3D Printer Specs: What do they mean?

When the 3D printing industry exploded in 2014, a myriad of new companies rushed in, claiming to be the next revolution in 3D printing. Every week, I’d see a new professional 3D printing company crop up—each of them touting a product with a “new” feature or a “unique” specification.

Naturally, all of this novelty caught the attention of consumers and business buyers. With each product launch, more and more people became interested in applications for 3D printing, particularly in industrial engineering and design prototyping. However, as that interest grew, so did the use of meaningless marketing jargon in professional 3D printer specification charts.

To illustrate that trend, here’s a common specification comparison chart:

3D printer specifications

What do you notice about it? For me, what stands out is all of the capital letters, numbers, and parentheses. If I didn’t know better, I might look at this information and assume that I needed the highlighted printer. After all, it has the best specs and the most impressive (albeit confusing) set of numbers.

The problem? That chart doesn’t actually say much of anything.

If I were buying a professional 3D printer, this chart wouldn't help me understand what really matters: how the part will come out. That approach doesn’t help customers choose the right 3D printer for their needs and, in the long run, it doesn’t help the professional 3D printing industry grow.

This post isn’t meant to be a super technical breakdown of every 3D printer specification out there. Instead, my goal is to shed light on what some commonly discussed 3D printer specifications really mean and help businesses understand what they should actually be looking for.

Let’s start by diving into some of the individual specs listed in the chart above:

XY Resolution

XY resolution is the most talked about specification for stereolithography (SLA) 3D printers. In many circumstances, it also happens to be the most useless.

Typically, XY resolution is used to describe the details or features of a part. In the chart above, the XY resolution listed for this digital light processing (DLP)-SLA printer (25-80 microns) is amazing, but what does that number actually describe?

In all likelihood, it’s the resolution of the actual projector (which is why it’s a variable range). That number doesn’t really tell the whole story. Ultimately, there are a plethora of variables that can affect a printer’s output. By looking only at XY resolution, we’re led to believe that there’s a 1:1 ratio between the size of a pixel on the projector and the cured resin of the part.

Here’s why that’s a faulty calculation: It doesn’t take into account the material itself, the print process, the software used, or numerous other variables (professional 3D printers have over 100 different settings that impact part quality). As a result, this spec doesn’t tell us anything about what you could actually produce with this machine.

Layer Thickness

The print resolution, or layer height resolution indicates the height of each layer making up a print. A print with a smaller layer height will typically look better than one printed with a larger layer height (depending on other factors). Typical layer height resolutions for consumer printers are usually 100, 200 and 300 microns (0.1, 0.2 and 0.3mm). Lower layer height resolutions (below 100 microns) are available on a growing number of printers and on professional 3D printers a layer height under 50 microns is pretty standard. Additionally, a lower print resolution will lead to a longer build time due to the fact that more layers need to be placed to create a print.

Maximum Speed

Maximum speed is a hard metric to quantify, particularly across different printers. Again, there’s not enough information for us to really understand how these printers will perform when producing parts. Not only do the standard variables impact print time, so too do factors like geometry and orientation of the part.

For instance, a taller part will take more time than one oriented closer to the build plate because there are more layers to print. Also, the way that an object is oriented and supported will change the time it takes to print the part.

A common benchmark is how fast a printer can produce a one-inch cube. The problem with that example is that it’s very specific. Unless you’re a dice manufacturer, one-inch cubes aren’t a great way to estimate how long your part will take to print.

Print technology

is what technique is used to print an object. Most consumer level 3D printers use FDM/FFF (Fused Deposition Modelling), although SLA (stereolithography) and DLP (Digital Light Processing) printers are becoming more common place in the consumer market. SLS (Selective Laser Sintering) 3D printers are also available; however they are limited to the professional market.

  • FDM printers work by extruding filament through a nozzle onto a print bed.
  • SLA printers use a laser to cure resin together to make each layer
  • DLP printers are similar to SLA printers; however they use what is essentially a projector to cure each resin layer.
  • SLS printers use a laser to fuse powdered material together.

Positioning precision 

Positioning precision describes how accurately an axis can return or go to any specific point/height. For example, a printer has a Z precision of 2.5 microns and the user tells the printer to go to 100mm on the axis (vertical axis or height), it will be capable of going to that point within +-2.5 microns. So this means the actually height would be somewhere between 100.0025mm and 99.9975mm.

Surface Finish

Don’t get me started on this one. Decisions in life would be so much easier if “good” and “bad” were the only ways of quantifying specifications. Surface finish was discussed earlier in relation to layer thickness, but one thing to keep in mind: there is no real specification for surface finish. Surface finish can differ depending on the geometry (curved vs. straight surfaces) and orientation. The only way to compare surface finish between printers is if every 3D printing company published results from an industry standard part and profilometer. Probably not going to happen anytime soon.

Build volume

Build volume is measured in three directions. The Z axis is the height and the x, y axis are the width and length respectively.

Nozzle temperature

Nozzle temperature can either be stated as the max temperature the nozzle can operate at or the printing temperature recommended. Different materials may require different printing temperatures.

Print bed specs

This may include the max temperature or the operating temperature of the heated bed (if it has one). Some manufacturers may include information on the tolerance of the bed as well.

Auto-calibration

Many 3D printers require manual calibration of the platform level and height relative to the nozzle; however there is a growing number of 3D printer manufacturers that are offering automatic calibration. Automatic calibration uses sensors to automatically level the platform and set the correct height for printing, without any human interaction required.

Extruder

Extruder is the extruder model and number of extruders the printer has. Some 3D printers have multiple extruders which can print in multiple colours or materials. Additionally, the manufacturer may list whether the extruder is a Bowden or Direct. A Direct extruder is mounted just above the hot-end, while a Bowden extruder can be located on the back of the printer and pushes filament down a tube into the hot-end.

Filament

Filament manufacturers will usually list what filament types are supported by the printer. The most common filament materials supported are ABS (Acrylonitrile butadiene styrene) and PLA (Polylactic acid); however there are a large number of printers that support other materials such as nylon. Additionally the vast majority of printers use either 3mm or 1.75mm filament sizes.

File Type

File Type is the type of file that is used to print a model with. This file is sliced into individual layers by the printing software and then sent to the printer. Some of the file types you may come across in 3D printing could include:

  • STL – files are a standard file type that interfaces between Computer Aided Design (CAD) software and 3D printers.
  • OBJ – OBJ is an open file format that represents 3D geometry.
  • X3G – X3G is the file type that interfaces with MakerBot 3D printers.
  • VRML – VRML (or WRL) files are commonly used when a 3D model has colour.
  • AMF – is a new XML-based open standard for 3D printing. Unlike STL, it contains support for colour.

Firmware

Firmware is a program which resides on the printer’s motherboard. The firmware is the link between software and hardware, it interprets commands from the G code file (generated by the file and 3d printing software) and controls the motion accordingly.