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"Walk the Line" - Implementing cost savings from c-parts

Keller & Kalmbach, the specialist for fasteners and fastening technology, has added a new service to its portfolio: the LineWalk. The experts take a close look at the assembly processes and find starting points for cost reductions and assembly time reductions.

Every manufacturing company needs C-parts like screws. Nowadays, good C-parts management goes beyond the purchase of parts: clever eKanban systems, for example, reduce the process costs for reordering and completely outsource the procurement of the important small parts. Keller & Kalmbach, a specialist for fasteners and fastening technology, goes one step further. The company's service portfolio has recently been joined by the so-called "LineWalk". Here, the assembly process of a product is scrutinised in order to realise cost savings. Roland Salomon, Director Application Engineering & Development and Head of Technical Project Purchasing at Keller & Kalmbach, explains: "By a LineWalk we mean a production inspection. We inspect the development and manufacture of the product from start to finish in order to identify optimisation potential at the level of the product itself, the assembly processes, screw technology and surfaces."

LineWalks can be used in assembly lines where standard products are produced, for example in the automotive industry, in mechanical engineering or in medical technology - but also in other production models. Salomon says: "A certain volume of C-parts must be installed for a LineWalk to pay off." Pi times thumb, according to the expert, a company should have a purchasing volume of 50,000 euros or more for C-parts so that relevant savings can be realised. The offer is available to all interested companies, even if they are not a Keller & Kalmbach customer.

When a company has been implementing similar processes and products for years, a certain "design blindness" can set in. After all, what has worked for years is often not changed of its own accord. Keller & Kalmbach, with its years of expertise, brings new insights and suggestions in the field of fasteners that can help customers rethink their products.

LineWalk briefly explained 

So what does a LineWalk look like in practice? Salomon explains: "We go to the customer and look at a specific assembly line in detail within a day." Within the scope of the LineWalk, not only developers, but optimally also purchasing and quality assurance are involved. In this way, commercial aspects as well as possible weak points of the product can be evaluated from the very beginning. The project team goes from assembly station to assembly station and notes how the assembler at a station works. Whenever the experts from Keller & Kalmbach see a potential for optimisation, it is written down. In the next step, the specialists draw up a profile for each case, on which the actual situation is compared with one or two proposed solutions, if necessary with a picture or CAD drawing. The proposals are calculated and the realisable cost savings are compared to the required investment costs. In addition, the experts note how their idea can change the assembly time and how long it will take to implement the proposal. "Our target figure," Salomon extrapolates, "is that a project can be realised in a maximum of three months with a high savings potential." Ultimately, it is the customer who decides which of the proposals presented will be implemented.

Standardising the assortment

But why want to save on C-parts at all? The unit price of small parts is often in the cent range. The "hidden costs" or "total cost of ownership" are often forgotten: in addition to the unit price, process costs for ordering and logistics are decisive and are often many times higher for C-parts than the pure unit price. If, on the other hand, the product range is reduced, this results in simplified structures in purchasing and logistics. Salomon explains, "You have to realise that each C-part generates its own digital order number and the process costs for managing such a product, despite a very low unit price, can be in four figures annually." Sometimes, buying larger quantities of certain C-parts even results in volume discounts.
But in reality, such arguments are rarely implemented across the board: In larger companies, many different designers usually work on one product; in the automotive industry, for example, four different development departments are involved: They are responsible for bodywork, interior, engine and chassis. Coordination among them is not always ideal. It is therefore not uncommon for a product to have a wide variety of different types of connecting parts. Practice shows: If one or the other type is replaced, the types of screws used can be reduced. However, "such optimisations can only be recognised when the product is considered as a whole", says Salomon about the advantage of this approach.
Not only the process costs, but also the assembly times can be reduced with such a measure. It often happens that one designer uses a screw with external engagement, the next one with internal engagement. In production, this means that the assembler has to switch between two different screwdriving tools. "These are assembly times that can be avoided," says Salomon.

Use standard products

The C-parts area is still treated stepmotherly in many companies - and not only the small and medium-sized ones. Salomon considers this to be problematic. "The product variety in the area is overwhelmingly large, so in-house expertise is often insufficient." Many companies already work with so-called "modular systems" or "preferred assortments" in which designers are provided with a selection of C-parts. This selection should be adhered to where possible. In practice, however, Salomon sees time and again that such measures are not sufficient.

It happens that designers ignore the standard products and request special solutions, for example in an "intermediate size", where a "standard" screw would also have done. "Special solutions are easy to produce, but they feed the product diversity in the company," Salomon explains.
Another problem is that designers "miss the mark". Let's imagine that a designer needs a heat-resistant - and thus more expensive - special screw for a certain component. Another designer finds the screw in the system, looks at it only superficially and also installs it - although the heat resistance is not important at this point. A cheaper standard product would have sufficed. "In the course of electromobility, there are additional requirements for C-parts in terms of cleanliness, corrosion protection and packaging," explains Salomon. Here, too, it is important to look very closely.

Include A and B parts

If a connecting part is replaced by another, the C-part used may well be more expensive. However, it is often the case that although the screw becomes more expensive, the component itself can now be manufactured more cheaply. Since, for example, a cast or bent part is often a B-part, which is definitely more expensive than the fastening technology itself, cost savings can also be realised here. "That's why it's important for purchasing to be part of the LineWalk," says Salomon. (sd)

What a LineWalk can achieve

During a production walk, the experts look at the assembly of a product. Suggestions for optimisation can be:

  • Standardise the assortment: Harmonise fastening elements, for example through a modular system or preferred element, also across development departments.
  • Use standard products: Match C-parts exactly to the application in order to avoid unnecessarily expensive parts with special properties.
  • Include A and B parts: The use of cheaper A and B parts can also result from a close look at the connecting parts

Goal of the LineWalk

  • Savings at product level (e.g. through quantity effects and the use of standard parts)
  • Savings at process level (e.g. through product range reduction)
  • Savings in assembly times (e.g. through reduction of tool changes)

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