DFMA beyond the hashtag / Offsite 2024 PrefabAUS Roadmap to 2033 / Nick Hewson / Arboralis
At the Offsite 2024 PrefabAUS Annual Conference, Nick Hewson, Director of Arboralis, presented a compelling address focused on the future of prefabricated construction and the industry’s roadmap to 2033. Hewson, a structural engineer with extensive experience across design, manufacture, and installation, offered deep insights into the principles of Design for Manufacture and Assembly (DFMA) and their application in prefabricated building systems. He shared his journey from being known as the “timber guy” to becoming a leading advocate for mass timber and prefabricated timber frame construction, highlighting key lessons learned and innovative practices that can reshape the industry.
Through case studies such as the Iron Creek Bay project in Tasmania, he demonstrated the challenges, mistakes, and critical solutions that have informed his approach to prefabricated construction. Hewson’s presentation also provided actionable tips for designers, emphasizing the importance of collaboration, optimization, and continuous feedback loops to achieve more efficient, sustainable, and cost-effective building practices. His address underscored the need for the industry to embrace innovation, leverage technology, and integrate DFMA principles more deeply to meet the growing demands of the future.
DFMA – What does it mean?
DFMA stands for Design for Manufacture and Assembly. It is a design approach that focuses on simplifying and optimizing the design of a product for ease of manufacturing and assembly. The goal is to reduce costs, streamline production processes, improve quality, and decrease time-to-market by considering manufacturing and assembly aspects in the early design stages. Essentially, it ensures that a product is designed with its future manufacture and assembly in mind, allowing for efficiency improvements in both areas.
Design for Manufacture (DFM): This component focuses on simplifying the design of individual parts to minimize manufacturing complexity. The main objective is to reduce the part count, standardize parts and materials, and simplify production processes. This can lead to cost reductions, improved production efficiency, and enhanced product quality.
DFMA is often divided into two components:
Design for Assembly (DFA): This component emphasizes the design of the product for ease of assembly. The aim is to reduce the assembly time and costs by minimizing the number of assembly operations, enabling more straightforward assembly processes, and often, facilitating automated assembly. The focus is on reducing the complexity of the assembly process and ensuring that the final product can be assembled efficiently.
Together, these components help create products that are easier and less costly to manufacture and assemble, leading to increased efficiency, which is particularly beneficial in industries such as automotive, aerospace, and electronics, as well as in construction, where DFMA principles are applied to prefabricated building components.
DFMA – What does it mean to me?
The concept of Design for Manufacture and Assembly (DFMA) emphasizes that design should not only focus on the aesthetic and functional aspects of a product but also on its manufacturability and ease of assembly. The principle of integrating design for manufacture (DFM) and design for assembly (DFA) suggests that these elements cannot be considered in isolation. Instead, they must be addressed concurrently during the design process to optimize both the manufacturing and assembly processes and to ensure the product is designed efficiently from the start.
DFMA is typically characterized by a linear process flow where the design is initially created, then passed down to manufacturing and lastly to assembly. However, this linear sequence often results in missed opportunities for improvement because feedback from the manufacturing and assembly phases does not always flow back upstream to influence the initial design stages. This lack of feedback can lead to inefficiencies, higher costs, and longer development times.
To enhance the effectiveness of DFMA, it is crucial to establish a more iterative process where information and insights gained during manufacturing and assembly are fed back to the design phase. This feedback loop can lead to continuous improvements in product design, making it more aligned with practical manufacturing capabilities and assembly requirements. By doing so, potential problems can be identified and corrected earlier in the process, which can significantly reduce costs, improve quality, and speed up the time to market.
Implementing a system where feedback is actively sought and utilized requires changes in communication and workflow processes. It necessitates a collaborative approach where designers, manufacturers, and assemblers work closely together throughout the project lifecycle. Such collaboration ensures that knowledge and experiences are shared, leading to more informed design decisions that consider all aspects of the product’s lifecycle.
My journey in timber
Early Career and Introduction to Timber
Nick Hewson began his career as a consultant structural engineer. During these initial years, he gained broad experience across various domains of construction and engineering. However, his path took a significant turn towards timber when he found himself frequently called upon as the “timber guy” in projects needing specialized knowledge to impress clients. This role not only highlighted his aptitude for working with timber but also ignited a passion for exploring more about this versatile material.
Specialization and Mastery
As he delved deeper into the world of timber, Nick’s expertise grew, leading him to spearhead several projects that showcased the potential of timber in modern construction. His move to Melbourne in 2010 marked a pivotal phase in his career, bringing him into closer contact with innovative timber construction techniques, including Cross-Laminated Timber (CLT). His experience in the UK with CLT provided a strong foundation, but the dynamic construction environment in Australia offered new challenges and opportunities for growth.
Manufacture
In 2016, Nick Hewson joined XLam, a pivotal move that marked his deeper involvement in the manufacture aspect of construction, particularly focusing on the prefabrication of timber. At XLam, he experienced a significant epiphany, realizing the vast potential and his own previously untapped depth of knowledge in timber construction. This realization spurred him to undertake a crash course in the ‘M’ part of DFMA (Design for Manufacture and Assembly), significantly enhancing his expertise and positioning him to lead innovative projects in timber prefabrication. His time at XLam not only broadened his technical skills but also solidified his commitment to advancing prefabricated timber solutions within the construction industry.
Lessons and Mistakes
During the construction process, several challenges were encountered, particularly in the handling and machining of Cross-Laminated Timber (CLT) panels. A significant issue was that some of these panels required more than four hours to machine. This extended machining time was not only a productivity concern but also impacted the overall project timeline and cost-efficiency.
Additionally, the lifting of some of the CLT walls presented another set of challenges. The flexibility of these walls raised concerns regarding the safety and efficiency of the lifting process. Ensuring that these large, flexible panels were handled correctly required careful planning and precise execution to prevent any structural damage or safety incidents.
To address these challenges effectively, spending time with the factory team proved invaluable. This direct engagement allowed for better communication, immediate feedback, and quicker problem-solving. It facilitated a deeper understanding of the practical difficulties faced during the manufacturing phase and led to the development of more efficient processes for future projects. The collaboration between the design and manufacturing teams was crucial in identifying and implementing practical solutions to reduce machining time and ensure safer handling procedures for CLT panels.
Mistake #1: Excessive Use of Small Panels
The first mistake identified was the excessive use of small panels in the construction process. While CLT offers numerous benefits in terms of strength and sustainability, its application in the form of numerous small panels proved to be inefficient. These smaller panels necessitated more connections and increased the complexity and time required for assembly. Furthermore, handling small panels can often negate the time-saving and structural benefits that larger CLT panels typically provide.
It was observed that these construction elements would have been better suited to alternative materials that are more accommodating to smaller sizes without compromising efficiency and effectiveness. The lesson here was to more carefully consider the scale and material characteristics in the design phase to match the material attributes effectively with the project’s structural and aesthetic needs.
Mistake #2: Lack of Optimization in Panel and Opening Design with Architects
The second mistake revolved around the collaboration and optimization processes between the design teams, particularly the architects, and the manufacturing requirements. There was a specific instance where the right-hand panel design significantly outperformed other panel designs in terms of manufacturing efficiency. This panel was easier to handle and required less CNC machine time, which is crucial for maintaining project timelines and reducing costs.
The core issue was the initial failure to optimize all panel designs and openings comprehensively with the architectural plans from the beginning. This oversight led to inefficiencies in other panels that did not align as effectively with the manufacturing processes, resulting in increased labor and time, which could have been minimized with better upfront coordination.
From these mistakes, the crucial takeaway is the importance of integrating architectural design and manufacturing considerations from the earliest stages of the project. This integration ensures that all elements are designed not only for aesthetic and structural integrity but also for manufacturing and assembly efficiency. Adopting a more collaborative approach between architects and manufacturers can lead to optimizations that save time, reduce costs, and enhance the overall quality of the finished structure.
Iron Creek Bay, Tasmania: A Case Study in Prefabricated Construction
In the picturesque setting of Iron Creek Bay, Tasmania, a significant prefabrication project was undertaken, comprising 19 buildings divided into three distinct types. This project required a collaborative effort where materials and engineering design were meticulously coordinated to cater to the unique requirements of each building type, including pavilions. The focus was on optimizing the use of materials and minimizing on-site operations, a critical factor given the repetitive nature of 15 similar structures, making efficiency improvements particularly impactful.
Design and Structural Strategy
The architectural strategy involved the use of Cross-Laminated Timber (CLT) fin walls that played a dual role in both aesthetics and functionality. These walls effectively supported the roof, which was strategically designed to span from front to back across internal walls. This design not only provided the necessary structural integrity but also enhanced the spatial dynamics of the interiors.
Challenges and Lessons Learned
Mistake #1: Steelwork Design Misalignment
The project encountered a significant challenge related to the steelwork design, which was handled by a different engineering team. The steel structure intended to support the CLT was not robust enough, leading to a softer cantilever design than anticipated. This issue with tolerances not being met highlighted the need for more integrated teamwork and better communication between different engineering disciplines to ensure all components work harmoniously.
Mistake #2: Installation Issues with Pre-Installed Membranes
Another critical issue arose with the pre-installed membranes on the panels. There were instances where these membranes were manufactured or installed incorrectly, sometimes even reversed. This mistake led to additional time and resources spent on corrections during assembly. The lesson learned was to design these components in such a way that they can only be installed in the correct orientation, potentially through the use of keyed features or asymmetrical designs that prevent incorrect installation.
Mistake #3: Design Flaws with CLT Fin Walls
The design of the CLT fin walls also presented challenges. These walls were intended to hang off the floor, forming a downstand, and cantilever past the roof to create a parapet. However, the precise execution required left no margin for error, resulting in inevitable gaps. Future designs were recommended to include a separate parapet or an overlapping detail to allow for some level of adjustment and to accommodate on-site conditions more effectively.
Conclusion: Advancing Through Innovation and Reflection
The Iron Creek Bay project, despite its challenges, provided numerous insights into the potential and pitfalls of prefabricated construction. Each mistake encountered served as a stepping stone for refining methods and improving future projects. The key takeaway was the importance of integrating design, manufacturing, and assembly considerations from the outset and ensuring clear communication and collaboration across all teams involved. As the industry moves forward, these lessons become vital in shaping more efficient, reliable, and sustainable construction practices.
Case Study: Innovative Restaurant Building Design Using Folded Plate Structure
In the pursuit of constructing a modern restaurant building, the initial architectural concept featured traditional coffers, which while aesthetically pleasing, posed challenges in terms of material usage, transportation logistics, and on-site construction time. The need for a more efficient and cost-effective design led to the exploration of an alternative approach leveraging the principles of Design for Manufacture and Assembly (DFMA).
Original Design Challenges
The original design with coffers involved complex structures that required extensive materials and labor. Additionally, the presence of multiple balcony columns not only interrupted the visual and functional flow of the space but also added to the structural complexity and material costs.
Transition to Folded Plate Structure
In a strategic shift, a proposal was made to utilize a folded plate structure instead. This innovative design approach significantly streamlined the construction process by reducing the number of distinct structural elements needed, thereby minimizing material requirements and simplifying assembly. The folded plate structure also allowed for the removal of balcony columns, creating an unobstructed, open space that enhanced the architectural appeal of the restaurant.
DFMA Implementation and Cost Savings
Applying DFMA principles to the folded plate design facilitated precision in manufacturing and streamlined assembly processes. By designing components that were easier to produce and assemble, the project realized considerable reductions in manufacturing time and on-site construction duration. Moreover, the transport of these prefabricated components to the site was more efficient, further cutting down logistical costs.
The implementation of DFMA not only optimized the structural design but also brought significant cost savings specifically related to the roof construction. The roof, integral to the folded plate structure, was designed in a way that maximized material efficiency and minimized waste. This approach not only reduced the immediate costs associated with materials and labor but also contributed to long-term savings in maintenance and energy consumption, thanks to the inherently sustainable design features.
Conclusion: Enhanced Aesthetics and Functionality
The transition from a coffered structure to a folded plate structure, guided by DFMA principles, not only addressed the practical considerations of cost, time, and material efficiency but also enhanced the aesthetic and functional qualities of the restaurant building. The removal of balcony columns opened up the space, providing patrons with an uninterrupted dining experience and a visually striking architectural environment. This case study exemplifies how innovative engineering and design approaches, when aligned with DFMA principles, can transform a project, delivering both economic benefits and superior architectural outcomes.
Top Tips for Designers in DFMA
For Designers:
Hands-on Experience: Emphasize gaining practical, hands-on experience with both manufacturing and assembly processes. It’s crucial to visit factories and sites, especially for projects you are directly involved in, to get a real sense of how designs come to life.
Communication with Suppliers: Maintain regular and open communication with suppliers. The landscape of manufacturing and materials can change rapidly, and staying informed helps in adapting designs efficiently.
Clear Scope Definition: Ensure clarity in the scope of what you are providing versus what the supplier is responsible for. Be prepared to offer flexible solutions when complete answers aren’t available at the outset.
Purposeful Documentation: Analyze the purpose and value of your documentation. Decide whether it is primarily for the manufacturer or the installer, and tailor it to suit their needs.
Precision in Tolerances: Establish clear tolerances early in the design process to avoid discrepancies during manufacturing and assembly.
For Manufacturers:
Engagement Activities: Organize more open days, hands-on demonstrations, and tours to bridge the gap between design concepts and manufacturing realities.
Capability Updates: Provide regular updates to designers about manufacturing capabilities to ensure design feasibility and to foster innovation.
In-House Design Consultation: Clearly communicate how much design work is handled in-house versus the expectations placed on external consultants.
For Assemblers:
Feedback Mechanisms: Don’t wait until the end of a project to express concerns. Close the feedback loop continuously throughout the project to ensure improvements and adjustments are timely.
Early Engagement: Engage with the design team early in the process. Consider being involved in the design phase, or even initiating design proposals, to ensure assembly considerations are integrated from the start.
By adhering to these tips, all parties involved in the DFMA process can work more cohesively, leading to more efficient, cost-effective, and higher-quality outputs. This collaborative approach not only enhances the individual components of a project but also the architectural integrity and functionality of the final construction.
Closing the Loop
Closing the loop in the linear workflow of design, manufacture, and assembly is crucial for enhancing the efficiency and effectiveness of production processes in the construction industry. By fostering a more interrelated and interactive approach among these stages, stakeholders can ensure that feedback and insights gained during manufacturing and assembly inform and refine the initial design phases. This iterative loop not only mitigates the risks of discrepancies and errors but also promotes innovation by allowing real-world assembly and manufacturing challenges to influence design modifications directly. Such a dynamic and cyclic process ensures continuous improvement, leading to cost savings, reduced time frames, and higher quality outcomes. Implementing this integrated approach requires robust communication channels, collaborative planning sessions, and a shared platform where data and feedback are actively exchanged between designers, manufacturers, and assemblers, thus truly closing the loop in the project workflow.
