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Lamiflex – Company Profile

Lamiflex has been operating in the composites sector since the mid-70s, originally as a supplier and inventor of rapier tapes for looms machines and related toothed wheels, all made by composite materials and used on textile machines.

Over the course of the last 38 years since Lamiflex was set up, the company has constantly introduced improvements and innovations in line with the strictest principles of modern industry: advanced technology, undisputed management know-how, intelligent use of ideas and materials. The results clearly prove that Lamiflex is a constantly growing, competitive company: a dynamic approach, strict production and research standards and constant technological innovation have all meant that the group is a market leader in Italy and on the international market when it comes to hi-tech composite laminates, offering innovative, often revolutionary products at the cutting-edge of the industry.

In line with the company’s desire to penetrate new markets and offer innovative products, it has set up Lamiflex Composites, dedicated to the production and development of new products. Over the years it has diversified its operations to include the production of pressure pipes, rollers and scraper blades, rollers for the paper industry, radiology beds and X-ray machine accessories, not to mention components for the sports and design sectors. It has embraced nearly all the latest technologies used for the construction of advanced composite components with epoxy resins. It is a qualified vendor for AgustaWestland and Alenia Aeronautica, supplying them with composite components.

Lamiflex has years of experience in the production of components using RTM technology, for static and dynamic structural applications. It firmly believes that RTM technology is a successful and effective method for the production of advanced structural components and therefore keeps a close eye on developments in this field.

Lamiflex works closely with Alenia on the development of infusion/RTM structural components (develop program IMAC-PRO) as part of its research programs and provides expertise on concept, mould construction and process technology.

Lamiflex currently has about one hundred employees and an R&D division that works full time on new projects and development programs aimed at the continuous improvement of composite technologies and materials.

Beside the technology there are different markets approached:

Aerospace

For the aerospace sector, Lamiflex uses a special “autoclave polymerization of composite materials” process certified by AgustaWestland. It produces both stiff and flexible lightweight ducts for the pressurizing and air-conditioning control plant installed in aircraft (ECS systems); ducts/shielding and conducting systems to protect cables and electronic devices against electromagnetic interference in aircraft or high performance vehicles; and machinery used by the military and in the telecommunications industry. The R&D staff deal directly with the client and work in synergy with them to optimize the geometry, size and development of details and items used in this sector.

Industrial

Lamiflex offers products with a wide range of applications in the industrial sector: Rollers and cylinders for the packaging sector, where composite materials make for significant reductions in friction and thus faster speeds; pressurized pipes for desalters, where a structure made from a composite material avoids the problems of corrosion found when metals are used; doctor blades made from various composite materials and different resins for cylinder scrapers in the paper industries; flexible arches used to construct braiding machinery for the production of steel cables; flat semi-finished sheets for the weapons industry; composite material thin plates for the engine sector; blades for vacuum pumps; and many other applications.

Medical

Lamiflex is mainly involved in the production of patient Table Tops for X-ray diagnosis machinery in the medical sector (CAT scanning, urology, angiography and cardiology). The R&D staff deal directly with the client and work in synergy with them to optimize the geometry, size and development of details and items used in this sector.

Textile Machinery

Lamiflex has invented and developed rapier ribbons made from composite materials for the textile machinery sector and many other dynamic loom accessories, such geared wheels for moving these ribbons. Lamiflex has thirty years’ experience in this field and is the main supplier for some of the world’s most important companies in this sector.

Design

Niche applications in the world of sport and in the furnishing/design sector. Lamiflex produces wheel rims made from composite materials for the car industry, saddles and wheels for racing bicycles, light covers and – a recent development – the Ciclotte stationary exercise bike.

Shielding Solutions

Lamiflex produces advanced composite materials for use in a wide range of industrial applications. Thanks to an exclusive supply agreement with a partner specialized in the metallization of fabrics for electromagnetic shielding and electrical conductivity, the company has developed composite shielding solutions EMI and RFI that combine the high conductive surface that can shield a wide range of frequencies with light weight, design flexibility and cost advantages of composite materials. Lamiflex’s shielding materials include a family of semi-manufactured preimpregnated materials based on nickel, zinc, gold and silver in reinforced polyester, glass Nomex, carbon and epoxy resin. The company also produces customized, finished parts based on these composites that can be adapted to any geometric solution. Lamiflex’s composites have industrial and military applications in many sectors, including aerospace, telecommunications, automotive, undersea systems, and electronics.

Why Shield

The enormous development of systems, installations and equipment that generate electromagnetic fields in the environment, such as telecommunications systems, remote broadcasting, radar and remote sensing, the increasing use of electromagnetic heating technologies in industrial, civil and medical applications, development of wireless systems for data transmission and multimedia, the increase of voltage in the electricity transmission systems and extend of its distribution network to contribute towards the urban environment and often also in the rural levels of electromagnetic field several orders of magnitude.

The rules to guard against this danger are four:

  1. measure the amount of radiation
  2. maintain a safe distance
  3. limit the exposure time
  4. shield the source, the living site or the person

Synergies at work

Lamiflex combines the characteristics of shielded materials and those of composite materials by creating a new components that combines the advantages from both sectors.

FEATURES of shielded materials

  • High electrical conductivity on the surface
  • Wide range of types of fabrics for a high coverage of the frequency spectrum

FEATURES of composite materials

  • optimization of weights
  • versatility of feasible geometries

The material synergies offer High Added Value in term of technical advantages of the components:

  • Broad spectrum frequencies to be shielded
  • Electrical conductivity
  • Thermal conductivity
  • Mechanical strength
  • Flexibility in design
  • Lightness
  • Getting immediate benefits:
  • Ease of installation
  • Reduced installation time
  • Design Optimization
  • Cost reduction

Lamiflex portfolio

Lamiflex can offer a wide range of application based on customer requirements, as shielded Pre-preg, sandwich panels, rigid and flexible ducts.

In-Depth Review: Composites for Shielding Solutions for Structural Applications utilizing RTM Technology

Technological evolution in all industrial sectors, including civil and military sectors, is accompanied by an ever more increasing use of electronic instruments that handle, automates and simplify technology itself. Wireless connections and greater power transmission have made clear how delicate and vulnerable electronic technology has become.

Electromagnetic interferences are often the cause of malfunctioning that can lead to accidents, loss of machinery and instruments and in the worst of cases to loss of human lives.

A few years ago, use of metal equipment provided secure protection through the “Faraday cage” effect but the greater use of composite material to lighten structure has caused electronic technology to be lacking in this type of protection and therefore more vulnerable.

SEM Image: Poliester metallized
SEM Image: Poliester metallized

Companies specialized in electromagnetic protection, like EMI and RFI have united their skills and joined companies in the composite sector creating a new series of products that can fuse lightness with conductive shielding properties.

Lamiflex has consequently developed a series of semi-manufactured pre-impregnated material starting from metallic textile solutions with different types of metal: nickel, zinc, gold and silver according to the high levels of electrical conductibility or the high resistance to corrosion they provide or the compatibility of human interaction without causing health risks as is the case with zinc.

Also the types of reinforcements developed can provide a wide range of choice according to the specific type of application. As a result pre-impregnated articles in low grain polyester material can be produced in order to create layers of conductive shielding combined with pre existing composite structures with minimum impact on weight but with a low signal measuring between 40 and 70dB for each layer depending on frequency. Thus, pre-impregnated products can be obtained with reinforcements in metallic carbon for the construction of parts that have the necessary requirements for mechanical functioning and shielding.

The Faraday pre-impregnated series developed by Lamiflex technicians, brings together the above characteristics creating a series of pre-impregnated pieces in reinforced polyester, glass, Nomex, carbon and epoxy resin with an ample range of temperatures for polymerization (from 120° to 180°) in order to satisfy a wide range of applications that are compatible with most aeronautical approved resins (tests carried out on Hexel resins for example – 1454)

Panels shielding test
Panels shielding test
Panels shielding test
Panels shielding test

The choice of pre-impregnated pieces of this kind combines the drapability of the material and its conductive capacity making more complex forms possible that perform well and offer a high degree of shielding.

However, it is important to know how to handle these fabrics, in fact, incorrect use could cause problems of conduction due to unforeseen and unchecked excess resin that can form an insulating film and impede the electrical contacts necessary to close the circuits.

Electrical joint
Electrical joint

Lamiflex technicians have set up a series of user techniques and complementary conductive material that optimize the electrical contacts so that pre-impregnated material can be adapted to any geometric solution.

The main applications for this type of material is certainly cable trucking and protective paneling for containers of electronic equipment.

A practical example that shows the union of textile flexibility with the technology of composite material concerns the creation of ultra-light rigid and flexible tubes for the helicopter sector which continues to have an increasing need to combine the reduction of weight with greater and more complex avionics that, in the absence of protective metallic structures, is more vulnerable.

Apart from producing semi-manufactured articles like pre-impregnated pieces, Lamiflex can also produce finished parts or make products conductively shielding in composite material already in use by means of molding conductive layers with a suitable cycle in an autoclave or oven which permits products to have shielding characteristics without rebuilding the whole piece.

Flexible pipe
Flexible pipe

Because of the complexity of systems and precision of requirements of military products and more stringent on electromagnetic compatibility, all military products are mandatory through the EMC standards. Electromagnetic shielding pre-preg are to achieve electromagnetic compatibility of the election will be the composite shielding material, widely used in supporting land, sea and air military communications equipment, electronic module, cabinet shielding, satellite radar, military terminals.

Avionic equipments are easily interfered by electromagnetic waves. EMC shielding pre-preg helps to protect millions dollars of advanced avionic devices.

Multisection pipe
Multisection pipe

Due to communications equipment industry’s own high-speed digital signal processing and wide microwave operating band, highly sensitive to electromagnetic interference, communications products have enacted mandatory electromagnetic compatibility standards and procedures for complex networks. According to the applications and equipment work of the different environment, wave shield to provide communications equipment electromagnetic compatibility composite shielding materials.

Other uses of these materials may find its way into applications where there is need of localized heating by Joule effect (heating, deicing, etc…) and all other designs where the imagination can wander.

Rigid complex pipe
Rigid complex pipe

Consequently finished products are available for final application that could potentially attract sectors technically more sensitive to costs such as civil and construction sectors.

If we consider domestic electronic gadgets and the increasing use of wireless devices we can imagine (and we’ve had proof of this in the last few years) the rise in interferences and problems when using increasingly more indispensable instruments on a daily basis like mobile phones, GPS, and other equipment to access the web network.

In conclusion, it can be said that Lamiflex is introducing a new constructive solution to the market, a response to the ever more frequent electromagnetic interference problems that are part of electronic technology in continuous evolution.

In-Depth Review: Advanced Composites and Complex Geometry

By Mauro Maggioni and Federico Ciatto, R&D Lamiflex Group

Continual developments in mechanical structures, especially dynamic ones, combined with a trend for more lightweight structures has led to a preference for composite materials rather than metal alloys in recent years.

The most popular construction technique for structural parts is surely that of the autoclave, where a series of preimpregnated materials (“pre-pregs”) – fibres pre-treated with a non-polymerised resin – are stretched over a mould and then cured with the aid of temperature and pressure inside the autoclave. This production process is used for almost all advanced composite components. More specifically, this technique is used in the aircraft industry where materials, training of production personnel and the treatment cycle are regulated by a series of highly detailed specifications, thus making this a special process. The “laminators”, highly skilled technicians responsible for laying out the pre-impregnated laminate to specific designs, are crucial to the process and can affect the quality of the moulded parts: an oversight during the lamination process or forgetting to add layers during the construction of the laminate can lead to unnecessary waste or even to the failure of a structural element. The considerable manual intervention required in autoclave technology also affects productivity levels. On the other hand, the components produced using this technology have a high fibre/matrix ratio and an excellence adhesion/strength ratio, making them ideal for aircraft.

The geometrical designs of the components produced this way are, however, often very simple, “linear” and far from having the complexity possible with metal. This limit is based on the fact that the reinforcement fabrics are planar structures that, in order to become non-developable complex 3D shapes, require a lot of distortion, cutting or even overlapping, leading to problems with their thickness and very complex designs, especially in terms of mechanical simulation.

Cuts, overlapping, distortion, these all change the intrinsic properties of the composite and thus its elastic coefficient. Moreover, ultimate strength tests on flat samples need to be applied to 3D structures, causing a certain degree of uncertainty and hence some often very high safety factor findings.

Fig. 1 - fiber content vs. productivity
Fig. 1 – fiber content vs. productivity

Meanwhile, other production processes have been developed, thanks to strong pressure from the automotive industry. One such is RTM technology (Resin Transfer Moulding) which allows for the direct injection of a liquid resin into a mould. The liquid resin then fills the cavities in the mould, which have been previously lined with a dry fabric structure.

The volume fractions possible with this technology just a few years ago have today been increased to levels comparable to those with autoclave technology due to the increasing availability of structural reinforcements dedicated to this new technology, especially in the case of multi-axial structures.

Another factor that has significantly limited the use of RTM technology in the aviation sector is the lack of literature and data on the characteristics of these materials, needed for computerised design simulations.

In any case, RTM technology offers many advantages over autoclave technology in terms of automation, productivity and less dependence of the final quality on the human factor.

The purpose of this article is to highlight the advantages of using RTM technology for structural parts, as an alternative to the autoclave for linear structural parts and complex “H” section beams in particular. This work provides highly versatile construction guidelines for the creation of geometric shapes that come very close to those possible when using CNC machined metal.

Fig. 2 - examples of complex beam shapes
Fig. 2 – examples of complex beam shapes

The concept of the pre-form is of special importance here: this can be created outside the moulding tool and provides a construction logic that is so versatile that it can be applied to a

large number of beam type structures. The pre-form in question and the construction system have both been patented by Lamiflex.

One result of this study is that we have collected a large amount of technical design data for a new range of materials, meaning that this technique and related materials can now be considered even at the design stage for future structural programs.

In fact, the output of this project includes elastic coefficients, shear values, ageing and moisture absorption values, glass transition temperatures, ultimate strength values and data on the corresponding yield mechanisms.

The study has been mainly carried out by Lamiflex technicians, but has also involved important contributions from the Department of Aeronautical Engineering at the Politecnico di Milano and suppliers of raw materials and equipment dedicated to RTM technology, Hexcel and the Huntsman Corporation in particular.

The study was carried out in the following basic stages:

  • Study of reinforcement materials and resins
  • Mechanical and chemical / physical testing of samples
  • Construction of the pre-form
  • Moulding
  • Analysis of moulded parts

Study of Reinforcement Materials and Resins – Test

Fig. 3 - sample moulding
Fig. 3 – sample moulding

Mainly axial reinforcement panels joined by a system of unidirectional seams using polyester yarn were chosen to provide greater resistance properties in preferential directions. The axial frame supplied by Formax (12K HR T700, structure 0°;+/-45°; 90°) allowed for good manipulation and s tability of the reinforcement during cutting and bending, at the same time ensuring the optimum orientation of the fibres after major distortion.

Moreover, the almost total isotropy of the material meant the moulded parts saw a net reduction in internal residual stress and hence better dimensional stability. Layers of UD were placed in the required directions to obtain proper orientation of the properties. The resulting laminates were compared with the approved standard materials currently in use, especially those in the aviation industry, and with excellent results.

Fig. 4 - breaking sample
Fig. 4 – breaking sample

We deliberately chose a broad assortment of resins to allow for a full range of data and to enhance the study for a wider range of applications (not just for aircraft). We therefore decided to use a range of resins ranging from low Tg (c. 80 °C) to Tg values of more than 200 °C. These epoxy-based r esins were supplied by Huntsman, Hexcel, and Gurit.

After creating a carbon mould for flat laminates, we produced a number of samples by combining multiple laminates and resins resulting in a total of 13 laminations. Samples were obtained from the moulded plates to test their shear and flexural strength, DMA, DSC, moisture absorption, volume fractions, porosity, etc. The Polytechnic of Milan (Department of Aeronautical Engineering) was of great assistance here, especially PROF. ING. Luca Di Landro’s technical staff, who provided the equipment and technical expertise needed to make this work scientifically exhaustive.

Fig. 5 – Example of DMA test (resin two dots Hexcel RTM6)
Fig. 5 – Example of DMA test (resin two dots Hexcel RTM6)
Fig. 6 – Mechanical behaviour of RTM samples
Fig. 6 – Mechanical behaviour of RTM samples
Fig. 7 - Elastic coefficient
Fig. 7 – Elastic coefficient

Table 6 contains the most important technical results in terms of structural performance. Here we can observe the very good, and in some cases superior, behaviour of the materials in question with respect to the aeronautical standards. The engineering data are thus a good source for the design of composite structures processed using RTM technology. Figure 7 shows the complete structural elastic coefficients for the axial frame/UD/RTM6 resin combination.

Construction of the Pre-Form

The key to this project is obviously the pre-form, which makes it possible to get complex geometric structures very similar to those made from machined metal. The concept is based on butt-joint construction to create an “H” shape (a Lamiflex patented system) with overlap. The typical “H” shape is normally achieved by bending the flat part of the material to the web of the beam. However, if the beam is not prismatic and has far more complex forms, this construction logic leads to problems because the distortion limits of the reinforcing materials dictate a narrow range of feasible shapes.

Fig. 8 – Standard beam concept vs. RTM concept with butt-joint
Fig. 8 – Standard beam concept vs. RTM concept with butt-joint

It follows that should one wish to create this type of component in a composite material or replace the machined metal element, the shape of the entire beam needs to be redesigned. The construction concept proposed by Lamiflex, on the other hand, combined with the use of appropriate reinforcing materials, makes it possible to create a wide range of shapes. Figure 8 (left) shows how the high degree of distortion required of the reinforcement in the corners (clearly not feasible) would lead to the elimination of the corner itself, thus creating an open and inherently less rigid structure than that shown in Figure 8 (right), which is easily produced as shown in Figure 9 (right).

Fig. 8 – Standard beam concept vs. RTM concept with butt-joint
Fig. 8 – Standard beam concept vs. RTM concept with butt-joint

If we consider the shape shown in Figure 2, obtained by machining a solid lump of metal, Figure 9 shows the typical approach adopted to get this shape using composite materials. The butt-joint technique produces the same shape with excellent distribution of the reinforcement fibres and with a complex geometry very close to that obtained by machining.

Fig. 9 – Examples of carbon pre-form
Fig. 9 – Examples of carbon pre-form
Fig. 9 – Examples of carbon pre-form
Fig. 9 – Examples of carbon pre-form

This type of geometric structure is inherently more rigid, hence increasing the rigidity of the structure as a whole. The presence of the multi-axial reinforcement material reduces the residual stresses inside the piece and improves the fatigue resistance of the component.

Fig. 10 – Fibre distribution in the “H” shape and FEM simulation
Fig. 10 – Fibre distribution in the “H” shape and FEM simulation
Fig. 10 – Fibre distribution in the “H” shape and FEM simulation
Fig. 10 – Fibre distribution in the “H” shape and FEM simulation

Moulding and Testing

Fig. 11 – Thermal profile of mould
Fig. 11 – Thermal profile of mould

Moulding is via peripheral injection for good distribution of the resin and to liminates the risk of internal voids. An important innovation has been the creation of the carbon mould temperature control system using a set of heating elements incorporated in the mould and controlled by an external PLC heating unit with PID control. The latter also records signals from thermocouples used to construct the temperature profile of the pre-form and the mould inside this. This has made it possible to verify the correct temperature distribution and optimise the curing cycle in detail. Figure 11 shows the temperature profile of the mould in steps of 2 °C/min.

Fig. 12 – 3D RTM tool
Fig. 12 – 3D RTM tool

The material used to build the mould is HEXTOOL® M81. This is a 3D random carbon mat developed by Hexcel which allows for machining of the surfaces after moulding and working temperatures of up to 200 °C. There is no need, the refore, for a master model as the final shape is obtained through machining.

The structure of the carbon mould minimises thermal expansion caused by the working temperatures, thus optimising the dimensional tolerances of the moulded part.

During the moulding concept stage we decided to use a polyurethane resin with low Tg (c. 80 °C) inject ed with Gurit Top 20 resin (Fig. 14) in order to verify the injection strategy and filling times. The mould was found to be light, functional and quick to create, suitable for even small runs and particularly low cost.

Fig. 13 – Carbon pre-form and moulded part
Fig. 13 – Carbon pre-form and moulded part
Fig. 14 – Resin mould for concept development
Fig. 14 – Resin mould for concept development

Ultrasound analysis of the moulded part showed a lack of internal voids, meaning good fatigue resistance. At the time of writing, sections of the beam are being surface tested to measure the rate of porosity.

Conclusions

The study highlights the effective applicability and repeatability of RTM technology for complex load-bearing structures. It has led to the creation of a major database of design data and has created a network of companies that have each contributed the most advanced technology in their own fields to the development of RTM technology.

The study described here will be presented in detail in a Work Shop scheduled for October 2012 at the Lamiflex headquarters. This will also include a practical demonstration of the moulding and curing of a carbon beam. For further information visit the Lamiflex website: www.lamiflex.it

NOTES:

The Araldite ® trademark is the property of the Huntsman Corporation or an affiliate thereof, or licensed to Huntsman Corporation or an affiliate thereof.

The HexForce®, HexFlow® and HexTool® M81 trademarks are the property of Hexcel or an affiliate thereof, or licensed to Hexcel or an affiliate thereof.

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LAMIFLEX SPA

24028 Ponte Nossa (BG) Italy

Via E. De Angeli, 51

Tel: + 39 035 700011

[email protected]

www.lamiflex.it

***

Contact: Meir Levy – Israel Representative

[email protected]

+972-52-777-3009