The magazine of Friedhelm Loh Group

The magazine of Friedhelm Loh Group

LKH Tech Talk

Plastic: Keeping costs under control

From product design and engineering, material selection and mould engineering all the way through to production and packing – injection moulding offers more ways of cutting costs than you might think. Which ones are the most promising, though? We asked Thomas Ritter, Head of Engineering at LKH, how he works with his customers to make components more cost-effective.

Text Meinolf Droege ––– Photography


Which tweaks help?

Mr. Ritter, according to a German saying, having good intentions is the opposite of doing things well. Do you see tendencies of this kind amongst your customers, especially when they are stepping up their efforts to make savings?

Ritter: I certainly do, but it’s definitely not a new phenomenon and there’s also an explanation in most cases. Customers wanting a new plastic product, design engineers, mould makers, injection moulding companies and material suppliers all have their own specialist knowledge. This is used with good intentions – often, though, without realising the consequences of the relevant improvements on the overall value chain, which extends from the product idea through to series production and logistics.

Can you give us an example?

Ritter: Special plastics are often the solution of choice for the reliable handling of high mechanical stresses. In most cases, though, these materials are expensive and involve high processing temperatures in processes with very narrow tolerances, which also drives up costs and increases the carbon footprint. However, making carefully considered changes to the component design at an early stage has the potential to get cost drivers under control. It may also make designing the injection mould simpler.

You said specialist knowledge alone does not suffice. What approach does LKH adopt?

Ritter: For a long time now, we have been operating in very diverse sectors such as automotive, electrical and plant engineering. As a result, we have broad-based user knowledge and process knowhow. We benefit from our comprehensive in-house material expertise. This has led to the successful completion of numerous projects that involve substituting metal with plastic or one plastic with another, including design modifications – for Rittal and also for many other customers. The same goes for recycled plastics. We can very accurately predict how tweaks to specific aspects will impact total costs down the line. You could say our piggy bank is an ever-present feature throughout the entire process chain.

One of the key cost drivers is energy usage during the process. What is the best way of tackling this?

Ritter: We could be here all night (laughs)! I’ll just mention two points. We know exactly how much energy our injection moulding machines use on which settings. Based on well-established data, we can therefore already estimate the approximate energy usage at the material selection and mould engineering stage. This can lead to unconventional solutions such as the preferred choice being a higher-priced stack mould, but one that runs on a smaller machine with lower amortisation costs and, above all, much lower energy costs.

Another possibility is switching from metal to plastic. We have carried out some interesting projects in this area in recent years, including for products that have mechanically and thermally critical characteristics or very high electrical engineering requirements. Plastic needs far less process energy than metal die-casting and offers more possibilities for cost-saving functional integration than sheet metal components.

What do you make of your customers’ requirements when it comes to carbon footprint?

Ritter: Our customers want reliable statements about the expected carbon footprint of new products. However, only a small number of companies can calculate the specific energy requirements early on in the injection moulding process. We are able to do so, but that’s only half the story. Data of this kind is now available for many of the materials we use. At the sampling stage, we therefore sometimes adopt the approach of having two alternative materials approved – a conventional plastic and a sustainable one, for example. This offers our customers flexibility. They can react quickly to the latest cost situation for the relevant plastic and opt for the alternative, without having to work their way through a new, lengthy approval process.

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