»Critical for any industry to develop and mature«

Interview: Thomas Masuch — 21/01/2019

At first glance, standardization might seem a rather dry topic, but everyone is talking about it at the moment. At Formnext 2018, for example, the first transatlantic »AM Standards Forum« was organized in conjunction with the US Commercial Service. Here, experts from Europe and the United States discussed the international developments in production standards. We spoke with experts from the USA and Europe about recent trends in this field.

Why is standardization so important for the world of AM?

DR. MARKUS HEERING: Standards are becoming increasingly important as a result of the successful transition from rapid prototyping to industrial series production. Product liability alone requires manufacturers to verify the quality of additive serial components and ensure reproducible quality when setting up their manufacturing processes. Standardized processes and procedures in quality assurance are the means of choice when it comes to avoiding having to repeat quality certification for every component. And they will be the basis for any kind of certification for AM providers going forward. In user industries like aviation and medical technology, certification is mandatory for manufacturers and suppliers alike. And certification of this kind is often based on compliance with standards.

PAT A. PICARIELLO: In order for the technologies that live under the additive manufacturing umbrella to be fully embraced by the diverse collection of industry sectors that presently exists, confidence is needed to ensure that things made using AM will perform in a way that’s comparable to things made using more traditional subtractive technologies.

TERRY WOHLERS: For most of the AM industry’s 30-year history, it has lacked international standards. They are critical for any industry to develop and mature. Imagine not having standards for electricity, lighting, computing, fuels, automobiles, aircraft, and traffic control. Life would be much less efficient, and in some cases, chaotic and unsafe. Almost everything would cost more to produce and purchase and life would be very different.

There have been various efforts in this area for many years, one of the most recent being the AM Standards Forum at Formnext. How far along are we in the AM industry?

PICARIELLO: In every new area of technology, the gap between research and market (theory and practice) can loom large. AM is certainly no exception to this, and the need to bridge this gap is one of the reasons Committee F42 was originally organized back in 2009. Standards, and the consistency they provide, are critical to market acceptance. How do we know that a particular material, process, system, or service will behave as intended (and marketed)? Standards development is a barometer in areas such as this, and in that regard, the AM industry has never been more evolved than right now.

WOHLERS: The additive manufacturing industry has made good progress in recent years with standards. Each standard comes with a lot of hard work, often by expert volunteers, many of which are very busy people. This can make it challenging, even difficult, to create new standards. That’s why they often take years to develop. Yet, they are vitally important to the growth and maturity most industries. A lot has been accomplished since 2009, but a mountain of work is ahead.

Standardization processes take time in any industry.

HEERING: Standardization processes take time in any industry, not least because the players involved often have different interests. A young, innovative technology like AM is driven by different players, each acting independently. Efforts to achieve standardization start as soon as a number of them agree on common interests. It’s not really possible to give a specific answer the question of how far along we are with standardization as an industry. AM is a vast, heterogeneous technological field that is constantly producing new processes and procedures. While some manufacturers are already supplying additively manufactured aircraft parts and medical implants subject to strict regulations, the AM industry as a whole is still laying the groundwork for standardization.

Especially in the metal sector, AM usually requires postprocessing with other technologies. What challenges does this present?

WOHLERS: Standard procedures for powder removal, handling, storage, and recycling are important. Likewise, it is important to standardize other post-processing steps, such as thermal stress relief, hot isostatic processing, surface treatment, and inspection. For processes to remain repeatable, it is critical that a very specific and consistent set up steps are followed to maintain quality standards. Developing and following these steps can require a great deal time and effort, but companies have no choice if they want to apply AM to production applications.

HEERING: The interfaces are one of the major challenges – both the data interfaces and the purely physical transfer of components from one station to the next. When a build envelope is optimally filled, dozens of components of different sizes and complex support structures are created in it. During unpacking – a task that will in the future be automated for cost reasons –, the robot has to know the sequence in which it removes the components from the build envelope, where it can grip them and with what force, and which postprocessing station it transfers them to. This is difficult with AM components because they are often one-offs or customized small-series items. So it is necessary to uniquely identify them, and the parts ultimately have to find their own way through the postprocessing chain – which puts us firmly in Industry 4.0 territory. Inline quality assurance is also a major issue. Our road maps make it clear that there many challenges still lie ahead in postprocessing.

»I believe the 80/20 rule applies.«

Various AM standards have already been published. Most relate to one manufacturing technology (e.g. powder bed) in combination with one particular material. The increasing number of AM technologies and materials available raise the question of whether these ever growing numbers of combinations can be covered. Or will we need a different approach in the long term?

WOHLERS: I believe the 80/20 rule applies. About 80% of the time, users will use 20% of the AM processes and materials currently available. These numbers are a rough approximation, but I hope you get the point. In other words, not all AM processes and materials will be used for production applications, and therefore do not require the same types of standards associated with them. Even so, a great deal of work is still ahead.

HEERING: That is indeed the question. One result of our VDMA working group is a committee dealing with the application of additive components within the scope of the European Pressure Equipment Directive (PED). Manufacturers of chemical equipment and fittings, and manufacturers and operators of large-scale plant from the chemical industry work together with representatives of the DIN Standards Committee Mechanical Engineering in the VDMA as well as with experts from various monitoring bodies. Manufacturers of molded parts, materials specialists, and representatives from the world of research and from universities are also involved. Together, they have developed an internationally agreed draft for a DIN standard, which is to be incorporated into international standard procedures. This example shows one possible approach: The users involved know the regulations in their industry better than anyone else. And they have the greatest interest in rapidly achieving standardization. Our working group brings together users from various industries and AM specialists. The first step in any standardization process is dialog between stakeholders.

PICARIELLO: Committees operating under the ASTM umbrella tend to develop standards that are very targeted and focused – tending to eat the elephant 1 bite at a time – and this is certainly reflected in the current F42 portfolio. There is also a need for standards that focus on use of a single AM technology, using a single feedstock, to produce a part. How this evolves remains to be seen, but my sense is that at some point there will be sufficient micro-standards activity to generate comfort in the development of more macro documents.

 

Different industries and sometimes even companies develop their own certifications and standards. Does that really make sense? Isn’t there a danger of unchecked growth? And how could this be countered?

PICARIELLO: We operate in a world of multiple paths, and this flexibility has both positive and negative impacts. As long as there is communication among the entities operating in the AM space, a variety of options is beneficial. If, however, organizations operate in a vacuum and somehow miss or ignore what currently exists or is under development, we run the risk of duplicative or much worse conflicting activity. Over its 120 years of existence, ASTM is a firm believer in communication as a mechanism to prevent wasted resource allocation – bandwidth in the AM world is a precious commodity, every attempt possible should be made to ensure it’s not wasted.

WOHLERS: Corporations will develop company- specific standards, guidelines, and procedures. These same organizations will also adopt industry standards published by ASTM, ISO, and others, using a combination of them and their own. Making industry standards available to all organizations helps to advance them and specific industries, such as additive manufacturing.

HEERING: Standards or even certifications without transparent and comprehensible origins and requirements are no use to anyone. They tend to make users uncertain. In the VDMA, we took the initiative a good five years ago and, with the Working Group Additive Manufacturing created a platform, where players from all parts of the AM value chain get together to share and discuss their experiences. This dialog is the ideal prerequisite for preventing unchecked growth before it begins.

Road maps of VDMA Working Group Additive Manufacturing

With the VDMA Working Group Additive Manufacturing, Germany’s Mechanical Engineering Industry Association (VDMA) has created a platform on which almost 150 member companies contribute their expertise from all areas of the process chain and share their views on the technology. Together, they have developed two road maps on powder bed processes for plastics and metals. The VDMA deliberately started out with a step-by-step analysis of the process chains. These road maps show the development and standardization requirements for each step, from the first preliminary consideration right through to packaging of the finished AM component.

Committee F42

ASTM Committee F42 on Additive Manufacturing Technologies was formed in 2009. F42 meets twice a year. The Committee, with a current membership of approximately 400, has 6 technical subcommittees; all standards developed by F42 are published in the Annual Book of ASTM Standards.