3D slicers define how a model is built and instruct the 3D printer how it's printed. Learn all about this essential software in 3D printing.
How You Slice It
A slicer is a program that converts digital 3D models into printing instructions for a given 3D printer to build an object. In addition to the model itself, the instructions contain user-entered 3D printing parameters, such as layer height, speed, and support structure settings.
Every 3D printing technology creates 3D objects by adding material layer-by-layer. Slicer software is therefore appropriately named because it virtually “cuts” 3D models into many horizontal 2D layers that will later be printed, one at a time.
In this article, we’ll discuss the role of slicers in 3D printing, detail how 3D slicing works for FDM and SLA, and finally finish up with slicing in other 3D printing technologies. Let’s get started!
Computer-Aided Manufacturing?
Although not usually associated with slicer software, computer-aided manufacturing (CAM) is helpful in our understanding of what a slicer does. CAM is the use of computer software to assist, facilitate, or automate manufacturing processes. In practice, it serves as a bridge between digital 3D models (produced through CAD) and manufacturing systems by translating drawings into instructions for the machine to perform.
These instructions are transmitted in the form of command lines, usually referred to as computer numerical control (CNC). As the name implies, inputted commands control all of the machine’s aspects, including movement speeds, temperatures, and cooling. While there are many different ways to “talk” to these machines, the predominant language is G-code, which is used across different kinds of manufacturing systems.
While 3D slicers aren’t strictly categorized as CAM software, they perform the same function in the 3D printing process since they output digital files containing detailed instructions for the printer to perform. In most cases, as we’ll see next, they even generate G-code commands.
3D slicing procedures might look straightforward for anyone who’s printed a 3D model. But what really happens behind that tidy user interface? Let’s take a look at what we need to have a successful slicer experience.
Requirements
In order to successfully prepare a model for 3D printing, the slicer requires two different inputs: the 3D model itself and the set of printing parameters that tell the machine how the actual printing must be done.
3D Models
Digital 3D models can be created using a wide variety of CAD software, ranging from the open-source and artistic Blender to the professional and highly-technical SolidWorks. The problem is that any digital file created with a specific CAD tool has a particular format, like “Blend” (.blend) for Blender and “part” and “assembly” (.sldprt and .sldasm) for SolidWorks.
If 3D slicers were to process all of these different formats, they would require a huge support base, and even so, they surely couldn’t cover all the modeling software out there. For this reason, a standardized file format is used and the most common associated with 3D printing is STL (.stl), being exported by most 3D modeling software programs.
3D Printing Parameters
With a 3D model in a format that a slicer can understand, the next step is to provide printing details, like layer height, speed, part positioning, and several other manufacturing-related settings. These user-entered values are defined prior to printing.
During this step, the 3D model can also be partially modified: Overall dimensions can be changed through scaling features, and parts can be partially or entirely hollowed, filled with infill patterns, and provided wall-thickness values. This step also includes the enabling of support structures, which is one of the most practical features of a 3D slicer.
FDM Slicing
Fused deposition modeling (FDM) is a material extrusion technique where a print head moves across two different directions (X- and Y-axes) while plastic filament is melted and pushed through the nozzle to create a 2D layer. This process is repeated until, layer-by-layer, the 3D object is complete.
FDM printers depend heavily on movement to build a 3D object, with fine, multi-axis control being required for an accurate print. Once the 3D model and the print settings are defined, the slicer will process these inputs and generate a G-code file that’s then uploaded to the 3D printer.
The final step is done entirely by each 3D slicer’s internal algorithms, which means that it’s not user-related and that each slicer will do this differently. For simple models, any differences between slicers might go unseen, but for the more complex ones, they’ll surely be noticeable. It’s possible that certain slicers perform better with certain 3D printers, but there’s no hard-and-fast rule to know which one will work best for you.
There are many 3D slicers for FDM available, several of which are free. While Cura is probably the most popular within the open-source community, Simplify3D is the premium (and costly) choice.
SLA Slicing
Stereolithography (SLA) uses UV light in different forms to cure and solidify liquid resin into layers. Once a layer is solidified, the build platform moves to allow fresh resin to fill and form the next layer until the 3D part is created.
This 3D printing technique relies less on movement when compared to FDM. For “true” SLA printers, a deflecting mirror is rotated to direct a UV laser beam at the resin, outlining and forming each 2D layer. For DLP and MSLA 3D printers, the only real movement is done by the build plate, which travels exclusively along the Z-axis during the entire printing process.
One difference from the FDM printing process is that SLA printers don’t use G-code in their output files. In fact, most desktop SLA printers use their own proprietary format, and therefore, their own slicer software. Still, there are some third-party SLA slicers available, like ChiTuBox and FormWare, which are compatible with many desktop printers.
Slicing for SLA is somewhat similar to FDM, but the 3D printing parameters are different. Rather than nozzle temperature or cooling, SLA settings include exposure time and lifting speeds. However, layer height and features like support structure allocation are also present in SLA, just as they are in most 3D printing technologies.
A Slice from the Rest
Other 3D printing technologies like SLS, SLM, or even EBM and binder jetting require specific slicers due to the extra complexity and diversity of their processes. For instance, an SLS system from one manufacturer won’t function the exact same way as its competitor, which is why most of these machines use slicer software from the official manufacturer.
Even so, Belgium company Materialise has an entire suite of software that can be used across 3D printing technologies, including a powerful 3D slicer called Magics. This software can be enhanced by different post-processors modules, which output the appropriate sliced file for specific machines of different 3D printing processes, including metal-working machines like the Arcam and Concept Laser from GE and HP’s material jetting systems.
Source:
https://all3dp.com/2/what-is-a-3d-slicer-simply-explained/
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