Automotive Part 2

Your masterclass in product design and development

Our Insight video series will help you master digital manufacturing.

Every Friday we’ll post a new video – each one giving you a deeper Insight into how to design better parts. We’ll cover specific topics such as choosing the right 3D printing material, optimising your design for CNC machining, surface finishes for moulded parts, and much more besides.

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Insight: Automotive Part 2

Transcript

Hi. Welcome to Protolabs Insight.

If you watched last week’s video you’ll know that we’ve been talking about ways to reduce the weight of automotive components, with an eye on boosting fuel efficiency without compromising performance.

Last week we talked about some of the most common materials you might use, mostly a long list of high-strength, low-weight plastics. Today, we’re talking all about the many different manufacturing techniques out there.

Click to enlarge

Let’s keep last week’s discussion on materials in mind. After all, despite the flexibility in material options, it’s a good idea to understand what material peg fits into which manufacturing hole.

For example, stereolithography – known as SL – can be considered the grandfather of all additive manufacturing technologies. It’s a well-established industrial 3D printing process used to create concept models, prototypes, and complex parts with intricate geometries in as little as one day, and we use it to print parts from nine grades of polymer across three primary groups: ABS, polycarbonate and polypropylene.

Remember, these materials mimic plastics and are not rated for functional product use, but SL does a great job of producing highly accurate prototypes and, as such, is a logical first step for an initial touch and feel of light weighted concept parts. You can also use it to test the form and fit of products that are ultimately destined for die casting with SLArmor – a nickel-plated, ceramic-filled additive material that is very light yet still strong enough to fill in for metal in certain cases.

The process works by essentially drawing the shape of the part with an ultraviolet laser aimed onto the surface of a liquid thermoset resin. After a layer is imaged on the resin surface, the build platform shifts down, a recoating bar applies the next layer of resin and everything repeats layer by layer until the build is complete.

Next up on our 3D printing list is Selective Laser Sintering – SLS – which is generally limited to four types of engineering-grade nylon materials, only two of which are reinforced for high-heat applications and greater structural integrity. Like all the additive processes we use, SLS uses a laser to draw each part layer – this time, onto a bed of nylon-based powder.

It’s ideal for making functional parts that have greater toughness and higher impact strength than parts produced through SL, but it does lack the surface finish and fine feature details that SL offers. Still, this all means it’s good for functional testing.

Of course, as flexible as they are, you don’t always want to use plastic in your parts. This is where the ability to 3D print metal parts comes in incredibly handy, as it can allow you to try out new, lighter designs without having to set up complicated tooling.

The process used for this is known as DMLS, or direct metal laser sintering. This is an incredibly powerful technique that works on a similar principal to SLS. It’s just that, rather than a nylon powder, it uses the laser to sinter layers of metal powder as thin as 20 microns.

Here at Protolabs we use DMLS with aluminium and titanium, both obvious contenders for manufacturing lightweight parts, but it can also be used with stainless steel, cobalt chrome alloy, and Inconel - super strong metals known for their extreme heat resistance and durability rather than weight reduction.

Now, you may be thinking “wait, I thought this was supposed to be all about lightweighting – why on earth are we talking about making things out of steel?

Well, the answer lies in the fact that DMLS can be used to make some truly incredible shapes that would be utterly impossible to manufacture otherwise. Think of parts that are as hollow as an Easter egg but still incredibly strong, or pieces with sloping curves or spider-webbed lattices that provide all the toughness you need but only weigh a fraction of what a solid metal part would. These are just a few of the lightweighting possibilities DMLS can offer.

Now, there’s no such thing as free light weighting. It’s a simple fact that DMLS is slower than other additive processes, and also more expensive. If your part design can be efficiently machined or moulded… well, DMLS may not be the right manufacturing method.

But, if you’re working with complex assemblies, improbable shapes, or parts where small amounts of superalloy go a long way, DMLS might be just the ticket to reduce part weight and cut manufacturing costs.

And that, is the end of our automotive industry two-parter. Have a great weekend and be sure to check back next week for another Insight.

With special thanks to Natalie Constable.