According to Wikipedia, “a voxel represents a value on a regular grid in three-dimensional space”
Voxel is a takeoff of the word Pixel. Pixels are a common term in photography. Pixels are the dots that are printed (or emit light) at a specific number per inch (“dpi”), at a specific size, and with a specific color. The 3D analog of pixel is “voxel,” where a voxel has depth and a pixel is more of a two-dimensional reference.
A pixel is for 2D presentations. Having higher resolutions like 1920 by 1080 means there are about 2 million pixels on the screen showing the image.
The screen size matters. A big screen VS a small screen on a 1920 x 1080 resolution means you have the same number of square pixels. On a big screen, the pixels are larger. So what does this mean for our 3D printing endeavors?
Resolution descriptors works for TV and image projecting devices because they are 2D. For 3D printing, we have the third axis (Z axis). So we need to voxel values instead of pixel values.
Manufacturers tend to boast the resolution values of their printers which is unnecessary. What we need is voxel specifications.
So when they cramp the number of “pixels” on a 3D printer LCD screen, what we should also look at is the Z- axis height limitations.
Normally, our printers are set to 50 microns for per layer for printing. As per the example beside, at 50 microns, there would be 704 layers. Our LCD will be switching on and off for 704 time for about 5 hours. Printing at 10 microns per layer, that is 3520 layers for 20 hours. The 3d print will turn out perfect barring any other failures and design quality. The trade off is the longevity of your LCD screen.
A typical Z axis is a T8 lead screw with 2mm pitch driven by a 1.8 degree stepper. That is 100 full steps per mm which means any multiple of .01mm is optimal. The lower (z-axis microns) you go, the higher your voxel resolution will be. The result will be a very detailed print.
To be clear, Print Resolution is the size of the printed voxel which, in DLP printing, is dependent on the resolution of the Masking LCD screen of the 3D Printer (X-Y Axis). A 2K screen means there are 2,048 x 1,080 pixels. This results in a total pixel count of 2,211,840. Keeping in mind the size of the mono-screen, this results in an XY axis Precision of 0.051mm^2.
XY resolution is the smallest feature the light source can reproduce within a given layer. That means ~50 microns squared is the best we can do with a 2K machine in the XY plane.
So if you plan to print at 50 microns always, 2k printers are sufficient. 4k 8k 40k printers don’t really matter.
