Polymer Selection Funnel Example - Vacuum Cleaner Canister and Canister Holding (Example Electronics Consumer Goods)

Hello and welcome to another polymer materials selection example using the Polymer Funnel methodology. In this post we discuss the selection of a vacuum cleaner housing. Figure 1 presents the four different stages of the material selection funnel and this overview serves us as a guideline.

Figure 1: Polymer Selection Funnel - overview of the four different funnel stages 

Global Electronics Consumer Goods Market

The global electronics consumer goods market has a predicted growth rate of around 6% CAGR till 2030 and can be split into four major segments: 

• Household Appliances

• Consumer Electronics

• Toys - famous example is the LEGO brick using ABS (detailed post here and review on ABS here)

• Others

Household appliances are the largest segment. Leading polymers are Polyolefins (PE, PP), Polystyrene PS, Acrylonitrile butadiene styrene ABS, Polycarbonate PC, Polyvinyl Chloride PVC, Polyamide PA, and Poly(methyl methacrylate) PMMA. 

Polymer material selection for vacuum cleaner canister with canister holding

Figure 2 shows a bagless canister vacuum cleaner. The transparent canister is attached to the upper holding element allowing for easy removal and cleaning. Task is to select the optimal material for the canister and the holding element. 

Figure 2: Example of a vacuum cleaner with transparent canister and canister holding

Funnel stage 1: Material selection factors

In Funnel stage 1 we assess the canister and holding requirements:

• Good Surface Quality & Paintability and high surface gloss

• Scratch Resistance

• Colorability for housing parts

• High flowability, 

• Dimensional stability, 

• Good heat resistance

• Thin wall capability (reduction of material usage and part weight ->> easy handling)

• Impact behavior

• Recyclability

The canister itself needs to be transparent, allowing to check the dust filling level. The holding element requires no transparency. 

Table 1 summarizes the important requirement information with quantitative and qualitative values (requirement worksheet).

Table 1: Requirement worksheet for the vacuum cleaner parts.

Funnel stage 2: Decision on thermoplastic or thermoset

In Funnel stage 2 we decide between the thermoplastic and thermoset material route. Transparency and flowability can be fulfilled by both classes, however thin wall stability with good impact behavior and recyclability is better achieved by thermoplastics. Therefore, a first material screening is done and grades for both parts are summarized in Table 2. 

Table 2:  Overview preselected grades and their commercial suppliers.

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

Now we reached the core element of the Polymer Selection Funnel: the selection discussion by using qualitative matrix analysis. In the first step we take the requirements from Table 1 and insert them on the top of the matrix table. This is followed by giving them a priority number (0= low priority; 5= high priority). After this we add the materials from Table 2 followed by a ranking of each material for each requirement (how good can this requirement be fulfilled? 5= perfect). Then we multiply each requirement priority number with the fulfillment number and add them up. In the end we have on the right side a ranking of the selected materials. In our case, for the canister holding part,  ABS (118HF) has the highest number (85), followed by ABS (LX-0951) with 81. for the transparent canister itself, transparent ABS reached 80 points and PMMA 76 points. They are close to each other and for Funnel stage 4, both can be tested. The same is valid for the canister holding part. ABS (118HF) and ABS (LX-0951) can be tested. 

Table 3: Qualitative matrix analysis for canister holding part

Table 3: Qualitative matrix analysis for the canister

Funnel stage 4: Testing, selection of material and vendor

We reached the final Funnel stage and started with material evaluations, followed by producing prototypes for functional tests. After completion of all tests, the final decision can be done. In our case, ABS (118HF) was selected for the canister holding part and transparent ABS (LX-0951) for the canister itself. 

Check out more polymer material selection examples: baby bottles and plumbing water pipes.

Thanks for reading and #findoutaboutplastics

Greetings Herwig

Herwig Juster

Interested to talk with me about your polymer material 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

My YouTube channel

My personal website

Literature: 

[1] https://www.plasticstoday.com/consumer-electronics/high-flow-high-gloss-abs-customized-vacuum-cleaner-housing

[2] https://adrecoplastics.co.uk/abs-plastic-properties/

[3] https://www.sonderhoff.com/de/branchen/staubsauger-1/

[4] https://www.ristenbatt.com/xcart/External-Structure-Materials-and-Durability.html

[5] https://www.globenewswire.com/en/news-release/2022/08/25/2504593/0/en/Global-Electronics-Consumer-Goods-and-Plastics-Market-to-Garner-Around-USD-59-Billion-by-2031-and-to-Grow-with-a-CAGR-of-6-during-2022-2031-Lightweight-and-Corrosion-Resistance-Pro.html

[6] https://www.ristenbatt.com/xcart/External-Structure-Materials-and-Durability.html

[7] https://www.plexiglas.de/en/service/product-info/scratch-resistance

[8] https://www.plasticstoday.com/consumer-products/ineos-introduces-high-flow-abs-grade-appliances

[9] https://www.elix-polymers.com/news/183/miele-selects-high-flow-abs-grade-elix-118hf-for-its-new-battery-powered-vacuum-cleaner-model-triflex-hx-1

[10] https://product.lottechem.com/cn/tech/case_study/108/view.do;jsessionid=D8AE3CED6602072A0D1B7243CDD5A0A4?pcsCate=&page=7

2 Component Injection Moulding: How TPS (SEBS) Can Stick to Polyamide or Polycarbonate Without Using Additional Adhesive?

Overmoulding PA and PC with PC - 2 component moulding

Hello and welcome to a new blog post in which we discuss how TPS can stick to Polyamide or Polycarbonate in 2 component injection moulding. 

During polymer material selection, one scenario can be that a solid plastic housing, made out of Polyamide, needs to have a sealing moulded on it. The selected sealing material is a styrene-ethylene-butylene-styrene (SEBS) from the thermoplastic elastomer class. A two-phase block copolymer with hard and soft segments forms the basis of SEBS. 

SEBS (Figure 1)  is used in different applications such as footwear, and seals which have low requirements towards chemicals and (heat) aging. Furthermore SEBS has excellent weatherability making it useful for many outdoor applications. It is also known for its ability to uptake oil and soften its Shore hardness. SEBS is non-polar leading to a harder adherence on polar polymers such as Polyamide. 

Figure 1: Structural formula of SEBS.

How can we increase the adherence of SEBS towards PA and PC?

There is a chemical trick one can apply: grafting maleic anhydride (= acid anhydride of maleic acid) onto the ethylene butadiene mid-blocks allows for better connection. The functional groups enable an adherence to polar PA or PC. 2 component overmoulding applications can be done and no additional usage of adhesives is needed.

Thanks for reading!

Greetings

Herwig Juster

Interested to talk with me about your polymer material 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

My YouTube channel

My personal website

Literature:

[1] https://www.hexpol.com/tpe/resources/tpe-academy/what-is-tpe/what-is-tps/

[2] http://plasticnotes.blogspot.com/2009/11/polymer-polarity.html?q=polar

Rule of Thumb - Residence Time and Temperature Profile of Engineering Polymers

Hello and welcome to a new Rule of Thumb post. Today we discuss the importance of melt temperature and residence time of engineering polymers. Here the link to the residence time of high performance polymers. 

Melt temperature - injection moulding 

In general, melt temperature and residence time of the polymer melt are strongly linked and have a high impact on reaching the mechanical properties of your part. It is best to follow the recommendation of the material supplier for the optimal melt temperature. For example, if you decrease the melt temperature 10 Kelvin, starting from the recommended optimum value, tensile strength and elongation can drop 25 %. Reason are unmolten particles which enter the final part during moulding and cause a drop in mechanical properties.  On the other side, a 10 Kelvin increased melt temperature is not as critical as the lower temperature profile. The final part still will have 95% of the mechanical properties. The polymer melt can handle short increases in temperature which in turn leads to a better flow profile too. 

Residence time of engineering polymers - injection moulding 

Next to the temperature is the residence time. The biggest impact on the residence time has the size of your plasticizing unit and its optimal selection. If you have a high metering stroke, residence time is low. If you have only a small metering stroke, residence time will be up and you have to check if you are not above the maximum residence time of the polymer. It can encounter this by using an increasing temperature profile on your plasticizing unit. Figure 1 shows the maximum residence levels of different engineering polymers. POM and TPE can have high residence times (up to 30 minutes) and Polyesters (PET, PBT, PC) should not be much above 6 minutes in total residence time (including hot runners if applicable). 

Figure 1: residence time (minutes) of most used engineering polymers. 

I created also calculation tools which allows you to estimate the residence time for injection moulding and extrusion - here the link. 

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig Juster

Interested to talk with me about your polymer material 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

My YouTube channel

My personal website

Literature:

[1] Kunststoff Taschenbuch - Hanser

[2] Serie Kunststoffpraxis Teil 12: Verweilzeit und Temperaturprofil - Plastverarbeiter 

Long Fiber Plastic Processing - How to Not Make Long Fibers Short (Rule of Thumb Series)

Hello and welcome to this blog post which is part of our Rule of Thumb series. Today we discuss the processing of long glass fiber plastic compounds using injection moulding. 

Long glass fiber (LFT) plastics 

LFT compounds have a fiber length between 9 mm and 12 mm and most are produced via pultrusion technique. Aim in processing is to keep the fiber length as long as possible since it is needed to build up a 3D-network consisting out of entanglements. Having an entangled system allows for high impact and strength properties as well as increased thermal performance of the final part. 

How to not make Long Fibers short - processing recommendations

In general we have to avoid excessive fiber breakage during all phases of injection moulding in order to have a long enough fiber length to form an entangled three dimensional network. 

1. Injection moulding setup: the feed hopper must be large with a slope angle of 45°; the hopper flanges do not need to be cooled and it is enough to have the same temperature as the feeding section of the barrel. A general three section screw can be used (screw diameter above 35 mm), however if possible use a longer feeding zone (> 60% of total length; compression and metering section 20 % length). Regarding the compression ratio, 2:1 or 2.5:1 is recommended. Avoid the use of mixing and shear elements along the screw sections. There are long-fiber screws available and they dramatically improve fiber length. Figure 1 compares the fiber length reduction over the different screw sections of a long-fiber screw and a standard 3 section screw. 

Figure 1: Glass fiber length reduction of a long-fiber screw and a standard screw [3]

2. Processing temperatures: in terms of processing temperature it is advantageous to have a temperature above the melting temperature before the compression section, together with the avoidance of shear heating. Avoid shut-off valves since they induce fiber breakage. Reduction of shear can be achieved by using a flat or reverse barrel temperature profile. Aim to ease melting in the compressing section. 

3. Plasticizing unit: keep the screw speed rotation in a low to medium range (< 100 RPM) together with low back pressure (0 to 10 bars). 

4. Injection moulds: reduction of glass fiber breaking is achieved by using large gate sizes (>80% of wall thickness). Proper venting of the tool will support weld line quality of the final part. Hot runner system can be used, however shut-off valves are not recommended.

5. Recycling: using post industrial waste or post consumer waste is possible up to 10 weight %. 

Additionally, most LFT parts I have seen had a fiber length between 2-3.5 mm and it was efficient enough to have 1.5 mm in average length for good strength properties. With 1.5 mm already ~80% of the strength was reached and after that it leveled off into a plateau with increased fiber length.

Key properties of LFT compounds can be found here and more Rule of Thumb posts here.

Thanks for reading and #findoutaboutplastics

Greetings

Herwig Juster

Interested to talk with me about your polymer material 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

My YouTube channel

My personal website

Literature:

[1] https://www.ptonline.com/articles/the-long-and-short-of-it-part-1tips-for-molding-long-fiber-reinforced-polymers

[2] https://www.solvay.com/en/brands/xencor-long-fiber-thermoplastics

[3] K. Kikikawa et.al.: History of development of injection molding machine technologies and future perspectives

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Polymer Selection Funnel Example - Plumbing Water Pipes (Building and Construction example)

Polymer Material Selection - Example water pipes for plumbing (Herwig Juster)

Hello and welcome to this new blog post with the topic of polymer material selection. In this post we cover the material selection of water plumbing pipes as an example of the building and construction market. For the selection we will apply my developed Polymer Funnel Method (in detail explained here and in this video).

Figure 1 presents the four different stages of the material selection funnel and this overview serves us as a guideline.

Figure 1: Polymer Selection Funnel with its four stages.

What are the top 5+ plastics used in building and construction?

Most used plastics in building and construction are polyvinyl chloride (PVC), high density polyethylene (HDPE), expanded polystyrene (EPS), polyurethane (PU), polycarbonate (PC) and polymethyl methacrylate (PMMA). PVC is used for window frames and floorings, HDPE for tubing and piping, EPS and PU for outside and inside insulation. PC and PMMA is used for transparent sheeting applications applied for example at carports. 

Benefits of using plastics in construction are that they are lightweight, energy efficient, quick and safe installation compared to other materials, cost effective and high resistance to UV and fire. 

Polymer material selection for water plumbing pipes

Let us get started with the funnel.

Funnel stage 1: Material selection factors

In Funnel stage 1 we assess the water supply piping  requirements. We have to consider the three legs of the Environmental Stress Cracking (ESC)-triangle: 

• Environment including temperature rating: inhouse mounting; no exposure to UV-light and no special weatherability conditions are needed; temperature of water is up to 80 °C.
• Stress: mainly the fluid pressure and the pipe is fixed (no permanent bending movement); 
• Chemicals and chemical compatibility: water and chlorinated water
• Agency ratings: EU 10/2011; NSF/ANSI 51
• Space layout: limited; flexibility of piping is needed, 
• Function: transport drinking water (hot and cold) from heating station inside the house to different sanitary locations within the house; 
• Lasting: 50 years life span
• Costs: medium cost range since volume is on high end; 
• Recyclability: must be given at end of life

Table 1 summarizes the important requirement information (requirement worksheet).

Table 1: requirement worksheet of Funnel stage 1. 

Funnel stage 2: Decision on thermoplastic or thermoset

Since flexibility is needed for mourning the pipes in confined space thermoplastic solutions are preferred. Apart from the already discussed thermoplastics used in plumbing, there are two major types of thermosetting pipes: 1) reinforced plastic mortar (RPM) pipe and (2) reinforced thermosetting resin (RTR) pipe. Together with glass fiber reinforcement such pipes show high strength, however they cannot be melted and reformed again. 

In our example, thermoplastics are preferred due to easier forming and mounting, as well as high regulatory fulfillment for drinking water. 

We pre-selected:

• BorPex HE2590 (PEX)
• BorSafe™ HE3490-LS (HDPE)
• Vestolen™ P 9421 (PP-R)
• Vinnolit® S 3268 (PVC-U)

Table 2 summarizes the pre-selected thermoplastics and its details which will be used for the detailed selection discussion in Funnel stage 3.  

Table 2: overview pre-selected thermoplastics.

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

Funnel stage 3 represents with the qualitative matrix analysis the major element for the selection discussion. Table 3 summarizes the outcome of this process. In the first step we rank how good each material can fulfill the requirements (0 to 5=best) and then we assign priorities to each of the requirements (0 to 5 = highest priority). In the last step we multiply the requirement fulfillment with the priority and add the values up. 

In our case PP-R (score: 99 points) and PEX (score: 97 points) have the highest rank and both materials should be evaluated in Funnel stage 4. 

Table 3: result of the qualitative matrix analysis. 

Funnel stage 4: Testing, selection of material and vendor

We reached the final phase of the Polymer Selection Funnel where we test and further evaluate our findings from Funnel stage 3. 

Both PEX and HDPE are suitable for usage in our application case, however PEX is due to its cross-linking not as easy for recycling as HDPE. However, this is changing too, since chemical recycling of PEX waste makes promising steps. Therefore, recycling challenges will be no limitation. 

Check out here another polymer material selection example (baby bottles).

Thanks for reading and #findoutaboutplastics

Greetings Herwig 

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

*NEW* my Polymer Material Selection book is available for purchase here *NEW*

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 YouTube channel

My personal website

Literature: 

https://www.acplasticsinc.com/informationcenter/r/applications-of-plastic-construction-materials

https://www.freshwatersystems.com/blogs/blog/types-of-plastic-water-pipe

https://www.globalspec.com/learnmore/flow_control_fluid_transfer/pipe_tubing_hose_accessories/plastic_pipe

https://healthybuilding.net/blog/585-what-to-know-when-selecting-water-pipes

https://www.thespruce.com/basic-types-of-plumbing-pipes-1822487

https://www.acplasticsinc.com/informationcenter/r/common-plastic-building-materials

https://theconstructor.org/building/plastics-construction-material/12438/

https://pvc4pipes.com/pvc-pipes/pvc-pipe-categories/#:~:text=Unplasticised%20PVC%20is%20also%20known,PVC%2DU%20have%20many%20benefits.

https://www.globalspec.com/reference/54714/203279/polyethylene-pe-pipes

https://www.globalspec.com/reference/54717/203279/thermoset-plastic-pipe

https://www.borealisgroup.com/news/neste-borealis-uponor-wastewise-group-enable-chemical-recycling-of-hard-to-recycle-plastic-waste-into-new-high-quality-plastic-pipes

Plastic Multipoint Design Data: Tensile Stress and Strain of Thermoplastics as a Function of Temperature

Hello and welcome to this blog post. Today we discuss the tensile stress and strain data of selected thermoplastics as a function of temperature. 

Why  are multi-point data important in polymer material selection and part design?

Multipoint data of different polymer and polymer compound properties prevail information which would otherwise may be overlooked during material selection and product design. Most property data shown on technical data sheets are single-point values at failure level. Most of the time only a single temperature is covered (room temperature). This is useful for comparing different material data sheets however for part design it has its limitations. Multipoint data help to think in time-dependency and temperature-dependency behaviors. Graphically such behaviors can be better accessed. Single point data can lead to misjudgment.

Stress-strain curves of thermoplastics as function of temperature

In Figure 1 the results of stress experiments and in Figure 2 the strain results of different amorphous and semi-crystalline plastics are shown. Following grades were analyzed: 

PBT: Ultradur® B 2550 FC

PA 6-GF30: Ultramid® B3EG6

PC: Makrolon® 2205

PA 6: Ultramid® B3K

PMMA: PLEXIGLAS® 6N

PPS-GF40: TEDUR L 9107-1

POM: Ultraform® H4320 Q600 

PA 12-GF23: VESTAMID® L1833

Figure 1: Stress vs. temperature of thermoplastics

Figure 2: Strain vs. temperature of thermoplastics

Through the increase in temperature, mobility of the polymer chains is increasing and some brittle polymers turn into more tougher polymers allowing them to withstand certain loads. 

Conclusions

DMA and stress-strain curves used combined are an efficient way to explore part application properties at use temperature. 

Check out here more multipoint data 

Thank you and #findoutaboutplastics

Best regards, 

Herwig 

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

*NEW* my Polymer Material Selection book is available for purchase here *NEW*

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 YouTube channel

My personal website

Literature:

https://www.campusplastics.com/campus/en/datasheet/Ultradur%C2%AE+B+2550+FC/BASF/20/128f11a1/SI?pos=3

https://www.campusplastics.com/campus/en/datasheet/Ultramid%C2%AE+B3EG6/BASF/20/3675d41d

https://www.campusplastics.com/campus/en/datasheet/Makrolon%C2%AE+2205/Covestro/22/9b29274b/SI?pos=10

https://www.campusplastics.com/campus/en/datasheet/Ultramid%C2%AE+B3K/BASF/20/3a22f000

https://www.campusplastics.com/campus/en/datasheet/PLEXIGLAS%C2%AE+6N/R%C3%B6hm/21/2d5df2ec/SI?pos=2

https://www.campusplastics.com/campus/en/datasheet/TEDUR+L+9107-1/MOCOM/5/91e531bc/SI?pos=1

https://www.campusplastics.com/campus/en/datasheet/Ultraform%C2%AE+H4320+Q600/BASF/20/2ebf4379/SI?pos=8

https://www.campusplastics.com/campus/en/datasheet/VESTAMID%C2%AE+L1833/Evonik+Operations+GmbH/66/f991fc87/SI?pos=12

Rule of Thumb for Thermoplastic Material Design: 3 Effective Ways to Achieve ESD properties

Hello and welcome to this new Rule of Thumb post. Today we discuss three effective ways to achieve Electrostatic discharge (ESD) properties with thermoplastics. 

Overview and introduction to ESD 

In Europe the ATEX Directive (from the French "ATmosphère EXplosive") 94/9/EC contains regulations for the use of components and systems in potentially explosive atmospheres.

If an electrical discharge in a potentially explosive area (so-called EX area) produces the necessary ignition energy, a spark may be generated which ignites the explosive substance. 

Thermoplastics with specific conductive properties can discharge static charges in a controlled and permanent manner. They are used in many industrial sectors such as electric & electronics, semiconductor industry, medical technology, chemical and pharmaceutical industry, and other industries handling dusty bulk materials, combustible substances. It is important during polymer material selection to ensure the maximum safety for these applications by modifying the selected plastic.

Plastics are insulating and their electrical conductivity ranges between 10^-18 to 10^-12 Siemens per meter (S/m). In general plastics have an eclectic surface resistance of >10^15 Ohm and can be electrostatic loaded. Anti Static conductive behavior is achieved from 10^-9 to 10^-3 S/m with a corresponding resistance of 10^6 to 10^10 Ohm. For electromagnetic shielding (EMI), electrical conductivity of 10^3 to 10^9 S/m is needed. 

3 ways to have ESD properties in thermoplastics

3 effective ways to achieve ESD properties in thermoplastics

Stainless steel filler

Stainless steel fillers are an effective way to provide thermoplastic compounds with conductive properties. They can be directly added during injection moulding by a master batch or in a continuous way during compounding. 

Achieving ESD properties, 0.25-0.5 vol.% of steel fiber (4 w%) needs to be added. This is enough to have a volume resistivity of <10^2.

Inner anti static additives

Fatty acid esters and  Fatty acid amides are added either directly or over a masterbatch to the polymer compound. They migrate onto the surface of the finished plastic part and create a hydrophilic layer which in turn takes water up. The result is an electrically conductive outer layer. Anti static masterbatch concentration is between 3 to 50 w%.  Also, hydrophilic polymers such as Polyamidcopolymer can be added which results in a surface and volume conductivity. 

Conductive carbon black

Conductive carbon black in a concentration up to 15 w% is often used in polyolefin compounds. Specific volume resistance between 10^2 to 10^5 Ohm cm can be achieved. Apart of conductive carbon black, carbon fibers can be used too. 

More Rule of Thumb posts can be found in my "start here section".

Thank you and #findoutaboutplastics

Best regards, 

Herwig 

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

*NEW* my Polymer Material Selection book is available for purchase here *NEW*

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 YouTube channel

My personal website

Literature:

[1] https://www.roechling.com/industrial/characteristics/esd-plastic

[2] https://www.bekaert.com/en/products/basic-materials/materials-plastic/esd-protected-plastics

[3] Sachtling Kunststoff Taschenbuch, Hanser