In-process Inspection: Improving 3D Printed Parts

Writer’s Note: This the first in a series of blog posts describing the details and applications of our brand new printer, the Mark X. In this post, we’ll be discussing the In-Process Inspection, the groundbreaking feature that allows users to see how their printer is performing while it’s printing. This feature is the first step in closing the loop of 3D Printed Parts. 

Why Closing the Loop is Important

In an ideal world, there would be no gap between designing a part and the part tangibly existing. Assemblies would fit together effortlessly, bearings would spin perfectly aligned shafts without any pre-stresses for low cost, and complex geometries would look as beautiful in person as they do in CAD. Unfortunately, the world isn’t perfect and none of the aforementioned cases are realistic. Because of imperfections in fabrication, tolerancing exists. Tolerancing serves a simple purpose: explicitly defining how wrong can a part be while still being usable. Its brilliance is in its adaptability: designers can set common sense goals for fabricators to achieve while machining parts. This both limits cost on parts that require less precision while also ensuring that incredibly precise parts are fabricated such that they can function effectively.

‍The bearing fit on this turbine housing was made possible due to a very tight tolerance print.

While part tolerancing is an incredibly effective tool for designers, they’re a necessary evil for fabricators. Each defined dimension needs to be painstakingly measured, checked, and verified by a machinist before it can be qualified. If any dimension isn’t up to snuff, the part is disqualified. Defining tolerances effectively closes the loop for designers; however, checking them remains a decidedly open-loop tool for machinists. Parts can only be measured after a fabrication process is completed, which means it’s nearly impossible to know if a feature is perfect before it’s been fabricated. This problem exists in almost all fabrication processes, but it’s particularly problematic with 3D printed parts. 3D printers are completely open loop. Once file is uploaded to a printer, its adherence to tolerances is unmeasurable until the completion of the print. That’s what we’re trying to change with in-process inspection. We want to take the guesswork out of our processes and give users unprecedented transparency into their prints.

‍Behind the successful prints that are featured on our blog are many unit tests and disqualified parts. Closing the loop could drastically reduce the amount of time required to create qualified parts.

How We’re Doing It

‍A laser micrometer in action, moving back and forth to scan a brake lever.

The Mark X takes the first step in closing the loop in 3D Printing. Here’s a quick walkthrough of how users will be able to leverage the process to improve their workflow when creating 3D printed parts.

  1. When setting up a part in Eiger, the user defines layers to be scanned. The scans will vary in time with part size and scan resolution. The scan will be accurate to up to 1 micron in the Z axis and up to 25-50 microns in the XY plane.
  2. After a layer is scanned, the details of that scan are accessible through Eiger, our cloud based software. The scan itself is color coded by distance from part to printer.
  3. Within this scan, the user can manipulate Eiger to check dimensions the on different aspects of their part. There are several measurement tools currently available, including a circle tool, distance tool, and a rectangle tool. Using these tools, a user can quickly and easily check if a part is within tolerance while it is still printing.
  4. If the user is unsatisfied with the dimensions of the print, they may cancel it at any time.
‍A detail scan of the hole on one of brake lever sample parts. Note the detailed dimension callouts on the top-left corner of the image. Using the circle tool, the user defined three points that are geometrically interpolated into a circle that is then measured.

While the loop is still human-closed, we’re giving users a much closer look at how their parts are printing mid print. If when investigating a scan the user finds a tolerance issue with their part, adjusting the CAD of the part to account for the error will likely solve the problem on the next print. This means that you’ll be making usable parts faster, cheaper, and more reliably than ever before.

Looking Towards the Future of 3D Printed Parts

The Mark X is a game-changer in the world of 3D printed parts. However, it’s also just the first step in making 3D printing fully closed-loop. Additive Manufacturing should be as smart, inexpensive, and reliable as possible. The Mark X is an amazing machine; in fact, we’ve barely scratched the surface in working with the laser hardware ecosystem. In the coming months, our engineers will continue to leverage the laser to create easier to use and more advanced software. Buying a Mark X is not merely purchasing a machine. Instead, it’s an investment in the future of fully automated 3D printing. This is merely the first step in closing the loop, and we’ll continue to keep working towards enabling an ideal manufacturing world.

In the meantime, here are some ways you can learn more and get more involved.Learn more about the Mark X.Follow us on FacebookTwitterInstagram, and LinkedIn.

Daniel Leong
October 6, 2016
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