Filament-wound poles provide design flexibility | World of Composites

2021-12-08 06:24:55 By : Ms. Nina Wu

In Turkey, a telegraph pole manufacturer has combined filament winding, automation, glass and carbon fiber composite materials to expand its product line. #outofautoclave #marketing #cuttingtools

Electric pole with filament winding. Mitaş Composites can wrap filaments on composite lighting poles up to 12 meters long and 800 mm in diameter. Source | Mitasch Composites

Mitaş Group (Ankara, Turkey), a manufacturer of steel towers, power distribution and transmission poles, and substation structures for the energy market, has invested in a filament winding production line for the manufacture of composite utility poles. The manufacturing capacity of automation-ready equipment is 1,000 poles per month, making Mitaş one of Turkey's first manufacturers of composite poles and enabling the group to expand and diversify its existing product range.

Mitaş was established by the Turkish government in 1955 to help build the country's energy infrastructure. In the following years, public ownership was gradually reduced, and Mitaş, which was completely privatized in 1990, began an international expansion strategy. Today, the group operates nine production facilities in four locations in Turkey and Italy and exports to North America, Europe, Africa and the Middle East. The Mitaş Poles plant in Ankara has an annual production capacity of 30,000 metric tons and produces 12-50 m long galvanized steel poles for transmission and distribution lines, lighting, aerial tramways, telecommunications, signs, flags and other applications. Enhanced aesthetics and ease of installation are key customer priorities for the new pole design.

The decision to invest in composite materials production facilities was formalized about three years ago. “Mitaş is essentially a 60-year-old steel company, but for many years it has been thinking about finding alternative materials that provide easier installation and lower maintenance costs,” explained Sezgin Üstün, Operations Director of Mitaş Composites Inc.. "We are seeing growing market trends for lightweight composite rods in North America and Europe. In mid-2016, we decided to enter the composite market."

Mitaş also sees composite utility poles as a differentiating factor in the highly competitive steel utility pole market. The composite rod is also consistent with the company's focus on innovation as a way to grow its global business.

The earliest utility poles were made of wood, but later concrete, steel and composite utility poles were introduced to improve performance and durability. Steel is now the main material because steel rods have higher performance and longer service life than wood, and it eliminates concerns about the environmental impact of preservatives used to treat wood rods. However, steel rods are still relatively heavy and costly to transport and install, and are galvanized or coated to improve their corrosion resistance, increasing initial and entire life cycle maintenance costs.

The extreme market by application. The global fiber reinforced plastic (FRP) rod market segmented by end-use industry in 2018. Source | Lucintyre

Composite poles have advantages over alternative pole materials in terms of installation, reliability, maintenance and service life, and are especially cost-effective for places where access is restricted and corrosion is a major problem. The weight of composite poles is usually 35-50% lighter than wooden poles and steel poles, which reduces transportation costs and makes installation easier and faster. The composite pole can be transported and assembled by hand-without heavy lifting equipment-saving a lot of cost for installation in narrow urban spaces, remote areas or challenging terrain without road access. The composite pole has a design service life of more than 70 years and usually does not require regular maintenance. They are coated to provide UV protection, will not rot or corrode, and are not affected by the natural threats that often plague wood poles, such as termites and woodpeckers. They are not affected by salty air and humidity in coastal and humid environments. In these environments, steel needs to be recoated regularly and will not immerse any chemicals in the environment. Composite poles benefit the utility grid strengthening strategy by providing greater flexibility under extreme loads generated by bad weather. Composite poles have higher dielectric strength and are safer for workers, and they absorb more energy than steel or wood when impacted, thereby reducing damage to vehicles in road traffic accidents.

Despite these benefits, according to market research company Lucintel (Dallas, Texas, USA), composite poles currently account for less than 1% of the entire pole market, but its share is expected to rise from $228 million in 2018 At a compound annual growth rate, the compound growth rate (CAGR) in 2024 will be 5.7%, reaching 318 million US dollars. This will be driven by increased demand for infrastructure projects, replacement of wood poles, and the performance advantages of composite poles over wood, steel and concrete. Power transmission and distribution currently account for about 71% of the global composite light pole market, but driven by the replacement of traditional materials, the lighting sector (23%) may experience a relatively high growth rate.

Lucintel predicts that in the next five years, filament winding will still be the main process used to manufacture composite poles because it is suitable for mass production, can use a variety of thermosetting resins, and manufacture cylindrical, elliptical, and tapered poles. flexibility. Pultrusion is limited to the manufacture of rods with a constant (or nearly constant) cross-section. Due to its higher productivity and lower cost, it is expected to witness the highest growth, while centrifugal casting that provides good aesthetics is limited to relatively mechanical properties. Lower.

For Mitas, filament winding meets the company's requirements for manufacturing tapered rods.

“For tapered rods, there are only two production methods for composite materials-filament winding and centrifugal casting,” Üstün explains. "We chose filament winding because it uses continuous fibers, and we can obtain the high stiffness and strength required for utility poles. Fiber winding also allows us to flexibly manufacture other products-pipes, pipes or other structures-so we not only Limited to the telegraph pole market. After discussing with suppliers in China, Europe and North America, we chose to cooperate with Autonational because they have advanced technology, flexibility and adaptability to future automation."

For more information about Mitaş and its pole design process, please see this video:

Autonational Composites BV (IJlst, Netherlands) was founded in 1977 by two engineers who specialize in designing industrial production lines. Filament winding is often used, and it was decided five years ago to focus the business on this technology. Today, Autonational has approximately 60 employees and provides filament winding machines, auxiliary processing and test equipment, integrated production lines and automation solutions for the automotive, aerospace, infrastructure, and other markets. According to Harry Fietje, Marketing and Sales Manager, Autonational is seeing increasing demand for automated production lines, which now account for 75% of sales. He said that requests for quotations for utility pole lines are also increasing.

“The design of the Mitaş production line took about three months,” he pointed out. “It’s not difficult for us, but because Mitaş is a newcomer to composite materials, we work closely with them in part design and material selection. We proposed a two-stage approach to suit their investment plan and expected output increase."

The first phase involves providing an integrated production line to allow manual or semi-automatic manufacturing based on two mandrel lengths to reduce the complexity and cost of future automation. This makes it possible to manufacture glass fiber reinforced polyester composite tapered rods with a minimum diameter of 100 mm, a maximum diameter of 600 mm, and a length of 12 meters; carbon fiber reinforced epoxy composite cylindrical rods with a diameter of up to 600 mm and a length of up to 6 meters . The production capacity of this production line is 1,000 electric poles per month. The second phase of the project will address additional functions and automation issues.

After two months of construction, Autonational installed and commissioned equipment at the new Mitaş Composites plant in Ankara in April 2018, and trained Mitaş employees to operate the machines. The 17,750 square meter factory also has a pultrusion production line and a research and development laboratory.

The production line is composed of modular equipment, which can carry out filament winding, curing, mandrel extraction, mechanical processing and coating. Overhead cranes transport mandrels and rods between machines. These machines are started by operators and then run automatically under their supervision.

Step 1. The Autonational AMD SW 1000 triaxial filament winding machine is suitable for manufacturing conical and cylindrical rods up to 12 meters long. Source | Mitasch Composites

At the start of production, the steel mandrel manufactured by Mitaş is transported to the filament winding machine, where it is cleaned and prepared. (A separate mandrel preparation station can be added in the future to increase production capacity.)

Step 2. Fiber transport tool on Autonational AMD SW 1000 fiber winding machine. Source | Autonomous

In order to transport the fibers to the winder, Autonational provides two creels/tensioners. The pallet rack is suitable for up to 16 tows and 64 bobbins, and can provide a fiber tension of 2-20 Newtons, which is suitable for high output of glass fiber. For higher performance applications of carbon fiber or glass fiber, the dynamic creel with servo-controlled tension can achieve precise fiber tension of 5-50 Newtons. The creel is based on a modular configuration of two sets of four stacked bobbins and is located on a guide rail connected to the filament winder carriage.

Mitaş obtained glass fiber material from Şişecam (Istanbul, Turkey) and carbon fiber from DowAksa (Istanbul, Turkey). Polyester resin can also be obtained from Turkish suppliers, but epoxy resin must be purchased from international companies.

Step 3. The basic winding geometry of the fiberglass polyester rod. Source | Mitasch Composites

Autonational provides equipment for storing, pumping, mixing and metering resin into the winder via resin impregnated pans. The fiber is fed from the creel to the resin tray, which is suitable for glass fiber and carbon fiber. Each resin has its own fiber guide insert, based on 16 polyester fiber bundles and 8 epoxy fiber bundles. The resin tray has automatic level measurement and temperature control functions, designed to provide good fiber impregnation and consistent resin fraction.

The impregnated roving is guided to the mandrel by standard fiber transport tools on the Autonational AMD SW 1000 three-axis uniaxial filament winding machine. The winding machine uses Siemens Sinumerik 840D CNC controller, which is compatible with most filament winding software. According to the selected program, the winder uses a trolley that moves back and forth along the mandrel axis to lay the resin-impregnated roving on the rotating mandrel to create a continuous reinforcement layer. The program defines the direction of the fibers to achieve the required rod strength, flexibility and thickness. The winding operation lasts about 1 hour.

In addition to this three-axis winder, Mitaş also uses a four-axis machine (Autonational AMD SW 800 RD) to manufacture rods up to 6 meters long, as well as carbon fiber tubes and complex parts for R&D projects.

Step 4. The processing station is used for drilling, cutting blades and finishing the rod surface to prepare for coating. Source | Mitasch Composites

After winding is complete, the mandrel and magnetic poles are transferred to an input buffer-a shuttle table-in front of an electrically heated batch furnace. When the required number of mandrels is reached, the shuttle is moved into the oven. The oven has a maximum temperature of 150°C and can accommodate up to four poles with a diameter of 600 mm or 16 poles with a diameter of 100 mm. After curing (for about 8 hours), move the shuttle back to the cooling zone outside the oven. After cooling, a hydraulic mandrel extractor is used to separate the wound rod from the mandrel. The system can handle rod lengths of 6 to 12 meters and mandrel diameters of 100 to 600 mm. The maximum extraction force is 100 kN, and the operation usually takes up to 20 minutes.

Next, the rod is transferred to the processing center, which is an improvement on the AMD SW 1000 filament winding machine. The fiber guide of the winder is replaced by a milling/saw device, the head and tailstock are equipped with improved tools, and the turning/milling software is installed in the CNC controller. The device can drill, mill, grind and cut tapered and cylindrical rods. The required drilling, cutting and surface finishing operations usually take 1 hour, and then the rod is returned to the AMD SW 1000 filament winder for coating. In this operation, the fiber delivery tool of the winding machine is replaced by a spray gun, and the resin supply is switched to a colored topcoat to provide UV protection for the rod. This process takes 1-2 hours and allows the coating to cure in the factory. For automated production, a separate coating station will be added.

Step 5. From left to right, Mitaş Composites’ “smart” poles, 3-meter-long carbon fiber flag poles and decorative light poles. Multiple modules are integrated in the smart pole to enable radar, camera, Wi-Fi and other functions. Decorative poles are designed for use in natural areas such as parks and gardens. The light pole (available in different colors) is installed in the pole to illuminate the shaft. Source | Mitasch Composites

Mitaş started producing filament-wound poles in May 2018, and now produces a variety of products, including power distribution poles, antenna poles and decorative light poles. Standard fiberglass tapered light poles range from 12 meters in length (top inner diameter 120 mm; bottom inner diameter 273 mm) to 4 meters long (top inner diameter 62 mm; bottom inner diameter 102 mm). The poles can be provided in a variety of colors, with opaque or luminous shafts, as well as steel or composite material bases and access doors. Carbon fiber is used for flagpoles and some sports applications, such as sailing masts.

"We have a lot of flexibility," Üstün points out. "We can produce poles up to 12 meters long in one segment, with diameters ranging from 60 mm to 1,000 mm. We have provided a large number of mandrels for our standard design, but if the customer needs a different option, as a steel producer , We can easily adjust the mandrel internally."

These poles are mainly installed in Turkey, but a small number of them are installed in other countries, including Ukraine and Qatar. So far, customers have requested small orders, up to a few hundred rods, for demonstration purposes.

“The equipment designed by Autonational has a manufacturing capacity of 1,000 poles per month, but we have not yet reached this value,” Üstün explained. "So far, we have produced about 1,000 rods because we are in the market development stage. If we have high enough demand within one to two years, we can increase automation."

Automation options include adding logistics systems such as monorails, robots, and spindle buffer systems to automatically move spindles and products around the production line, as shown in the video. Tracking and tracing functions can be integrated into the product to record manufacturing variables.

Watch Autonational's video to learn more about the production process.

Step 6. Mitaş Composites light poles are exhibited at the Ankara factory. The red rod is 12 meters high and has a diameter of 120-273 mm. The gray pole is 10 meters high and has a diameter of 120-253 mm. The top fitting is bolted to the rod. The base of the red pole is composite; the gray pole has a steel base. A carbon fiber flagpole can be seen on the left side of the red pole. Source | Mitasch Composites

"The Mitaş production line can work in a similar way, with transportation between automated stations and manipulators moving the spindles and rods to the machine," said Autonational's Fietje. "The entire production area can be supervised by one operator. It is possible to produce a finished rod every 20 minutes instead of the current possible 80 minutes."

Üstün stated that the feedback on the Mitaş composite poles was positive: “Customers like their appearance. The lightweight of the poles is also very interesting for them, because they can lift a 6-meter-high pole by themselves. One A 6-meter-long glass fiber rod weighs about 15 kg, while a similar steel rod weighs 35 kg or more."

However, Mitaş faced obstacles related to prices and customer misunderstandings about composite materials.

"The initial cost is higher than steel, so if customers are concerned about the price, they will always check the initial cost," he said. "We tried to convince them by focusing on the life cycle cost and sustainability aspects of composite poles."

"The other concern we heard from customers is that composite poles are brittle and they are worried about vandalism. We got these responses from customers-they just treat composites as a kind of plastic, and it will take some time to convince them We plan to continue our marketing development activities by participating in exhibitions, publishing papers and, most importantly, trying to persuade the authorities of the target country."

The American Composite Manufacturers Association (ACMA, Arlington, Virginia, USA) recently announced an initiative aimed at increasing confidence in composite utility poles. The ANSI-approved FRP composite utility pole standard specification was published in May and was developed by ACMA's Public Utilities and Communication Structure Committee to provide a single reference point for power companies. Its purpose is to promote a deeper understanding of the differences between composite poles, wooden poles, concrete poles and steel poles, and to explain the manufacture, assembly and correct installation of composite poles.

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