At the crossing of highway 70 and highway 259, Broken Bow Oklahoma, with about 5000 inhabitants, hardly ever finds itself in the media spotlight. It is a typical small American town in the Middle West, idyllically located between lakes and creeks, woods and mountains. The neighbouring State of Texas across the Red River, and the State of Arkansas, are both within a stone’s throw.
It was in this rural backwater of the US on April 13, 2004 that a record was shattered as a new OSB mill produced its first board on the world’s longest continuous press.
The Siempelkamp ContiRoll press is 60.3m long and 8ft 6in wide and belongs to the J M Huber Corporation, operating under the name Huber Engineered Woods.
J M Huber Corporation is a well funded medium-sized business in the US. It is not listed on the stock exchange and is wholly family-owned.
When Joseph Maria Huber from Munich went on his first business trip to New York City in 1883, nobody on either side of the Atlantic Ocean could have imagined that the business would one day reach a turnover of US$1bn.
The J M Huber Corporation is based in Edison, New Jersey. The products of the company range from raw materials to speciality chemicals and forest products, to building materials.
One of the significant business units of this multinational company is Huber Engineered Woods LLC. Headquartered in Charlotte, North Carolina, this group has developed into one of the most innovative OSB producers in North America.
People may wonder why an eastern USbased company should build a mill in Oklahoma, far from its base. The answer lies partly in the wood resource of southern yellow pine, partly in the availability of labour and partly in the fact that Broken Bow, and McCurtain County in which it resides, both support jobs and infrastructure revival.
Andy Trott, president of Huber Engineered Woods, is proud of all that has been achieved. Up to now his unit was in charge of four plants producing Engineered Wood Products (EWPs), mainly for the home construction market.
Construction of the Broken Bow OSB plant, representing an investment of more than US$130m, started in 2002.
That investment has created more than 250 jobs in the area, for example, in the service provider sector. As a result, US$25m will be flowing into the financial cycle of the town, county and state annually.
Andy Trott describes the close relationship between the company and the region in the following way: “We are not just a company in Oklahoma.We are friends and neighbours who wish for this state to grow and flourish.”
Huber says its ultimate business principle is to build trust. This does not only include making the right choice for a location but also selecting reliable partners who help to lead this and the other investments of the group to success.
Those partners are suppliers from different sectors, for example, plant engineering and construction, controlling and information technology, construction and assembly, and the service industry. After the assembly of four OSB plants – in Easton (Maine), Commerce (Georgia), Crystal Hill (Virginia) and Spring City (Tennessee) – all partners know their job and can rely on one another.
This positive attitude of all partners has also worked for Broken Bow. Just as in those other plants, the making of the heart, brain, veins, and all other vital organs of the Broken Bow plant was given to a group of companies that Huber felt had delivered in the past. Siempelkamp from Krefeld in Germany with its subsidiaries and associate companies ATR, Büttner, CMC Texpan, Imal, Pal and SHS received orders for Broken Bow.
However, machinery quality and integration of the latest developments are only one side of the coin.When it comes to a reliable partner the ‘soft’ factors, for example, punctual deliveries, also play a big role.
The Broken Bow mill has an annual capacity of around 550,000m3 a year, or 620 million ft2 (3/8in basis). That amounts to 1.88 million ft2, 3/8in (1,660m3) of OSB daily, as Ed Milburn, plant manager, points out proudly.
With such large production volumes, the first technical challenge is the drying of the wet strands. Büttner Drying and Environmental Technology, a Siempelkamp subsidiary, solved this task. The Broken Bow plant’s demand for dried material requires two single-path drum dryers. Due to transportation difficulties with drums of the size required, Büttner had them delivered in sections for final assembly on site.
The Quadradyn – an OSB screening innovation by Pal of Italy – had its world premiere at Broken Bow. This screens the strands on a roller system. The separation of the strands into fines, core and face is said to be precise and the composition of the future board is thus more homogenous and better structured. The fines are then super-screened with an oscillating screen and once again fractioned into fines for fuel and fines for recovery.
The latter can be added back to the core layer forming process after separate blending, using the Fines Recovery System.
After the dry strand bunkers, Imal, an associate company of the main contractor Siempelkamp, supplied the blending system for the fines and the density and thickness gauges in the press line.
Clarke’s International Inc supplied three 75-unit wet bins and three 75-unit dry bins (one unit equals 2,100ft3 or 60m3) to the Huber project.
The matforming station was supplied by CMC Texpan. Each matformer screens the strands in such a way that the largest strands are placed to the outer face of the mat, where they contribute most to the stiffness of the board.
The formed mat is directed through electromagnets and a metal detector, thus, metallic impurities are removed. Finally the edges of the strand mat are trimmed and before the mat enters the press it is checked by an Imal traversing x-ray mat density gauge.
The detailed engineering of the whole plant was realised by CPM Consultants Inc of Vancouver.
That massive ContiRoll is equipped with a mat pre-heater system and screen imprint. The patented Pre-Heater ContiTherm has now been installed four times throughout the US in Siempelkamp ContiRoll OSB lines.
A mixture of hot air and steam is applied to the mat directly before it enters the press. Pre-heating the mat in this way results in an increase in press capacity. By means of adjusting the ratio between hot air and steam, the target temperature of the mat is precisely set. The mat is plastified in the pre-heater, reducing the specific pressure needed in the press. In addition the moisture content of the mat is raised, resulting in lower thickness swell of the board and better board properties.
Some products require the typical screen imprint on one side of the board which is why the press was equipped with the patented screen imprint system; if needed, an endless screen runs together with the top steel belt through the press. This produces a perfect screen imprint, which is identical to that which customers are used to seeing from boards made on multiopening presses.
BioReaction Industries supplied a biofilter installation for HAP and VOC emissions control on the ContiRoll.
In addition to the 7/16in OSB mass product, the plant also produces very specific products, for example, the 23/32in premium sub-floor, AdvanTech.
After leaving the press, the endless board is taken over by machines and equipment which have been delivered by SHS (Siempelkamp Handling Systems). It is trimmed on both sides and then cut to size with a double diagonal saw. The final master board size is typically 8ft x 24ft. For the production of rim boards, the master board length can be reduced to 12ft.
After a first quality check, the boards pass a reject station before they are cooled in two star coolers. The boards are then sorted and stacked according to quality and transported to the intermediate storage area, which utilises a fully automatic crane system.
The storage system serves as an OSB curing area and is also used to distribute the output from three shifts of press production to value-adding processes, such as sanding, cut-to-size and T&G, which run only in two-shift operations. The warehouse management system allows the operators to directly retrieve stacks from either the sanding line controls or the book saw control system.
There is no operator required in the crane area to store or retrieve stacks. The storage system also allows for re-storing of cut-to-size boards after they have been processed through the book saw system.
The sophisticated control system for this area is supplied by ATR Canada (today Siempelkamp Canada Inc) which engineered, together with ATR Germany, the plant automation system, starting from the dry bunker discharge up to the packing line.
Beside the sanding line, with its integrated sorting line (A and B quality boards), the book saw is another important production component at Huber. The cut-to-size book saw system can be fed from several sources: the crane storage system, the sanding line, or directly from the master board stacker.
The high production capacity of the book saw is achieved by processing of a ‘book’ of master boards with a height of up to 260mm (10in). This saw’s motor power is about 100HP – as much as the engine of a full-size car.
The book saw is versatile. Rim boards can be produced and then transported directly to the rim board packing line. Thus, the boards can be processed and packaged in their standard height of 260mm without further cuts.
Other OSB finished goods (commodity products) are cut-to-size according to operator- selected cutting patterns. Cut-to-size books of boards leave the book saw and are stacked by means of rake stackers.
The OSB stacks are then separated by a stack separation unit and are transported by a stack transfer cart to one of three packing lines, the T&G line, or back into the crane storage system.
The T&G utilises Siempelkamp’s board separation system which eliminates the gap between them, thus significantly improving the cycle time of boards.
In addition, without board gaps, the quality of the T&G is improved since break-outs at the board edges occur less often.
Precision Technologies, a division of Eugene, Oregon’s Willamette Valley Company, supplied two robotic spraying installations in the mill for marking up the packs. The 20ft x 20ft x 14ft robotic spray booths use six-axis industrial application robotic arms by Motoman, West Carrollton, Ohio.
For the last 20 years, OSB has experienced a similar spectacular development to MDF or particleboard since the 1960s.
While in North America in 1985 about four million m3 (4.5 billion ft2) of OSB was produced, in 1993 the number had already increased to about 10 million m3 (11.3 billion ft2). Then in 2002 the 20 million m3 (22.6 billion ft2) mark was crossed for the first time.
Sixty-one plants in the US and Canada cover about 70% of the North American building materials market for home construction with OSB. This means each American home is statistically made up of 6.4m3 (7,200ft2) of OSB.
In North America the OSB market is huge. Europe is following this trend with average OSB production increases of over 30%.
