- MIXING Know-how
The HF MIXING GROUP adapts to the needs of its customers and supplies them not only with mixers but increasingly with complex mixing room systems as well.
Nothing is more constant than change. This expression from the ancient philosopher Heraclitus has not lost any relevance in modern times. On the contrary, the world seems to be changing faster and faster. Even the HF MIXING GROUP is constantly changing, sometimes in order to optimise internal procedures or to fulfil new legislative requirements, but usually in order to meet the changing demands and needs of its customers. Its transformation from being purely a manufacturer of mixers to being a supplier of complete mixing room systems also falls within this category.
This began some years ago: at first it was only a few technical rubber goods manufacturers who lacked either the know-how or the time and human resources to deal with the selection and purchase of all of the individual machines and components themselves, and therefore asked the HF MIXING GROUP for mixing room systems. Recently, some tyre manufacturers have followed this example. Unlike in the past, when most were self sufficient and equipped their mixing rooms with machines they purchased separately, today more and more of them leave the entire task to the machinery supplier.
‘Until recently only a few technical rubber goods customers requested this service, but today tyre manufacturers also rely on the full-service package from HF.’
‘One of the basic reasons for this lies in the growing complexity of the complete systems,’ explains Maik Rinker, Business Unit Director for Systems/Automation of the HF MIXING GROUP. ‘The engineering of the overall system is becoming more and more important. After all, the solution selected should remain technically viable for many years. Moreover, a wide variety of new standards and regulations must be observed, in order to obtain CE certification, for example. This is because the operator of the system is subsequently responsible for safety. Accordingly, he should be able to rely on the supply of CE- compliant machines and the documentation required in connection with complete systems. It is also necessary to arrange the complete system in such a way that it works as energy-efficiently as possible. Taken together, these factors raise the level of complexity to a point where more and more customers prefer to leave the job to an expert. The primary reason, though, is surely the fact that the increased degree of automation has repeatedly led to interface problems between the individual components that would cause downtimes to occur often and sometimes for long periods of time, or would lead to prohibitively long and expensive commissioning phases. After all, a mixing room system consists of a wide variety of individual machines that must be assembled into a single functioning unit. In this respect, we can offer our customers the big advantage of working with many suppliers in accordance with standards specified by the HF MIXING GROUP.’
The full spectrum of mixing room equipment
The Board of Management of the HF MIXING GROUP recognised these market demands early, and strategically positioned the company. It launched the Systems/Automation Business Unit in which the systems expertise of the HF MIXING GROUP is pooled, developed and optimised. The business unit, which now has over 60 employees worldwide, handles the full spectrum of mixing room equipment for the customer, from the concept to the procurement process to commissioning. ‘On the basis of the requirements specified by the customer, we first create a mixing room concept tailored to these requirements,’ explains Christoph Sänger, Head of Global Systems Technology. ‘We select the appropriate machinery on the basis of the respective application, the required throughput rate and the desired quality, and also handle the design of the upstream and downstream components such as the material feed system, rolling mill systems, twin-screw extruders, batch-off units, etc. In cases where we outsource the manufacture of those system components, we work in close cooperation with our suppliers. Even in this early project phase the automation specialists come into play and develop the appropriate automation concept.’
The HF team begins with the detail engineering as soon as the mixing room system is approved by the customer. This includes things such as the planning of the material flow in the mixing room, the system layout, the foundation plans including a proposal for the structural steelwork as well as the calculation of the static and dynamic loads of the machinery and components. The relevant parameters for the coolant, compressed air and energy requirements for the layout of the building and the technical infrastructure are also determined in this phase. The routing of the cables and media lines as well as the material flow and storage are also planned. And one more important thing: all of the (mechanical and electrical) interfaces are defined.
A wide variety of components must be connected to one another in a mixing system: the material weighing and dosing system, the mixer with all of its auxiliary equipment and the downstream equipment, to name just a few of the basic elements. A large number of interfaces must be taken into consideration as early as in the concept phase when joining these individual elements.
This involves interfaces for the supply of the fillers, plasticisers, rubber and small-scale components for the auxiliary equipment such as hydraulics, tempering, lubrication or drive train, for the downstream equipment as well as the transfer chute, the feed belts or the warehouse. The building and the supply of electricity, coolant and compressed air as well as the safety features must also be intelligently connected via interfaces.
Eliminating interface problems
The HF MIXING GROUP offers a fully integrated mixing room automation system for this with ADVISE®. ‘ADVISE® eliminates interface problems even before they can occur – interface problems that could otherwise result from using several different control systems from various suppliers in the mixing room,’ explains Hans Martin Monyer, Head of the HF Automation product segment. ‘All machine and device control systems as well as process control systems and operating stations, from material acceptance to the interim storage of premixes and final mixes, are intelligently interconnected with one another by means of standardised interfaces. The uniform user interfaces at all workstations also provide the transparency required in such complex systems, prevent operating errors and thereby increase efficiency in the mixing room.’
As a complete solution, ADVISE® offers enormous advantages for the mixing room operator – and not just in the long term: ‘If the customer connects individual control systems together into a line then, in addition to the interface problems, there are often functional overlaps as well, which lead to additional procurement costs overall,’ says Monyer. ‘The costs for spare parts are also reduced with a standardised total system such as ADVISE® because uniform components are installed in all parts of the control system.’ In addition to the cost benefit, uniform automation also offers the customer further benefits: when using control systems from different suppliers it not uncommon to have trouble determining clear responsibility in case of malfunction. As a result, the customer may have to struggle with ambiguous responsibilities over the entire service life of the system. A total solution using ADVISE® also guarantees a high-quality and uniform technical documentation of all control systems in the mixing room. ‘I have actually seen some customers using systems for which there were four circuit diagrams drawn completely differently,’ says Monyer. ‘Over the years, things like that make work harder for the maintenance personnel and repeatedly interfere with fast fault correction.’
Energy savings through optimally designed drives
The greatest potential for energy savings in the mixing room lies in the optimal design of the mixer drives. In the past, drives were designed generously according to the mixer size and rotor geometry. ‘More than a few companies would use the proverbial cannon to kill a mosquito,’ says Monyer, descriptively explaining the lack of focus on efficiency in earlier times. The HF Drive Design Tool developed by his department prevents oversizing and its associated wasting of energy by enabling engineers to precisely determine the power requirements for the use, the mixer size and the rotor geometry and to design the drive appropriately. ‘Against the backdrop of the fact that only a one-digit percentage of the total life cycle costs for a mixer drive go to procurement costs but the largest portion goes to energy costs, enormous savings can be generated through an optimally designed drive!’ It is therefore no wonder that the HF MIXING GROUP has sold more drives in the last five years thanks to the Drive Design Tool than in the entire 15 years before it.
A full-service package for the customer
In addition to the concept and engineering, HF MIXING GROUP also handles the entire project management for a system project: starting with the selection and coordination of the suppliers, and ranging from scheduling, order placement, change management, inspection of suppliers, in-house commissioning and acceptance, all the way to transport to the customer and assistance in obtaining CE certification. ‘In doing so, we also carry out the entire construction site coordination from the determination of the required installation material to the resource planning for the installation all the way to the coordination of the commissioning,’ says Christoph Sänger. ‘In addition, our colleagues also support the customer in the test phase and with the start-up and optimisation of the system. The training courses that we offer are also very important. We use these to ensure that customers get the optimal benefits from our products.’ Customers thereby receive a full-service package that significantly reduces the pressure on their schedules and personnel. Because the HF MIXING GROUP takes the responsibility for the entire project, it stands to reason that this would incur high costs. However, this is not the case: in terms of the total costs of a system project – i.e. the costs for machinery, automation, installation and commissioning – only a share of approximately ten per cent goes to the system project services of the HF MIXING GROUP.
Good prospects for system technology
The advantages of system technology for the customer are so impressive that even large-scale customers who have their own in-house machinery know-how are now taking advantage of this offer.
‘The importance of system technology will continue to grow,’ says Business Unit Director Maik Rinker with confidence. ‘Ever-faster processes and improved line management with regard to preventative maintenance, recipe management and production planning are required. In addition to a lot of know-how, all of this also requires an increasing degree of automation. Energy efficiency will also play a greater role. New drive concepts and energy-optimised auxiliary equipment will therefore become even more important in the future. We perform research and development in all of these areas and have the entire system under control. I am therefore very confident about the future of our system technology and automation.’