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Prototyping is a vital process in product development but how do you know which process is best for you and your project?
In this article we asked our Customer Engineer Manager, Europe, Robert Musselle, to explain what you need to consider.
Q1. Why should I go to the time and cost of prototyping my part in the first place?
Robert: It’s a big mistake to skip prototyping and testing because if you do find an error it’s much quicker and cheaper to fix it in the early stages of development than when you are committed to manufacturing.
And rapid prototyping as the name suggests is fast. You can often have a prototype delivered within 24 hours of uploading your CAD.
Q2. With so many prototyping processes available, how do I choose the right one for me?
Robert: It really depends on where you are in the product development cycle. We all know about 3D printing and how that has revolutionised rapid prototyping, but just like any other process, it has its advantages and disadvantages.
You may find that you use more than one technology before you finally sign everything off ready for manufacture.
Q3. What are the different technologies that can be used for prototyping?
Robert: In theory, you could use any production technology for prototyping. Exactly which one you use will depend on a number of different factors such as speed, appearance, what material properties are important at that time, how many prototypes you need for testing and cost.
Everyone thinks about 3D printing and it’s worth noting that there are a number of different additive manufacturing technologies out there that can produce not only plastic parts but also metal. But that’s not the only prototyping technology, CNC machining is also commonly used, as is rapid injection moulding.
Q4. If I am developing a new part, where do I start?
Robert: You would normally start with an idea or concept model. At this stage, you may simply want something to present and talk through. So, speed and probably appearance are going to be important.
3D printing is an obvious route to go down as you can get models in lots of different materials including metal, but it’s not the only answer. CNC machining provides a part that is very strong with a great surface finish.
Q5. When the concept model is approved what are the next steps in prototyping?
Robert: Typically, there would be a number of stages that you would need to go through before you are ready to move to manufacturing.
Once the concept is agreed and you know that you can actually manufacture your design, you will probably need to check its form and fit to make sure that you can assemble the parts – so you are checking for dimensional differences and tolerances.
When you are happy that the part can be assembled you need to move on to functional testing. At this stage, you need to consider what material you are using for the final part. This is where material choice is vital. What mechanical properties do you need? Does it need to resist certain chemicals? What about electrical and thermal conductivity and so on?
Crucially when it comes to a material’s properties you must remember that these are affected by how you process it and this could affect which technology you choose. You might also need a higher quantity of prototypes to test at this stage.
After this you might need to move on to life testing, regulatory testing to meet certain industry standards and even a pilot launch to test your concept with customers.
This means you might for example move from 3D printing for early-stage prototypes to injection moulding for the latter stages – assuming of course that it is injection moulding that is the final production process.
But even that is a bit over-simplistic. If we are looking at prototyping plastic parts then there are different additive manufacturing technologies. Which one you choose will depend on what material you want to prototype, what accuracy you want and a number of other factors.
You need to ask what stage of prototyping am I at? And what attributes do I need to test for at that stage?
Q6. Any other advice?
Robert: Remember why you are prototyping and what the final goal is. Prototyping should check three things.
First, the part’s functionality, in other words, will the prototype represent the end product – not just for assembly but also its material properties.
Second, can you actually manufacture the part using the final production process? And third is it viable - do you need to do any market testing?
As far as the details are concerned in terms of selecting the best prototyping process, you need to understand the various technologies each of which is better for some things than others. If you outsource the rapid prototyping then get the supplier involved right from the beginning and talk to their engineers.
The Protolabs team are always available to support Designers and Engineers on their product development journey. To access more tips and resources, head to the website https://www.protolabs.co.uk/resources/