Safe and energy-saving solutions: central cooling systems for an entire line of machines

04.04.2019
Category: KLH, 2019

Expansion and internationalisation - this is how the last ten years of VCN mass turning from Groningen can be described best. The supplier has specialised in the machining of different types of steel, stainless steel, aluminium, copper and brass. Boudewijn van Die, managing director of VCN mass turning, plans to double the company's capacities over the next ten years. The success of the Dutch company is mainly due to the special setup of the production facilities with large lines of identical CNC machines.

The challenges that suppliers like VCN mass turning BV face are manifold: Although the quality of the usually small parts is important, the customers expect a high level of flexibility and a fast turnaround. This is aggravated by strong price pressure in a global competitive environment combined with high expectations in terms of an efficient production. 'It is among this diversity of partly conflicting interests that we have to handle increasing energy costs and the continuous extension of our expertise in the field of new materials and processes,' explains van Die. Together with his mother, the managing director leads the family-run business founded by his father in 1990. At the beginning, VCN - still under the name of Van Die Constructie - produced agricultural machinery before the company switched over to machining as its core activity in 1992 by installing the first CNC machine.

The company grew rapidly over the following years. Thanks to ongoing investments, new services became part of the portfolio, while others, e.g. milling operations or the production of small series, were discontinued. While the specialist from Groningen, like so many other companies, was hit by the 2008 economic crisis, the company still recovered quickly. Today, it employs more than 75 people. It is with this workforce that VCN reached a turnover of approx. 18 million euros in 2018. Only 45 per cent of this turnover was actually generated on the domestic market. Today, numerous customers from Germany, Austria and even the US have noticed the Dutch company.

To be able to meet the increasing demand, the company has continued to invest in new production facilities and machines throughout 2018. At present, the company has a production area of 8,300 square metres following the completion of a new hall this year. The plan is to increase this surface area to a total of 9,500 square metres. 'We have provided new space for four additional lines, the first of which with seven systems so far is already operating,' explains van Die. For VCN, a line is a group of identical machines such as the Index C200. A total of 21 of these machines are in use in Groningen, divided into three lines. This setup is based on the following concept: The identical lathes for complex workpieces facilitate the production planning for different parts to a considerable extent. 'When we get an order, we can fulfil it with any of the 21 machines. The entire setup can be controlled centrally, and the operators do not have to adapt to different machines or procedures,' explains van Die. As a result, some of the machines run through three shifts for a single customer and a specific part over long periods of time. Other orders with the same requirements do not have to be pushed back due to the fact that the machine is still occupied. Instead, they can be fulfilled in parallel on the next free lathe without any extensive personnel planning or technical conversions.

Customers from the field of construction, the automotive industry or sensor technology appreciate this high level of flexibility just like customers from the heating, furniture and beverages industries. 'It is important that we can provide a consistently high level of quality of our mass-produced parts,' states van Die. This means keeping the production as simple as possible. As a result, his company can supply its products reliably according to the just-in-time principle. The continuous growth of the company in recent years is testimony to the fact that this strategy works. Due to the unbroken demand of its customers, VCN plans to at least double its capacity within the next decade.

Comprehensive efficiency
The second important advantage of a line-based setup: At VCN, the lathes do not have their own, separate cooling systems. Instead, they are supplied via a central cooling system - a further simplification with the additional benefit of considerable energy savings. Harrie Winkel is a sales representative of VCN. When he shows visitors around the production area of the family-run company, he not only praises the line concept. Instead, he admits freely: 'What we cannot afford is the failure of an entire line.' Due to the redundant setup, the failure of a single machine is a problem that can be managed rather easily. If, however, the central cooling system is no longer available, an entire line will have to be stopped. 'To put it mildly, this would be very bad,' says Winkel. 'However, the energy cost savings and additional savings, e.g. in terms of maintenance, are so high that we are completely convinced of our central cooling concept. All we needed was a partner offering the required level of reliability.'

In 2008, the Dutch company found what they were looking for: klh Kältetechnik GmbH from Bad Doberan in Germany. The company, which is part of the technotrans group, has just delivered its fourth efficient central system with a cooling capacity of up to 130 kW to Groningen. The special features of the systems are perfectly adapted to the requirements of VCN. For Jan Kühne, the product manager for industrial cooling systems at klh, these customisations are the reason why the two companies have been cooperating so closely for ten years: 'The aim is not to simply deliver a standard product. Instead, we must show initiative and proactively find a solution for the customer. Once such a partnership has been established, it will be a lasting one.' In the case of VCN, this solution consists of using central cooling systems instead of separate water chillers for every individual lathe to ensure reliable cooling. Such a central cooling system can cool up to ten machines. To ensure the necessary level of reliability, klh has integrated several special features.

Production reliability thanks to a redundant setup
The most obvious redundant feature is the integration of two pumps. Only one of these pumps is active at any given time, with the other one being ready as a backup pump should it be needed. The pumps are speed-controlled, thereby adapting to the required output, which leads to a further reduction in energy costs. In addition, all of the distribution stations are equipped with a connection to the municipal water supply. This water will be used for emergency cooling if the standard water-glycol mixture is not available for some reason. This gives the technicians time to solve the problem without any production downtimes. The central cooling system of a line is controlled via only one control unit (HMI) which considerably simplifies the operation of the system for the line operators. If this control system fails, they can control the entire system manually.

The HMI also provides access to the active or free cooling functions. Thanks to the ambient temperatures in the Netherlands, VCN can use the free-cooling systems installed on the roof for the klh solution for the most part of the year. Up to an outside temperature of 14°C, these systems reach 100% of their capacity, thereby enabling considerable cost savings for VCN. 'It is only when it gets warmer that we use the active cooling mode to ensure an optimum operating temperature of 18°C in the lathes,' explains Winkel. The klh system also conditions the cooling lubricants. In addition, whenever klh identifies other opportunities for increasing the operational reliability or effectiveness of the systems, the company proactively contacts VCN. The ideas are then mutually discussed and implemented.

Kühne is sure that 'thanks to this approach, all of the important functions of the cooling systems are ensured at least twice.' According to Winkel, this partnership with klh is a true blessing for VCN. 'We noticed the company because it was an OEM for Index. Nobody could know at the time that this would lead to the truly excellent relationship that we have today.' The first central cooling system installed in 2008, however, was a real challenge, since it was a completely new concept resulting in a series of questions and new ideas that had to be put into reality. However, klh was always highly committed during this phase, stresses Winkel. 'klh always shows a very high level of initiative and has always fulfilled all of our requirements. It is a very reliable and sincere partnership.'

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