The Resolution, Printing Size and Accuracy in Resin 3D Printer
When it refers to resin 3D printers, the resolution, printing size and accuracy are often discussed but difficult to understand. What’s resolution in 3D print world? What’s the relationship between resolution and printing size? Are accuracy and resolution the same one? When considering final dimensional part accuracy, what matters most: X, Y or Z? Don’t be frustrated. In the following content, let’s figure out those concepts.
Resolution and Printing Size
Resin 3D printers including Stereolithography (SLA), Digital Light Processing (DLP) and Liquid Crystal Display (LCD), use different light sources to project a complete profile of a layer.
Thus, Resolution (width x height), is the fixed number of pixels displayed by a laser when using SLA, a projector when using DLP, an array of LEDs shining through an LCD when using LCD.
The fixed nature of the build vat with liquid photopolymer results in a related build area or printing size. The equations between resolution and printing size (build area) are:
Width / X Axis = Height / Y Axis = Native Pixel Size
Native Pixel Size * Desired Resolution = Build Area Width
Native Pixel Size * Desired Resolution = Build Area Height
For example, a DLP printer offers a 1920 x 1200 resolution projector. This projector delivers a total of 2.304 million pixels (which is determined by multiplying the number of pixels in width and height) within a build area of 7.6 x 4.7 x 9.06 inch (192 x 120 x 230 mm).
So there is a build area 192mm wide along the X axis. Divide 192 (the X axis) by 1920 (the projector width resolution in pixels), this will equal 0.1mm (100µm). And the native pixel size is 100µm.
Just like it is possible to have two devices with the same screen size and different resolutions, the same light source can be used for different build areas. However, the higher the resolution (the smaller the native pixel size), the higher the detail in the print.
If the resolution doesn’t match the printing size, the modle will be screwy and anamorphic.
Left: Anamorphic Right: Normal
3D printer resolution is also separated into two different segments: Z resolution (vertical) and XY resolution (horizontal).
In 3D printing, no factor is more crucial than XY resolution (horizontal resolution or minimum feature size) when considering what matter most to accuracy. XY resolution is the smallest movement (on the horizontal plane) within a given layer. The lower the value, the better the details.
Left: 75µm Pixel. Right: 37µm pixel
Driven by the design of the build platform, the Z resolution is different and need to be treated separately. The Z resolution (vertical resolution) is the minimal thickness of a layer which is actually a better indicator of surface finish. The smaller the layer height, the better the printed surface.
Left: 100µm layer thickness Right: 50µm layer thickness
But in turn, thinner layers do not always guarantee better prints as it requires more repositioning of the build plate in the Z axis during the build process and more opportunities for motion control and repositioning errors.
Software is the Key
Because 3D printing is digital production, it’s necessary to have a slicer software to convert digital 3D models into printing instructions for your 3D printer to create an object. Slicer software settings do impact the quality of your print so it’s important to have the right software and settings to get you the best quality print possible.
For example, ChiTuBox, a free slicer controls the resolution and size. With lots of inbuilt machine parameters, it provides a simple and intelligent foolproof 3D printing experience for beginners to fix out those complicated relevances.
If you want to print something with intricate details, you will get the best print with a thinner layer height and a suitable printing speed. ChiTuBox recommends settings of 0.05mm layer height and 65mm/min speed for a high resolution print. Also lift distance, exposure time and light-off time are available to be customized.
If you are a professional user, you can even create a G-code by slicing a file in ChiTuBox and saving it. G-code is the programming language of your 3D printer which is used to tell the printer how to do something. The saved file will be converted to g-code, a language the printer understands and uses to create a 3D print.
As a conclusion, 3D print accuracy is related with light source resolution, native pixel size and XYZ resolution. But in fact, it’s more complicated when it comes to the relationship between accuracy and resolution as there are a variety of factors to consider. When starting with 3D printing, it’s better to keep patient and achieve perfect prints through trial and error. And remember, accurate 3d slicer settings are one of the most important factors to achieve a successful 3D print.