Whilst for ‘form and fit’ the material options are wide open, if function is to be achieved, then materials need to be considered with care.

loop wheels prototype testing

It is also important to review the level of functionality required and whether aesthetics are combined or treated as part of a separate brief.

SLS is a common starting point

The most common starting point for a functional prototype is Selective Laser Sintering or SLS. Producing the part additively in a nylon based material makes for a very adaptable process with a competitive price point. With more than 15 years experience working with SLS, Plunkett Associates are very well placed to advise on suitability to your project. (Material parameters and options can be found here.)

SLS is however, far from the only option, and due consideration should be given to other additive processes (eg FDM, SLA), CNC machining, and vacuum casting to mention a few. Stereolithography (SLA) is included here as some of the current resins offer a surprising level of functionality and combine a superior surface finish to SLS parts.

At high resolution and micro levels, SLA also provides a level of detail/accuracy that cannot be found in FDM or SLS making it one of the few additive options for really small items; all of which we can help you with.

loop wheels prototype function testingFor a good range of material options consider CNC 

In terms of material options, CNC machining excels. Plunkett Associates can provide options from polyethylene (PE) and polypropylene (PP) through (polycarbonate) PC and ABS to glass filled nylon and Ultem. Part size is unrestricted and whilst not offering the material flow characteristics of a moulded part, does allow a good emulation of the final component.

Metal Prototype Options

When addressing function, there will be many applications that require metal prototypes. Plunkett Associates can offer additive options through Direct Metal Laser Sintering (DMLS) from EOS and Laser Cusing from Concept Laser. However the vast majority of prototypes produced are CNC Machined as this offers a fast, accurate option with little or no post processing.

Consider the production intent material

In all cases one of the most helpful indicators as to the best prototyping material will be the production intent material. Sometimes it is possible to work with the same generic material type, other times it will serve as a good indicator of the design requirements.

Other factors (beyond strength) that can influence selection will be temperature both ambient and operating, ductility, hardness, chemical resistance, humidity resistance and aesthetics. Plunkett Associates can advise and support you through your selection process with the latest material data alongside process compatibility.

prototype function testingAre aesthetics important at this stage?

As indicated earlier, there can be a desire to incorporate a cosmetic finish with a functional prototype. This may be straightforward but can also realise some limitations. If for example, a living hinge requiring PP material is required in a particular colour. PP can be cnc machined, but does not take a very good finish and is difficult to paint. In some situations like this it may be necessary to separate the cosmetic and functional requirements into two different prototypes, or utilise a process usually targeted at greater quantities such as vacuum casting or one of the tooling options.

Plunkett Associates is here to ensure that you get the best from your prototyping experience. With no vested interest in any one process, we can offer truly impartial guidance on the options, and support you all the way from initial prototypes to subsequent tooling and production.

If this is what you are looking for, please give us a call or upload an enquiry here.