By Felix Manley & Sasha Bruml, Co-Founders, 3D People
Across all manufacturing processes and industry sectors, high quality output is crucial in determining product performance, which in turn directly impacts both customer satisfaction and ultimately long-term business success. For highly regulated industry sectors that have to adhere to regulatory frameworks it becomes even more important.
For additive manufacturing (AM) processes, it is no different, except perhaps in terms of perception. As a relatively young manufacturing process type (compared with CNC machining, injection moulding, etc) AM is today capable of fulfilling a range of production applications.
However, AM technology can and does regularly face pushback in this regard:
“What about the surface finish?”
“What about dimensional accuracy?”
“What about consistency and repeatability?”
These are just some of the questions related to quality that we regularly have to answer for new enquiries. As an AM service provider, our team is well placed to overcome such concerns. Obviously, every application is different and our industrial plastic powder bed fusion (PBF) processes — specifically MultiJet Fusion (MJF) and Selective Laser Sintering (SLS) — are not always a good fit. If that’s the case then we say so up front. Always best to be honest in these cases. We believe in AM as a manufacturing solution for many applications but not the manufacturing solution for all applications. It’s an important distinction, and one that has not always been made clearly in the past, and possibly why there is still so much push back now.
One factor that does overcome many of the pushbacks against AM, both in general and for us specifically, is quality. The ability to demonstrably prove quality control across the entire workflow and produce high quality parts consistently.
Unsurprisingly, quality output from AM systems does not happen by accident. Rather, it is the result of dedicated efforts to maintain precision, consistency, reliability and repeatability throughout the entire manufacturing workflow. It is important to understand that quality parts do not just depend on monitoring the AM systems in isolation. Of course, quality monitoring of the production process itself is vital, but, for AM processes (and any or all post build processes that are necessary) it is essential to implement continuous quality monitoring across every stage of the workflow. This means from the earliest stages for design validation right through manufacturing and finishing to the final inspection of the finished parts.
This multifaceted and holistic approach is essential for any users of AM, even more so for service providers like us, to ensure the highest quality outputs are consistently achieved for clients.
From Start to Finish:
To meet the quality demands of customers and their often critical applications, 3D People has purposefully and rigorously implemented a series of advanced quality monitoring and calibration protocols across its entire manufacturing workflow.
Design Validation
The quality control process begins long before production even starts, with comprehensive preliminary checks at the design stage. 3D People, for instance, has developed and utilizes an advanced automated online quote tool that automatically inspects the uploaded files for any issues that could compromise part quality during the build. Any errors are identified, which subsequently triggers a warning that means that the file cannot proceed without corrective action. This pre-emptive validation of 3D files helps catch potential design flaws early on before money, machine time, material and energy is wasted – this is good for our clients and good for us.
Once an order is placed, a further, more refined check is performed automatically to ensure the design is fully compatible with the AM process selected and any finishing process(es) required. Files that fail this second check are flagged for manual review by a technician who uses advanced analysis software to further examine the problem. If necessary, the customer is contacted, and no design proceeds to production until it has been successfully validated or repaired. By ensuring that only validated designs are allowed into manufacturing, this process safeguards the integrity of the final product, saves costs for clients and maximises efficiency.
Into Production
After a design has been validated and approved it moves into production where numerous quality control measures are executed.
Maintaining dimensional accuracy of parts is absolutely critical and to this end machine calibration is crucial. At 3D People we use control samples for every print run that are measured across the X, Y, and Z axes. If any control sample falls outside of predefined tolerances, the entire build undergoes additional measurement to identify and eliminate any defective parts. This step allows us to maintain the required precision standards for all parts that we produce.
Monthly machine calibrations are a given, and scheduled religiously. For this large-scale calibration parts are built and then analysed to detect any deviations over time that could affect machine accuracy and production quality. If any significant misalignments are identified, the machine is taken offline for recalibration, to ensure the consistency of the manufacturing process.
Real-time machine monitoring and predictive maintenance are also essential components of quality control through the production stage. Through live tracking of machine performance, we can promptly detect any irregularities or operational issues, minimizing downtime and ensuring smooth production. This system also allows the company to anticipate wear on machine components. By tracking wear rates and scheduling pre-emptive part replacements, the company avoids unexpected machine failures, which can interrupt production schedules and compromise part quality. This predictive approach ensures that the machines are always in optimal condition for high-quality production.
Environmental factors also have to be factored into optimal print quality. 3D People actively monitors room humidity levels to prevent fluctuations that could affect material properties, particularly when working with the MJF process. If humidity levels are not controlled, variations in material consistency can result in part defects.
Cooling rates and conditions also have to be closely monitored and controlled, especially during the de-powdering process. Precise control over the cooling temperature helps avoid internal stresses and warping of parts. This preserves the dimensional stability of parts and maintains overall material integrity.
Maintaining such environmental controls is vital for achieving high-quality outcomes in every print run.
Above & Beyond
User touchpoint monitoring, with quality logs, is another layer of transparent quality assurance that 3D People has developed to maintain accountability at every stage of production. Each part is inspected at multiple key stages of the workflow, including print preparation, nesting set-up, post-print inspection, and final validation after depowdering. At each of these touchpoints, operators verify and log their approvals, creating a comprehensive traceability system for customers. This maintains consistency in the manufacturing process. The use of detailed quality logs ensures that the entire process is transparent and that each part is meticulously monitored from start to finish.
All these quality controls are not only a testament to 3D People’s commitment to excellence but also to the robust quality management systems that we have developed and implement on a daily basis. We operate with ISO 9001 accreditation, and during our most recent ISO 9001 audit, it was rather satisfying to have the auditor praise our bespoke quality control systems as some of the best he’s seen. A true reflection of our dedication to quality control and monitoring as a fundamental pillar of our business — end-to-end.