How to Ensure Industrial-Grade Quality
for Products in 3D Printing?
Technical Focus | 25 May 2017
“Ensuring consistent product quality with 3D printing requires expertise in both engineering and production as well as integration between them two.You can’t produce a plastic bottle with a CNC machine, nor a car chassis with an injection press. When designing and industrialising products, you must consider your production system characteristics. When you produce, you must monitor the process deviations to ensure the products are up to specifications. 3D printing is just like any other production system, where same rules apply.”
– Paul Guillaumot, CEO of Spare Parts 3D
The current mainstream technology in manufacturing process is plastic injection moulding. It takes four main steps to launch a new product: specification, design, engineering and production. Specification refers to the set of activities to define the high-level and detailed-level of product functions: dimensions, mechanical strength, visibility, etc., in other words, what the product should do to meet the perceived market needs. Based on the specifications, a team of design engineers will go through every detail of the specifications and turn them into a particular product that meets the requirements at the same time can be manufactured in volume under current machining conditions, considering factors like materials, mechanical properties, software applications, costs, time to produce, etc. Then a group of product engineers will take care of the multi-step engineering process including manufacturing samples, several rounds of quality check based on the feedback loop, and final products. They also need to deal with issues of cost, producibility, performance, reliability, serviceability, expected lifespan and user features. After all these steps, the production will begin. But till then there are still possibilities of problems that occur due to neglects of one or two tiny details in the former steps and the manufacturing process will loop back to the beginning of the process.
What we are trying to explain exactly here is that there is no major difference. Additive manufacturing shares the main features of any other traditional manufacturing process and demands the same level of expertise that involves groups of multi-disciplined engineers. It is therefore unreasonable to imagine that industrial level production by 3D printing will be performed any time soon in customers’ houses!
Ensuring final products’ consistent quality requires both steps 4 and 5 of the APQP process: ensuring product & process validation, then monitoring production performances and applying corrective actions in case of process divergence.
To do so, the quality assurance system shall at least cover two aspects: ensuring that the outcome of industrialisation (process of converting a design into a production process) fulfils the design specifications, then monitoring quality consistency in the distributed production process. Guess what, that’s exactly what we do!
During industrialisation, our engineers outline the optimum set of parameters that will define how the part will be printed by the 3D printer. These include variables such as printing temperature, speed, and toolpath. Factors that are taken into account while defining these parameters include part geometry, mating features such as keyways, and the required mechanical strength. This process can be re-iterative to ensure the final print is of the highest quality. Finally, a set of final parts are produced, and their dimensional and mechanical features tested and verified, before the set of computer instructions, or ‘G-code’ used to print the part is finalised.
When the part is required to be produced at one of our 3D printing service providers, the final G-code is transferred securely through an online 3D printing cloud service. Before production commences, the printer(s) at the provider are calibrated to ensure that their X, Y, Z calibration, and extrusion state are within acceptable bounds. This is carried out by running a set of calibration tests on the printer(s). The same set of calibration tests are conducted on a daily, weekly and monthly basis on the 3D printers in our engineering HQ in Singapore, to ensure that the industrialisation process is carried out on well-tuned and properly functioning printers.