Retrofit, a cost-effective alternative

Investing in a new machine or retrofitting the existing manufacturing equipment: that is the question often asked when a decline in productivity is noticed. However, workpiece costs must not be calculated based on per-piece costs alone. Other important “qualitative factors” to be considered, for example, include spare parts availability and maintenance costs.

When companies opt for a retrofit instead of investing in a new machine, it is mostly considered a modernisation of existing equipment and control technology from the financial point of view.

What is often not considered in this ap-proach is the fact that, compared to pur-chasing a new machining centre, the in-vestment required for the integration of the machine into the existing process only amounts to 15 to 18 percent of the cost. To Andreas Markpfleger, Head of Technical Support Global Services at HELLER, the production infrastructure has a major impact on the concept of the planned modernisation apart from the component portfolio: “First of all, you need to look at the workpiece range. If a company produces high volumes of identical parts, high dynamics and speeds are prerequisites. In these cases, a retrofit is unlikely. However, it is also important whether the machine is used as a stand-alone unit or is integrated into a manufacturing line. Is it possible at all to integrate a new machine into the line and, if so, what are the impacts? If the old machine, for example, was equipped with a 100-place rack-type magazine, purchasing a new machine would mean that new tooling, tool holders and fixtures etc. would be required. Then, buying a new machine would not be recommended. All in all, the question is whether availability or per-piece costs are in the foreground.

However, a specific example of a project at a major German automotive manufacturer shows that quality and process dependability can be points in favour of a retrofit. The machining of steering knuckles presents special challenges in manufacturing. Due to the stability and process dependability they provide, the company uses older HELLER machines with flat bedways and retrofits them regularly.

Productivity increases of up to 20 percent are feasible

At a globally leading tractor manufacturer, workpieces are transferred to the manufacturing cell as raw parts and leave the system finish machined, including gauging. Batch sizes vary between 800 and 900 pieces/year, whilst some of the components are only produced two to three times. The various workpieces require a total of 100 different NC programs. Due to the required flexibility of the infrastructure, the company regularly performs retrofits. Currently, retrofits on the HELLER MCH models purchased in 2002 have begun.

Part range, infrastructure and the productivity to be achieved not only determine whether a retrofit is a possibility, they also determine the scope of it. Whilst one component is replaced with another in a general overhaul, HELLER distinguishes between “Quality” and “Premium” machine retrofits. Here, “Quality” means that the original state is restored. Wolfram Stein, Head of Component Strategy at HELLER, however, considers the “Premium“ machine retrofit the most cost-effective solution, focusing on optimal per-piece costs: “You don't expect to achieve higher productivity when performing a general overhaul. Yet, a measurable increase is achievable. According to the customer's wishes, we install all available technological upgrades released since the original delivery of the machine, enabling productivity increases of up to 20 percent.”

Until now, HELLER concentrated on the retrofit of the BEA series built from 1979. Due to the declining distribution of machines, the company decided to broaden the portfolio and place the focus on the machines from the MCP (built from 1992), MC (built from 1996) or MCH series (built from 2002).

According to Dr. Gerd Schöllhammer, Head of Sales Support Global Services at HELLER, thorough and careful weighing of the pros and cons of a retrofit or the investment in a new machine is important in the fore-front of a planned retrofit. The focus must be on determining the achievable per-piece costs as precisely as possible, considering all boundary conditions. In the end, what matters is to find the best, i.e. the most cost-effective, solution for the customer. “HELLER machine tools have been designed for a second life. That is why we promise our customers Lifetime Productivity. We consider a retrofit an important contribution to Lifetime Productivity, helping to create a second life. Based on the assumed 20 percent increase in productivity mentioned above, the efficiency achieved will be lower than that provided by a new machine. That is exactly why we show our customers what is feasible, weigh the pros and cons and will also simulate processes in the future. Therefore we believe that from these perspectives, retrofitting of the BEA series only adds value in exceptional cases.”

Whether you refer to a retrofit vs. a new in-vestment as Plan B or A2 and depending on workpiece portfolio and existing infrastructure, it can present a cost-effective and viable solution. As a prerequisite, the modernisation has to be performed by the original equipment manufacturer, using original state-of-the-art parts, who, like HELLER, provides a decentralised network and 24-hour helpline.

Nothing is left to chance

As part of the standard procedure, HELLER replaces all wear parts against new components and performs a control retrofit, including installation of a new control cabinet and fluidics module. The test and acceptance criteria are the same as for a new machine.