3D Printing Tools: The Slicer

My background has always been in software. While I have tinkered with engineering (the physical kind), it has never been extensive. So, when I started to get into 3D Printing, it was with a keen eye to how software helps this process. The slicer is what has impressed me the most so far in this space.

As we look at the process of 3D printing, it necessarily starts with a design. There is a plethora of tools available today to create these designs, each with its own strengths and abilities. These tools are a far cry from my youth, but that is a discussion for another time. The process ends with the printer printing thin layers of material in order to make the design real.

But, how does one get from a design to those layers being printed. The printer is simply obeying orders given to it in a “gcode” file. The software which creates these instructions from the design is called a Slicer.

The slicer takes in multiple inputs – the design, the printer and its capabilities, the raw material and its properties. Then it does the heavy lifting to determine the best way to print the product.

3D Printed parts are typically hollow. But what does hollow mean? All external surfaces on a design are considered “walls”. It is the area inside these walls that are called infill. An infill of zero would mean completely hollow but would make the print extremely weak. An infill of 100% percent would make a solid print, but would negate multiple advantages of 3D printing. Generally, 3D prints are printed with an infill of about 20%, but this could vary greatly depending on the application of the print. So, when slicing, you specify the thickness of the wall, the infill percentages you want and, maybe, the pattern you want the infill in (the pattern also contributes to the strength of the print along different axes). The slicer automatically determines the boundaries of the design, creates the walls and the infill patterns and specifies it in the gcode file. The below are some examples of different fill patterns at different densities.

Source: Researchgate.net

While 3D Printers can do a lot, they certainly cannot print in thin air. They need a base to print on. So, how do you print a horizontal part coming out of a vertical one, such as the arm on the figure below? The answer is supports. Supports are printed along with the design in a way that they provide a base to such surfaces and can be removed once the print is done. While supports can be incorporated into the design, it is a tedious job to identify every surface that needs support and create one for it. In comes the slicer. You can tell the slicer that you would like supports and the angle at which your printer would not be able to print the overhang (typically 45 degrees). The slicer then identifies the surfaces and automatically creates the supports for them.

Source: pinshape.com

In the end, the slicer does an impressive job of analysing the design and performing multiple functions that end up making the job of 3D printing much easier. Most industrial machines come with their own slicer that can do the job. However, there are multiple slicers that can be used for hobbyist machines, some of them open source. I will surely keep a close eye on what else will be handled automatically by these products. Any ideas?

Printing in 3 Dimensions

I grew up around newspaper printing machines. They changed the world since the first printing press was invented in 1440 in ways that would have been considered incomprehensible at the time. 3D-Printing (officially called Additive Manufacturing) has the potential to change the world in ways that may be even more impactful.

What is 3D-Printing

3D Printing is the process of depositing a material layer by layer to create an object that one desires. Various techniques are used to achieve this. For example, heat is used to melt plastic and lay it down in layers (FDM/FFF). Ultraviolet rays are used to cure resin into shapes (SLA). Lasers are used to solidify powders to achieve the same end (SLS).

Why would you use 3D-Printing

There are multiple advantages worth discussing.

3D printing allows us to create customised products. If you can create a 3D design, it is quite likely that it can be printed. It also allows manufacturing to move closer to the point of use. As an example, use of 3D printers at home by hobbyists continues to grow. The combination of these 2 has resulted in a plethora of freely available designs to solve everyday problems. A visit to sites like Thingiverse will give you a taste of this.

Additive manufacturing results in minimal waste given that we are not carving material away. The process also allows us to do things which are not possible/easy with other processes. It can create assemblies in one piece such as chains. We can configure the material filling within a shape, making the product lighter by using less material.

The usage of this technology continues to grow, almost on a daily basis. It has grown beyond hobbies and replacement parts done within the home.

3D Printing is not nirvana (yet!). It is slow. What can be made industrially at multiple pieces a minute may take hours, or even days to print. Cost is another factor – the combination of raw materials, electricity, etc does not always justify using the technology. Quality is still a concern – the finished product may not stand up to the stresses of real life when compared to a similarly machined product. But, a lot of progress has been made in this space over the past decade or so. The progress continues to accelerate, in my humble opinion.

So, in essence, I am excited! Looking forward to talking about the impact in upcoming articles.

What can 3-D Printing do today?