Size Matters!

All the time people say to me that machines have to be this size or that in order to be taken seriously for mass production in metal AM, well what does that really mean?

It often comes across that unless AM is capable of building whole engine blocks for motor vehicles, or huge parts of a landing gear or airframe structure, then the technology can't be considered as a production tool of today. This is probably driven by the fact that to date these two sectors have been the main targets by those developing the technology. However, the industrial world?has more to offer than just lighter?aircraft and fancy cars. In fact, it is very probable that the vast majority of metal AM prototyped?parts to date, that could be mass produced,?and that have been built on a mid-sized AM platforms, have been from outside of these two sectors.

Therefore, as with multi-axis machine tools, that come in all sorts of sizes, it is really dependent on what is being produced and whether the part, or parts, concerned have been properly designed for Additive Manufacturing. However, it also has to depend on?the actual production requirements driven by the market demand, and once a part can be built in a stable process, on whether there is a well defined set of post-processing steps to finish the parts accordingly.

As an example, the main image above shows a close-up from a whole platform of the now famous Renishaw bottle openers. It's a fully functional part and designed for AM from the start.?It is, therefore, easy to build in a single layer when just a couple of hundred are required. All well and good until perhaps you need a lot more than just a couple of hundred. Almost, automatically this has lead many to believe you either need more machines or a much larger machine. However,?all it actually takes is to think about the whole available build volume that a machine has to offer.

So by thinking just a little differently about how this part could be built it is fairly simple to show that it's also possible to create multiple layers of parts in a single build, as?demonstrated below. In this demo build there?are 4 layers of parts totalling 480 units; that's certainly a fair production batch, and can be built as and when required at a moments notice. It was made possible due to the correct use of support structures between each layer in the stack. The efficient use of supports also resulted in all of?the parts?being easy to remove from the build plate, and they needed very little hand finishing. The finishing?step could, in fact,?easily be?carried out in a?tumbling machine for?volume production,?What's more these are in AlSi10Mg, and after the proper heat treatment, yes they work!

There are obviously risks associated with stacking parts in this way, but for the appropriately designed part, and that also includes the correct choice of alloy that the parts are to be built with,?the risk is minimal. However, as with many build layouts, there?will be?more than one strategy that could enable the user to?successfully build?parts. Hence,?by considering a relatively simple change to the build layout of this particular part,?we could achieve a?higher packing density with up to five layers. Then?it would also be possible with the right laser scanning strategy to produce well over a 1000 per build in a single machine, and without any change in the size of the AM machine being used.

It turns out then that it's not the size of the machine that might be the limiting factor but instead the understanding of support strategies, and having the software to implement them, coupled with the flexibility to change laser scanning strategies to optimise for a particular production build requirement. Ok, it's not an "industrial" application,?and unfortunately there's not yet the freedom to publicise any such examples, but hopefully it serves to start some creative thinking in terms of considering mid-sized AM platforms for full-scale AM production.

One such combination of?build preparation software, that also allows the ability to create?bespoke laser scanning strategies, and machine is QuantAM and either the AM 400 or?RenAM 500M from Renishaw.?Furthermore, the?Additive Manufacturing Solutions Centres are available for companies to test the waters of metal AM production so you don't have to be on your own, or have to figure things out for yourselves. Feel free to make contact to find out how Renishaw can assist in acquiring the knowledge and understanding needed to create successful build strategies.

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