Plastic Part Marking – Overview Codes and Standards (incl. miniguide for downloading)

Hello and welcome to a new post. In this blog post we have a closer look at the plastic part marking standards and their differences.

I made a short presentation about this topic which you can watch here:

Why Part Marking Codes?

Identification of plastics products is easier with a part marking system. This allows for better decision making for:

•        handling plastic products,
•        better waste recovery
•        more efficient disposal.

Overview of Marking Standards

There are three main standards; however there are additional ones for each of the polymers.

ISO 11469:2016: Generic identification and marking of plastics products

Example: acrylonitrile-butadiene-styrene polymer “>ABS<”

ASTM D7611: Resin Identification Codes (RICs) consisting out of a equilateral triangle, Resin Identification Number, and abbreviated term for polymeric material.

Example:

ISO 1043, ISO 1629 (rubber), ISO 18064 (TPE): Plastics – Symbols and abbreviated terms:

Part 1: Basic polymers and their special characteristics

Part 2: Fillers and reinforcing materials

ISO 1043 - Part 2: Fillers and reinforcing materials (material)

ISO 1043 - Part 2: Fillers and reinforcing materials (form)

Part 3: Plasticizers

ISO 1043 - Part 3: Plasticizers

Part 4: Flame Retardants

The tables below show an overview of the most common flame retardant classes, as well as the detailed codes. We can distinguish between halogen compounds, nitrogen compounds, halogen-free organophosphorus compounds,inorganic phosphorus compounds, metal oxides, Boron and zinc compounds, silicon compounds, and graphite.

ISO 1043- Part 4: overview of the most common flame retardant classes

ISO 1043 - Part 4: Flame retardant codes

Example:

Examples of often found part marking codes on plastic parts

In this blog post I highlight examples of often found part marking codes on plastic parts and their meaning using the standard ISO 1043.

ISO 16396-1:2022 (prev. ISO 1874) [2]: Polyamide moulding and extrusion materials

Another part marking standard is the ISO 16396 which was introduced particularly for Polyamides used in injection moulding and extrusion (PA 6, PA 66, PA 69, PA 610, PA 612, PA 11, PA 12, PA MXD6, PA 46, PA 1212, PA 4T, PA 6T and PA 9T and copolyamides of various compositions for moulding and extrusion).

The designation consists out of five data blocks:

-Data block 1: identification of the plastic by its abbreviated term (PA), and information about the chemical structure and composition

-Data block 2: position 1: Intended application and/or method of processing; positions 2 to 8: Important properties, additives and supplementary information

-Data block 3: designatory properties

-Data block 4: fillers or reinforcing materials and their nominal content

-Data block 5: contains additional information which may be added if needed

Example: PA6T/66 MH, 14-190, GF50

PA6T/66: Polyamide 6T which is a homopolymer based on terephthalic acid and Polyamide 66 which is based on hexamethylenediamine and adipic acid. 

M: injection moulding; H: heat ageing stabilized

14-190: viscosity number (in ml/g) > 130 but below 150; 190: tensile modulus of elasticity between 17000 MPa and 20000 MPa

Summary of standards:

 

In terms of plastic part design for recycling, part marking codes play an important role as well. I have summarized some key point in this post here.

More examples of part marking codes for different plastics compounds can be found here and for PolyArylAmides here.

 Miniguide "Plastic part marking"

Supporting this topic, I  made a miniguide which can be downloaded below. 

Check out my post on flame retardant classifications according DIN EN ISO 1043-4 here.

Thanks for reading and #findoutaboutplastics

Herwig Juster

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

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

🎤My Polymer Expert Talks Podcast

📹My YouTube channel

📚 My Polymer Material Selection book 

My personal website

My dedicated site for Polymer Material Selection

Literature: 

[1] https://www.iso.org/standard/50590.html

[2] https://www.iso.org/standard/81940.html

Find Out About Plastics Blog – The Top 10 Most Watched Posts in 2020

 

The eventful year 2020 is drawing to a close and in this post I present you the top 10 most watched blog posts of 2020.

Starting from highest to lowest rank:

1.  Design Properties for Engineers: Weldline Strength of High Performance Polymers

2.   The Secret of High Performance Polymers: Why They Can Handle High Heat and Harsh Chemicals?

3.     Design Properties for Engineers: Chemical Resistance of High Performance Polymers

4.   EMI Shielding for EVs: Thermoplastic Compounds vs. Coatings – What is Better?

5.  What is the Difference Between an Industrial Designer and a Design Engineer? incl.Polymer Part Design Checklist [Guest Post]

6.     Plastic Part Failure – Part 1: Reasons

7.  Microplastics: What Should We Know About Them and How Are They Impacting Our Life?

8.  Design Properties for Engineers: Coefficient of Linear Thermal Expansion (CLTE) of High Performance Polymers

9.     Plastic Part Failure – Part 2: The Antidote

10. Strategic Sales and Marketing in Plastics Industry: My 2x3 Matrix Approach

Outlook

In 2021, I will continue to present posts which evolve around 4 main categories:

- Polymer material selection

- High performance polymers

- Design properties for engineers

- Rule of Thumbs in polymer engineering

Furthermore, I invite you all to leave topics you would like to read about in 2021 in the comment box below or leave me a short message here.

Last but not least, I would like to thank all readers of my posts!!!

I hope to welcome you next year again.

Thank you 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

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

Rule of Thumb for Polymer Processing: The Importance of Melt Uniformity in Injection Moulding

 

In this rule of thumb, we discuss the importance of melt uniformity in injection moulding.

In a previous rule of thumb, we showed that there is a 20% variation in viscosity due to the intrinsic polymer structure (here thefull post). Additionally, non-molten plastic pellets and non-uniformity of melt can cause several more problems in the final part.

Here are some of the problems related to improperly molten resin pellets:

1. Decrease in part performance and increase in part failures

2. Increase of part warpage issues

3. Shot-by-shot filling not uniform, combined with short shots

4. Decrease in weld-line strength

5. Black specs caused by material degradation (dead spots)

20% of part failure can be related to processing. However, the biggest causes for part failure are poor specification and materialmisselection [1].

How to improve melt uniformity?

There are several ways to improve the melt uniformity in injection moulding: changing the injection moulding screw, the use of in-situ monitoring devices such as ultrasonic-based systems, and the processing conditions itself (temperatures, pressures).

General purpose is no purpose and why screw design matters

Let us focus on the change of injection moulding screw. Most moulding machines have a three section screw consisting out of solid conveying, compression, and metering zone. It is commonly referred to as General Purpose (GP) screw. And there it starts the challenge. Often people say that the general purpose screw is a no-purpose screw. Following the pellet melting model of a GP screw, it can happen that not all pellets are melted up. This can cause solid-bed break ups, which in turn decrease the overall mixing quality. Furthermore, material degradation and black specs can occur.

However, there are alternatives and all the major injection moulding machine manufacturers put a lot of focus and resources into developing improved screws. A well-known example is the barrier-screw, which allows the formation of a more homogeneous melt. Also, there is no need of having mixing elements anymore. Barrier screws are double flighted screws and they allow the pinpointing of the location where melting is completed. The aim is to separate the melt from the solid polymer by using a smaller diameter on one of the screw flights. Allover, plasticizing is easier; however it is not suitable for all polymers.

In conclusion, using special screws in injection moulding operations can lead to a reduction of melt temperatures, reduction of backpressure, removal of coloring problems due to non-melted pellets, reduction of screw cleaning operations and reduction of cycle times. Due to the aforementioned advantages, specialized screws pay off already within several months.

Thanks and #findoutaboutplastics,

Greetings and happy Christmas holidays,

Herwig

 If you liked this post, please share and like!

Check out my other rule of thumb posts: 

Rule of Thumb for Polymer Material Selection: Key Properties of Long Fiber Thermoplastics (LFTs)

Rule of Thumb for Plastic Parts: 4 Factors Impacting Plastic Part Performance

Rule of Thumb for Plastics Injection Moulding: 20% Material Viscosity Variation over Time

Rule of Thumb for Plastic Part Design: Increase HDT & Modulus With Fillers

How to Reduce Environmental Stress Cracking - Rule of Thumb for Plastic Part Design & Material Selection

Rule of Thumb for Injection Moulding - " What happens in the cavity..."

The 5P’s – Rule of Thumb for Plastic Design and Processing Operations

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

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] https://www.findoutaboutplastics.com/2020/11/plastic-part-failure-part-1-reasons.html

[2] Saechtling-Kunststoff-Taschenbuch, Volume 30, Hanser, 2007

[3] https://www.ptonline.com/articles/improve-quality-productivity-with-advanced-screw-design

[4] https://www.ptonline.com/articles/the-melting-precision-of-barrier-screws

[5] https://www.findoutaboutplastics.com/2016/06/polymer-injection-moulding.html

Polymer Material Selection for Electric Vehicles (xEVs) - Introduction to New Online Course

 

Electrification of vehicles, in particular of private cars, gained momentum in 2020. All major car makers are rolling out their electric vehicle programs. In 2020, the European average CO2 emission target for new fleet cars will be 95 g CO2/km. From 2012 to 2019, the reduction target was 130 g CO2/km. The main driver for this is the regulation (EC) 443/2009.

Electric Vehicles (EVs) offer several advantages such as emission free driving, sourcing of energy in a renewable way, less car parts and reduced maintenance, together with decreased noise polution. This is the overall macro level.

Looking at the micro level, EVs face some roadblocks. One of them being materials. Currently, it is challenging to find the optimal polymers for electric car applications. There are 100 base polymer families which result in 20,000 grades offered by over 500 different suppliers. This is even for a polymer expert a challenge. 

Furthermore, 45% of plasticpart failures are linked to material misselection and poor specification. This was found out in the study of Mr. Wright [1].

Allover, this cannot remain unsolved. Thus I took this as a motivation to create a new online course to provide support in the polymer material selection for EV applications.

New online course

Polymer Material Selection for Electric Vehicles is the name of my new online course, which can be found on Thinkific.

In 42 lessons, split over seven modules I will show you: 

- Why proper material selection is important (Module 1)

- How electric cars work and the main EV architectures (Module 2)

- What are the polymer material requirements, technologies and applications (Module 3)

- The use of commodity polymers, engineering polymers, and high performance polymers for EV applications (Module 4-6)

- How to compare different materials and applications (Module 7)

During the training, we discuss suitable materials from all major material suppliers. This supports you to cut down on the time for finding suitable polymer compounds for evaluation. Time is crucial and development lead time of projects becomes shorter and shorter.

How can I get started?

There is a free preview of different modules available upon registration on the Thinkific platform. This allows you to become familiar with the training system. You can also watch the introduction videos of the different modules.

Altogether, this training course helps you to sort out through the plastics grade jungle and choose the optimal polymer compound for your application.

Let’s do it! - start your training now! 

Additionaly, I made an introduction video which you can watch here:

Thanks 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

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Literature:

[1] David Wright, Failure of Plastics and Rubber, 2001, Rapra Technology Ltd.

Rule of Thumb for Polymer Material Selection: Key Properties of Long Fiber Thermoplastics (LFTs)

 

Rule of Thumb for Polymer Material Selection: Key Properties of Long Fiber Thermoplastics (LFTs)

In this blog post, I present to you another helpful rule of thumb for plastics part design and materialselection.

Long fiber thermoplastics (LFT) – an overview

The pellet size of LFT is between 9 mm and 12 mm. The use of low shear injection moulding enables a 3D network out of long fibers in the part. LFTs are suitable for up-engineering lower cost plastics in order to replace higher cost engineering polymers. Moreover, LFTs are materials for metal replacement and replacement of underperforming polymers.

In the picture above, unfilled Polyamide, 50% short glass fiber PA 6.6 and 50% long glass fiber PA 6.6 are compared to each other with key properties such as HDT, strength, impact, and creep. Long glass fiber PA is outperforming short and unfilled PA in several areas.

When looking at the properties in detail, three of them stick out:

Stiffness: using long fibers will increase the modulus of ductile polymers. Depending on the fiber type (glass, carbon, and natural), different increases are achieved. Furthermore, short term temperature performance will be increased too which is reflected in the higher HDT (heat deflection temperature).  

Strength: increased strength is the result of higher aspect ratio due to longer fiber length. This in turn leads to a higher resistance towards deformation and creep. Fatigue endurance is improved too.  

Toughness: the long fiber network allows transferring impact energy more efficiently between polymer matrices and fibers. Energy dissipation is all over the part and not restricted to an isolated area.  

Additionally, LFTs increase the cyclical fatigue endurance due to the dissipation of stress energy over an extensive part area. The longer fibers decrease crack formation and propagation lowering the overall part failure. 

In addition, properties of LFT are highly process dependent meaning that without taking the process into account no reliable statements about properties are possible. There is always the risk to mill down the fibers when exposed to high screw rotations. Several studies have shown the fiber breakage due to moulding. For creating the 3D network, fiber lengths between min. 1 -5 mm are essential.

Thanks and #findoutaboutplastics

Greetings, 

Herwig

If you liked this post, please share and like!

Check out my other rule of thumb posts: 

Rule of Thumb for Plastic Parts: 4 Factors Impacting Plastic Part Performance

Rule of Thumb for Plastics Injection Moulding: 20% Material Viscosity Variation over Time

Rule of Thumb for Plastic Part Design: Increase HDT & Modulus With Fillers

How to Reduce Environmental Stress Cracking - Rule of Thumb for Plastic Part Design & Material Selection

Rule of Thumb for Injection Moulding - " What happens in the cavity..."

The 5P’s – Rule of Thumb for Plastic Design and Processing Operations

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

Polymer Material Selection (PoMS) for Electric Vehicles (xEVs) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] https://www.plasticomp.com/long-fiber-benefits/

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

Design Properties for Engineers: Water and Moisture Absorption of High Performance Polymers

Design Properties for Engineers: Water and Moisture Absorption of High Performance Polymers

In this blog post, we discuss the water and moisture of high performance polymers.

Important for material selection is the behavior of polymer compounds when they are exposed to water (part immersion) or humid environment. Contact of plastics with water and humidity is possible; however water can diffuse into the plastic and change its physical and dimensional properties. This is depending on the contact time and geometry of the plastic part.

Depending on the polymer, water remains on the surface or it diffuses into the polymer. Diffusion lowers the inter-molecular binding forces and in turn increases the chain mobility. As a consequence, mechanical strength is reduced. Furthermore, electrical and other physical properties are reduced too. Also, dimensional changes occur. Polymers which show a strong volume change (high diffusion rate) are called hygroscopic.

The good message is that most of those processes are physical nature and are reversible by applying a proper drying process. However, when polymers are often exposed to water vapor, the risk of hydrolysis (=chemical reaction in which water molecules rupture one or more chemical bonds and can lead to chain breakage) is much higher compared to normal water exposure.

Measurement standards

Classification of water and moisture uptake is done by using ISO 62 (water absorption 24 hours, 23°C) and/or ASTM D570.

Low water uptake

Among the high performance polymers, fluoropolymers such as PTFE and PVDF take up very low amounts of water. The same is valid for Polyphenylene Sulfide (PPS). Polysulfones (PSU, PESU, PPSU) take up a limited amount of water. Polyarylketones (PEEK, PEK, PEKEKK) absorb low amounts of water too.  Hydrolysis resistance of the aforementioned materials is outstanding. Water vapor sterilization is several times possible without compromising on the properties.

Hygroscopic high performance polymers

On the other hand, Polyimides are hydroscopic. They take up high amounts of water already in normal climate conditions (50% humidity in air). Direct contact with water results in even more water uptake (e.g. PBI: 14%). Hydrolysis resistance is lower compared to PEEK or PPS and as a result cracks are formed over time when exposed to water. If the plastic part is wet and will be rapidly heated (in case of high temperature applications), expansion of water turning into vapor can cause damage to the part.

A small water uptake of PAI is influencing the physical properties immediately: elongation increases more than 10% at 2% water uptake. Impact strength increases 20% compared to the starting point. Sometimes, changes due to water uptake can be an advantage too. There are lots of parts which need to be mounted and in such cases it is beneficial to have more elongation due to water uptake compared to a dry part.

Polyphthalamide (PPA), especially PA6T/6I and long chain PPA (PA9T and PA10T) show much lower water and moisture uptake compared to aliphatic polyamides. 

A word on moisture uptake and dimensional changes after moulding 

Moisture absorption begins in the moment the part leaves the mould (in particular for hygroscopic materials).

As moulded, the moisture content of the part is approximately equal to that of the pellets that went into the moulding machine. Let us assume that e.g. an aliphatic Polyamide such as PA 6.6 is properly dried before moulding, this would place the moisture content for a part produced from unfilled PA 6.6 below 0.20% (referred to as dry-as-moulded).

Water molecules force the polymer chains to increase and this leads to volumetric expansion. The part size increase can be equal to 0.5-0.6% in an unfilled PA 6.6 (at room temperature; higher temperatures results in higher changes). However, glass fiber reinforced compounds can reduce the dimensional changes down to 0.1%.

Thanks and #findoutaboutplastics

Greetings,

Herwig

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

Polymer Material Selection (PoMS) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] Erwin Baur, Tim A. Osswald, Natalie Rudolph: Saechtling Kunststoff Taschenbuch, Hanser Munich 

[2] https://www.ptonline.com/articles/dimensional-stability-after-molding-part-4

 

Basics of Plastic Part Failure Evaluation in Injection Moulding

 In this Youtube video we cover the basics of part failure evaluation in injection moulding.

The video is divided into three parts: 1) Types of plastic part failure -Mechanical, thermal, chemical, environmental failures, combined with time 2) Areas of part failure in injection moulding -Premoulding, moulding, postmoulding, and Application (end-use) 3) Failure analysis in injection moulding In injection moulding, problems can occur in one of the four areas: - Raw materials - Additives involved in the material formulation - Injection moulding machine and tool in operation - Process control, settings, and monitoring Furthermore, there are two types of defects in injection moulding: - Moulding defects, occurring during injection moulding (short shots, air entrapment, etc) - Moulded part defects, which are identified after the part was moulded (jetting, weld lines, bubbles, etc). In conclusion, there are several root analysis tools which can be used to identify the problem and develop a solution to solve the moulding problem. Examples are the Pareto chart technique, the 5 Whys, the Fishbone diagram, and the Failure Mode and Effects Analysis (FMEA). Important is to have a systematic approach which helps to diagnose and solve part issues of the injection molding operation. Greetings and #findoutaboutplastics Herwig

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

Polymer Material Selection (PoMS) - check out my new online course

Enroll here for watching the free parts of the course

Rule of Thumb for Plastic Parts: 4 Factors Impacting Plastic Part Performance

 

In this blog post, I present you another rule of thumb for your daily polymer engineering operations.

There are several factors which impact plastic part performance. Altogether, we can divide them into four major categories [1]:

- Material and materialselection: 45% of cases related to part failure [2], are due to wrong material selection, together with insufficient specifications.

- Component design: there are 10 basic design rules [3] which serving as a helper when designing for injection moulded products:

1. Wall thickness as thin as possible

2. Continuous wall thickness to prevent accumulation of mass

3. Corners and edges with radius

4. Ribs designed for moulding: 40-60% of wall thickness for ribs

5. Avoid plane and even surfaces

6. Use draft angels 

7. Avoid undercut sections

8. No more accurate machining as necessary

9. Check for possibilities of function integration

10. Past performance of design can be guarantee of future results

- Part processing and assembly: depending on the processing technique involved, it is important to take proper care of the material (e.g. drying), mould (e.g. temperatures), machine conditions (e.g. temperatures).

- Service conditions of the part: this is linked to the first point “material”. If the requirements are well explored, then specifications are properly set which in turn allows optimal material selection. If e.g. the continuous service temperature is too high, reduction of mechanical properties may occur, together with material degradation.  

The four categories are schematically shown in the above figure.

In case of a plastic part failure, several factors combined lead to failure and it is rare that a single factor leads to part failure.

Therefore, keeping all four categories in mind during part design will reduce part failure and allow you to get the best performance out of your part.

Thanks for reading and #findoutaboutplastics

Greetings, 

Herwig 

If you liked this post, please share and like!

Check out my other rule of thumb posts: 

Rule of Thumb for Plastics Injection Moulding: 20% Material Viscosity Variation over Time

Rule of Thumb for Plastics Injection Moulding: 20% Material Viscosity Variation over Time

Rule of Thumb for Plastic Part Design: Increase HDT & Modulus With Fillers

How to Reduce Environmental Stress Cracking - Rule of Thumb for Plastic Part Design & Material Selection

Rule of Thumb for Injection Moulding - " What happens in the cavity..."

The 5P’s – Rule of Thumb for Plastic Design and Processing Operations

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

Polymer Material Selection (PoMS) - check out my new online course

Enroll here for watching the free parts of the course

Literature:

[1] Jeffrey A. Jansen: Finding Fault, applianceDESIGN, 2006

[2] David Wright: Failure of Plastics and Rubber Products, Rapra, 2001

[3] https://www.findoutaboutplastics.com/2018/04/plastics-part-design-10-holy-design.html