In my last article I talked about the secret of manufactured construction. Off the back of that I’ve had a good number of people asking for me to delve deeper. In this article I’ve decided to burrow further into the rabbit hole of “Design for Manufacture and Assembly” (DfMA). We hear a lot about this topic in relation to modular construction but what does it really mean? Let’s think about what manufacturing is all about first. Well, to make anything you need to start by buying some “raw materials” or component parts. You take these materials and parts and you do something to them, you apply a process. The result is your product.
When manufacturing a modular building the raw materials and various component parts are very similar, if not the same, as the things used in traditional construction. The way they are assembled is just a lot more systematic and efficient.
For example, if a pallet of OSB boards come in from the supplier, it will still come in standard board sizes. In traditional construction this pallet will probably sit somewhere on the construction site and a subcontractor will go backward and forward, trapesing through mud and up and down stairs with a tape measure and cutting boards to suit every nook and cranny. In modular construction this process is more streamlined and not so laborious. In modular construction the process is planned from the design stage. Boards are laid out in the CAD model and a cut-list is generated for each module. This cut-list is then used at a board saw to have different board sizes pre-cut. The different sizes of boards should then be gathered into batches. The batches should correspond to a module so that they can be transported to the right place in the factory at just the right time to be fixed in position or “consumed” by the manufacturing process.
Quite simply DfMA is all about how we can design a product to be consumed by the manufacturing process as quickly and with as little waste as possible.
By thinking about the entire building and examining it in a 3D model, your designer could even design the modules to minimise or optimise the amount of boards needed to be cut – in which case maybe you don’t need to replace the saw blades as often or maybe you don’t even need buy that expensive board saw in the first place!
SNAPPING IT TOGETHER
You can also imagine that maybe, just maybe, there is a way that you could “design-out” the need to fix those boards with screws? Imagine that they somehow just snapped into place. Well, if you can do that then give me a shout and I’ll hire you! Joking aside, by coming up with a way of snapping the boards in place you’ve just decreased the process time and not just that, you’ve also reduced the number of processes needs to fix the boards. If you can apply this type of thinking to every bit of the modular building, then you’re on the right track to decrease your Takt time and increase your throughput – you’ll make more buildings faster and cheaper. Incidentally you’ll probably also be increasing safety, reducing waste and saving money!
To apply DfMA successfully you need to use tools like 3D CAD and you also need to really understand each step you need to go through during your manufacturing process. With the right tools and the right approach, you’ll be able to demystify DfMA and make sure that your modular construction company is constantly improving.
The above is a very simple example. Maybe too simple! In fact, DfMA needs a collaborative approach to design. When we run DfMA into our design process we integrate the structural engineer, the supply chain, the M&E consultant, the production engineers and even the QS so that we have a clear 360-degree view of every little thing that impacts the design, ensuring decisions aren’t made in isolation and helping us to ensure that we design something that can be manufactured and assembled in the most efficient way possible.
What’s your interpretation of DfMA? Has this simple example changed what you thought it was?