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Engineering insights: BMC creates new dimensions in underhood apps

 
 
Specially formulated material enables production of high-tolerance automotive engine air intake component.

By Staff | August 2007

The past 20 years have seen the introduction of numerous metal-to-composite conversions in automotive engine-compartment applications. Although weight reduction can be a factor in such conversions, the focus increasingly is on improving performance at the same cost, or reduced costs vs. metallic components through parts integration, materials and processing innovations or both.

Most of the easy substitution of plastics for metals in engine compartments was done in the 1980s and 1990s. Today, composite-for-metal replacement is complicated because the opportunities for part conversion involve more stringent mechanical and thermal demands and, therefore, require the use of high-strength, usually glass-reinforced polymers with excellent mechanical performance at operating temperatures of 140ºC/284ºF and higher. Fortunately, modern design tools and improved molding technologies are enabling replacement of metals with high-temperature thermoplastics and thermosets in applications that only a few years ago were thought to be too difficult for polymer-based materials.

A case in point is the throttle body used in fuel-injected engines. While some simple mechanical air-control valves have converted to composites, more sophisticated electronic throttle control (ETC) valves steadfastly re-mained in die-cast aluminum until last year, when 1.4L and 1.6L engines built by a joint venture between automakers BMW (Munich, Germany) and PSA Peugeot Citroën (Paris, France) debuted with ETCs manufactured from injection molded bulk molding compound ( BMC). Used in vehicles such as BMW's Mini and the Peugeot 207, the ETCs take advantage of dimensional stability advancements of-fered by a specially-formulated bulk molding compound (BMC) and precision molding technology. Tier 1 air and fuel management systems supplier Siemens VDO Automotive AG (Regensburg, Germany) designed, developed and supplies composite ETCs to BMW and PSA, working with molder Helvoet Rubber & Plastic Technologies NV (Lommel, Belgium) and BMC supplier TetraDUR GmbH (Hamburg, Germany), a subsidiary of Bulk Molding Compounds Inc. (BMCI, West Chicago, Ill.).

 

BMCI

Multifunctional device keys engine efficiency

The replacement of conventional carburetors with fuel injection was a major leap in gasoline engine fuel efficiency and emissions control. At first, the flow of air to the engine in injection systems was directly controlled by the movement of the gas pedal via a mechanical linkage between the pedal and the throttle body. But engines developed in the last decade, especially those in Europe, have incorporated the ETC. The ETC uses a more sophisticated system: the gas pedal sends a signal to a sensor that activates a motor housed in the control body. The motor adjusts a valve that controls the amount of air entering the engine. Additionally, oxygen sensors adjust the amount of fuel that is injected to maximize fuel efficiency and reduce emissions. Other electronics optimize engine torque, idle speed control and transmission control to improve the smoothness of the engine and the vehicle ride.

The key to achieving optimum ETC performance is accurate and smooth valve movement and repeatable valve seating — characteristics controlled by the throttle body's dimensional precision and stability. The traditional method used to manufacture the valve plate and throttle housing is to die cast the parts in aluminum and machine them to the final dimension, a costly extra step. Also, because the parts operate in the engine compartment, they must withstand temperatures as high 150°C/302°F and resist damage from fuels and other engine fluids.

In 2001, faced with rising costs for aluminum and a need to reduce ETC weight and cost, Siemens VDO turned to Helvoet to explore production of ETC bodies in reinforced plastics. Already a significant supplier of high-tolerance, precision-molded components, such as phenolic fuel pump impellers, which require dimensional control at the micron level, Helvoet quickly determined that phenolic and high-temperature thermoplastics, such as polyphenylene sulfide (PPS), would be too expensive. The decision was made to investigate polyester BMCs, in part because they are 40 percent less expensive than aluminum on a cost per cubic centimeter basis. The primary question was whether polyester BMC could meet the demanding tolerance and temperature requirements.

modified material prevents in-mold shrinkage

The first step in evaluating substitute materials, says Herman Koks, sales/marketing manager for Helvoet, was the fabrication of a test mold, consisting of a cylindrical bore and a flanged landing area around the cylinder. With this tool, Helvoet and Siemens VDO could quickly screen materials for mold shrinkage, concentricity, dimensional tolerances and other characteristics. In mid-2002, TetraDUR was invited to submit a range of compounds for evaluation. "We had to make some modifications to obtain a material that met the requirements," notes Brett Weber, currently VP of European and Asian operations for TetraDUR's parent, BMCI. At the time of development, Weber was stationed in Europe and active in the material's development. He explains that the conventional method for formulating low-shrink molding compounds involves the use of thermoplastic additives in the base polyester resin. The additive, however, often reduces the compound's mechanical strength and thermal performance, so a delicate balance between part dimensional stability and performance must be achieved.

In the end, the selected material, BMC L4220, was a mixture containing 15 percent chopped glass and 60 percent specially blended mineral fillers in a modified polyester resin. It provides thermal performance above the required 150°C/302°F, and the coefficient of thermal expansion (CTE) is 18µ/m/°C (18 microinches/inch/°C), very close to that of aluminum and less than half that of glass-reinforced thermoplastics. The compound easily passes all the requirements for strength and chemical resistance, including resistance to FAM-B, a high-methanol proxy fuel mixture used for testing, which Weber says is more severe than 90 percent of the fuels sold in Europe.

Significantly, the BMC L4220 exhibits near-zero in-mold shrinkage such that the molded part dimensions are an accurate replication of the mold cavity. As a result, it produces parts with exceptional dimensional repeatability. The measured variability of the BMC parts is typically one-fourth to one-half the allowed diametrical tolerance, which for the throttle body's bore size of 60.05 mm/2.36 inches, is only ±0.05 mm (±0.002 inch), permitting proper operation of the valve plate, which is now produced in PPS (polyphenylene sulfide) with a steel shaft. This means the parts need no postmold machining. After demolding, they are deflashed and ready to ship, emphasizes Koks. "There's no machining or postcuring," he notes, "and no threaded inserts to install." Instead, bolts pass through the housing's mounting holes and into threads in the engine's intake manifold.
 

Specially formulated material enables production of high-tolerance automotive engine air intake component.

By Staff | August 2007

Source: Karl Reque

The asymmetrical design and large variation in wall thickness of the complex ETC (interior view of lower shell is shown) poses problems for traditional plastics and composites due to the need to compensate for mold shrinkage. BMCI and Siemens overcame this issue by developing a composite bulk molding compound with near-zero mold shrinkage. The high creep resistance of the thermoset BMC permits direct mounting to the intake manifold without metal inserts.

The housing was designed in two halves, an upper and lower, each approximately 7.25 inches long by 7 inches wide (184 mm by 178 mm). When assembled, the halves encase the motor that operates the air valve, with the 3.5-inch /89-mm high assembly's parting line placed at the pivot point of the valve plate. The initial production molds, a two-cavity tool each for the upper and lower shells, were made from hardened steel (the European equivalent of H13) and chrome plated for increased durability. (Koks says a four-cavity mold for the lower shell will be in production later this year to compensate for production differences between the upper and lower shells.) Molds are outsourced from a local vendor, and parts are produced on injection molding equipment provided by KraussMaffei GmbH (Munich, Germany). Because the part is based on an aluminum design that features thick, solid mounting flanges, wall thickness of the BMC parts vary considerably, from 2 mm/0.080 inch to more than 10 mm/0.400 inch, says Weber. Injection molding cycle times are still relatively short at less than 80 seconds. While thermosets can be molded with greater thickness variation than thermoplastics without creating large stresses and warping, a design optimized for BMC by reducing thickness in the flange area could shorten cycle time further. "The aluminum designs have had many years to be refined," Kok points out, noting that BMC throttle bodies will undergo similar transformation. "New parts are being designed specifically to take advantage of the BMC's properties."

Development of the manufacturing process was aided by the use of mold flow analysis, performed by consulting firm Corex Design Group Inc. (Glen Rock, N.J.), and multiple design iterations, which were conducted by Siemens VDO and Helvoet. Special care was taken to minimize knit lines and move those that occur to the lowest stress areas of the part. Prior to successful field durability and performance testing by BMW and Peugeot, Siemens VDO satisfactorily completed its own rigorous dimensional analysis of the parts. Assembled throttle controls were put through demanding tests for stress cracking, bolt torque resistance and humidity as well as temperature and mechanical fatigue, which validated the capabilities of the selected materials and the molding technique.

Production started in mid-2006, and the finished upper and lower housings are shipped to Siemens VDO facilities in Bebra, Germany, where the motors are enclosed and the two halves are bonded together with epoxy adhesive to seal the unit. The BMC housing is approximately 25 percent lighter than the aluminum one it replaces. Approximately 500,000 units will be made this year, and Koks says the figure will escalate to more than 1 million in 2008 as additional vehicles incorporate the new engines.

Production accelerates at rapid pace

Koks sees additional advantages to manufacturing such parts in BMC rather than aluminum. It's cheaper and faster to set up an injection molding cell close to the Tier 1 customers, in one of the global Helvoet facilities, than to set up an aluminum die casting operation, he explains. Further, local production is eased by the fact that BMCI already has compounding sites in China, Brazil, Mexico, the U.S. and Europe, so supply logistics for the raw material are already in place for key markets.

Source: Karl Reque

The ETC's parts require no postmold machining to enable part-to-part fit, bore diameter accuracy or mounting-surface flatness. Parts can be demolded, deflashed and shipped to the final assembly point.

The favorable combination of prod-uction efficiency and logistics has en-couraged additional Tier 1 suppliers and OEMs to initiate conversions of ETCs from aluminum to BMC, with at least one other program already in production. Weber predicts that the market for composite ETCs will reach or exceed 4.5 million units by 2010 with the potential for much more growth, considering there are 30 million vehicles built annually in Europe and North America alone.


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Aluminium tools reduce volume moulding costs

Plasma electrolytic oxidation enables aluminium to be used as a replacement for expensive steel tools by improving the durability and the release properties of the surface

In a variety of moulding applications, Keronite Plasma Electrolytic Oxidation (PEO) enables aluminium to be used as a replacement for expensive steel tools by improving both the durability and the release properties of the surface. Using the patented, chrome-free Keronite technology, mould surfaces are transformed into a complex ceramic composite by anodic conversion under plasma discharge conditions in a non-toxic electrolyte solution.
 

* Hardness and wear resistance - depending upon the alloy used and the thickness of the ceramic layer created by the process, the hardness of Keronite surfaces ranges from 500 HV to 2000 HV - well above the capabilities of hard anodising.

Aluminium surfaces can thus be rendered harder than steels, glass, and many silicon-containing compounds.

This hardness improves the wear performance of surfaces, but it the combination of this hardness with compliance of the Keronite layer that really makes it ideal for wear resistance.

Research at the University of Cambridge, UK, demonstrated that the stiffness of Keronite layers can be as little as 30GPa, making them far more strain-tolerant than most ceramic layers.

When impregnated with PTFE, the wear resistance of Keronite surfaces can be even further enhanced.

 
more about it
 
... ...
 
 

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Composite Q & A

http://www.moldedfiberglass.com/f_q.html
Q.A.
What is a Composite?A Composite is a combination of two or more materials yielding properties superior to the individual ingredients. One material is in the form of a particulate or fiber (called the reinforcement or discrete phase). The other is formable solid (called the matrix or continous phase). The region where the reinforcement and the matrix meet is called the interface. Composite properties are determined by chemical mechanical interaction at the interface as well as the properties of the combined materials. Fiber glass reinforced plastic (FRP or GRP) combines fiber glass (the reinforcement) with thermoplastic or thermosetting resins (the matrix).
Q.A.
What are the Advantages?While materials like metal are strong, this strength is equal in all directions. The advantage of composites is that strength characteristics can be custom tailored in a specific direction. Placing more material where needed and less where it is not, is one of the major advantages of composites over other materials.
Q.A.
How do we Design with FRP?The variation in design options, resins and reinforcement selection, and molding process that give composite materials an advantage over other materials can also make working with them a bit more complicated, especially when one needs to maximize the quality and reduce costs. The key is to match the correct variables with the application.

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Grancrete : Spray-Form Building

Grancrete : Spray-Form Building
 
Monday, February 7th, 2005

Grancrete (pdf ) by Argonne offers a step up from the spray-forming concrete products like Shotcrete available today. The ceramic composite of locally available, biodegradable ingredients is stronger than concrete. Since the material is sprayed onto a simple frame made of Styrofoam or locally woven fibers, we know the process offers a wide architectural formal vocabulary, allowing multiple translations of the material into its specific local customs. The material is currently going through its final testing prior to worldwide distribution for cheap housing.

via World Science : World changing

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Application Techniques used in the Composites Industry

Outlined below is a brief overview of the different types of applications used in the manufacture of products in the composites industry. For more detailed information, please contact your nearest Harveys Composites branch.


1) OPEN MOULDING


Open moulding is a process of laminating a gel coated mould under ambient atmospheric conditions, using resin and glass reinforcement with hand lay-up or spray-up techniques.


a) Hand Lay-up

Hand lay-up is the process of applying the material, resin and fibreglass by hand. Brushes, rollers and wet-out guns can be used to apply the resin. The reinforcing materials are usually mat, cloth, woven roving, or core materials.


b) Spray

In spray - up moulding, chopped roving is sprayed along with catalysed resin onto the gelcoat surface and then compacted. This versatile process has proven to be a cost effective method of producing large volumes of open moulded parts.

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2) CLOSED MOULDING

a) Resin Transfer Moulding (RTM):


RTM processes are those in which a liquid resin is transferred into a closed cavity mould. The reinforcing fibre and any embedded cores and inserts are placed into the cavity before the resin is injected.

Over the years, a number of RTM variations have been developed. Examples include Conventional RTM, Vacuum assisted RTM and Vacuum infusion.

In general, the materials used in RTM, are the same as those used in ordinary open moulding, with the most significant differences in the reinforcement technology. The process production rate determines many of the requirements for materials. Higher production rates require the use of pre-made reinforcement preforms and resins with short gel and cure times.


b) Compression Moulding

Compression moulding involves moulding a pre-manufactured compound in a closed mould under pressure and often using heat. A pre-manufactured compound is a combination of some or all of the following: thermoset resin, catalyst, mould release, pigment, filler, various additives and fibre reinforcements.

Compounds can be produced in several forms including sheet moulding compound (SMC) and bulk moulding compound (BMC).

i) SMC

The sheet moulding compound process involves three basic steps. First a compound paste is mixed that includes all the formulation ingredients except for the reinforcement. Second the compound paste and reinforecement are combined and formed into a sheet. Thirdly, the compound is allowed to thicken or mature. The compound paste and reinforcement are combined and the compound machine-formed into a sheet using an SMC machine.

A schematic of the SMC process is shown below.


ii) BMC

During the manufacture of bulk moulding compound all formulation compounds are combined in a mixer. Liquid components are initially added and agitated until dispersed. Dry components, except for glass fibre, are added next and mixed until thoroughly wet.The glass fibre is the last formulation component added and is mixed in until thoroughly wet. Continued mixing of the compound after glass wet out can result in unnecessary degradation of the reinforcement. BMC is ready to mould when it is discharged from the mixer.


c) Pultrusion

Pultrusion is a continuous, automated closed-moulding process that is cost effective for high volume production of constant cross section parts. Pultruded custom profiles and standard shapes (channels, angles, beams, rods, bars, tubing and sheets) have penetrated virtually every market.

The process relies on reciprocating or caterpillar-type puller/clamping systems to pull the fibre and resin continuously through a heated steel die. Roving is pulled from material racks and is then wet out, typically in an open resin bath. Excess resin is squeezed out by shaped bushings positioned ahead of the die. The compacted package then enters the die, where the part cures. The cured part is pulled out of the die and finally into a saw system at the end of the machine. The saw travels downstream whilst it cuts the part to a pre set length. Puller and saw motions are synchronized, usually through computer controls. Alternative injection wet out systems have been developed. Multiple streams can be pultruded in a single die with several cavities. Heat control is also critical, and controllers are available that monitor and maintain a pre-set temperature in various zones throughout the die and mandrels.

d) Vacuum Moulding

Vacuum moulding may be used for the production of parts from medium to large dimensions. It allows for the creation of parts with both faces having a smooth appearance. This method is generally limited to the manufacture of parts with relatively simple shapes and is recommended for small to medium volumes.

Vacuum moulding works combined with low pressure injection moulding techniques. This process allows the separation of the functions of mould closure and resin flux. The mould closure is done by a peripheric circuit with a high level of vacuum. The resin flux is obtained with a low pressure injection or manually applying the resin inside the mould before its closure; when the closure follows the vacuum is created inside the mould cavity.

The more usually applied resins are low viscosity polyesters which may be combined with mineral extenders or fillers.

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3) CAST POLYMER

With the evolution of new processes and products, the name 'cultured marble' has come to be identified with gel-coated calcium carbonate filled and cast polyester matrix. With onyx (gelcoat with fillers) and densified (no gelcoat, ATH or other fillers) products coming into the market place, the market trend has been to identify all these products as 'cast polymers.'

Cast polymer is used to make vanity tops, counter tops, wall panels, window sills among other items. It can be produced in a limitless variety of colours and configurations.

Cultured marble is made by combining polyester resin with a filler. Parts are fabricated by casting the resin and filler combination in open moulds.

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4) FILAMENT WINDING

Filament winding is an automated, high volume process that is ideal for manufacturing pipe, tank, shafts and tubing, pressure vessels and other cylindrical shapes. Machine sophistication varies from basic two-axis mechanical chain-drive operation, to computer controlled multi axis and spindle systems.

The winding machine pulls dry fibre glass from supply racks through a resin bath, and winds the wet fibre around a mandrel. Both removable mandrels and in-situ mandrels, which remain with the part, can be used. For best part performance, fibre tension must be equal on all fibres. Resin is typically worked into the fibres by roll coaters or by breaker bars in dip tanks.

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5. CONTINUOUS PROCESSES

a) Panel lamination

Continuous moulding between layers of film is used for production of Sheet, both coloured and translucent, in flat or profiled (such as corrugated) configuration. The main applications are in building (cladding and roofing) and agriculture

The different steps are as follows:

- continuous impregnation of rovings chopped in situ, or of chopped or continuous strand mats, by resin, on a carrier film,

- above the impregnated material, the second film is deposited, that will be used as a mould,

- shaping, normally in a progressive manner, as permitted within the curing cycle to result in the finished product on exiting the oven,

-   lateral edge trimming and transverse cutting the products to the designed length. The films having served to transport the material are rewound at the exit of the oven prior to trimming. Typical machine speeds are 5 to 15 m/min., depending on the sheet width, which may be up to 3m.

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REFERENCES:
Polyester Products Application Manual; 9th addition; CCP
Cray Valley Unsaturated Polyester Application Guide
Saint-Gobain Vetrotex India Basics of Composites
Saint Gobain Vetrotex Brazil web site

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The AEWC Center’s wood plastic composites pilot plant is a world-leading facility offering industrial clients a range of manufacturing and testing services

 The AEWC Center's wood plastic composites pilot plant is a world-leading facility offering industrial clients a range of manufacturing and testing services. AEWC's range of manufacturing equipment and capacities serve a global list of manufacturers interested in initiating, improving and/or diversifying their wood plastic composite extrusion capacities. AEWC's ISO 17025 accredited testing capacities enable manufacturers to evaluate wood plastic composite products according to international standards recognized by building code and other product certification agencies.

 

Davis Standard Woodtruder

The centerpiece of the AEWC Center's Wood Plastic Composites Pilot Plant is a Davis Standard WT-94 Woodtruder™ . The Woodtruder includes twin and single-screw extruders, a blending unit, a computerized blender-control system, a die tooling system, a spray cooling tank with driven rollers, a traveling cut-off saw, and a run-off table.

The Woodtruder™ can process fibers from sawdust, wood (both hard- and softwoods), sisal, rice hulls, kenaf, flax, peanut shells, recycled polymers, and many other materials.  These are combined with such plastics as polypropylene, high-density poly ethylene (HDPE), and poly vinyl chloride (PVC), which are variously found in many consumer goods such as milk jugs, house siding and plumbing materials. Work is also underway examining the processing of wood fiber with engineering thermoplastics (nylon).

As processing begi ns, fiber is placed into the unit's Colortronic Graviblend Plus 1 station blending unit and weighed within. The wood is fed into the throat of the twin screw extruder and the fiber is dried from 5 to 8 percent moisture down to below 1% through a series of heating zones with atmospheric venting.

 Meanwhile, separate from the fiber, the plastics are melted. This separation insures that fibers will not be burned during processing when the melted plastics encapsulate the fibers completely. These materials are then mixed and any remaining moisture or volatiles are removed by vacuum venting.                                                                                          

 

 

 

 

      Next, the materials are shaped in a die           cooled in the conveyor spray cooling tank,

                                                     

cut to the desired length with the Model MST-6 traveling cut-off saw and collected on the Model DT20-6 run-off table

 

Compounding and Pelletization

To meet specific processing parameters of various commercial manufacturers of wood plastic composite materials, the Center has capacities for specialized compounding – the action of mixing together several types of materials with a polymer matrix. Compounded strands which can be manufactured in the Davis-Standard Woodtruder or in the smaller Cincinnati Milacron CM55 conical twin-screw extruder, are cooled and directly fed into a pelletizer, a machine that has a rotating set of blades that chops the strands into pellets of a user-controll  able length. These pellets are dried and bagged and may be used by polymer processors anywhere in the world.

 

 Agglomeration

The Center's pilot plant has capacities for agglomeration, a process of particle size enlargement which gathers small, fine particles such as dusts or powders into larger masses, clusters, pellets or briquettes. These agglomerated materials can then be used as end products or in a secondary processing step. AEWC's Pallmann Pulverizer makes the Center one of the premier developers of this process in North America.

 

  Injection Molding                                                                                                                                               

AEWC's Engel CC90 injection molding system generates test coupons for testing materials in flexural bending, tension, and impact and allows in-house determination of the operating and mechanical properties of various WPC formulations developed from compounding, agglomeration, and pelletization. This system provides a tool to gauge and establish base-line performance data for various wood plastic composites.

 

 

Dryer

The steam tube dryer is available to dry wood flour and other fiber materials to moisture contents below 1% in order to faciliate extrusion compounding for the CM 55 extruder and the Woodtruder.

 

 

 

Material Property Testing Capabilities at UMaine-AEWC for Wood Plastic Composites

 The AEWC Center performs a variety of ASTM Standard tests, as well as custom tests. The staff consists of full-time, dedicated personnel supported by supervised graduate/undergraduate students. This flexible staffing arrangement enables the Center to provide quick turnarounds on routine testing. Frequently, one-week service is available for common tests. Examples of ASTM Standard tests performed at the AEWC Center are listed below.

 

Test

ASTM Standard

Set-Up Costs

Cost per sample

Flexure

D 6109, D 1037

$100 $50

Tension, Compression, Shear, Fastener Tests

D 143, D 1037

$100 $25

Freeze-Thaw

C 666

$2000 $20

Specific Gravity

D 2395

$100 $15

Moisture Content

D 4442

$100 $15

Slip Resistance

F 1679, D 2394

$100 $25

Abrasion

D 4060

$100 $25

Thermal Expansion

D 696

$300 $35

Moisture Absorption

D 1037

$100 $35

Impact Testing

D 4495, D 6110, D 256

$200 $35

Accelerated Weathering (QUV)

G 154

$600 $35

Flame Testing

D 635

$300 $35

Decay Testing (Soil Block)

D 1413

$2000 $40

Marine Borers

D 2481

Varies $35

Termite Tests

D 3345

Varies $40

Field Decay Studies

AWPA E7

Varies $40

 

Contact:   Douglas J. Gardner
                Professor of Wood Science
                University of Maine
                208 AEWC Building
                Orono, Maine 04469
 
                TEL: (207) 581-2846
                FAX: (207) 581-2074
 
                Email:
Doug_Gardner@apollo.umenfa.maine.edu

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Polyurethane Composites: New Alternative to Polyester & Vinyl Ester

High toughness, fast cure, and no styrene fumes are taking urethane composites beyond SRIM into pultrusion, filament winding, vacuum infusion, and spray-up.

By Lilli Manolis Sherman, Senior Editor

http://www.ptonline.com/articles/200603fa2.html

Gains in processing know-how and advances in reactivity control to extend working time have placed polyure-thane in the running for composite applications long dominated by unsaturated polyesters and vinyl esters. In the last two decades, PUR composites made inroads primarily in foamed structural RIM (SRIM) automotive interior and exterior parts such as pickup truck boxes, load floors, package shelves, and inner door panels. Such applications have gained PUR 3% to 5% of the long-fiber and continuous-fiber composite market.

But the last six years have seen development of PUR pultrusion, filament winding, vacuum infusion and long-fiber spraying technologies. Primarily non-foamed, full-density PUR composite systems are being used with these traditional composite processes for applications from window lineals and bathtubs to electric light poles and large parts for trucks and off-road vehicles.

Why polyurethane?
PUR composites are produced with rigid thermoset resins, as opposed to elastomeric or thermoplastic polyurethane (TPU). "Composites manufactured from these PU resins have superior tensile strength, impact resistance, and abrasion resistance compared with composites based on unsaturated polyester and vinyl ester resins," says Michael Connolly, composites product manager at Huntsman Polyurethanes. He cites typical values for tensile modulus around 430,000 psi, tensile strength of about 12,500 psi, and elongation to failure of over 7.5%. Craig Snyder, market channel representative for non-automotive applications at Bayer MaterialScience, adds that reinforced PUR can be foamed to provide weight savings of up to 20%.

Connolly points out that the superior toughness of PUR composites pays off in secondary operations such as drilling, machining, and assembly. Machined and punched edges exhibit little or no micro-cracking compared with traditional thermoset composites, he says. "We recently measured force to pull out a self-tapping screw and found that the force in PUR profiles is 40% higher than that for a hybrid polyester/PUR composite, and 50% and 60% higher than for vinyl ester and polyester, respectively."

PUR pultrusion is making headway
PUR pultrusion is making headway in ladder rails, tool handles, electrical profiles, I-beams, and window lineals. (Photo: Creative Pultrusions)

PUR composites are also said to be attractive for their processing advantages. Cure times are much faster than for polyester spray-up—about 20 min versus 2 to 4 hr in non-automotive applications, notes Bayer's Snyder. PUR spray processes are also much less labor-intensive than polyester spray-up, which requires rolling out the glass to remove air and ensure complete wet-out.

In automotive parts, PUR SRIM takes 30 sec to 2 min vs. 2 to 10 min for polyester and vinyl ester SMC, says Terry Seagrave, Bayer's market channel manager for NAFTA automotive business. Labor is also re­duced with PUR composite automotive components, because SMC re-quires intermediate steps to prepare and B-stage the sheet. Snyder also notes that tooling costs are much lower than for SMC because of the lower pressures for SRIM.

There has also been a downside to the reaction speed of polyurethanes. According to Lisa Shaner, marketing manager at PUR machinery supplier Krauss-Maffei Corp., "In the past, a drawback to producing large glass-reinforced PUR parts was the fact that the chemistry was so fast that it often did not leave sufficient time to close the press." However, the flexibility of PUR chemistry and new equipment designs have overcome that previous limitation.

"While current technology does not allow use of PUR resins for long open times of more than a few hours or for processing into prepregs intended for storage and later use, the fast reactivity of PUR makes it a good candidate for some open-mold processes, such as spray-up of tubs, provided the appropriate engineering controls are in place for MDI," says Connolly.

PUR composites have another advantage: They contain no styrene and do not generate large amounts of volatile organic compounds (VOCs). On the other hand, PUR does contain MDI, which is a regulated material. However, Bayer sources believe that MDI emissions from PUR composite processing should usually be negligible due to the low vapor pressure of MDI and results of industry emissions tests.

Jeld-Wen's exterior residential door skins
Last year saw a "breakthrough" for long-fiber PUR composites in Jeld-Wen's exterior residential door skins. Low pressure used with Krauss-Maffei's spray-in-mold LFI SRIM system and Bayer's solid Baydur STR material reportedly makes PUR more economical than compression molded SMC.

OSHA's permissible exposure limits for MDI are 0.02 ppm as a short-term ceiling value and 0.005 ppm as an 8-hr time-weighted average. "Our experience in workplace exposure monitoring indicates that unless MDI is heated or sprayed, the likelihood of these limits being exceeded is small," says James Chapman, Bayer's director of product safety. He says proper ventilation is used to control workplace exposures. In addition, protective equipment such as gloves and eyewear are recommended.

The Regulatory Compliance Assistance Program (RECAP) of the Alliance for the Polyurethanes Industry helps processors determine their MDI emissions for environmental permits and EPA Toxic Release Reporting. (RECAP can be accessed at www.polyurethane.org/regulatory/emissions.asp.)

SRIM & its variants
Advances in SRIM materials and processing equipment have made this the fastest growing area of PUR RIM and a promising alternative for processors of composites via RTM, spray-up, and SMC. Traditional SRIM has a lot in common with RTM. Like RTM, it is a closed-mold process whereby a glass preform or mat is placed in the mold, which is then closed and the PUR chemicals are injected. But newer advances in RTM have turned it into more of an automated spray operation.

Robotic "spray-in-mold" or "spray molding" systems emerged in 1995 with the Long-Fiber Injection (LFI) process of Krauss-Maffei, which chops and wets out glass fibers inside the mixhead. The reinforced mix is sprayed onto the bottom half of an open mold. The mold is then closed to cure the part. Because the glass is wetted inside the head, no rollout is needed.

PUR spray equipment suppliers
PUR spray equipment suppliers are adding glass choppers for two-component PUR spraying. Bayer's CSM-Multitec process is shown here.

Other competing SRIM technologies of this type are InterWet from Cannon and CSM Baydur (formerly called FipurTec) from Hennecke Machinery Div. of Bayer MaterialScience. Since 1999, each of these three OEMs also has offered variants of these processes that allow for use of natural fibers.

More recently, Bayer introduced three more CSM (Composite Spray Molding) variants to the U.S. (they are already established in Europe). Two of them are CSM-Baypreg and CSM- Baypreg NF. The former produces Baypreg sandwich panels consisting of a paper honeycomb combined with glass-fiber mats that are impregnated with PUR chemicals sprayed onto both sides of the lay-up. The laminate is then compression molded and cured under heat. The panels are said to have greater lightweighting potential than other sandwich products, making them attractive for automotive and other applications. A recent example is the roof sun shade that replaced SMC on the 2005 Toyota Avalon.

The CSM-Baypreg NF (Natural Fiber) process (formerly called NafpurTec) is quite similar, but it yields thin-walled and extremely lightweight automotive components made from natural-fiber mats without a honeycomb core. Inner door panels are a prime application.

Bayer's newest process is the CSM-Multitec short-fiber PUR system, a version of open-mold spray-up. The PUR mixture is applied in several layers, solid or foamed, with or without reinforcement, and is allowed to cure in the open mold. In this process, glass fibers are chopped 5 to 12.5 mm (0.2 to 0.5 in.) long in an external chopper device mounted on the PUR spray gun. Explains Lutz Heidrich, Hennecke's manager of molded foam, "Traditional PUR equipment manufacturers are adding glass choppers to their two-component PUR equipment, and polyester spray equipment makers are adapting their equipment for PUR."

Bayer's Composite Spray Molding (CSM) technology
CSM-Multitec chopped-fiber PUR systems have expanded the use of Bayer's Composite Spray Molding (CSM) technology to large parts such as this bathtub and tractor fender.

Beyond foamed SRIM
Foamed low-density SRIM has dominated PUR composites for several years, particularly in auto interior applications such as door panels. More recently, non-foamed, high-density SRIM systems were proved viable. One of the first cases was the cargo box of the 2001 GM Silverado 1500 pickup truck, based on Bayer's Baydur 426 HD-SRIM PUR system. A more recent use of the same system is the inner midgate panel of the 2005 Chevrolet Avalanche hybrid utility vehicle.

A breakthrough application for large, non-automotive, "solid" PUR long-fiber composites was unveiled last year with the new line of exterior residential doors from Jeld-Wen of Klamath Falls, Ore. The solid Baydur STR composite system is used to form the skins of the doors using Krauss-Maffei's LFI system. "The lower molding pressure makes this more economical than compression molding with SMC," says Bayer's Snyder.

Huntsman's Connolly says his company has worked on projects using both the InterWet and LFI processes to make full-density PUR composites. "Parts as large as a tailgate and tonneau cover have been produced by these process methods."

Bayer's CSM-Multitec allows cost-effective production of larger molded parts than other CSM techniques and is also suited to small-to-medium production runs. Recent commercial applications include tractor hoods and fenders and bathtubs—which made their debut in Europe last year. One bathtub has a thermoformed cast-acrylic skin backed up with Baydur 60 rigid PUR integral-skin foam. Eight layers of Multitec, some foamed, some solid, with 12-mm chopped glass are sprayed onto the back of the tub skin. The composite backing only takes 3 to 5 min to cure.

BASF has been focusing on sprayed PUR composite applications such as spas and recreational vehicles as a one-to-one replacement for polyester composites. According to technical services supervisor Jim Turnbach, large spas up to 20 ft2 can be made with combinations of full-density rigid PUR, elastomers, and foam. BASF has also worked on smaller R.V. components such as front caps and back sections, but Turnbach sees potential for large applications such as side panels.

Huntsman's data
Huntsman's data show that PUR pultrusions are 88% higher than polyester composites in flexural strength and 66% higher in elongation parallel to the fibers. Flex modulus changes less because it is affected primarily by the reinforcement.

A hit in pultrusion
Polyurethane pultrusion is here to stay despite having taken several years to come to commercial fruition. While it appears that not more than a handful of pultruders are currently processing polyurethane profiles, material suppliers confirm that several developmental programs are under way.

North American pultruders are seeing strong competition from China in products such as ladder rails and tool handles, says Huntsman's Connolly. The added toughness and strength of PUR give domestic pultruders an opportunity to distinguish their products, he notes.

A widely acknowledged leader and pioneer in PUR pultrusion is Creative Pultrusions, which has more than five years' commercial experience in this area. It offers an eight-page brochure on its SupurTuf PUR pultrusion on its website. New business development manager Dustin Troutman says the firm currently offers more than 25 PUR pultruded profiles. They range from ladder rails and electrical cross arms to sheet pilings for waterfront bulkheads and other high-strength, high-impact applications in construction, transportation, and infrastructure.

Huntsman has led the thrust into pultrusion with development of non-foamed formulations specifically suited to this process as well as filament winding and vacuum infusion. BASF has also developed such resin systems, and Bayer plans to launch Baydur PUL 2000 systems for pultrusion this year.

Two-component metering equipment and closed injection systems
Two-component metering equipment and closed injection systems are two key requirements for a PUR pultrusion set-up. (Illustration: Huntsman)

Catalyst and resin developments allowed Huntsman to extend PUR gel times at room temperature to more than 30 min. Despite the extended resin pot lives, these systems still maintain rapid cure rates at the elevated temperatures used for pultrusion. As a result, line speeds of over 6 ft/min have been achieved for unidirectional pultruded profiles, similar to the best polyesters but much faster than the typical 2 to 4 ft/min for vinyl esters and 1 to 2 ft/min for epoxies, according to Connolly. One Huntsman customer, CE Composites Inc. of Ottowa, Ont., has been pultruding PUR hockey sticks for several years.

A typical polyurethane pultrusion set-up includes a two-component feed system running out of drums or pots, a range of pump assemblies, and a transfer line into a conventional PUR low-pressure mixing head with a static mixer. A closed resin injection process is generally used with PUR.

The main market so far for PUR pultrusion is smaller profiles such as ladder rails, tool handles, and rods. Window lineals are a promising new area of growth. Experienced pultruders today are making PUR channels and I-beams up to 6 x 6 in. Larger I-beams—over 1 ft square—remain a challenge for PUR because they would require extended pot life in an open impregnation bath, where the MDI could react with atmospheric moisture. Huntsman's Connolly indicates that this hurdle could be overcome. In recent trials, much larger parts than have been produced commercially to date were achieved by Huntsman, although he won't disclose the size.

Urethane's exceptional impact and tensile strengths, plus interlaminar shear strength more than double that of polyester, may allow existing pultrusion applications to be re-engineered for lighter weight and lower cost. For example, Connolly says an I-beam of PUR can be made thinner and lighter by using less continuous-strand mat (CSM) and a higher proportion of glass roving. "By reducing from three to two layers of CSM, and replacing some CSM with roving, the I-beam thickness can be reduced from 3.3 mm to 2.6 mm while maintaining longitudinal stiffness." He says this results in 7% lower cost and 13% lower weight.

Sheet pilings for waterfront bulkheads
Sheet pilings for waterfront bulkheads are an example of promising infrastructure applications for pultruded PUR. (Photo: Creative Pultrusions)

Troutman from Creative Pultrusions says very thin sections can be pultruded with PUR. "Polyurethane allows you to reduce weight and fabrication cost and eliminate surface preparation prior to bonding." He says the cost of PUR pultruded profiles is in line with that of high-end vinyl ester profiles. He adds, "Pultrusion applications that were not feasible in polyester and vinyl ester due to strength limitations are now practical with superior-performing polyurethanes."

PUR filament winding, too
Replacing polyester composites in filament winding, a market two to three times bigger than pultrusion, is very much of interest to PUR suppliers. One recent breakthrough is the RStandard modular composite utility pole, manufactured by RS Technologies of Calgary, Alberta, using its proprietary Version PUR resins and a patented filament winding process. Made in lengths up to 135 ft, it is the first all-PUR pole and the first use of composites for electrical transmission poles. Polyester composites are used mostly for smaller distribution poles.

The inner layer of the pole is made with an aromatic grade of Version PUR, while two layers of aliphatic resins are used on the outside. This resin system is said to be stronger and tougher than polyester, vinyl ester, or epoxy and to offer a greater strength-to-weight ratio. Also, proprietary fiber-placement technology reportedly cuts the amount of reinforcement needed to make poles that have strength equal to or better than those made with traditional thermosets.

The special filament winding system makes zero-degree winds, placing fiberglass in the axial plane of the pole, while typical winding processes can create minimum wind angles of 7° to 8°. Optimized placement of glass and resin can reduce thickness and overall weight by up to 45%.

reduce thickness and overall weight of electrical utility poles
RS Technologies' patented resins and filament winding system allows optimized glass placement to reduce thickness and overall weight of electrical utility poles by up to 45%.

RS Technologies developed some of its own machinery for a system that can wind 2200 lb/hr. In most cases, standard mandrels, heaters, and control systems are used without modification. The composite poles are heat cured.

Other applications where PUR composites have potential to replace polyesters in filament winding include infrastructure, according to Connolly. BASF has been active in PUR filament winding, particularly in Europe, where the target is "long-term infrastructure" that requires good corrosion resistance, notes Turnbach.

Another potential market is filament-wound pipes for corrosion-resistant applications or potable-water infrastructure in places like the Middle East and Southeast Asia, says Connolly. Hot-water tanks are another promising area, he says: "Early trials have revealed 40% to 50% improvements in burst strength of PUR filament-wound tanks over those using polyester."

PUR vacuum infusion
The viability of PUR vacuum infusion, a version of RTM designed for very large parts (e.g., boat hulls), is also being explored. This approach requires only one mold half, plus a plastic film to cover the lay-up. According to Connolly, achievement of more than 30-min pot life for PUR makes possible fabrication of parts by RTM, VARTM, and other infusion pro­cesses. "We have been successful at infusing moderately large parts—using over 50 lb of resin—in trials at customer sites and aim to have these components commercially launch­ed in the near future. The commercial viability of infusing PUR into very large parts—greater than 500 lb of resin—is unclear, but it may be possible."

Bayer's Snyder says new formulations look promising for vacuum infusion. RS Technologies is exploring both vacuum infusion and pultrusion using its Version PUR resins.

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Shakespeare Begins Shipping Tuff-Hinge Composite Poles



Shakespeare Composite Structures has begun shipping its new Tuff-Hinge Composite poles, designed for easy servicing of luminaires without lifts or trucks.

The Tuff-Hinge poles lay a Tuff-Pole on the ground when you need to re-lamp or perform other service, and raise it when the work is done, all without lifts or trucks. A four-foot Direct Burial portion of the pole is embedded into the ground, leaving Shakespeare Composite Structures innovative hinged base at ground level. Made of 356-T6 aluminum and bonded to the pole's two sections, the hinge uses a stainless steel hinge pin. The top portion is an "O" series composite Tuff-Pole, one of the company's most popular styles for strength and good looks. The lightweight composite pole simply tilts over, all the way to the ground, for relamping or other luminaire service.

The product of the newest technologies in fibreglass and resin systems, along with advanced manufacturing process controls, all Tuff-Poles are engineered with new resin mixes and fibreglass configurations and automated process controls to tighten manufacturing tolerances and quality control. They employ advanced UV inhibitors and coatings that provide even longer lasting protection in extreme weather.

Shakespeare has also received RUS (Rural Utility Service, US Department of Agriculture) acceptance of its Lewtex composite crossarms. The RUS acceptance is the first ever listing of a composite crossarm. The Lewtex design is a standard 3� x 4� profile that matches existing hardware and brackets. The arm is manufactured hollow, then filled with high-density, closed-cell foam that prevents the entry or migration of moisture through the arm. The crossarms can be field drilled without the need for inserts or other auxiliary materials.

Now a division of GenlyteThomas Group, Shakespeare Composite Structures has since the 1950's pioneered the use of fibreglass reinforced composites in lighting and utility poles.



Publication Date: 10/09/2007
WWW Link: http://www.skp-cs.com

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The success of wind energy would not have been possible without the use of composite materials.

Composites on the Upturn
27 August 2007

The success of wind energy would not have been possible without the use of composite materials.

 

Roman Gaugler, owner of company Gaugler & Lutz oHG from Aalen Ebnet says "In the next few years we will see a yearly increase in the number of wind turbines from 15 to 20 percent. Above all this is due to large offshore projects and the now very loud demands for climatic protection." In addition the plants will have continually improved performance. "Currently more and more 5 MW wind turbines are being ordered, the future is likely to be 10 MW wind turbines and 80 metre long rotor blades. Moreover, longer rotor blades mean that more material will be needed - we are counting on this."

 

In the meantime material deliveries to the wind energy sector form almost 80 percent of the total sales volume of Gaugler & Lutz. Its list of customers includes all the well-known German wind power plant constructors. The company has about 150 employees and is specialised in the processing and fabrication of core materials for light and sandwich construction. Gaugler & Lutz will present an insight into its product range at the coming COMPOSITES EUROPE (6th to the 8th of November 2007, Stuttgart ), the European trade fair for composite materials. As well as special foam materials and balsa woods, the trading company supplies reinforcement fibres for the entire composite sector and operates its own production facilities. The company's processing spectrum ranges from CNC controlled fabrication to hand fabrication, various types of surface processing, the manufacture of kits, and right up to thermoforming.

 

Low weight but high strength and rigidity – these properties make composites interesting as construction materials. Composites being light weight materials are used in many industries, especially for wind energy generation. The giant rotor blades consist of two half shells, which have the appropriate shape and are made of cross-linked dense, rigid foam in which balsa woods are incorporated and are then glued to another. The balsa wood is grown on plantations in Ecuador and felled after six years. The approximately one metre long tree pieces are cut into square timbers and glued together to form 1.22 meter long and five centimetre wide blocks.

 

These blocks are cut, in the opposite direction to the grain, into boards and given a fine spraying of resin solution to protect them against humidity. Then on one side a fine glass fabric is laid on which is then punched out from the other side into small square pieces. The rigid foam elements have a density of 60 kilograms per cubic metre and are supplied in 2,450 by 1,150 times 78 millimetre size blocks. Afterwards they are split into boards then cut to size and numbered according to the specified format. After the edges have been trimmed the blocks are packed. Using the help of a layout plan in each box, the respective part is allocated to the rotor blade shape accordingly.

 

"Currently, vacuum injection is the main processing method used. It offers significantly better industrial safety, an exact dosing of the resin, there are no bubbles produced in the laminate and it adheres better to the core materials", explains Gaugler. About 4,000 rotor blades per year are produced in this way using the help of materials made by this company, which is located in Baden-Wurttemberg. The owner reveals that "at the moment the smallest measures 27, the largest around 60 metres". At the beginning of the 1990's, Gaugler & Lutz introduced the so-called kit construction of light components for the wind energy sector into their product range.

 

Not only the right raw materials are needed but also their specific composition is an important prerequisite for their use in the wind energy. The industrial production of the giant wings would not be possible without the use of specialist plastics. Neither the model, the moulds for the construction of the rotor shells, nor the rotor blades could be manufactured without these plastics. Also the gluing of top and bottom shells would not be achievable. So that the epoxy and polyurethane resins as well as modelling and adhesive pastes can be prepared in the correct composition for use, two component dosing and mixing plants are necessary such as those manufactured by the company Tartler GmbH from Lützelbach – also an exhibitor at the COMPOSITES EUROPE.

 

The company has developed special, more efficient, flexible two component mixing plants for the economic production of wind turbine rotor blades. If SMP (Seamless Modelling Pastes) or epoxy pastes are used in large quantities then the Nodopox 200 mixing plant is used during the construction of the models. Depending on the viscosity and composition ratio it can extrude up to five kilograms per minute. The dosing ratio can be steplessly controlled from 100:10 to 10:100. The dosing pumps and mixing heads are driven by frequency regulated motors. There are appropriately alternative uses for PU pastes. Nodopox machines are also used during the construction of laminated shapes for the wing halves, which are made with epoxy resins.

 

Tartler manufactures Nodopur two component mixing and dosing systems for the production of the two half-shells. They can produce up to 40 litres per minute and can intelligently control the vacuum supported injection of glass fibre reinforced epoxy resins during the vacuum infusion procedure or directly using Resin Transfer Moulding (RTM). Tartler also supplies an acceptable mixing and dosing machine for the adhesive paste used in the "marriage" of both wind wing half shells. If the surfaces of the finished rotor blades are to be given a highly reactive coating the CG 52 machine is suitable for this job.

 

One of the special features of the machine is its rotating mixing nozzle with rpm control. These in-house developments enable a high rpm and produce an optimal mixing of the components. At the same time stiffeners on the mixer components increase their service life. Furthermore, there is no dead space in which the material can move independently; this is because the mixing components reach right up to the front end of the mixing tube. Also, a premixer directly at the valve outlet ensures an immediate mixing.

However, composites not only help reduce the weight of rotor blades. The company FWT Wickeltechnick GmbH in Neunkirchen in Austria produces drive shafts for wind turbines using glass reinforced plastics (GFC). About 60 units were delivered last year. "Low weight, temperature resistance and reliable transmission of force make this material very interesting for this application", explains managing director Günther Kautz. Another decisive criterion is the electrically isolating nature of the glass fibre.

 

During the processing the company uses Filament Winding Technology (FWT). Using the help of this winding technology rotationally symmetric components are manufactured by laying resin-soaked fibre rope onto winding mandrels. The manufacture of a shaft or a tube is divided into the steps: winding, hardening as well as parting and removal. Then the fibres with spools weighing between one and six kilograms are placed into the spool spindles. Using pneumatic pressure the spool brake is activated in order to keep the tension in the fibre during the winding process, which helps achieve a good laying.

 

The fibres are unwound from the spool spindles and through the resin section in which they are impregnated. A dip roller takes resin from the bath and soaks the fibres with it. The pressure of a squeeze roller is used to wipe off excess resin from the fibres and they can then be fed on to proper winding process. The resin bath can be heated according to requirements in order to influence the viscosity of the resin. From there it goes to the winding mandrel, which is coated with non-silicon release agent. The laying of the fibres is carried out on a CNC controlled winding machine with four programmable axes. This guarantees an exact layout and the reproducibility of the components.

 

After the winding process the wound mandrel is then placed into a circulating air oven and rotated. It is hardened according to a resin-specific hardening cycle. During the process the chamber temperature is recorded using a non interacting recording instrument so that compliance with the hardening cycle can be checked. The hardened tube is cut to the required length and then pulled from the mandrel using the pull-out device. Afterwards the tube is processed further according to the customer's specifications. "In the winding procedure all normal types of fibre can be processed such as glass, carbon and aramide fibres", says Kautz. His company also presents itself at the COMPOSITES EUROPE.

 

Vestas, Enercon, LM Glasfiber — as well as the top names in the wind energy industry there are also worldwide around 1,500 suppliers from the plastics processing industry that are customers of the company BÜFA Reaktionsharze GmbH & Co. KG from Rastede, another COMPOSITES EUROPE exhibitor. "Over the last few years the subject of wind energy has become more and more important", says managing director Jürgen H. Aurer. In the meantime, twelve percent of the turnover of 70 million euros is generated in this sector. In addition to a special adhesive – an adhesive resins based on vinyl ester, which is used to glue the rotor blade shells together – the most important product in this segment of the market are:above all release agents, glass fibre materials as well as GFC processing machines. "One can say that around 1,000 rotor blades are produced every year thanks to our help", Aurer reckons.

 

The vinyl ester resins of the company with around 160 employees are custom made according to the requirements of the moulder. These are easy workability, very good physical properties, especially when used with fibre reinforcements, and the endless new ways of customising them according to the changing requirements. They are especially suitable for the manufacture of rotor blades because they can be easily removed from the mould. The moulder must achieve shorter and shorter cycle times. The moulds for the rotor blades are extremely expensive. This means that the mould must be emptied and refilled as quickly as possible", Aurer describes the material specifications.

 

The managing director of BÜFA expects a rapid growth in wind energy in the next few years. Up to the year 2010, experts predict a doubling of the currently installed power generation capacity of 74,000 megawatt, whereby the USA due to appropriate political decisions will undertake a leading roll. A yearly rate of increase in the double figure percentage range is therefore pre-programmed. "This wind energy sector is a strategic growth segment in our company. Therefore we have formed our own group of experts", says Aurer.

 

Contact:


Dr. Mike Seidensticker
Press Spokesman
Phone: +49 (0) 211 90191-128
Fax: +49 (0) 211 90191-138
mseidensticker@reedexpo.de
Christian Reiß
Press Officer
Phone: +49 (0) 211 90191-221
Fax: +49 (0) 211 90191-138
creiss@reedexpo.de
 

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