Hello and welcome back to our article series about composite manufacturing, where we try to introduce you to the fundamentals and the complex specificities of designing, programming, and manufacturing CFRP components. While last year’s articles focused on Fiber Placement and prepreg composite materials, we will now introduce you to another set of additive manufacturing processes. We will compare different 3D printing methods, explain what slicing is, why it is necessary and why it can be a complex process, and ultimately showcase some applications where we combine the benefits of fiber placement with the benefits of 3D printing.
Figure 1: A custom-made 3D printing end-effector is printing polymer filament into a curved shape. This complex shape usually needs support elements, but intricate path planning helps alleviate additional supports. Additionally, this end-effector is attached to a KUKA robot. Utilizing a robot opens up many new possibilities due to its flexibility in orientation. A polymer filament is melted and placed to create the desired shape.
In this series, we discuss the pros and cons of 3D printing (additive manufacturing), the different types of 3D printing, its applications, and solutions for the challenges that arise. But let’s start slow:
Common 3D printers can manufacture objects of almost any structure. One of the main characteristics of 3D printing is that these objects are manufactured layer by layer. Depending on the process, the raw material (such as titanium, steel, polymers, etc.), may be gaseous, liquid, or solid and is deposited in the desired locations. The material is then solidified e.g., by applying heat. In most processes, the material is heated during placement and hardens afterward. Sounds simple, right?
Starting with a digital 3D model, a software called the “slicer” slices the object into many layers that are manufactured sequentially. The slicer generates G-Code that is transferred to the printer. The G-Code contains all relevant information to manufacture the part: movement coordinates, velocities, material output, heating levels, etc. Slicers are highly customizable software components. In the following weeks, we will showcase some of the inner workings of slicers and how layers may be optimized.
Let’s compare 3D printing to other methods of manufacturing – why has it become such an important factor in many manufacturing applications? 3D printing is considered an additive, rapid prototyping manufacturing method. This means that it is most efficient when a small quantity of complex parts is manufactured, and the design is subject to change. Nowadays, since the 3D printing processes are constantly being improved and enhanced, material usage of printed components is constantly reduced to the minimum. There are examples of series productions of high-performance polymers for aerospace and medicine. [1, german]
For hobbyists and prototyping, the benefits of 3D printing start to shine: parts are produced quickly, and compared to conventional manufacturing, no additional tools or toolings are required, saving a lot of time and money in the short run and enabling fast and efficient development cycles.
You might be wondering why additive manufacturing is considered more efficient. Check the following table to see why:
|Additive||Subtractive / Conventional
|Gaps, holes, etc. are omitted by design. Only the necessary material is placed (called “addition”). Offcut material is minimized.||Starting from a whole, solid piece of material, gaps, holes, etc. are created by removal (called “subtraction”).|
|Examples are 3D printing and fiber placement.||Examples are cutting, lathing, milling, and drilling.|
The more complex a part is, the harder it is to manufacture using conventional manufacturing methods. A hollow cube, for instance, is easy to print but impossible to manufacture conventionally without additional welding. This also means that the harder it is to manufacture conventionally, the more efficient it is to print! 3D printing has some downsides too, however: depending on the manufacturing process, prototypes might not be as strong as their conventionally manufactured counterpart. It also takes time to manufacture single prototypes, and producing high quantities is inefficient. It is however better to manufacture a part inefficiently as opposed to not at all…
We hope this article gave you some insight into 3D printing, rapid prototyping, and their applications. We will go into more technical details in the future and hope to see you again soon!
Until then, stay safe and stay tuned.