3D Printing: Rapid Prototyping Capabilities and Limitations

The evolution of 3D printing technology is remarkable. With more and more advanced printers reaching the market every year, product development companies will continue to leverage these machines. With certain applications, 3D Printers can facilitate lower costs and faster speeds for complex parts that could not be fabricated otherwise.

3D Printing has enabled engineers to rapidly iterate their designs with these prototyping capabilities. In some instances, leveraging this technology can eliminate the need for more traditional methods such as injection molding or other high volume processes. However, 3D printing should not be a direct replacement for all traditional engineering practices. It is a dynamic tool for engineers to utilize but the technology should be supplemental to a more comprehensive development process. Companies that incorporate this technique as part of a larger process will likely develop more easily manufactured products that reach the market faster. There are several reasons for this including material considerations, tolerance issues, concerns surrounding part strength, as well as certain testing limitations. We have expanded upon these topics below.

Material Considerations

Prototypes made with 3D printers may not be an exact replica of the final manufactured part in terms of material, strength, fit, and functionality. 3D printed parts can be made in various materials (i.e. Plastic, Rubber, Carbon-Fiber, Kevlar, even Metal) and depending on the application, utilizing the appropriate material can be critical to the appearance, functionality and overall design of the device.

Tolerance Issues

In general, 3D Printed parts cannot achieve the same accuracy as production level components. Although there are some 3D printers that advertise, “Ultra precision” they typically  (i.e. more often than not) require more in-depth tolerance studies and corresponding design adjustments to achieve appropriate functionality compared to other more standard techniques like CNC fabrication.

Often times part draft is excluded from 3D printed parts due to inexperience or simply to expedite the prototype development . However, in some cases, drafts are absolutely critical to the model to ensure the correct part fit, performance and or appearance. Drafts should always be addressed and implemented to provide extensibility to the final design from all perspectives.

Strength Concern

The strength and durability of 3D printed parts is another common issue with this technology. The structural integrity should always be assessed prior to fabrication to assure that the correct 3D print material is selected. There have been many advances with 3D print materials and it is suggested that they are roughly 70% the strength of the corresponding milled or molded material. However, after extensive testing and experience with this technology we have determined that this value is closer to 50% and always consider this discrepancy during product development.

3D printing is an additive manufacturing process which requires a layer-by-layer fusing technique and is generally susceptible to delamination issues especially when large-shear forces are applied. This is especially evident with FDM 3D printing and  can be exacerbated  if positioned incorrectly during print tray layout. These items should be addressed to accommodate for the products requirements.

Even 3D printed metal parts have issues with strength, tolerance, and surface finish relative to standard metal processing. These metal printed components are certainly much more structural than their plastic counterparts, however they also require secondary filling, heat treating and machining to achieve functionality which is not required with “plastic” 3D printing.

Testing Limitations

Testing 3D printed parts can prove difficult for several reasons. Again, the technology is still mainly a prototyping tool and these parts printed may simply not be durable enough to withstand some of the harsh test environments required with military, industrial and automotive industries.

Regulatory agency tests such as drop, thermal, cyclic and environmental tests will most likely destroy 3D printed components much faster than standard prototyping techniques. More importantly, it could deter a part from delivering the performance data required to optimize product design and ultimately delay time to market.

Datum3D has multiple 3D printers in-house and we encourage the use of this technology. We use them extensively in conjunction with our other prototyping tools and manufacturing background.