Blue Angel mattresses – because sleeping is a celestial experience!
A person spends one third of his life asleep in bed. Mattresses have to withstand high stresses and strains and keep their shape for many years. It is very important that a mattress keeps its quality characteristics and supports us every night as much as possible, so that body and brain can relax optimally. A silent night enhances the personal well-being and increases the effectiveness during the day. Therefore the manufacturers of mattresses are permanently controlled by the industry with quality inspections. New Cannon manufacturing plants for moulding Polyurethane foam mattresses have been installed recently in Germany, after many years of successful use in other world's countries: the high quality of the produced mattresses has been certified by the leading German institutes as “Stiftung Warentest”, “Ökotest”,”LGA” and “Blauer Engel” (“Blue Angel”).
• Use of several foaming systems at the same time to cover the complete range of different volume weights and degrees of hardness
• The load profile of a mattress has to be divided into a multitude of hardness zones, either with complex contours or with the multiple zone pouring technology
• Zones with a different hardness has to be signed with a different colour
Different approaches The solutions for the foaming technology of the two plants are totally different, while the approach for the mould's manipulation is very similar. The alternatives for the introduction of the reactive blend of Polyurethane chemicals into the moulds are two: open- mould pouring and closed-mould injection. When pouring in open moulds the foam is dispensed with two mixing heads travelling very quickly across the mould: defined foam grades, hardness and eventually also special zones can be colour-marked. For closed-mould injection technology the entire quantity of foam must to be quickly introduced into the mould via an injection hole drilled in the mould. With a optimum inclination of the mould a perfect part is produced, with complex contours and no voids, often created by air pockets stagnating in some blind cavities of the mould's surface. Also here specific qualities can be colour-marked to ease the work of logistics and assembly personnel.
Advantages of both techniques • Less logistic effort oOne raw material (PUR) as input – One ready product (a moulded mattress) as output
Closed mould injection has been selected by Breckle for their new mattress foaming plant.
Conventional production of mattresses Mattresses are produced with different technologies and materials. Until now a combination of latex foam and coil springs as a core, bordered by different surfaces including cut PU blocks, or a combination of different PU foam grades cut in complex contours, is assembled inside a linen cover to make a finished product. In their own in-house “sleep laboratories” the mattress manufacturers are constantly working on the extension of their existing product range as well as on the development of new innovative solutions. Above all lie characteristics, durability, deformation indexes and elastic force at special points, which are verified in successive tests.
New manufacturing technology Sophisticated technical solutions are often hidden within many common articles that we use everyday… and nobody suspects their intervention! Also the new Cannon manufacturing plants for mattresses belong to that kind: thanks to the availability of properly- sized metering and mixing devices, a complete mattress foam core can be produced in one moulding process even using a fast-reacting foam. Cannon Deutschland (www.cannon-deutschland.com
) installed two of these new plants at two dedicated mattresses manufacturers in Germany - Breckle GmbH (www.breckle.de
) located in Northeim and Dunlopillo GmbH (www.dunlopillo.de
) located in Hanau. For both Companies the ultimate target was to reach the same high ergonomic level of comfort with that new manufacturing process as they did with the conventional technology and moreover to reach higher cost-effectiveness.
Requirements to be met • Production of the whole range of mattress measurements has to be possible
• Filling of different weights into the same moulds • Obtaining different hardness grades in the same moulds
oNo need to transport and stock different grades of block foams oNo time-consuming intermediate steps as block production and contour cut (a capital lock-up)
oStorage areas and waste are considerably lower.
• High flexibility oIn the production of moulded foam cores in different grades oIn the processing of orders, as it is possible to change the foam quality from shot to shot while the mould is still installed – a minimal lot size of one part will become economically feasible
oThe production capacity can be adapted to the incoming orders in any moment
• Energetically a very positive production process
Cannon supplied to both customers a similar set of basic equipment, although positioned differently in their production halls, due to the different foaming technique: • the turntables handling the mould carriers • the mould carriers an their energy supplies • the automatic pouring process • the dosing technology as two- or multi-component plant • the several auxiliary units for colours and activators • the automatic release agent spraying • the suction hoods • the safety equipment • the plant control unit
A turntable plant with four stations proved to be the most reasonable configuration, allowing one “place” for each foreseen function: automatic application of release agent, foam pouring or injection, polymerisation and unloading. The mould carriers are planned to carry moulds for all established mattresses sizes – for widths from 800 to 1,400 mm and lengths up to 2,100 mm. The operation of both types of plant can be run from one person only. Therefore a lot of designer's efforts were spent to ensure an easy and ergonomic access to both mould halves, for fast, easy and painless demoulding and cleaning operations.
Sealing a Quality Deal
Frechem GmbH & Co. KG (www.frechem.de
) have been developing and producing for more than 40 years high quality Polyurethane systems in Frechen, Germany for the processing industry and for commercial end users. Their innovation potential, flexible development and production, as well as certified quality management, have contributed to their success. A new Cannon low pressure dosing unit with 6-axis robot helps them to maintain their high quality standards, automatically manufacturing their gaskets and seals.
Quality as a way of life Frechem is entirely focused on continually improving materials, processes and services so as to always be one step ahead of the individual demands of the market. Their ISO 9001:2008 certifications are the foundation of a quality philosophy, which is a way of life in every area of the Company. For the production of their gasketing products they recently installed a Cannon low pressure dosing unit with a 6-axis ABB robot, which precisely applies Polyurethane from liquid to high viscosity (thixotropic) systems. The mixing unit is combined with an EcoCleaner washing system to clean the mixing head with ecological solvent. Due to the recycle system the cleaner can be used several times. The dosing unit allows for the use of formulations featuring mixing ratio from 2:1 to 7:1 (A:B), with a total output capacity from 0.3 g/s to 5 g/s. The working area of the robot, 2,000 x 900 mm, gives them a wide production flexibility, allowing for real 3-dimensional application of their own Frechfoam® chemicals even on large parts.
Applications Frechem produces gaskets and seals for all kind of electrical enclosures (plastic, metal), filters, luminaries, packaging (plastic, metal, fibres) as well as moulded parts for the automotive industry. Their Frechfoam® gasket systems are characterised by a wide range of viscosity: the thixotropic formulations vary from 35,000 to 100,000 mPas, while the liquid ones go from 1,000 to 5,000 mPas. The final products hardness – in the Shore 00 scale – vary from 30 to 65. A temperature stability going from -40°C to +90°C allows for a wide series of end-uses of their gaskets.
The fully tiltable presses guarantee optimum access to both plattens to the Dunlopillo operator.
Whether pouring into open moulds or injecting into closed moulds – the foaming technology is heavily affected by the used mixing heads.
Closed-mould injection For high component's outputs and the option to work with several Polyurethane systems plus additional components (colours/activators) which can be varied from shot to shot, the mixing head type FP2L32 – AN is recommended, injecting in closed moulds. A 3-component “A-System Servo” 200 dosing unit has been supplied in this case. For the injection of foam either a commercial robot or a dedicated Cannon head holder, designed to insert the mixing head into few pre- determined fixed positions, can be used.
Open-mould pouring When pouring in open moulds these large parts – which can weigh up to 20 kg each and whose foam must be completely dispensed in the mould within a time frame of 10 sec – must be produced using two heads pouring simultaneously. Therefore two metering machines working in synchronised tandem are required. Two FPL 24/3 heads perform this task, fed by two “A-Compact” 60 with two CCS units for the colour dosing. The automatic distribution of foam in the open mould, following repetitively precise and pre-defined pouring paths, can be done either with a commercially available robot or with a cartesian Cannon robot with two mixing head's arms.
The core piece of the plant control system is the product management system, a data base where the required product- related data records can be easily assigned to the installed mould carriers. Each data record is consisting of: • The raw material formulation • The desired shot weight • The traverse path for the pouring robot • The traverse path for the release agent robot
All plants are working with high efficiency, producing quality mattresses in the required foam grades. The satisfaction of both customers was reached thanks to the supply of a turn-key solution and by the professional cooperation of all involved parties. The mattresses of our customers are certified and approved by the “Blue Angel” testing institute: is it, maybe, because sleeping on these mattresses is a real celestial experience?
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