High-quality tires delivered at speed

27.10.2016
from Guido Veit für KGK Rubberpoint Online

High-tech tools for plant planning

As the complexity of rubber compounds used in tires increases, tire production facilities must handle expanding requirements,as well as simultaneously needing to manage growing time pressure by means of technologically and commercially sound plant planning.In fact it is possible to structure the planning process in such a way that it not only saves time, but also reduces costs.There are several tools available to help with this, such as 3D planning, which also improves the accuracy of planning.

To deliver products to today’s standards, tire manufacturers need highly flexible and fully automated rubber-mixing facilities. Recipe accuracy, prevention of material loss and cross-contamination, process efficiency, availability, tracking of raw materials, flexibility, short set-up times, space optimization, cleanliness, scope for expansion – the list of requirements can be extensive. As a foundation for meeting these requirements, an efficient planning process must be devised. “The interval between deciding to invest in a new plant, or modernization of existing facilities, and the start of production should be as short as possible,” says Guido Veit, Business Unit Director Plastics & Rubber Plants at plant specialists Zeppelin Systems in Rödermark. This objective can be achieved through intelligent planning management:The more detailed the preliminary planning in advance of construction approval, the more time can be saved.

Detailed preliminary planning,  rapid time to market

The company has developed the concept of Value Engineering, an approach that can be applied right from the development phase,and which makes it possible to obtain relevant data even at a very early stage. “These data include process flow diagrams of the complete plant, installation planning or energy usage for example, but also costs, volumes, and of course, deadlines,” Guido Veit explains. Removing time constraints from preliminary planning allows for concepts to be fine-tuned, thereby creating a better-established basis for their implementation. This in turn facilitates detailed discussion and optimization of the plant design in model review form, whereas currently, model review is usually only conducted during contract performance, at a point in the process where the remaining scope for concept optimization is limited. However, the better and more in-depth the planning at the start of the project is, the more potential there is for reducing the length of the implementation phase –and here it is important to remember, of course, that the amount of work on any subsequent changes will also be reduced. Zeppelin Systems moved away from a sequential planning process long ago, and as such it can now execute any number of planning steps in parallel,which itself already leads to significant time savings. It should also be noted that proper planning allows better definition of interfaces with suppliers, and can avoid coordination conflicts arising on the construction site.

Benefit from a wealth of experience

The fact is, potential opportunities to save costs and time can even be identified in individual process steps,with various tools available to support this. The plant’s technical specifications are created in the context of front-end engineering and design (FEED).This phase is crucial to determining the plant’s efficiency, as some 80% of the total costs for planning and construction, as well as operation, are defined here. It results in a scheme that encompasses all volumes, dimensions, key indicators, and workflows, allowing sufficient scope to further optimize the plant. Here, the concept’s main components are already integrated into an overall layout plan;the planning basis is also established, with the plant going through a kind of optimization phase in its first dry run.

Implementing complex requirements in older facilities

Companies in the tire industry can benefit from the expertise of an experienced plant engineer not just when planning new plants, but also in refurbishing older plants.With the arrival of new materials such as silica, silanes, and many other liquid additives, along with various chemicals and recycling materials, rubber processing today must manage a range of additional requirements.To meet these demands, existing plants must be modernized with the necessary equipment to make tire production fit for the future.Refurbishment of an aging mixing room is a difficult undertaking though; in fact, investment in this area is often delayed for many years, because no one wants to tackle the complex challenge it represents. There is considerable cost potential that lies dormant in aging rubber processing plants,with high material loss and maintenance costs being the main generators of costs, along with low efficiency.Further disadvantages come with a lack of options for integrating the latest additives into mixtures, as well as poor recipe accuracy and reproducibility of mixture quality. It is also necessary to attend to factors such as increasingly stringent requirements for production cleanliness and workplace safety.There are many other examples that illustrate the challenges inherent in converting or extending an existing plant, as well as the complexity of existing process steps.

Rising proportion of liquid additives

In recent years, material loss, maintenance costs and low efficiency have been the main drivers in the development of technologies supporting tire production.Further disadvantages come with a lack of options for integrating the latest additives into mixtures, as well as poor recipe accuracy and reproducibility of mixture quality. It is also necessary to attend to factors such as increasingly stringent requirements for production cleanliness and workplace safety.Further examples illustrate the challenges inherent in converting or extending an existing plant, as well as the complexity of existing process steps.Rising proportion of liquid additives. Recently developed technologies accommodate the rising proportion of liquid additives and other requirements. “It’s all about how to integrate these new raw materials into existing plants,” emphasizes Guido Veit. Zeppelin Systems has decades of experience with liquid additives to draw on, and has used this to develop a special system that is designed, produced and installed as a turnkey solution. At the core of the liquid dosing system (LDS) is the liquid scale used to prepare softeners, oils, molten wax and other liquid additives. It features a specially designed volumetric cylinder that allows for precise, flexible, and rapid metering of many liquids. During this metering process, the temperature of the product can be set to any figure up to 80°C. The liquids are stored and supplied in tanks or IBC containers,from where they are fed into the dosing cylinder via a ring pipe with feed pump. The liquids are quickly and precisely dosed in a closed system:They are injected from the cylinder through multiple injection pipes with no risk of contamination, via a special injection valve with six connections, and from there into the mixer.The liquid dosing system is supplied as a turnkey system that includes the control unit.

Complete mixing room analysis and optimization

In a modern, cutting-edge mixing room, it must be possible to incorporate raw materials with diverse properties into the process at any time and in variable quantities, reliably, quickly, accurately, with no dust, loss or contamination, and preferably in closed systems.A modern feeding system can automatically respond to changes in conditions such as pressure, temperature and humidity, or variable raw materials and conveying distances, and ensures the supply of raw material into the mixing process, for example by using intelligent air quantity control for pneumatic conveying. The plant engineering specialist supplies these systems from a single source, encompassing everything from raw material intake, through storage and conveying systems and the weighing and metering of natural rubber, carbon black, silica, filler materials, and other additives and chemicals, to the turnkey mixing room.

Production optimization and  increased energy efficiency

Extensions to existing plants always pose a huge challenge to planners and project managers, because it is rarely possible to shut the system down for long periods. As Veit puts it: “It’s often an open heart surgery procedure.”He goes on to explain that “there is only a short time window available for reconnecting the plant, and before that happens you need to make sure there is as little disruption to production as possible.” Unplanned changes and on-site modifications must be kept to a minimum, as the timeframe within which it is necessary to integrate new plant parts into the existing system is extremely tight.In these circumstances it pays not only to have a well-prepared project with all the right methods and tools, but also to be able to call on the support of plant engineering experts should anything go wrong. Modernization of these highly complex facilities also brings a number of challenges from a planning viewpoint. “When we look at existing plants, we often find that there is no usable documentation,and even where there is documentation, it is inaccurate or simply doesn’t take account of modifications that were made during construction or while the plant has been in operation,” reports Veit. “Moreover, evaluation of these documents – if they exist – can be time-consuming and expensive,meaning they are often not subjected to proper scrutiny during the conversion planning phase. This can unfortunately lead to costly mistakes.”

3D model of the existing plant

Nonetheless, failing to modernize such a facility is undoubtedly the wrong choice. Tools are now available that improve the planning process when dealing with highly complex existing buildings,including laser scanners to help create a precise model of the current plant. “This is extremely helpful if we find that modifications have not been recorded over time, data formats cannot be converted, or the drawings provided don’t match up with the actual situation,” explains Veit.In this scenario, an analysis of existing data would not be cost-efficient and would be too imprecise,not to mention the impossibility of being certain that all changes made over the period had been noted. Operators and plant construction companies have no choice usually but to basically start from scratch, surveying the plant with a laser and meter rule to establish its current state. The experts are aware that this method is very unlikely to be effective in complex tire production plants: “These plants cannot be surveyed using conventional methods.” If the available time for the modification or extension is very limited, or if the modification is very complex, schedules soon begin to unravel. Laser scanning, on the other hand, allows all relevant plant data to be recorded quickly.

Realistic mapping, achieved point by point

Zeppelin Systems has been using the 3D laser scanning process for some years, initially only in building planning. Technical equipment is far more complex, and requires a similarly demanding approach when preparing to scan.Once the plan is done, the entire plant is recorded point by point, using the 3D laser scan. There is also the option to take photos of all or part of the plant. The process is completed with the integration of all the scans to create a “point cloud”, that is then converted into a photo-realistic model with the help of software. Laser scanning is not only quicker than manual measurement, but also maps every detail and records the plant in full, meaning planners can make use of a detailed and up-to-date 3D map of the plant – though it should be noted here that the planner must first convert the point cloud data into a usable information format for planning. The planner is then able to identify functional units, and extract these units from the overall plan,making it possible to take an informed decision on which components of the old plant should remain and which may be dismantled during modernization. Similarly, if there is a conflict of objectives in planning, or if clashes arise, the priority of structural elements can be analyzed to ascertain the best way to resolve the situation. Using this 3D model of the steel construction, components and pipework, the plant can be quickly and reliably optimized in terms of aspects such as accessibility for maintenance and service, or optimal use of space. In summary, it enables plant conversion to be planned precisely, and carried out with little disruption to production and high safety standards.

Mapping alone is not enough

Zeppelin Systems has been active in the tire industry over the past four decades, of which 3D scanning has been in regular use for ten years Though it is certainly valuable, we recognize that the data and images created by 3D scanning can only represent the groundwork for conversion or extension planning. The company has also invested heavily in suitably aligning planning system environments; so for example, our planning departments now only work with point clouds, rather than vector-based systems as in conventional CAD systems, as this is the only way of deriving an intelligent model from a raw scan. This model maps an integrated extension with no interface problems, as little interference with the existing plant as possible, and the avoidance of clashes or expensive conversion work during installation.

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