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Individual Adaptation

The previous articles highlight the different parameters that can be used to optimize a CFRP laminate. These laminates can be optimized according to several criteria: Time: Reduction in manufacturing time Cost: Optimization of material usage and machine time Quality: Minimization of the chance that defects occur Using the Time/Cost/Quality triple constraint analogy helps us understand that only two of these three criteria can be met at the same time and that there always is a trade-off when selecting them. If a laminate needs to be manufactured quickly and at low cost, its quality is likely to suffer, and defects may [...]

Minimum Gap Length

When a CFRP part is integrated into an existing assembly, the CAD definition of the laminate may contain holes for screws or other fasteners. The laminate, however, should not contain any holes as these would lessen the structural strength of the part. Inserting fasteners later will almost always be a better choice than leaving holes in the laminate, as such holes are then not covered by fibers in the process at all. In such cases, CAM software is necessary to provide the programmer with the possibility of controlling how large a gap must be to be left out when placing [...]

Achieving minimum tow length

In this series of blog posts, we present the manufacturing process of CFRP components. We split the many, closely linked subjects into separate posts that can be easily understood. If you are new to this series, we recommend starting here: AFP Endeffectors . In this blog post about end effectors, we give you an overview of the structure of AFP layup heads, how they are constructed, and which functions they need to fulfill. One very important factor of AFP layup heads is that the tows are limited in length by the minimum tow length , and, of course, by the [...]

Boundary Coverage Types

If you look at the previous article about staggering plies , you will notice that tows often start and end outside the given boundary. Although this may be considered a waste of material, it is neither good nor bad - it depends on how the laminate will be processed and what kind of boundary was used. Oftentimes, there are multiple boundaries – an Engineering Edge Of Part ( EEOP ) and a Manufacturing Edge Of Part ( MEOP ). The EEOP denotes the dimensions of the finished part, while the MEOP denotes the boundary to be used for manufacturing the [...]

Ply Optimization: Staggering

In the previous article , we introduced a lot of parameters that are used to optimize the laminate to be manufactured. “Optimizing” a laminate can refer to reducing the waste produced during the manufacturing process or decreasing the chance that defects in the finished part may occur. Now we will look at the so-called staggering , why it is needed and what exactly it is supposed to do. Background : To accurately calculate the mechanical parameters of CFRP laminates - like the moduli, strength, the coefficients of thermal expansion, and stress responses of the material - the Classical Lamination Theory [...]

CFRP Laminate Structure

In the last articles, we gave insight on where carbon fiber reinforced plastics (CFRPs) are used, how they work, and how they can be used to manufacture highly durable, high-performance parts. Furthermore, we highlighted which basic functions a layup tool must fulfill to properly handle prepreg tows. Now we will show you how the plies, also called the ”stacking”, can be defined using our AFP process planning software CAESA® Composites TapeStation . This type of software allows for the offline process planning and programming of AFP processes and closes the gap between design and manufacturing . The design requirements (see article [...]

AFP End-Effectors

In the last article , we gave a short summary of the AFP process and how laminates are built. In this article, we will go into detail about the tools that are required to manufacture CFRP laminates from prepreg tows. We will focus on the structure of AFP layup heads and for illustration purposes we will use the fiber placement head from our colleagues at the IFW in Stade . Note that the term “end-effector” usually refers to the last element in a kinematic chain, such as a robot system. Since this fiber placement head is supposed to be attached [...]

The AFP Process

In this article, we want to outline the AFP process and showcase some of its advantages and limitations. Basic principle of Automated Fiber Placement (AFP) Process Narrow stripes of prepreg material (tows) need to be placed in such a way that a certain surface is covered by multiple layers of CFRP material. There should be no areas left uncovered. The result of the layup is a layer structure called laminate . In its simplest form, the laminate is made up of flat layers that are placed on top of each other. Every layer of the laminate is called a ply [...]

How to use CFRP?

In the last article , we mentioned different processes that can be used to manufacture CFRP parts. Here we want to give a more detailed overview of the most common manufacturing methods for CFRP parts and how they work. Wet carbon fiber layup In wet carbon fiber layup, the fibers often come in the form of twills, that need to be cut to size, are first laid out by hand onto a mold. The mold needs to be manufactured beforehand as its structure is what dictates the form of the part that is to be manufactured. They can be [...]