and recyclability, leading to both sustainable and economic advantages.

Thanks to Dirk and the team for the exchange on the new thermoplastic pultrusion technology! 

thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://plasticker.de/news/shownews.php?nr=46346&nlid=64581.d.h.2025-04-14

[2] https://www.technoform.com/en/reference/new-pultrusion-process-thermoplastic-profiles

[3] https://www.findoutaboutplastics.com/2024/06/plastics-sustainability-contradiction.html

Mastering the Melt: Your Guide to Shear Rate Limits in Injection Moulding (Rule of Thumb)

Hello and welcome to a new Rule of Thumb post on plastics processing. In my previous post we discussed how to locate the maximum shear rates by using injection moulding fill simulations. Now we explore what shear rate limits we need to consider to not harm the processed polymer.

Rheology of polymers

Plastics exhibit non-Newtonian fluid behavior, where viscosity is dependent on the applied shear rate. In certain polymers, shear rate exerts a more significant influence on viscosity than temperature.

Under high stress conditions, such as during processing, polymer molecules align, leading to a substantial reduction and stabilization of the resin's viscosity. This phenomenon is known as shear thinning.

Injection moulding and shear rate / stress limit of polymer melts

In injection moulding, the injection rate or fill time directly correlates with the shear rate experienced by the plastic material. Fill time is a critical process parameter that affects shear heating and shear thinning.

Variations in fill time can alter the viscosity, pressure, and temperature of the polymer within the mould cavity, ultimately impacting the quality of the final part. Maintaining a consistent, optimized fill time is therefore crucial for process stability across different machines.

Excessive shear rates can induce polymer degradation, resulting in a decline in both the aesthetic and mechanical properties of the moulded component.

The shear rate within specific mould geometries, such as sprues, runners, and gates with a round cross-section, can be calculated using the formula: 

γ˙​=4Q​/πr^3, where γ˙​ represents the shear rate (1/s), Q (mm^3/s) is the volumetric flow rate, and r (mm) is the radius of the channel.

Shear stress and shear limit control table

Calculated shear rate values can be compared against established material-specific shear rate limitations to identify potential processing issues related to excessive shear. This data facilitates the mathematical determination of optimal flow rates and mould design considerations. Your calculated shear rate should not exceed the shear rate limit  for the material. Figure 1 shows the shear stress and shear rates limits of different plastics, based on empirical experiments and literature. 

Figure 1: Shear stress and shear rate control table. 

Conclusion

In plastics processing, maximum shear rates can reach over 10,000 s⁻¹ in injection moulding and 1000 s⁻¹ in extrusion, with even higher rates (exceeding 1,000,000 s⁻¹) occurring in specific applications like wire coating. Calculating the shear rates of the material during processing and checking if they are below the shear rate limit of the material will lower the risk of polymer damage. Furthermore risk of plastic part failure is reduced since the part will have the desired properties. 

More Rule of Thumb posts can be found in the "Start here" section. 

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://s3.amazonaws.com/entecpolymers.com/v3/uploads/pdfs/Rheology-vs-Shear-Rate-RGB.pdf

[2] https://www.findoutaboutplastics.com/2015/04/injection-molding-filling-simulation-my.html

[3] https://www.findoutaboutplastics.com/2022/05/6-benefits-of-injection-moulding.html

Nature is built on 5 Polymers. Modern life is built on over 200 different Polymers - How to select the right one?

Hello and welcome to a new post. Today I would like to start with a quote of mine: 

"Nature is built on 5 polymers. Modern life is built on over 200 different polymers. Therefore, optimal polymer selection is key for successful applications and to prevent plastic art failure in the long run." 

"Nature works with 5 polymers," is a statement from Mrs. Janine Benyus and reflects a key concept in her advocacy for biomimicry. It highlights the efficiency and elegance of natural systems compared to human industrial processes. Here's a breakdown of what she means:

Polymers in Nature:

Polymers are large molecules made up of repeating smaller units. They are the building blocks of many materials. Nature primarily uses a limited set of these polymers to create a vast array of structures and functions.

These "five polymers" generally refer to:

• Cellulose: Found in plant cell walls, providing structural support. Cellulose was used in the past to create one of the first human made plastics: Celluloid. It is made by mixing nitrocellulose and camphor.
• Chitin: Forms the exoskeletons of insects and crustaceans, as well as fungal cell walls.
• Lignin: A complex polymer that provides rigidity to plant cell walls, particularly in wood.
• Proteins: Versatile polymers that perform a wide range of functions, from structural support to enzymatic activity.
• Nucleic acids (DNA and RNA): Carry genetic information.

5 Natural Polymers: Cellulose, Chitin, Lignin, Proteins and Nucleic Acids [1].

Biomimicry Application:

Benyus's statement encourages us to look to nature for inspiration in materials science.

By mimicking the way nature uses these polymers, we can create materials that are:

• Stronger
• More durable
• More sustainable
• Easier to recycle.

In essence, "Nature works with five polymers" is a powerful reminder of nature's ingenuity and a call to action for us to learn from its wisdom.

Modern life is built on over 200 different polymers - How to select the right one? 

An important step in the selection journey are the mastering of the what i refer to as the 6 Polymer Material Selection skills (6 POMS skills; Figure 1): 

P- Properties: Understanding key polymer properties

P - Part Design: Defining Application Requirements for Plastic Part Design

P - Polymer material values: Translating application requirements to qualitative and quantitative material values

P - Process: Polymer material selection process

P - Performance: Evaluation of material and part performance

P - Plastic supplier: Selection of material and supplier

Figure 1: Overview of the 6 Polymer Material Selection skills. 

Check out the detailed description of the 6 POMS here. 

In order for you to assess where you are currently ranking at the 6 POMS skills, I created a simple scorecard consisting out of 26 Yes / No questions and after completing the questionnaire, you receive an overall POMS score and detailed scores for each of the six critical elements of polymer material selection.

Also, you get a customised report with actionable steps to immediately start improving your POMS score and your impact in the field of polymer material selection.

A quick 5-step selection guide

Selecting the optimal thermoplastic material can be challenging and my aim is to provide you with a practical guide which leads you fast through the selection journey. 

Improper selection of plastics for the application is the leading cause for plastic part failure and since most parts fail along weld lines or knit lines, optimal mould design including filling and processing of the part are crucial too. 

Apart from the 200 polymers,  there are almost 100 generic “families” of plastics and additionally blending, alloying, and modifying with additives results in 1,000 sub-generic plastic types. Also, selecting the wrong polymer for your product may result in additional financial resources, since the selection process needs to be repeated (including making new tools) or even worse, product failure leads to claims and recalls. The following guide will help you to prevent the major mistakes and if you want to be sure, you can always reach out to a plastic expert to review your selection or help you to select the optimal grade.

What are the 5-steps (download here the guide): 

1. Define Application Requirements: In the first step we lay out all the application requirements and focus on Function, Loading Conditions, Environmental Factors, Regulatory Requirements, and Processing Considerations. A suitable acronym for this step is called FLERP:  F- Function; L- Loading conditions; E - Environmental Factors; R- Regulatory requirements; P- Processing requirements.

2. Identify Candidate Materials: Based on your application requirements, research potential engineering plastics that possess the necessary properties. Material selection charts and dashboards, supplier websites, and technical data sheets can be helpful resources. Consider factors like: Mechanical properties (short- and long-term; as a function of time and different temperature levels), thermal properties, chemical resistance, electrical properties, processing characteristics, and cost. 

3. Evaluate Material Performance: 

Carefully review technical data sheets from potential suppliers to understand the specific properties of different plastic grades within a material family. Most of the time only a single temperature is covered (room temperature). This is useful for comparing different material data sheets to each other, however for part design it has its limitations. Also, consider Multipoint Design Data which helps to think in time-dependency and temperature-dependency behaviors. Graphically such behaviors can be better accessed. Utilizing CAE software to simulate the filling of your part as well as the performance of your design using different material options.

4. Additional Considerations: Consider processing methods and cost. Evaluate environmental and regulatory factors.

Consider the material availability in order to ensure the chosen material is readily available from reliable suppliers. Additionally, evaluation of the environmental impact of the material, including its recyclability or biodegradability, if applicable can be done. Long-term performance check is needed to check the  material's resistance to degradation and expected lifespan in your application. 

5. Testing and validation. 

In the last step, prototyping is done. You can start by obtaining samples from material suppliers for simple analysis.

Next is to create prototypes using the previous identified candidate materials to test performance under real-world conditions. After concluding the final tests, final material selection can be done and a suitable supplier of the material chosen. 

6. Bonus Consult with Plastic Experts and Material Suppliers:

Discuss your application requirements with experienced polymer engineers and material suppliers. Seek recommendations based on their expertise and access to the latest materials.

My Polymer Selection Funnel Method

For a more detailed selection approach, as mentioned before,  I created the Polymer Selection Funnel methodology (POMS-Funnel).  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: Overview of the Polymer Selection Funnel method. 

Funnel stage 1: Material selection factors

In this first stage we map out the true part functions and material requirements. After this we translate the requirements into material selection factors.

Funnel stage 2: Decision on thermoplastic or thermoset

After translating the requirements into material selection factors, the first decision is made:

Which is the most suitable polymer chemistry to fulfill the listed requirements and selection factors? Thermoplastics or thermosets?

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

The third funnel stage represents a core element in the whole material selection funnel. It is a detailed selection discussion with a worksheet. I call it the decision matrix analysis and it ranks all of the pre-selected polymers. The decision matrix analysis consists of five steps. The base calculation principle is a scoring of each of the pre-selected materials for each of the material selection factors. In the end we add up all weighted scores for each material. The material with the highest score is most suitable for selection and further investigation in the fourth stage.

Funnel stage 4: Testing, selection of material and vendor

In the last funnel stage, we would like to know in detail how the materials with the highest scores perform as a final part in a system of plastic parts or as a single plastic part alone. After all the tests are done and the material has passed all tests, commercial conditions with the material supplier can be finalized and first small serial production can start. 

I created a dedicated page for Polymer Material Selection which contains all you need for your material selection, from taking the scorecard test, online selection tools, and examples which have used the POMS funnel method. 

If you want to see the POMS funnel method in action, check out this example: Base plate of a filter coffee machine.

Conclusion

In material selection, there is no "one-size-fits-all" solution. The optimal material will depend on the unique needs of your specific application. A balance between performance, cost, and processing is often necessary. By following a five step guide or the POMS funnel method, leading to a thorough evaluation, you can make an informed decision and select the optimal engineering plastic for your project!

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://www.amazon.de/-/en/Janine-M-Benyus/dp/1094025003

[2] https://wasserdreinull.de/en/knowledge/polymers/#how-many-different-polymers-are-there

[3] https://www.polymermaterialselection.com/

Metal Replacement with Plastics: A 5-Step Roadmap

Hello and welcome to a new blog post. Today I present to you a metal replacement roadmap which contains five major steps and when all steps are followed, success in metal replacement will be secured. 

Why Change from Metal to Plastic?

There are many reasons to consider changing from metal to plastic. Some of the most important benefits include:

• Part consolidation and function integration: Plastic parts can be designed to integrate multiple functions into a single part, which can save on manufacturing and assembly costs.
• Weight saving: Polymer have a lower density compared to metals, so switching to plastic can help to reduce the weight of products.
• Lower processing costs: Plastic parts can be manufactured using a variety of processes, such as injection moulding, which can be less expensive than metal forming processes.
• Fewer or no secondary operations: Plastic parts often do not require secondary operations, such as painting or finishing, which can save on manufacturing costs.
• Freedom and flexibility of design: Plastic can be molded into a variety of shapes and sizes, which gives designers more freedom to create innovative products.
• Corrosion resistance: Plastic is resistant to corrosion, so it is a good choice for products that will be used in harsh environments.
• Surface aesthetics, color aspects, markability: Plastic can be easily colored and marked, which makes it a good choice for products where aesthetics are important.
• NVH reduction: Plastic can help to reduce noise, vibration, and harshness (NVH) in products.
• Possibility to reduce the product carbon footprint; lead free material solutions

Metal to plastic conversion roadmap

As outlined before, replacing metal components with plastic ones offers several benefits, including reduced weight, lower costs, and improved design flexibility. However, the process requires careful planning and execution to ensure optimal results. This roadmap (Figure 1) outlines the key steps involved in efficient metal replacement:

1. Metal Part Identification

2. Polymer Material Selection

3. Design and Engineering

4. Prototyping

5. Production

Figure 1: 5 Step Metal to Plastic Conversion Roadmap.

What are the 5 steps leading to successful metal to plastic replacement?

1. Metal Part Identification

• Identify the specific metal components targeted for replacement.
• Define the objectives and required outcomes for the replacement.
• Outline the preliminary requirements and boundary conditions for the new plastic component.

2. Polymer Material Selection

• Choose the most suitable polymer material based on the application requirements.
• Consider factors such as mechanical properties, chemical resistance, and thermal stability.

3. Design and Engineering

• Develop a detailed CAD design for the plastic component.
• Conduct CAE virtual testing and simulations to evaluate the design's performance.
• Refine the design based on the simulation results.

4. Prototyping

• Create a prototype tool for the plastic component.
• Produce molded parts using the selected polymer material.
• Perform thorough testing on the parts to ensure they meet the required specifications.

5. Production

• Release the final part design for serial production.
• Manufacture the plastic components at scale.

By following this roadmap, you can ensure a smooth and successful transition from metal to plastic components.

How a metal replacement project can look like

Example Medical Device Metal replacement  

The following example explains the replacement of surgical retractors (Figure 2), used in total hip replacement replacement (THR) surgeries as a case study for metal-to-plastic conversion. In general, replacing metal with plastic can improve performance and reduce costs in medical devices. High-performance polymers such as PEEK, Polysulfones, and PARA offer similar strength and stiffness to metals, with added benefits. 

In addition, environmental impact can be reduced by switching to a plastic solution. This could be demonstrated by a Life Cycle Analysis (LCA; cradle-to-grave) of a single-prong metal hip retractor. Since the repeated washing and sterilization could be removed, 435 liters of water for each surgical knee procedure could be saved [4].

Figure 2: Surgical hip retractor as an example of metal-to-plastics conversion [1].

1. Metal Part Identification

Orthopedic surgery retractors are traditionally made from metal due to the high strength and stiffness required. The document provides a comprehensive account of converting both single-use and reusable retractors to polymer-based designs using polyarylamide (PARA) and polyaryletherketone (PAEK), respectively.

2. Polymer Material Selection

For medical devices, essential performance requirements include chemical resistance and the ability to withstand sterilization processes, such as steam autoclaving or gamma radiation.

Material selection for both single-use and reusable retractors involves aligning with boundary conditions related to sterilization requirements and usage cycles. 

PARA (Ixef GS-1022), reinforced with 50% glass fiber, is selected for single-use retractors due to its exceptional strength, compatibility with gamma radiation sterilization, and superior surface finish. It delivers performance levels comparable to stainless steel (in this case 17-4 steel)  and can be injection molded, eliminating machining processes and reducing costs.

For reusable retractors, PAEK (AvaSpire AV-651 GF30) is the material of choice, offering a high stiffness-to-weight ratio, hydrolytic stability at elevated temperatures, chemical resistance, and durability even after repeated exposure to disinfectants and steam sterilization. Its ease of processing through injection molding and design versatility further highlight its suitability.

3. Design and Engineering

To replicate the stiffness of metal counterparts in plastics, adjusting the area moment of inertia through design modifications, such as using rectangular geometries or adding ribs was needed. Advanced design using computer-aided engineering (CAE) leverages plastic’s inherent advantages to enhance aesthetics and ergonomics, improving the overall device performance and user experience. A notable design modification for the hip retractor includes optimizing the handle for improved grip and stiffness.

4. Prototyping

Prototyping is crucial in evaluating the feel and functionality of new designs, with 3D printing techniques like selective laser sintering (SLS) employed to create initial prototypes. Validation processes for single-use and reusable plastic retractors involve testing to ensure performance metrics match or surpass those of the original steel retractors. Both plastic versions offer significant weight reduction, decreasing the overall weight of surgical equipment. Additionally, transitioning to plastic reduces the cost of reusable retractors by half and enables economically viable single-use designs.

5. Production

Manufacturing decisions favor injection molding for its cost-effectiveness in large volumes, design flexibility, and quick production turnaround, particularly given the estimated demand for hip retractors over three years.

Metal replacements with high-performance polymers in the medical industry are expanding. Plastic material suppliers, manufacturers, and designers are increasingly focusing their efforts on integrating plastics into medical device designs. Through this transition, the industry aims to meet the dual objectives of enhancing device performance and reducing costs in response to the evolving landscape of healthcare and technology.

Conclusion

Replacing metal components with plastic ones offers several benefits, including reduced weight, lower costs, and improved design flexibility. However, the process requires careful planning and execution to ensure optimal results. The discussed 5-step roadmap outlines the key steps involved in efficient metal replacement.

Interested in assessing the feasibility of metal replacement in one of your components?

Please reach out to me here.

Check out my other metal replacement articles: 

Metal Replacement with Polyarylamide (PARA) for Single-Use Surgical Instruments

Metal replacement with High Performance Polymers: How to Design for Equivalent Part Stiffness?

Replacing Magnesium Die Casting with Engineering and High Performance Plastics

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://www.meddeviceonline.com/doc/medical-device-metal-to-plastic-conversion-in-steps-0001

[2] https://www.findoutaboutplastics.com/2020/02/metal-replacement-with-polyarylamide.html

[3] https://www.syensqo.com/en/product/ixef-gs-1022-wh01

[4] https://www.syensqo.com/en/chemical-categories/specialty-polymers/healthcare/metal-plastic-conversion

Polycaprolactone (PCL): A Versatile Polymer for Prototyping and Small-Scale Modeling

Hello and welcome to a new post. As a polymer engineer, you'll encounter a vast array of materials, each with unique properties suited for specific applications and systematic polymer material selection is key to success. Polycaprolactone (PCL) stands out as a particularly interesting and useful thermoplastic polyester, especially in the realm of prototyping and small-scale modeling. Let's delve into its key characteristics and advantages.  

Polycaprolactone: Low-cost, biodegradable, and incredibly versatile: PCL is a hidden gem in polymer engineering.

What is Polycaprolactone (PCL)?

PCL is a biodegradable, semi-crystalline polymer with a low melting point (around 60°C). This low melting point is a defining feature, making it incredibly easy to process and manipulate using simple techniques. It's synthesized through ring-opening polymerization of ε-caprolactone.   

Key Characteristics:

• Low Melting Point: This is perhaps PCL's most significant advantage. It allows for shaping and molding using hot water, heat guns, or even just hand pressure.
• Biodegradability: PCL degrades through hydrolysis of its ester linkages, making it environmentally friendly compared to many other thermoplastics. The degradation rate can be controlled by varying the molecular weight and crystallinity.   
• Biocompatibility: PCL is non-toxic and biocompatible, making it suitable for medical applications, including drug delivery and tissue engineering.   
• Flexibility and Toughness: While relatively soft, PCL exhibits good flexibility and toughness, allowing for the creation of durable prototypes.
• Ease of Processing: PCL can be processed using various techniques, including melt extrusion, injection molding, and 3D printing (specifically Fused Deposition Modeling - FDM).
• Solubility: PCL is soluble in hot water and in various organic solvents, such as chloroform, dichloromethane, and toluene, which can be useful for solution processing and surface modifications.   

Advantages for Prototyping and Small-Scale Modeling:

1. Rapid Prototyping:

Due to its low melting point, PCL allows for quick and easy modifications. You can rapidly iterate designs by simply reheating and reshaping the material.   

This makes it ideal for early-stage prototyping where speed and flexibility are crucial.

2. Low-Cost Modeling:

PCL is relatively inexpensive compared to many engineering plastics, making it a cost-effective option for hobbyists, students, and small businesses.

The simple processing requirements also reduce the need for expensive equipment.

3. "Hand-Formable" Properties:

The ability to shape PCL by hand using hot water or a heat gun makes it incredibly versatile.

This is particularly useful for creating complex shapes or intricate details that may be challenging with other materials.

4. Educational Tool:

PCL is an excellent material for educational purposes, allowing students to experiment with thermoplastic processing and learn about polymer properties.

It's safe and easy to use, making it suitable for classroom demonstrations and hands-on projects.

5. 3D Printing Applications:

PCL can be used in FDM 3D printing, enabling the creation of complex geometries and functional prototypes.   

It is often used in biomedical 3d printing applications.   

6. Mould Creation:

Because of its low melting point, it can be used to create moulds for other materials that have a lower melting point.

Applications in Prototyping and Modeling:

• Conceptual Models: Quickly creating tangible representations of design ideas.
• Fit Testing: Verifying the fit and functionality of components.
• Ergonomic Studies: Assessing the comfort and usability of products.
• Custom Tooling: Creating custom tools and fixtures for specific tasks.
• Art and Sculpture: Sculpting and molding intricate designs.
• Medical Models: Creating anatomical models for educational or surgical planning purposes.

Considerations:

PCL's low melting point can also be a limitation in high-temperature applications. It is relatively soft, so it may not be suitable for applications requiring high rigidity or strength. Long term creep can also be a factor to consider.

Conclusion:

Polycaprolactone, the polymer behind products such as Polydoh, Polymorph,  Re-Form,  Plastimake, and NiftyFix is a valuable material for prototyping and small-scale modeling, offering a unique combination of ease of processing, biodegradability, and biocompatibility. Its low melting point and "hand-formable" properties make it an excellent choice for rapid prototyping, educational purposes, and various creative applications. As a polymer engineer and student, exploring the properties and applications of PCL can significantly expand your materials knowledge and practical skills.   

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://www.researchgate.net/publication/366581952_POLYCAPROLACTONE_THE_FORGOTTON_POLYMER

[2] https://www.atamanchemicals.com/pcl-solid_u30611/

[3] https://taylorandfrancis.com/knowledge/Engineering_and_technology/Chemical_engineering/Polycaprolactone/

[4] https://materialdistrict.com/material/polymorph/

Polyarylamide (PARA; MXD-6) and Recycling: How much regrind is possible?

Hello and welcome to a new post in which we discuss the usage of regrind when processing the high-performance Polyarylamide (PARA; MXD-6).

Recycling Process:

Polyarylamide regrind (sprues, runners, etc.), containing reinforcements such as glass fibers, can be recycled with virgin PARA compound. Important is to exclude any contamination such as oil, release agents, and other additives.

Impact on Mechanical Properties and Color Variation:

Several studies and experiments have shown [1] that a split of 70/30 (70 wt% virgin PARA / 30 wt% regrind) is preferred. The compound used in each cycle was 70% virgin compound (containing 50 wt% glass fibers) mixed with 30% regrind from the preceding cycle. Very little change was observed in the mechanical properties (tensile strength, elongation at break) after recycling. Successive recycling may cause a slight change in color. 

Recommendations:

Important is to confirm the recycling rate experimentally to ensure the finished part meets specifications. Also, drying the regrind prior to injection unless directly grinded and reinjected at the moulding machine. Mark parts to facilitate after-use recycling (check out the part marking codes here).

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

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

📊 Discover your Polymer Material Selection score by taking quick test here

Literature: 

[1] https://content.solvay.com/ixef-para-processing-guide

Become a Master in Polymer Material Selection - Learn & Apply the “6 POMS” Skills

Hello and welcome to a new blog post. Over the course of my career as a polymer engineer, I have sought to delineate the requisite skills for effective polymer material selection. Through discussions with polymer engineers responsible for successful plastic product development over the past decade, it has become evident that proficiency in six distinct areas is consistently demonstrated. These individuals not only possess comprehensive knowledge but also apply it rigorously across multiple product development cycles. Through iterative refinement and detailed analysis, these six areas have been systematically mapped. Consequently, I have formalized these competencies into what I now refer to as the "6 POMS" skills (Figure 1).

The 6 Polymer Material Selection Skills

Figure 1: Overview of the 6 POMS skills helping to become a Master in polymer material selection [1].

Let us discuss each of the 6 P's:

P- Properties: Understanding key polymer properties 

To effectively select polymers for specific applications, a thorough understanding of their key properties is essential. This includes familiarity with polymer structure properties like morphology, molecular weight, and thermal transitions. Knowledge of mechanical properties such as tensile, flexural, and impact strength, stiffness, and elongation is crucial. Additionally, a grasp of thermal properties, including glass transition temperature (Tg), melting temperature (Tm), and heat resistance, is necessary. The ability to assess chemical resistance to acids, bases, solvents, and oxidation is also vital. Furthermore, awareness of both long-term and short-term properties and their relationship to application requirements is paramount. Finally, understanding multi-point property data and its relevance to application needs ensures optimal material selection.

P - Part Design: Defining Application Requirements for Plastic Part Design 

The success of a plastic part depends heavily on its ability to meet the specific demands of its intended application. To ensure this, a structured approach to defining requirements is essential. This involves using tools like requirement checklists and methodologies such as the FLERP approach (Function, Loading conditions, Environmental Factors, Regulatory requirements, and Processing requirements).

A crucial aspect of this process is the ability to write clear and concise product specifications. This requires a deep understanding of the part's true functions, load cases, and material requirements. Additionally, it is important to consider the data needed for plastic part design, including material properties, processing parameters, and environmental factors.

Finally, cost considerations should be integrated throughout the design process. This involves evaluating material and manufacturing costs to optimize the overall design and ensure economic viability. By following these steps, engineers can effectively define application requirements and design plastic parts that meet the needs of their intended use.

P - Polymer material values: Translating application requirements to qualitative and quantitative material values

Translating plastic application requirements into actionable material values is a critical step in the selection process. This involves understanding how qualitative and quantitative application needs correspond to specific material properties. A systematic approach, such as listing all application requirements and their translated material values in a dedicated system or sheet, significantly enhances the selection process by providing a clear and organized framework for evaluation.

P - Process: Polymer material selection process

The process of selecting polymer materials involves several key considerations. It's important to determine if a structured, step-by-step approach is currently in place. Utilizing online databases like CAMPUS or Omnexus for material identification is common practice. A fundamental understanding of how to interpret technical datasheets for plastics is also crucial. Furthermore, the selection process should involve a degree of critical thinking, including challenging the use of established materials and exploring alternative options. Questioning the rationale behind choosing specific resins and ensuring they align with actual requirements is vital. Finally, the use of decision-making tools can significantly facilitate the selection of appropriate plastics.

P - Performance: Evaluation of material and part performance

Evaluating plastic material and part performance requires a comprehensive approach. Utilizing CAE tools, like injection mould filling simulation and FEA, enables virtual testing and optimization of plastic parts. Familiarity with standard ISO tests, such as tensile tests, is essential for quantifying material properties. Physical prototyping plays a critical role in verifying material and part functionality. Ultimately, experience in testing both material and part performance is crucial to confirm the suitability of the chosen plastic for its intended application.

P - Plastic supplier: Selection of material and supplier

The selection of plastic materials and suppliers involves active engagement and collaboration. Regularly discussing application requirements with polymer application engineers is crucial for ensuring material suitability. Direct contact with material suppliers to obtain samples supports the selection process by allowing for physical testing and evaluation. Seeking recommendations from plastics experts and material suppliers on new material developments ensures access to the latest advancements and potential solutions.

How to train the 6 POMS skills and become a master in polymer material selection? 

Start by taking my new developed Polymer Material Selection test and discover your polymer material selection score. Assess where you are currently ranking at the different POMS skills and increase your ability to select plastics better. It is a simple test which consists of 26 Yes/No questions. After submitting, you will receive a report containing your overall POMS score, the detailed score and recommendations for improvements.

I invite you to take the test, get your POMS-score and review the suggested improvements.

Thanks for reading & #findoutaboutplastics!

Greetings, 

Herwig 

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

📹My YouTube channel

Literature: 

[1] https://www.polymermaterialselection.com/poms-score

[2] https://www.amazon.de/-/en/Polymer-Material-Selection-practical-systematic/dp/B0BSWM6BPD

📚 My new book, "Pumping Plastics 2024," is out now! Available as Paperback Worldwide on Amazon!

Dear community, I'm thrilled to announce the release of "Pumping Plastics 2024," featuring guest interviews with leading material manufacturers and medical-grade plastics consultants. Explore the latest advancements in high-performance polyamides (PARA), material selection, polymer design properties, and more. 

My new book, "Pumping Plastics 2024," is out now!

This book, weighting 135 pages, contains all the posts published on my FindOutAboutPlastics.com blog in 2024. It is part of my "Pumping Plastics" book series. 

For instances, this include topics such as:

• Guest interviews with innovative material manufacturers and medical grade
• plastics consulting
• High performance polyamides such as Polyarylamides (PARA)
• Polymer design properties and multi-point design data
• Polymer material selection examples

As a bonus, the first chapter of my first book "Polymer Material Selection" is included.

Pumping Plastics 2024 by Herwig Juster is part of the "Pumping Plastics" book series. 

Level up your materials knowledge – grab your copy here and stay ahead of the curve!

Thanks & #findoutaboutplastics

Greetings,

Herwig Juster

#PumpingPlastics2024

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

📚 My Polymer Material Selection book 

🎤My Polymer Expert Talks Podcast

📹My YouTube channel

My dedicated site for Polymer Material Selection

Injection Moulding of Polyphenylene sulfide (PPS) - The Key to High Crystallinity and Performance

Hello and welcome to a new post in which we discuss the importance of mould temperature for achieving optimal crystallinity and performance in polyphenylene sulfide (PPS) moulded parts.  

Why is mould surface temperature critical with PPS?

The high-performance polymer PPS is a semi-crystalline polymer and its backbone consists of aromatic rings (phenylene groups) linked by sulfide bridges. It has a glass transition temperature of 88°C, melting temperature of 282°C and a processing temperature of 320°C. It combines high heat resistance (UL 746B exceeding 200°C), with high chemical resistance and mechanical strength at an economical price range.  As a high temperature plastics, also attention to proper processing, especially injection moulding needs to be given. Achieving the optimal level of crystallinity of PPS parts is important. 

Crystallinity significantly impacts the part's performance and stability, and even cooling is essential for high-quality mouldings. Mould surface temperature for PPS should be between 135° and 150°C in order to obtain high levels of crystallinity (maximum crystallinity levels of PPS: 55%).

Injection mould temperature settings for PPS

There is the "hot mould" and "cold mould" approach.  "Hot mould" temperatures (above 135°C) are preferred for precision parts as they promote crystallization, resulting in the best overall appearance, thermal stability, and dimensional stability.  "Cold mould" temperatures (below 88°C), on the other hand, produce amorphous parts with a mottled/grainy surface appearance. While cold moulds offer some advantages in physical properties and less shrinkage directly out of the mould, hot moulds are generally favored for achieving the best balance of properties, especially in precision applications.

Important are suitable cooling methods, and it is recommended to use circulation-type systems using hot oil or pressurized water.  If heater cartridges are used, they should have a minimum capacity of 1 kW per cartridge. 

Differential Scanning Calorimetry (DSC) can assess crystallinity in an effective way.

After moulding the PPS part, we can use the DSC to check if the part was fully crystallized and as a consequence, all important properties such as thermal and chemical stability, as well as dimension stability are fully developed. Figure 1 shows the results of two DSC curves. The upper curve shows a not fully crystallized PPS, having a so-called cold crystallisation peak at 114°C (exothermal) and a melting peak at 282°C. The lower curve shows a fully crystallised PPS part having only a melting peak at 282°C. 

Figure 1: Example comparison DSC curve of a not fully and fully crystallized Polyphenylene sulfide (PPS) moulded part. 

Conclusion

In essence, the careful control and selection of mould temperature (135-150°C), along with appropriate cooling methods, are crucial for optimizing the crystallinity and ultimately the performance of PPS moulded parts.

If you need support in moulding high-performance polymers such as PPS and PEEK, you can reach out to me here .

Learn more about high performance polymers such as PPS in my series “High Performance Thermoplastics Selection” .

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

📚 My Polymer Material Selection book 

🎤My Polymer Expert Talks Podcast

📹My YouTube channel

My dedicated site for Polymer Material Selection

Literature: 

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

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

[3] https://www.solvay.com/sites/g/files/srpend221/files/2018-08/Ryton-PPS-Mold-Temperature_EN-v1.0_0.pdf