A specific projection angle was selected as the optimum one to the upper mould half is present, and many times it is not SoliSpray for innovative automotive Dash Insulators
guarantee complete control of the spraying pattern, allowing opened at a full 90° aperture during the spray job. The use of a
for a correct number of "passes" on the mould and for a small head with a lighter piping allows for better entrance over
minimum overlapping of foam between two contiguous the lower mould half, and for less risks of collision with the
The automotive industry increasingly requires superior noise CANNON SOLUTION strokes. After thorough development, helped by the use of a upper mould surface.
insulation solutions to provide vehicles which must be In the late 1990's Cannon were developing a number of laser simulator which optimised the computer-programming The development work was validated, and Cannon supplied a
acoustically comfortable and - at the same time - of manufacturing systems based on the spray technology. of the spray patterns, the best results were achieved with a complete solution including piston-dosing high pressure
lightweight and with ample spaces in the passenger's The InterWet solutions - for instance - allowed for the intimate overlapping width lower than 5% of the stroke's width. metering unit, the new spray head, plus all the required
compartment. mixing of PUR formulations with long chopped fibers of glass The same design allowed to define a spraying distance from ancillaries. This plant is in production in Germany since June
This article describes two applications for SoliSpray, the new and of other materials, as well as of heavy powders, milled scrap the surface of min. 300 - max. 800 mm, to cover the widest 2008.
Cannon technology for spraying highly-filled PUR of PUR flexible foams. This technology required a certain range of requirements dictated by the smallest and the largest A view of Adler's spray and foaming plant for FIAT's dash insulators near
formulations, developed for the manufacture of the Dash amount of efforts for the precise dosing of these external moulds used for this process. A positive Italian industrial experience Matera, Italy.
Insulator, a large element placed under the instrument panel. elements, which provided the Cannon PUR R&D team with Cleaning the head after the spray operation involved a number Adler is an Italian car part manufacturer belonging to a
special skills in handling and mixing these solids. of practical considerations, mostly linked to the repetitivity of family group which owns similar plants in Italy, adapt and optimise the process, and this co-operation worked.
Noise from the engine enters into the cockpit mainly from two Careful attention was dedicated to the design of heads able to results required by an industrial automated operation. The high Poland, France, Brazil, Turkey and India. They provide At the end of the lesson, few basic point were made clear: the
places: the metal wall holding the instrument panel and the two cope with large amounts of solid, abrasive fillers at relatively material reactivity required the development of a small washing all sorts of interior parts to Fiat, VW-Porsche, best results were obtained with an output range around 80
"pits" near the front wheels, where on one side the pedals are high output rate. One of these heads was designed with the device which cleans the discharge duct and the spray nozzle Peugeot, Iveco, Suzuki and other vehicle manufacturers, g/sec, an extremely precise control of the component's
mounted and - on the opposite one - the front passenger's feet are geometry of a standard L-shaped Cannon FPL, a Cannon with few grams of an ester-based cleaning agent, an utilizing several thermoplastic and Polyurethane technologies. temperatures was a must, some time has to be invested in the
resting. Patent of the late 1970's that has introduced a superior level of environmentally-friendly solvent recoverable by distillation. In their plant in Pisticci, strategically well positioned to supply beginning to define the most efficient spraying path for the
mixing efficiency combined with the absence of splash during Various types of pump- all Fiat's plants based in southern Italy, Adler produces - among robot, and the final skin should be composed - for practical
the open-mould pouring operations. This head - modified in its and piston-driven dosing units INDUSTRIALISATION OF THE PROCESS other parts - the Dash Insulator of the Grande Punto model. reasons linked with the maximum specific weight of the final
parts in contact with the solid, abrasive fillers - provided very are available at Cannon for the application Once applied all the described developments on the lab This large sound-deadening part (it measures 165x90 cm) rather piece - by a maximum of three layers. of spray foams for automotive components
good results when pouring simultaneously a standard PUR machine, a second series of trials was organised and run using than being made, as they do for other vehicles, by back-foaming The fast reacting formulation, fine tuned after several sessions
formulation and a number of solid fillers and reinforcements. After much work and efforts a number of good Heavy Layers moulds of potential customers of this technology, and the with PUR a PVC thermoformed skin, thanks to the availability of industrial trials, allowed for a very quick sequence of
When Cannon PUR R&D team was faced with the request of was produced: they were judged interesting and worth the results very soon proved that the development work had been of the new Cannon SoliSpray technology has been designed as a "passes" over the mould, optimizing the cycle time and
an alternative method to manufacture Heavy Layers for Dash continuation of the project. A sort of "starting point" of the successful. "All PUR" product composed by a thin layer of sound providing high productivity to the line. This high reactivity
insulators, the filled-spray alternative was immediately taken into technology was set, and the process entered in its "refining absorbing compact sprayed PUR, back-foamed with low- allows for the application of a uniform thickness of material
consideration. phase". density flexible PUR foam. also on the vertical slopes of the mould: dropping of liquid is
High mixing efficiency combined with the absence of splash - A number of basic problems was identified and duly tackled. The two different processes are applied in sequence on the minimized after its application over the mould' surface,
in presence of high percentages of solid fillers - are also very They mainly involved four areas: mixing quality, effect of same production line, a carousel system dragging several mould guaranteeing homogeneous layers of skin in each cross section
important features for a spray head. abrasive powders on the mechanical components, design of carriers. Each of these book-opening mould carriers holds one of the insulating part.
A number of technical constraints were there to be overcome, the spray nozzle and head cleaning procedure at the end of large mould. The thin, high-density skin is sprayed directly on
but the potential advantages of a "spray approach" immediately the spray job. the surface of the lower mould, and the flexible foam layer is
appealed the researchers:A typical Dash Insulator Mixing quality of Polyurethanes - in general - derives from lately poured over the skin by a second dosing unit.
• The possibility to eliminate half of the tools: a spray several factors: ratio and nature of components, output, size The upper part of the mould is closed over the lower part
foam only requires the lower half of a mould, not being this a and geometry of the mixing chamber. immediately after the open-mould pouring operation. Several solutions have been applied to meet contrasting needs: high
moulding process. When the components are (more or less) of the same order of The finished two-layers Dash Insulator is demoulded after a noise-insulation efficiency and low volume. Sandwiches of heavily-
• The elimination of heavy and expensive mould carriers: magnitude of viscosity, specific gravity and temperature, what short cure, and the cycle restarts.filled polymeric facings and flexible foams, felt-based mats, several
simple trays would be required to carry the lower mould happens in a traditional impingement mixing chamber is by The sprayed skin is composed by a two-component combinations of synthetic and natural materials. Lightweight,
halves on which the foam will be sprayed. now clear and consolidated - at least for those who know what formulation, which contains from 50 to 65% of mineral filler expanded textile-based mats provide an economic solution with
• The possibility to apply layers of insulating material they are dealing with. But when the same parameters are, as in over the finished product. For this application a fine powder of medium-good noise insulation, but they steal space inside the
only where it is really required: the mould areas where it is this case, heavily unbalanced, what happens in a tiny mixing Calcium Carbonate is employed, in a filler-to-polyol ratio of cockpit and are prone to moisture absorption.
unnecessary can be simply skipped during the spraying chamber is widely uncertain and cannot surely be monitored 150/100 that can reach the 250/100 value. RRIM-based injected parts provide good sound-proofing but are
operation. Where more material is needed, a second, even a with a video camera. Not in real life, at least. Only by using Again, also in this case the major obstacle for a correct made out of expensive chemicals as well as expensive production
third "pass" can be applied when the former is sufficiently dedicated FEA (Finite Elements Analysis) software and application of this formulation derives from the very high tools and presses.
dried-. mathematical models one can simulate those processing viscosity of this blend: at 25 °C the blend is a solid mass bearing Thermoformed combinations of heavy layers and various facings
• The possibility to position plastic and metal inserts in situations with a good margin of reliability, using less time and a viscosity of 40,000 cps. Only by heating it up to 80 °C its are quite labour intensive to obtain. Almost all the current products
mould prior to the spraying: positioned in mould either One Cannon piston machine is dispensing the heavily filled formulation, less resources than when using a "trial and error" approach. viscosity reaches a more reasonable - but still problematic to require expensive moulding tools, either because they must contain another feeds the second layer of sound absorber, a light flexible foam.
manually or using robots, they are fully encapsulated by the process - value of 16,000 cps.rising PUR foams or because they must be heated to provide
foam. Specifically for the Polyol side - characterised by a very high The piston-dosing high pressure metering unit is usually located over the spray thermoforming capability.
specific gravity and brought at very high temperature to lower booth. A perfect skin, whose weight is around 6 kg ( 1.8 kg/sqm for An alternative, simpler solution was demanded by this very cost- each layer of one millimetre of thickness), guarantees a nice
INITIAL DEVELOPMENTS its extremely high initial viscosity - a special new design of jets conscious market.
A development project was initiated, to explore the limits of the was derived from other branches of the industry, particularly A positive German industrial experience aspect for the external side of the piece and high adhesion for
available metering and mixing equipment and define the from the hydraulic science. An optimised stream of material One of the leading German manufacturers of sound the flexible foam PU formulation which is poured over it a few PROJECT BACKGROUND
parameters for the optimum solution. was obtained, whose speed can reach well above the 100 meter deadening systems for automotive applications - a seconds after the skin has dried. Acoustic shield for dashboards, providing a substantial reduction of
A piston-dosing Cannon HE lab machine was specially per second limit that transforms this flux of filled liquid Cannon customer for more than 25 years - required a Says Lino Mondino, Adler's Chief of the Engineering and the noise generated by the engines, have been produced with
modified and dedicated to this project, as well as a large portion almost in a water-jet cutting tool! solution for a large part they had to supply to BMW. Innovation Department: "It was not an easy learning, it was not as Cannon equipment for many years by the major suppliers of the
of the R&D lab with a robot handling the spray head, a fully- Opposite story for the Isocyanate stream, characterised by A heavily-filled formulation, based on Polymeric Isocyanate (35 fast as we hoped, but now it is there and it works very fine. We supply automotive industry.
enclosed spray cabin with forced ventilation of exhausts gases very low percentage, viscosity and specific gravity. For this pbw), Polyol with amine-based catalysis (100 pbw) and Barite, extremely good parts made efficiently and this is what our customers - and Lately, the preferred solution has been the so-called Heavy Layer, a
and all the necessary ancillaries and moulds. component a totally different injector was designed, that well dried to remove water (350 pbw) was tested, to produce a we too - like mostly! This is what counts, today.»single-material moulded element obtained by closed-mould
A team of specialists - from various departments of the performed optimally with the opposite one carrying the filled large Dash Insulator containing, in the final blend, 70% of solid injection of RRIM formulations heavily filled with Barite; this is a
Company - was fully dedicated to this task for several months. Polyol stream. filler. THE ADDED VALUE natural Barium Sulphate powder, containing small amounts of
First things first, a proper formulation had to be found. Seen in the pre-blending drum, the Polyol side looked like thick What did Cannon achieve from this new SoliSpray development abrasive silica and quartz crystals able to wear severely standard
To start with, also using the previous experiences with moulded mud. The simple idea of spraying that mud puzzled a lot the Six kg of filled PUR skin are sprayed over a naken mould: more than half project? Quite a lot: pumps and mixing heads. Piston-driven metering units have been
formulations, a level of 50% of Barite on the total applied development team. This blend was transferred to the Polyol of the formulation consists of a fine Calcium Carbonate powder! • An industrial process, currently in operation in Germany developed since the 1980's for these applications, combined with
polymer was set as the minimum one to guarantee good tank using a special pump, and once there it was recirculated for with 70% of Barite and in Italy with 50 to 65% of Calcium Major advantages of Calcium Carbonate versus the previously hardened heads and special injectors providing a stable functioning
acoustic properties. a while at 85°C and processed at this high temperature, working Carbonate.described Barium Sulphate - still maintaining a very high and constancy of mixing results in the long run.
The peculiar reology properties of fast and heavily filled with a pressure on the nozzle of 180 bar. The Isocyanate was • An important saving in tooling - if the process is applied insulation capacity - are the lack of abrasion effect over dosing Injection of the two-component formulation occurs in large, closed
formulations require special settings on the temperature control processed at 35 °C and pressure of 190 bar. without a subsequent back-foaming operation - because it machine and mixing heads, and a slightly lower specific gravity. moulds, and the pressure generated by the expanding PUR must be
side: extra heating capacity was built into the component tanks The result was beyond any expectation. A perfect layer of well- can even avoid the use of mould carriers and cuts to less than This translates into easier process and some weight reduction held by huge presses to avoid that "flashes" of polymers leak from
and feed lines, able to guarantee - at least on the filled Polyol mixed polymer was obtained, which allowed for the deposition half the investment in moulds. The larger the part, the more of the component, bearing a higher mileage to the vehicle to the mould junction, wasting material and forcing to manually trim
side - a running temperature close to 90 °C. of several "passes" one over the other, increasing the final part's convenient the process results. whom the Dash Insulator will belong. the parts after demoulding.
The matter was rather new also for experienced Raw Material thickness where it was needed and keeping a minimum layer • A high-quality finished part characterised by uniform Adler development and production staff - new to this filled When the industry tried to save some material by thinning the
Suppliers. A number of them - all the main players in this field there where it was just necessary a thin film, enough for thickness and constant distribution of solids within the spray technology - had to learn each and every trick of the trade section of the insulator, a quality problem quickly arose: heavily
of the Automotive industry - were invited to take part in this handling the part safely during the extraction of the part from polymer, and by a very high differential between thick and to reach an optimum result. filled formulations are very viscous, they flow with difficulty in thin
challenge. the bottom mould half. The lightweight mixhead produced a thin parts, not obtainable with a moulding process. As usual, the best compromise had to be found among cavities and produce parts showing air entrapments, heavy flow
The first of them came with drums of basic chemicals and jars perfectly triangular spray pattern, with a very flat and regular • A system usable for both a mass production of standard cars formulation, machine, head and mould, and the learning curve marks and poor surface aspect. The scrap rate quickly becomes a
of their "magic powders" and played in Cannon R&D Lab until Compact and characterised by a perfect spray pattern, the new Cannon head section. The external border of the spray left a minimal drop- and for small series of large parts for trucks, buses and was pretty long. Cannon worked very close to the customer to major problem, also due to the relatively high cost of the
a decent reactivity profile was obtained and reproduced for a performs very well with highly filled formulations. out of no more than 2-3% of material, free from any special vehicles. All with the same equipment.formulation, and to the high cost of disposing of these large,
sequence of spray applications of one grade of filled foam. pulverisation effect. The overlapping between contiguous The development continues, and interesting developments are scrapped elements.
The abrasion problem was a very serious one. Natural Barite "strokes" was - as expected - contained below 4% of the spray in the "boiler room" at the moment. Have a complex spray
Moreover the presses and moulds necessary to withstand the extracted from mines and roughly pulverised is sold "as is" width. project in mind? Talk to Cannon: They Know How!
injection pressure must be strong and stiff, therefore heavy, large Strong skin, in spite of the thin applied layers, and minimum overspray between including all its natural pollutants, mainly silica-based quartz- The measured thickness of a single layer was of one mm (www.cannon.com)
and quite expensive. layers was soon obtained in Cannon R&D Labs. rich sands. They are very abrasive, even if present in small (+/- 10%) across the whole "stroke". The "stroke" was applied
The automotive industry needed large parts, able to provide a good percentages. It is quite understandable that pumping through a regularly, continuously and with constant speed on the curves, A 100% PUR part, this dash insulator for the
level of noise insulation where required by the design of the metal Diesel-like injector a dispersion of a lot of this earth in Polyol, avoiding any effect of build-up or lack of material, typical of FIAT Grande Punto model.
substrate. Parts that must have very different thickness in specific at speed above 100 mps can be quite an experience - for both applications where the robot does not keep a regular speed
zones, that require back foaming with flexible foam and also a good the injector doing the job and for that positioned in front of it when changing its direction.
and robust surface finish, to be assembled by semi-automatic tool in a tiny mixing chamber. This aspect was solved many years This is an unwanted result deriving from the use of large, heavy
into the destined positions. ago for the RRIM heads. The solution was found by making heads with many high-pressure pipes: the new Cannon spray
Placed under the dashboard, these components permit the passage the injectors in hard metal alloys. The optimum very hard head deriving from this development - able to work in a output
of the many services crossing between the engine compartment grade was found with several sets of trials, and the specially range of 80-200 g/sec - features a size which is one quarter of
and the cockpit: each passage must be precisely sealed, so the designed injectors (plus their seats) were made with it. those used by a qualified competitor for the same task, it
finishing with water jet cutting and the weight tolerance are a must. The spray nozzle - positioned at the exit of the discharge weighs only 4 kg and can be mounted on a small robot, the
Not necessarily a part of constant thickness and not necessarily duct - seriously influenced two major processing aspects: the same size of device used for a simple painting task! Also the
"aesthetic" parts in terms of look: placed under the dashboard, geometry of the "stroke" of blend projected on the mould' number and size of pipes is very contained, limiting the
these are large components that even very few mechanics will have surface, and the industrial reliability of the process: seriously dimension of the device that must be brought over a mould for
the opportunity to notice in the whole life of a vehicle. attacked by the abrasive fillers, it required a special execution in a spray operation. This is a major advantage when the job must The special Cannon head guarantees a precise and uniform spray pattern, for optimum distribution of the
A different approach had to be found, using these Barite-filled very hard alloy and a peculiar design, to provide a very flat and be performed in a mould destined to perform a foam-backing filled formulation where it is needed by the part's design.
formulations or something else. regular triangle of projected material. task immediately after the spray operation: in this case, in fact,
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