Fastening Points

When should fastening be considered in the design process for composite and plastic materials? Should it be factored in during the initial concept phase, or during the detailed design stage? Or perhaps somewhere in between? 

In conventional design approaches (Ref1), where materials and manufacturing processes remain consistent, we often rely on established design guidelines and practices. This approach works well once things are standardized and mature. But what happens when materials or manufacturing methods change? When the usual guidelines no longer apply? Who creates new standards, or how do we go about developing new methodologies? 

 In many cases, we may find ourselves in uncharted territory—working with cutting-edge materials or manufacturing techniques where traditional approaches no longer work. This is especially true when tackling complex technical challenges or meeting demanding stakeholder expectations. 

The challenges of fastener choice  

How do we approach fastening when design guidelines are missing, and carry-over is not a viable strategy? Do we select a fastener at conceptual stage and design around it during detail design, or try to find a fastener that fits in with everything else once the concept is finalised and detailed design has begun? Designing around standardised fasteners often causes compromises, and trying to incorporate them into novel manufacturing processes can create extra complexity. Speciality fasteners, on the other hand, may seem like a flexible solution to ‘fit’ into the design later. However, in our experience at bigHead, we’ve seen that even these often lead to unforeseen challenges and compromises. 

So, how can we avoid these pitfalls? The key is to integrate fastening early in the design process, treating it as an essential component rather than an afterthought. To achieve design optimization and maximize manufacturing efficiency, requires an innovative approach1 to speciality fastener design. 

At bigHead we have defined a process for doing this; we call it Bespoke. 

Bespoke fastener design  

Our ‘Bespoke’ process ensures that fastening is considered as part of the overall design and development, and the first, critical stage of the process is to define the requirements fully. 

At the ‘Define’ stage we consider several factors relating to fastening that are easy to overlook in the overall design process. There is no exhaustive list or correct sequence to these considerations, which is why we offer guidance through the whole process. However, we’d like to share a little insight into what we mean by “discuss and define your requirements”. 

These factors play a key role in determining the right fastening solution.

Functional: What fastening elements must work together with each other? What principal components and sub-components does the assembly comprise and what are they made from? Should the fastening be serviceable or permanent? 

Performance: What are the in-service loading and durability expectations? What are the load requirements during assembly? What environmental conditions must the fastening undergo and withstand? 

Aesthetics: Should the fastening be invisible from the reverse side? Are there specific aesthetic or surface finish stipulations? Are there specific colour matching or finish expectations? 

Process integration: When and where do the fasteners integrate into production? Are there automation or tooling constraints that affect fastener designs? What is the impact of a production line–stop, and how can it be mitigated? 

Assembly: Is there sufficient access or clearance for installation? Are there specific torque or preload considerations? Will special equipment or training be required for assembly? 

By considering fastening as a core element of both the design and manufacturing process, you address these elements and make decisions from the very beginning, ensuring that your fastener works seamlessly with all other aspects of the design. Thereby you can avoid compromises and streamline your production. 

So, to answer the question we began with: ‘When should fastening be considered in the design process for composite and plastic materials?’ – Many bigHead customers have achieved success by treating fastening from the outset as part of their overall design & development process. Fastening was an integral element throughout the conceptual and the detailed design phases, leading to smoother production, fewer compromises, and better outcomes overall. 

Discover more about how our design partnership approach can enhance your projects by visiting our Bespoke webpage. 

Ref1 –  Pugh, S. (1991). Total design: Integrated methods for successful product engineering. Addison-Wesley.