Cost-conscious manufacturing

When times are tough, we cut our cloth according to our means: companies downsize in order to stay competitive; those who lose their jobs stop eating out; and engineers redesign products to make them less expensive to manufacture.

This last technique is an important way of improving profitability, and is known as value engineering. The concept was born back in the late 1940s and became commonplace in 1961 in the book ‘Techniques of Value Analysis Engineering' by Lawrence Miles, an engineer at General Electric in the US.

The value – or worth – of something is defined as the ratio of function to cost, so can be increased either by improving the function or reducing the cost. This can be maximised by applying value engineering.

Miles defined it as a way of identifying any “unnecessary cost” that adds nothing to a product, in terms of quality, functionality or appearance. It is a systematic process that looks at each part in detail in order to remove or reduce this cost – while maintaining quality or function.

However, value engineering is not always applied correctly. The aim is to get greater value for money, but simply cutting costs is not the answer. Too often, the need to control cost is mistaken for a need to cut cost. The end result often breaks the golden rule of value engineering: do not reduce the function.

Engineering is not just about creating products: they must be designed to a budget. During the design phase, a particular component may be over-engineered or overpriced – but this will be ignored if the overall system cost comes in on budget. Systematic analysis of function and cost, using value engineering, can flag this up. The next iteration of the product can then be produced at lower cost, resulting in higher profitability.

The first approach to the problem is to analyse a product – be it a coat, car gearbox or a ballpoint pen – using a cost/function matrix. This links the relative worth of these two elements, and identifies, in Miles' words, ‘unnecessary cost' – or, at least, parts whose function do not justify their cost.

A simple example might be a fountain pen comprising a barrel, top, nib and clip. It seems straightforward, but if the clip – which serves little function – is overpriced, this is the place to start when redesigning.

Broad spectrum Value engineering can be used across the manufacturing spectrum, for medical, electronic, automotive and many other types of product – some of them quite complex.

US-based contract manufacturer Cypress Industries recently used value engineering to analyse a steel turret that moves heavy mowing attachments on large tractors. The brief was to improve its durability and longevity – while reducing cost. The original turret was welded together from several different pieces, but the welded areas contributed to weakening the part. This meant that the turret – an expensive component – was the weak link in the machine. This was a clear area for improvement.

Because the dimensions needed to be identical, a total redesign was not possible. The only real option was to change the manufacturing process, and perhaps the material. After evaluation, Cypress chose to use sand casting to make the part, which reduced both the time and complexity of manufacture. The finished part required no welding.

The new part was also made in ductile iron rather than welding steel which increased strength and reduced the risk of porosity and inclusions being introduced during cooling. After manufacture, the iron turret was heat treated in order to increase hardness, and machined to match the configuration of the original part.

In this instance, value engineering helped to reduce the cost of the part by 60%, as well as speeding up leadtimes by four weeks. At the same time, it has moved the weak link back to its intended point – an inexpensive pin.

Hidden savings

It is often the redesign of small or ‘hidden' components that can improve the value of a machine. An enormous packaging converting line, for example, might cost upwards of a million dollars. To be profitable, it must run reliably at high speed.

A key set of components here are the ball locks that locate and hold rolls of material on winding and rewinding shafts. Though often taken for granted, they are vital elements in keeping slitters and rewinders functioning consistently and without error.

Dawson Shanahan has custom-engineered a new design of integrated ball lock that has helped a leading manufacturer of advanced slitters and rewinders to improve the performance of its secondary systems used in plastics, paper and board applications in the converting, packaging and labelling sectors. The innovative mechanism ensures precise control of web tension, minimises dust from cardboard cores and reduces leadtimes and component costs.

Previously, the customer had made ball locks in house from externally sourced components, which was a time consuming process. The production team had to source multiple parts, ensure that they met quality standards, then build and test each mechanism before it could be mounted on a rewind shaft. The company also had to hold and manage stocks of components, which took yet more time and drew the engineers away from their primary function.

Our solution replaced the older design of ball lock with a simpler, more efficient system that uses a sequence of custom-built units fitted along the length of each rewind shaft. Although simple in construction, the system is proving extremely efficient and reliable. Perhaps most importantly, the customer no longer assembles units in house. This realised significant savings in both production costs and leadtimes – as the need to hold stock was eliminated, and overall levels of quality also improved.

This latest generation of ball lock components is engineered to cope with large material rolls, while being simple to install, competitively priced and able to function for long periods with minimal maintenance.

Medical advance

In similar fashion, on another project we used value engineering to improve a number of components within a medical device. The initial brief was to produce a single component that was part of a larger mechanism within the device. However, we saw how precision cold forming could be applied to other components – enhancing their finish and quality, and ultimately saving the customer money.

In collaboration with the customer, we analysed the design of the parts and their functions within the larger device. Then, after creating the bespoke machining and tooling needed to make the components, we developed and tested the parts until an optimum solution was found. The final version of each component had the same functionality as the original non-cold formed components, but with greater quality and at lower cost.

Many customers can benefit from a value engineering-based approach. The key is to work with a precision engineering specialist that has the experience, knowledge and attitude to go beyond traditional component manufacture and engineer in value. By applying these principles – which were devised way back in the 1940s but are still so effective today – quality can be improved and cost savings achieved.

Dawson Shanahan
www.dawson-shanahan.co.uk