When you begin researching 3D printers one question often comes to mind: “What is the resolution of this 3D printer?” This is not an easy question to answer and has certainly led to failed expectations for the unsuspecting. So, before you let ‘resolution’ sway your next 3D printer purchase, let’s take a moment to define 3D printer resolution and some common misconceptions of the metric.
Just because a 3D printer data-sheet boasts a 1.25μ X/Y/Z resolution does not mean you can expect this from the finished part, nor does it guarantee a smooth surface finish.
What Is 3D Printing Resolution? It’s Not What You May Think.
Due to a lack of metric standardization in additive manufacturing, 3D printer resolution can go by a number of names including X/Y/Z resolution, positioning resolution, or theoretical resolution. In theory, this metric is a measurement of the smallest movement a 3D printer can achieve in each direction. Set by hardware and firmware, positional resolution is calculated by the number of ‘steps’ in a 360° rotation. These micro rotational movements are delivered by stepper motors and belts to drive the X, Y, and Z axes. The more steps, the finer movements a 3D printer can achieve. While this is important, manufacturers often provide a theoretical metric, unrealized by the user due to a number of factors including material shrinkage, belt tensioning, nozzle size, and more.
What You’re Probably Looking For…
For people new to 3D printing and even some tenured professionals, resolution is often misconstrued for one of two things, dimensional accuracy of the printed part and/or surface finish. These are both complex topics so let’s take a moment to analyze each. Keep in mind there are pros and cons to each 3D printing technology so this article should only be part of your overall assessment. If you need help, Dynamism’s 3D printing specialists are here to help.
Printed Part Dimensional Accuracy
Printed part dimensional accuracy is not solely defined by hardware. Instead, there are a number of influencing factors for each of the 3D printing technologies. Below, we break down influencing factors for two of the most common technologies.
Material Extrusion 3D Printers
For material extrusion 3D printers, the dimensions of your final part are influenced by positional resolution, nozzle size, die swell, belt tensioning, and shrink rate of the material. Material is a huge contributing factor here. Some materials have more die swell than others. Additionally, Styrene-based materials, like ABS, have high shrink rates which can result in parts smaller than intended. Thankfully, smaller nozzles can be added to most FFF 3D printers to achieve more accurate prints and smoother surface finishes but as a tradeoff, prints take longer to finish.
Resin 3D Printers
For stereolithography aka resin printers, dimensional accuracy is mainly determined by the material and laser spot size, or screen resolution for DLP 3D Printers. Some materials will shrink when undergoing the heat and UV curing process. Overall, SLA and DLP printers produce more accurate parts than material extrusion printers but as a tradeoff, most affordable market options have smaller build volumes and materials only emulate end-use materials, like ABS, Polycarbonates, and Polyamides. Exceptions do exist for build volume, like the Formlabs Form 3L and Nexa’s super fast NXE400.
Surface Finish
When looking for a smooth surface finish, SLA/DLP 3D printers provide exceptionally smooth finished prints. As mentioned above, the technology does come with some tradeoffs. For material extrusion printers, smoother surface finishes can be achieved with smaller nozzles and finer layers. Furthermore, some materials can be vapor smoothed, providing a surface finish that nears that of resin 3D printers.
Now That We’ve Settled That…
As you continue your 3D printer shopping journey, do not let 3D printer resolution sway your decision, as this metric is often theoretical and limited by other factors such as materials. If you need help selecting the right 3D printer, Dynamism’s 3D printing specialists are here to help. With a brand agnostic approach and large selection of technologies and brands, our goal is to get you the best possible solution for your application.
