Sunday, 22 May 2022

The Penguin Circle - A Symbol For Teamwork and Leadership

Hello and welcome to a new post. Today we have leadership and teamwork as the main topic, always in relation to the plastics industry. Read my leadership series here. 

The Penguin Circle - Teamwork and Leadership (Findoutaboutplastics.com / Herwig Juster)

Penguins - fighting the chilling freeze by huddling

Emperor penguins have their home in the Antarctic which is known to be a harsh environment with chilling temperatures. Penguins huddle together to heat up and stay warm. They also take turns to be in the center of the huddle. Researchers found it can get up to 37°C in the center of the huddle which can be too hot for the penguins. Also for breeding the circle formation is important since the male penguin takes care of the egg which is placed between the legs. 

Why is the Penguin circle so important?

What is valid for penguins is also valid for us: forming circles and huddling protects us from harsh cold conditions. It is better to be in the circle, otherwise you will freeze and face the danger of not surviving. The circle has several meanings. Most of us know the “Circle of Life” philosophy (life starts at the end and ends in the beginning), however the aforementioned penguin example shows the circle as a powerful symbol for teamwork and reaching goals together. 

Plastics industry - is the circle closed? 

In our plastics industry environment, tasks became complex and multi-leveled so that working together in teams is essential. It is in particular the interfaces between project stages, product development stages or production that bring challenges. It is well reported that other industries such as automotive, have to deal most of the time with interface challenges. Also, circular economy embraces to keep polymers in a loop.

Altogether, developing a feeling and empathy for the other working areas will help to close the circle and make the upcoming tasks more successful. 

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig 

#findoutaboutplastics

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature:

[1] https://www.gizmodo.com.au/2015/12/the-social-dynamics-of-penguin-huddles-are-more-complex-than-we-thought/

[2] https://theconversation.com/curious-kids-how-can-penguins-stay-warm-in-the-freezing-cold-waters-of-antarctica-116831#:~:text=Male%20emperor%20penguins%20gather%20close,huddle%20is%20below%20%2D30%E2%84%83.


Thursday, 19 May 2022

6 Major Benefits of Injection Moulding Simulation in Polymer Part Design and Material Selection

Hello and welcome to a new blog post. Today we have a closer look at how injection molding simulations support us in part design, polymer material selection and processing.

1. Injection point and gate placement

Finding the optimal injection point and gating is key to fulfill certain aesthetics or warpage requirements. Also, it helps to prevent flow line situations and as a consequence lower mechanical performance of your part. Nowadays most polymer injection molding simulations have gate placement tools integrated which can recommend you the optimal injection point. 

2. Placement and balancing of runners

Bringing the molten polymers towards the cavity, runners (thin channels) are needed. Aim is to ensure an even filling of your cavity. Runner analysis is hand in hand with the gating analysis from the previous point and most simulation software have a runner balance tool too. 

3. Warpage and shrinkage situation 

Analyzing the shrinkage and warpage situation is in particular needed when you use fiber-reinforced polymers which have an effect on the shrinkage and warpage of your part. Filling simulation can use the information of the velocity vectors to predict fiber behavior in the final part. And over this route, calculate the effect on shrinkage and warpage. 

4. Packing situation 

Analyzing the packing situation allows you to set the packing pressure and time for your part. There are several factors such as the material and mould shape which are influencing the packing. Packing analysis covers the prediction of the gate freeze time, clamping force needed in this phase, and predict areas where high volumetric shrinkage may appear. 

5. Cooling - mold 

There are injection moulding simulation tools which allow a design and optimization of the cooling channel layout of your moving and fixed moulding half. However, most tools simulate a uniform mould cooling at a set temperature.

6. Processing - identify critical shear rates

In case you work with polymers which are sensitive to mechanical stresses like shear rates then it is worth to have a plan of action how to locate critical areas and solve them by using simulation or in a simple way with analytic methods.

In the video I made you can see the perforated plate in the version of side gating and central gating. This applied method of shear rate tracer release is possible in the virtual molding package Sigmasoft.

In the following are the four steps of my procedure I use in the post-processing after I have done a process simulation:

1) Watch the shear rate contour plot to get the "big picture"

2) Activate the shear rate tracer

3) Analyze the release places and where the sheared material will end up in the part (to predict if there will be a decrease in the mechanical properties of the part)

4) Make geometry changes or process changes (melt temperature; inlet velocity profile)

The shear rate tracer method helps you to locate the punctual critical areas. So far, those are the advantages of such an approach. Another aspect is that the allover simulation will take more time and more memory as well as more working space.

In detail you can read here about my shear rate analysis. 

What are some of the most used injection moulding simulations?

There are several suppliers and often used are Autodesk Moldflow, SIGMASOFT Virtual Molding, Moldex3D, Vero VISI Flow, Simcon CadMould, and Solidworks Plastics.

Thanks for reading and till next time!

Greetings,

Herwig 

#findoutaboutplastics

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature: 

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

[2] https://www.findoutaboutplastics.com/2018/01/data-is-new-plastic-data-algorithms-in.html

[3] https://www.findoutaboutplastics.com/2021/03/the-future-of-plastics-manufacturing.html

[4]https://www.3erp.com/blog/how-injection-molding-simulation-software-helps-you-design-better-parts/

[5] https://www.downloadcloud.com/injection-molding-software.html


Tuesday, 19 April 2022

Design Properties for Polymer Engineering: Dynamic Mechanical Analysis (DMA) of Reinforced Engineering Polymers

Hello and welcome to a new blog post in which we continue with the DMA data. Today we discuss  reinforced engineering polymers (pls. find here the DMA data of neat resin, and here of high performance polymers)Here you can find the collection of all my posts on design properties for plastics engineering - engineering and high performance polymers.

Reinforcement such as glass fibers can increase thermal and mechanical properties of amorphous and semi-crystalline thermoplastics. 

Example Polyamide 6 (PA 6): neat vs. reinforced polymer

Figure 1 [1] shows an unreinforced Polyamide 6 which has a glass transition temperature of 65°C and a heat deflection temperature (HDT) of 65°C at 1.82 MPa. It can be shown that the modulus declines from 2.81 GPa (pre- Tg) to 0.56 GPa (post-Tg), resulting in a decrease of 80%. 

In the next step we add 14% glass fiber as reinforcements. This amount of glass fibers increases the HDT from 65°C to 200°C at 1.82 MPa. Also, modulus is almost doubled and the decline from pre- to post-Tg is 55% (from 4.46 GPa to 1.98 GPa).

In the last step we add 33% glass fiber reinforcements. In this final case, HDT can be slightly increased to 210°C at 1.82 MPa. However, modulus can be increased to 7.87 GPa and the decline is now below 50% (from 7.87 GPa to 3.99 GPa). 

Figure 1: DMA results of an unreinforced Polyamide 6 and glass fiber reinforced Polyamide 6.

DMA of reinforced engineering polymers (PBT, PA, PC and POK)

Figure 2 shows the elastic modulus of glass fiber reinforced PBT-GF30 (Valox® 420; SABIC), PC-GF20 (Lexan® 3412; SABIC), PA 6-GF30 (Ultramid® B3EG6; BASF), and POK-GF30 (RIAMAXX® HR; RIA-Polymers). 

PBT-GF30 and PA 6-GF30 have a similar elastic modulus behavior over the temperature range. Polyketone with glass fiber reinforcement is superior at lower temperatures, however above room temperature the behavior is similar to Polycarbonate. At higher temperatures (above 150°C), Polyketone is similar to reinforced PA 6 and PBT. 

Figure 2: Elastic modulus of glass fiber reinforced PBT-GF30 (Valox 420; SABIC), PC-GF20 (Lexan 3412; SABIC), PA6-GF30 (Ultramid B3EG6; BASF), and POK-GF30 (RIAMAXX® HR; RIA-Polymers).

All in all, DMA data allow you to decide if the selected material is suitable to fulfill the requirements of your application.

Thanks for reading and #findoutaboutplastics

Greetings, 
Herwig

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature: 
[1] https://www.findoutaboutplastics.com/2020/10/rule-of-thumb-for-plastic-part-design.html
[2] M. Sepe: Dynamic Mechanical Analysis for Plastics Engineering, Elsevier
[3] https://www.findoutaboutplastics.com/2020/07/design-properties-for-engineers-dynamic.html
[4] https://www.findoutaboutplastics.com/2018/12/dynamic-mechanical-analysis-dma-as.html

Sunday, 10 April 2022

Carbonated PET Bottles - Saving Material by Optimization Calculation

PET bottle - Learn how to optimize the wall thickness

Hello and welcome to a new post. Today I will discuss with you how to optimize the wall thickness of well- known PET bottles by using safety factors and the stress equations.

What are some requirements for carbonated bottles?

In general, PET drink containers need to contain the pressure of dissolved C02 safely, easy processing via moulding / blow moulding, transparent or translucent, and must be recyclable. PET bottles are the cheapest solution to fulfill the aforementioned requirements. Next best alternative would be PLA which has the lowest embodied energy [1]. 

What equations do we need?

Figure 1 shows the internal pressure situation of a carbonated drink bottle. Tensile stresses along the walls are created  due to the internal pressure p inside the bottle. There are two stresses, the circumferential stress (𝛔c = pr/t) and the axial stress (𝛔a = pr/2t). t is the wall thickness and r is the radius of the bottle. Based on those, we can derive the must-have wall thickness so that the stresses are not leading to bottle failure: t= S [(pr)/(𝛔y)]. S is representing a safety factor and 𝛔y is the yield strength of the wall material. 

Figure 1: internal pressure situation of a carbonated drink bottle. 


Example: wall optimization of carbonated  PET bottle

In literature it can be found that the working pressure of a standard soda PET bottle is 0.5 MPa and has a diameter of 2r = 64 mm. As a safety factor we take 2.5. 70 MPa is the tensile strength of PET at room temperature. 

How thick do we need to make the walls to handle the pressure safely?

We start with our equation from before: t= S [(pr)/(𝛔y)]

t= 2.5 [(0.5x0.032)/(70)] = 0.00057 m = 0.57 mm

The required wall thickness t is 0.57 mm. After consuming your next soda drink in a PET bottle, you can check the wall thickness and see if the bottle already uses as little PET as possible. 

In another post I show how to select the optimal polymer material for an injection / blow moulded water bottle.

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig Juster

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature:

[1] Michael Ashby: Materials and the Environment. Eco-informed Material Choice


Thursday, 7 April 2022

Design Properties for Polymer Engineering: Dynamic Mechanical Analysis (DMA) of Unfilled Engineering Polymers

Hello and welcome to a new post. Today I present to you dynamic mechanical analysis (DMA) data of most used unfilled engineering polymers. 

In a previous post we discussed the storage modulus vs. temperature behavior of different high performance amorphous and semicrystalline polymers. Also how DMA can be used as a polymer material selection tool. Here you can find the collection of all my posts on design properties for plastics engineering - engineering and high performance polymers.

In general, the DMA is a thermo-analytical method that estimates the viscoelastic properties of a given material over the course of different temperatures. It steps away from a single point view toward a multipoint data view which is beneficial for polymer material selection tasks.

Figure 1 shows the elastic modulus of ABS, POM, PBT, and PA 6.6 and Figure 2 shows it for PMMA, POK, PC, and mPPE. 

Figure 1: Elastic modulus of ABS, POM, PBT, and PA 6.6 (all unfilled)

Figure 2: Elastic modulus of PMMA, POK,PC, and mPPE (all unfilled)


Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature: 

[1] M. Sepe: Dynamic Mechanical Analysis for Plastics Engineering, Elsevier

[2] https://www.findoutaboutplastics.com/2020/07/design-properties-for-engineers-dynamic.html

[3] https://www.findoutaboutplastics.com/2018/12/dynamic-mechanical-analysis-dma-as.html


Monday, 28 March 2022

Dimensional Stability of Polymer Based Parts after Processing: 3 Considerations

 Hello and welcome back to a new blog post. Today we discuss three considerations for optimal dimensional stability of plastics parts after processing.

Polymer based parts have a dimensional stability which is not equal to that of metals. It can vary with several factors which we discuss in the following in more detail. If it is a critical part, this needs to be considered during the polymer material selection.

Definition dimensional stability

In short, dimensional stability means that the required dimensions are kept after processing and when the application is in use. Three considerations help to keep the dimensional stability of your part: moisture, mechanics, and thermal stability (Figure 1). 

Figure 1: Plastic part design - three considerations help to keep the dimensional stability of your part.

Consideration 1: Residual moisture and moisture uptake during use

General rule of thumb is that when materials are exposed to moisture, dimensional changes are likely to occur. In case your application has tight tolerance requirements, polymers with low moisture absorption should be taken. For example, an aliphatic Polyamide was specified for an application with tight tolerances. Due to the moisture uptake, part performance decreased and a replacement material is needed. In such a case, a semi-aromatic Polyarylamide (PARA) can be an alternative, since it has the lowest moisture uptake of Polyamides. There are also other polymers such as PEI, PPS, and PEEK, which have excellent mechanical, and moisture performance. PPS, PPA, and PEI can be used for applications, which are exposed to high temperature and moisture during the use of the application (water pumps in cars for example). Also during processing, keeping a maximum allowed moisture level is essential to not harm the polymer during processing. In this post, different maximum moisture levels after resin drying to ensure proper processing are shown.

Consideration 2: Mechanical strength

In case of structural applications, loading strength of the selected polymer is important and can influence the dimensional stability. For complete evaluation, short-term property data such as tensile and compression strength, together with long-term data such as tensile creep should be considered. Examples of high performance polymers which show high dimensional stability are PPS, PAI, and PEEK.

Consideration 3: Thermal stability

Temperature load can have a severe impact on the plastic part dimensions. Therefore, it is critical to evaluate the maximum use temperature and the continuous use temperature, together with the environment (air, water-glycol) of your application. For evaluation of the temperature impact, dynamic mechanical analysis (DMA) data, as well as head deflection data (HDT) of the selected polymers are helpful.

Overall, there are some factors, which influence the polymer part performance. In this post, I show you additional factors to consider for your plastic part design.



Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig 

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature: 

[1] https://apex-intl.com/2017/02/24/engineering-plastics-understanding-dimensional-stability-in-material-selection/


Monday, 21 March 2022

Decision Making in the Plastics Industry – Avoid the Survivorship Bias Trap

Hello and welcome to a new post. Today we have a look at a well-known cognitive bias that psychologists refer to as “survivorship bias” and how to use this information for better decision making in our daily plastics operation.

The focus on people, companies, or products that have themselves successfully established and forgetting about other important factors such as failure is referred to as survivorship bias.



Let us put this bias in relation to some examples

Analyzing of World War II bomber airplanes

Most famous example is the US Air Force dilemma of lost airplanes during World War II. They investigated the returning airplanes and found out that the wing tips, body and tail had the most holes. Their plan was to reinforce those areas for better protection. Luckily they had Mr. Abraham Wald as part of the Statistical Research Group (SRG) on their team. He explained to the military leader that this would be a terrible mistake since they did not look at the airplanes, which were shot down. The weakest parts are not the wing, tail or body. It is the engine and once you get a hit there, the airplane will hit the ground quite fast.

Example plastics industry

Looking at the engineering polymer Polyamide, it is a well-established and successful material, which is used in lots of applications. Material manufacturers, which have their focus on other polymer resins, may want to add such Polyamide resin and compounds to their portfolio to gain a share of the cake. However, it is better to look at companies which failed to enter the market place with their new Polyamide resin or compounds, followed by companies which have mediocre sales and profit numbers when they entered with their new Polyamides. Tendency is to look at the market leaders and established companies. 

In conclusion, it pays off to look at not successful launches of products too and not only the successful ones. It is harder to find the stories of failing products, however it is worth taking the extra step and fighting the survivorship bias. 

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

Interested to talk with me about your plastic selection, sustainability, and part design needs - here you can contact me 

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

Literature

[1] http://blog.idonethis.com/7-lessons-survivorship-bias-will-help-make-better-decisions/