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Practice - A6

From CKN Knowledge in Practice Centre
Welcome to the Practice volume. This volume contains a collection of practice documents providing guidance and step-by-step workflows on composite materials design and manufacturing. By clicking the links below, you can access the state-of-the-art practice to develop, optimize and troubleshoot a part, a process or a factory.

Want to learn more about the Practice volume? Refer to the Level I view to navigate the Practice volume quickly and learn more about the different type of workflows. Refer to the Level II view to learn more about the Practice volume and the underlying concepts of this volume.

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Are you deciding on your manufacturing process and need some guidance? This section of the KPC provides guidance on scoping out the process steps for a variety of cases. You will be guided from a blank page to conceptual and then detailed production design, and into production. You will also find detailed information on laying out your factory and the equipment and tooling you will need. Click here to explore the development practice documents.

Do you have an existing manufacturing process but would like to improve your part quality, or increase throughput rate, or reduce cost? This section helps you optimize your process and factory by using quality, rate, and cost as the objective functions. Click here to explore the optimization practice documents.

Is your manufacturing process failing to meet requirements? This may be the result of a single process step, or a combination of several process steps not meeting specifications. It may be due to the layout of the process steps themselves. Perhaps it is only a failure of your sensors which are providing you with a false negative. Click here to explore the troubleshooting practice documents.

How to use this volume[edit | edit source]

Volume Framework[edit | edit source]

Practice is where engineers spend most of their time and where a substantial amount of value and cost can be gained or lost. Good decision-making when putting knowledge into practice means that little rework needs to be done on the physical parts and the processes used to make the parts. This leads to efficient factories with minimal downtime, rework & intervention, non-conformances, scrapped parts, etc. The Practice volume consists of a number of practice documents that provide guidance on design analysis steps within each of three workflows:

  1. Development
  2. Optimization
  3. Troubleshooting

The guidelines are presented with the goal of assisting you, the knowledge user, with understanding what steps are best taken in order to make sound decisions while navigating these workflows. The practice documents rely on Foundational knowledge, Systems knowledge and information from the Systems catalogue when describing how and why certain steps should be taken. Method documents are particularly important and referenced throughout the practice documents since a given practice consists of executing the relevant methods. While practices for different factory layouts may have different high-level content, it is important to note that much of the low-level content (method documents, foundational knowledge and systems knowledge) is identical throughout, and that the same physics and interactions apply in all cases, even though some aspects may be more important to certain manufacturing processes than others.

As discussed in Systems Knowledge, there are four classes of objects that interact with each other as a system to fully define a (sub-)process: Material, Shape, Tooling and consumables, and Equipment (MSTE collectively). In this practice volume we utilize the concept of design-gate indices to describe the state of each of the MSTE object classes. The four possible design-gate indices are shown in the table below:

Design-gate Index Design-gate Index Name Design-gate Index Meaning
_ Blank page No decisions or commitments have been made yet.
1 Conceptual screening Conceptual decisions have been made. You have screened the type(s) of your manufacturing (MSTE) system but nothing has been purchased yet. At this stage you have significant freedom to make changes because the cost of change is low.
2 Preliminary selection Design choices are being evaluated and options down-selected. You have selected and specified all the objects of your manufacturing (MSTE) system. MSTE objects are fully specified and some may be purchased, but they can still be modified to alter their effect on the system. There is some freedom to make changes; the cost of change is high, but reasonable.
3 Detailed finalization The manufacturing (MSTE) system is now ready for production. You have finalized and qualified your manufacturing (MSTE) system and have met all specifications. You have essentially no freedom to change anything about your process. At a minimum, any changes will come with substantial cost.

In this context, Development workflows are workflows that have a goal of progressing forwards in production design, towards full production (design-gate index = 3). Optimization workflows have a goal of finding a better combination of design choices to improve the production configuration. In that sense the design indices always start and end at 3 (production) for an optimization workflow. Troubleshooting workflows seek to answer the question "why?". When a production configuration is not working properly it is important to understand what has caused this to happen and understand why the systems in your manufacturing process are lacking robustness. Troubleshooting workflows assist you in moving backwards through the development process (towards 1) to find the root cause so that the root cause can be corrected by following the appropriate Development workflow.

It is currently assumed that you have initialized your development process and have an overall idea of the MSTE objects at a conceptual level, that is your MSTE objects are already developed to at least the design-gate index 1. The proposed workflows therefore do not provide guidance on the design-gate index 1. This is summarized in the following table:

Object Class Minimum starting state Meaning
Material (M) 1 You have selected the types of matrix (thermoset vs thermoplastic, polyester/vinylester/epoxy, etc), reinforcement material (glass fibre, carbon fibre, aramid fibre, etc) and reinforcement architecture (unidirectional, woven, braided, NCF, nonwoven, knitted, etc) based on the main process/factory workflow, cost, rate and quality considerations.
Shape (S) 1 You have a defined functional structure and working principles. The overall size, shape and interactions with other parts is defined.
Tooling & consumables (T) 1 Considering the equipment and process/factory workflow(s) selected, you have some idea of the type of tooling and consumables you would like to use (one-sided tool/multi-sided tool, heated tool/passive tool, flow media, etc.
Equipment (E) 1 You have selected the main processes/factory workflows that you would like to consider for the part based on considerations such as cost, rate, quality, existing equipment, part geometry, etc.

Volume Features[edit | edit source]

Coming soon.

Content[edit | edit source]

Development workflows[edit | edit source]

Development is the process of advancing the part and process configurations beginning at anywhere from a conceptual state up to the production state. The development process begins with a design process initializations steps. At present, the Knowledge in Practice Centre (KPC) does not attempt to guide you through these initialization steps. This is followed by an iterative process where the factory cells are identified, developed and subsequently assessed for feasibility. The assessments are done for both individual cells and for the factory as a whole (considering all cells). This loop is iterated over until the factory is fully defined with all its cells and process steps at a production state and the assessment of the part and process against the functional requirements is passed. Click here to explore the development workflows.

Learn more about how to develop:

  • your product
  • your process
  • your equipment and tool
  • your factory

Optimization workflows[edit | edit source]

Optimization is the process of generating numerous possible part configuration and manufacturing processes, manufacturing cell configurations and then selecting the most suitable option for achieving the cost, rate and quality goals. In effect, optimization is an expanded development workflow where an extended number of possible configurations are considered and then down-selected to the most optimum configuration that meets the functional requirements. Click here to explore the optimization workflows.

Learn more about how to optimize:

  • your product
  • your process
  • your equipment and tool
  • your factory

Troubleshooting workflows[edit | edit source]

Troubleshooting is the process of identifying problems in the manufacturability of a part and then taking steps to trace and correct the root cause of these problems by re-developing aspects of the part and/or process. A good development workflow should result in a process that is robust and not prone to producing bad parts given the expected variability in the system objects. If this is not the case, then additional controls or modification of the process will need to be made, and the troubleshooting workflows provided here are intended to guide you through to find the most common problems. Click here to explore the troubleshooting workflows.

Learn more about how to troubleshoot:

  • your product
  • your process
  • your equipment and tool
  • your factory

About Help
CKN KPC logo


Welcome to the CKN Knowledge in Practice Centre (KPC). The KPC is a resource for learning and applying scientific knowledge to the practice of composites manufacturing. As you navigate around the KPC, refer back to the information on this right-hand pane as a resource for understanding the intricacies of composites processing and why the KPC is laid out in the way that it is. The following video explains the KPC approach:

Understanding Composites Processing

The Knowledge in Practice Centre (KPC) is centered around a structured method of thinking about composite material manufacturing. From the top down, the heirarchy consists of:

The way that the material, shape, tooling & consumables and equipment (abbreviated as MSTE) interact with each other during a process step is critical to the outcome of the manufacturing step, and ultimately critical to the quality of the finished part. The interactions between MSTE during a process step can be numerous and complex, but the Knowledge in Practice Centre aims to make you aware of these interactions, understand how one parameter affects another, and understand how to analyze the problem using a systems based approach. Using this approach, the factory can then be developed with a complete understanding and control of all interactions.

The relationship between material, shape, tooling & consumables and equipment during a process step

Interrelationship of Function, Shape, Material & Process

Design for manufacturing is critical to ensuring the producibility of a part. Trouble arises when it is considered too late or not at all in the design process. Conversely, process design (controlling the interactions between shape, material, tooling & consumables and equipment to achieve a desired outcome) must always consider the shape and material of the part. Ashby has developed and popularized the approach linking design (function) to the choice of material and shape, which influence the process selected and vice versa, as shown below:

The relationship between function, material, shape and process

Within the Knowledge in Practice Centre the same methodology is applied but the process is more fully defined by also explicitly calling out the equipment and tooling & consumables. Note that in common usage, a process which consists of many steps can be arbitrarily defined by just one step, e.g. "spray-up". Though convenient, this can be misleading.

The relationship between function, material, shape and process consisting of Equipment and Tooling and consumables


The KPC's Practice and Case Study volumes consist of three types of workflows:

  • Development - Analyzing the interactions between MSTE in the process steps to make decisions on processing parameters and understanding how the process steps and factory cells fit within the factory.
  • Troubleshooting - Guiding you to possible causes of processing issues affecting either cost, rate or quality and directing you to the most appropriate development workflow to improve the process
  • Optimization - An expansion on the development workflows where a larger number of options are considered to achieve the best mixture of cost, rate & quality for your application.