Using spark OES for metal additive manufacturing

Additive manufacturing – or 3D printing – has revolutionized component manufacture. The ability to form metal or plastic components layer by layer means that complex shapes with tight tolerances can be easily produced rather than using a subtractive method where material is removed from a larger part like carving an item from a block. Techniques like direct metal laser sintering (DMLS) and electron beam melting (EBM) are giving product engineers scope to design intricate components that weren’t possible or prohibitively expensive with traditional subtractive techniques.

Another benefit of additive manufacturing is that it’s easy and cheap to make a prototype. You don’t have to create specific tools or set up a costly production run, delivering less waste and better cost ratio for one-off or small-batch production. 

However, the move from prototyping tool to reliable manufacturing asset has thrown up several challenges for 3D printing, especially in the metal additive manufacturing sphere. Here, powder bed fusion is used to form complex shapes for sensitive applications, such as medical devices for implantation in the body, or aerospace components for use in flight. These are areas where components simply can’t afford to fail. 

Why is certification and chemical analysis crucial?

As with every other metal forming activity, the composition of the metal powder needs to be right for the final product to have the correct characteristics to not only meet specification and avoid defects but also to comply with the applicable local and national statutory regulations. Understanding how to meet requirements, satisfy appropriate conformity assessment procedures and achieve the necessary certification isn’t always easy to decipher though.

Each batch of raw powder should be checked for chemical properties and uniform particle size distribution using various test procedures. Despite intensive cleaning of the printer, material mix also can’t be ruled out for causing out of spec products. So, do you rely on the certificate of the powder you have purchased to ensure quality? How do you know if the powder complies with the specification after 3D-printing?

It’s worth noting that the frequent recycling of powder through several printing runs leaves the process open to external contamination, especially when switching from one powder type to another. Another source of contamination is gasses such as oxygen which can accumulate in the powder and have an adverse effect on the chemical composition and material properties. The 3D metal printing process itself can also create defects within parts. 

To prevent contamination of the finished part, it’s important to verify the raw powder before printing, and check the composition of the finished part before shipping to reduce scrap rates, increase yield and really capitalize on the benefits of additive manufacturing. And this is where spark OES can be a key ally.

OES - an established technique for new applications

Optical emission spectroscopy is the ideal solution for measuring 3D printed parts. This method of elemental analysis has been used for decades and it’s considered the most important method for the analysis of metals and alloys in the metallurgical industry. Spark spectrometers are used for seamless quality control in metal processing, starting with the analysis of the accompanying elements in scrap metals, the control of incoming materials, the melting process control, the outgoing goods to fabrication. 

As one of the highest turnovers and most labor-intensive industries in the world, the iron and steel industry is of great importance. Our most recently developed optical emission spectrometer range, the OE series, is ideal for the analysis of steel and ferrous materials. With its new detector technology, the OE750 offers outstanding performance in metal analysis. It enables the analysis of ultra-low carbon steels, the monitoring of nitrogen content in steel and iron casting processes, and the determination of other trace elements for these applications. And, of course, it provides reliable results for the most important alloying elements.


Find out more in our guide

My colleague Maryam BeigMohamadi, Application Scientist – OES and I have put together an in-depth guide that provides insight on how we can help you to find an optimal solution for your additive manufacturing process quality control.

In this guide we cover:

  • How does OES work and how to perform offline measurements
  • Why oxygen is an important process parameter
  • Spectrometer requirements
  • Example measurements of printed samples
  • Case study: Samson AG
Download the guide

Let us analyze your samples for you

We’ve been working alongside metal manufacturing and engineering companies for almost 50 years, developing analytical techniques and solutions that support manufacturing processes, including quality and process control, as the industry specifications get more stringent. As a result, we’ve become experts in material analysis and today, we directly support our customers in finding the right analytical solution for their (often niche) processes.

If you have quality control issues with your printed products or are looking to avoid them, we want to help you. By working together with our application team, we’ll be able to find the best solution for you.

Contact us about your samples


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Date: 7 November 2022

Author: Michael Molderings, Product Manager - OES

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