Pirelli Launches The New Mirs Process
Pirelli launches the new MIRS process: the mini factory that revolutionizes high performance tyre production
The new technology is based on the exploitation of 3 Pirelli patents dated
1975-76. MIRS will produce also a run-flat tyre with pressure sensors
Milan, December 2, 1999 - In a multi-modular, robotized area of 350 m2, easy to locate close to any customer, using a completely innovative process protected by broad patent coverage, Pirelli is totally revolutionizing the traditional technologies and methodologies of high performance tyre manufacturing. The name of this new technology is MIRS-Modular Integrated Robotized System.
Experiences achieved on the collapsible core drum covered by three Pirelli patents in the years 1975 and 1976 have been resumed in a totally innovative scenario.
The manufacturing of the tyre is achieved moving and orienting in different directions the drum, on which the extruders progressively apply the different components by depositing them in the direction of both the circumference and the axis. The robots, which hold the drum from a single side, allow extruders to follow the entire profile of the drum.
The first industrial pilot plant using the MIRS process will come on stream in the second half of year 2000 at the Pirelli Bicocca plant in Milan. In the next months, a strategic rollout plan-including North America-for the MIRS mini-factories beginning in 2001 will be communicated. The total projected investment is Euro 250 million (ITL 500 billion) over the next five years, entirely dedicated to an increase in production capacity and not to a substitution of capacity already in place.
In the MIRS process, the work of robots covers the entire production cycle, from compounding to finished product, without interruptions, without movement or storage of semi-finished components, without waste of energy, at high speed: MIRS is capable of producing a tyre every three minutes.
With its process, MIRS also revolutionizes the product manufacturing procedure: the production cycle, in fact, is continuously fed with standardized semi-finished elements. A tyre is no longer assembled in discontinuous batches: it is built by robots directly around a drum that the machines pass " from one mechanical hand to the next" , without stopping and without human contact. And the steps in tyre processing are drastically reduced: from the traditional 14 to only three.
Integrated software guides the robots' movements, automatically provisioning the materials, selecting the drum, assembling the tyre, curing it and handling the finished product. Just tell the program what type of tyre you wish to produce at a given time: the program does the rest.
Three components - i.e. the reinforced strips, the rubber strip and the steel cords - are enough to build carcass plies, belts and beads directly on the drum.
The production process is determined during the design phase, as all the complex geometry elements are built through a progressive increase of their section by the winding of successive and partially overlapping rubber strip coils. These coils are laid on the drum during the production phase, with a variable and prearranged orientation, through the same software used in the design phase.
The program that governs MIRS is part of a software package that, upstream from the manufacturing phase, oversees the engineering process, back to the initial design phase. It is a single architecture that, starting with the definition of product specifications, automatically intervenes in mould design, the choice of materials, the design of the building drum. The same software defines the path driver for the MIRS robots and manages their work cycles.
MIRS: a mini-factory plant with astonishing flexibility (a limit of one tyre per size) that can be modularly located according to local market requirements. It slashes costs, heavily improves product quality and uniformity and transforms logistics from a problem into an opportunity.
The investment for a mini-factory with a capacity of one million tyres/year is around Euro 45-50 million (ITL 90 billion).
The objective of the process and product MIRS technology is to offer the market, already in 2000, starting from Original Equipment clients, a new point of reference in the High Performance and Ultra-High Performance tyre segment and an industrially advanced response to the requests of total mobility in the field of the PTM-Pirelli Total Mobility project. MIRS generates an ultra-low-profile tire with characteristics totally innovative in terms of performance, reliability and comfort. On the occasion of the MIRS launch, Pirelli anticipates the first three "concept" tread patterns, and a prototype of a RUN-FLAT tyre with telemetric sensors for pressure detection.
The product range will therefore be enlarged to all other tyre production range.
The tangible difference in the MIRS process with the already known Pirelli automated production process FLEXI lies primarily in the introduction of a veritable revolution in the way tyres are manufactured and, an equally important factor, in its extraordinary production flexibility and its adaptability to limited areas with low-cost, totally robotized modules.
The MIRS technology has been totally developed in the Italian Milan laboratory of the Group also with the co-operation of the Bicocca University of Milan, especially in the area of mathematical calculation. The research program is partly sustained by the Ministero dell'Universit e della Ricerca Scientifica e Tecnologica.
The " Mini-factory"
Tyres are still being produced traditionally in large plants that can only become cost-effective when high levels of saturation are reached.
The MIRS technology, on the other hand, is based on " mini-factories" strategically distributed over the territory, both physically (a plant where one is needed) and over time (a plant when one is needed).
The complete tyre production process is concentrated in an extremely limited area, virtually eliminating the space required by the enormous quantity of materials and products that must be kept on hand for the standard process.
In the traditional process, in fact, only 12% of the materials are in processing at any one time, while the remaining 88% are stored, waiting to enter the processing cycle. In the MIRS process, on the contrary, the input is transformed from raw material to finished product without interruption and without the need for semi-finished storage. This sharply reduces the lead-time from the raw materials warehouse to the finished product warehouse: from six days with the standard process to 72 minutes with MIRS.
How MIRS works
In the standard process there are 14 processing steps: a discontinuous series of batch operations performed by large machines that exploit economies of scale. Each batch operation is followed by a period of intermediate storage: the components, processed at high temperature, must be cooled each time, in some cases covered with anti-stick compounds or protective coverings, moved through the various intermediate warehouses, once again stored and then sent on to the next step in processing.
In MIRS the processing steps have been reduced to 3: preparation of semi-finished elements (compound mixing excluded), building and curing, plus finishing. These three steps are accomplished with small machines that produce only the minimum quantities of material necessary for each individual component of the tyre.
In the first step of MIRS, the semi-finished content is produced by extruding the compound in the form of a continuous strip: under software management, each extruder or building machine specialized for each individual compound participates in the production of the strip, in the quantity and weight necessary for the various components.
The second MIRS step is an integrated one: building and curing. Beginning with the strip of intermediates fed continuously to the system, a series of robots deposits the material on a single rigid drum. In other words, the tyre is built around the drum as it is passed " hand to hand" from robot to robot, each of them constructing a part of the tyre according to a path managed totally by computer.
The last building robot physically " offers" the drum with the green tyre (i.e. with the polymers of the base rubber still in a plastic state) to the next machine that feeds the curing press.
Tyre building is achieved through independent steps each controlled to obtain green tyres synchronized with the movement of a revolving multi-mould curing press. The latter is a true roundabout made of six moulds which, revolving on its axis with a rhythm equal to that of the building, allows to keep a " continuum" process also in this phase.
This allows a high flexibility of the product mix with optimization of production efficiency.
The processing method is also new, without the usual curing chamber that fills with steam to force the casing against the mould: it is the drum itself that automatically provides the necessary motion inside the curing mold.
Following curing, the same robot returns the drum to the production cycle. If the type of tyre being manufactured changes, the machine itself procures a drum of the new required size.
The cured tyre, meanwhile, has reached the final finishing section: one every three minutes, without being touched by human hands.
Improvements in Product Quality
By eliminating the traditional batch approach, the MIRS concept ensures an improvement in product quality barely comparable with the already high quality of products derived from the standard process, and it also drastically reduces the percentage of scrap.
Each interruption in the cycle, each "human" intervention, in fact, offers a theoretical possibility to introduce product defects: temperature excursions of the intermediates in the handling and storage phases, the presence of assembly joints, unequal heat distribution in the curing chamber, etc. etc.
The Ecological Value
The MIRS process also has significant implications in terms of the environmental impact of the tyre manufacturing process.
The reduction in processing steps and their integration into a continuous process greatly reduces the energy requirements of production. In the traditional process, in fact, each interruption in processing means an enormous specific consumption of energy for cooling and handling.
By reducing the steps, energy consumption also drops due to the simplification of the process and the use of local generators in curing that drastically reduce the dispersion of heat.
Then there is the ecological value generated by the logistical flexibility of the plant: the reduction in transport flows-today tire manufacturing sets in motion hundreds of trucks daily just in Italy-bringing a general reduction in fuel consumption and thus pollution.