Surprisingly, I have found the NSL series of webinars called Tech Talk, easy to work into my schedule. Surprising, because I am not the kind of person who strictly adheres to any schedule. I may be focused and even methodical, but not overly organized when it comes to time. Also, I am known to get so wrapped up in a project that I miss other scheduled events. The Tech Talk topics are applicable to prominent manufacturing testing needs today, and even I can find the time.
Some professionals feel too busy to attend seminars. With this series of webinars, it’s worth taking an hour to watch, and you can view them from your office. If you don’t have time, but have “paperwork” to do, log in, log into the webinar while you work. Just be warned that you will probably find the information engaging enough to give it your undivided attention.
Worth the Time for AM Professionals.
I’ve been following advances and changes to the additive manufacturing (AM) industry, as new materials are developed for AM use. It is apparent that each time a manufactured-by-assembly product or part is due to be replaced with an AM product, tests must be performed to ensure product safety. It is just as critical that the veracity of those tests are reliable. Materials Testing Labs like NSL Analytical Services have experienced materials scientists, who can deliver reliable test results that are useful in manufacturing decisions.
Recently, Dr. Dave van der Wiel led Tech Talk Webinar on “Measuring Density of Additively-Manufactured Materials”. In Dr. Dave’s presentation, he reviewed testing methods on porosity of samples. How Porosity is measured depends on the test purpose, sample size, and available equipment. There is a level of uncertainty that can accompany material testing on samples, when the wrong testing approach is chosen.
The Archimedes Method
In the Archimedes Method, mass measurements were the dominant contributing factor in uncertainty, followed by a distant theoretical density and fluid density. In smaller sample sizes, test discrepancies are difficult to control. According to Dr. Dave, when using the Archimedes Method, materials scientists (as well as manufacturers) need to be aware that test sample size will impact the consistency of the test results. The difference between a one cubic cm specimen versus a two and a half cubic cm specimen was a relative standard deviation as high as 0.45%.
Pycnometry is a more consistent and reliable determinant of Density, as long as the researcher is using enough of a sample, so that the sample chamber volume is nearly filled. According to ISO 12154, the Determination of Density by Volumetric Displacement-Skeleton Density by Gas Pycnometry: “The most common mistake…is using too little sample”.
Dr. Dave proceeds to walk viewers through the Pycnometer calibration options, sample cell size with minimums and maximum recommended sample sizes for more accurate test results. He also covers optical microscopy tests and regular test differences between the methods. Microscopic imaging will rarely deliver corresponding density values that match those resulting from pycnometry or Archimedes test approaches. Because there are certain cases where pycnometry and Archimedes techniques do provide similar results, and because time is of the essence, it is vital to discuss manufacturing demands with the experienced professionals at NSL Analytical Services when inquiring about testing services available. NSL skilled team members can recommend the most efficient and accurate method of testing for your specific application. To learn about testing options or to get a quote for your testing needs, visit: www.NSLAnalytical.com.