Outline

The blog highlights the source of challenges in being able to design composites suitable for automated manufacturing with DFM considerations.

Abbreviations

DFM - Design For Manufacturing

Challenges at the early stage

As discussed in the previous blog, designers consider specific material, and fabrication limitations when creating designs. To know all about critical design parameters, material parameters, geometric constraints, etc. at an early stage is almost impossible. Thus, A lot of design decisions can not be made during the early stages as there are many unknowns, which leads to

• Challenge 1:  The threat of making too many critical design decisions in production in the early stages of design without considering the manufacturing process. As design maturity increases, it becomes increasingly difficult to implement design changes without affecting component performance or cost.

• Challenge 2: Reliance on isotropic material-based digital design tools constrained by certain geometrical shapes, limiting the design optimization domain to material thickness and geometries. This approach does not consider the different manufacturing process key advantages and limitations, resulting in material/defects probabilities, and shape limitations due to continuous fiber involved in the process. In short the black metal design approach (explained here)
  

There are numerous reasons why engineers pursue the black metal design approach. For one, the established guidelines make the design process straightforward. The challenge is that assessing the strength of a composite structure is more complex than assessing the strength of a metal structure. This is because the layered composites are made out of multiple plies, each with different spatial extents and angles.

• Challenge 3: Current methods and tools used by designers are either geared toward metal manufacturing processes or do not adequately consider composite manufacturing, rendering them a misleading solution. As a result, existing tools are either too component-specific or too general in their approach.

Challenges due to DFM tools

The DFM process requires manufacturing constraints to be known at the time of design creation, which leads to two challenges for composites  

• Challenge 1: Designing for novel manufacturing processes: If the design is using a novel manufacturing material/process, and the manufacturing constraints are not fully understood,
• Challenge 2:  Digital tools' Best practices: If the digital tools used to create the design are derived for use with a different material or process. A strategy for using digital design tools in the context of DFM is required.

Understanding the above-specified challenges provides a good grounding for the problem at hand. In the upcoming blogs, we will dig deeper into the state-of-the-art solution available to such challenges.

Key Takeaways

• The primary challenge of limited knowledge at the early stage of the design
• The heavy reliance of designers' training on metal (isotropic) design, limits their ability to see the composites design from a new approach
• Composites design requires heavy consideration of manufacturing parameters in design, as each process for the same given material will generate different properties
• The Design For manufacturing adds another layer of complexity as composites manufacturing is not a set domain and offers almost endless possibilities to combine and produce the part
• A good shop floor experience with a well-known digital process is a must and goes a long way for DFM in composites design

About Addcomposites

Addcomposites is the provider of the Automated Fiber Placement (AFP) ecosystem - including the Fiber Placement System (AFP-XS), 3D Simulation and Programming Software (AddPath), and Robotic Cells (AddCell). With the leasing program for the AFP system (AFPnext), composites manufacturers can work with thermosets, thermoplastics, dry fiber placement, or in combination with 3D Printers on a monthly basis.

Sources

Design for Automated Manufacture of Composite Structures

Design and Manufacturing Guideline for Aerospace Composites

Design tool for fiber-reinforced polymer structures

Carbon Fiber Composite Design Guide

Composites Manufacturing

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