Continuous  improvement 

Weyerhaeuser has invested $24  million in recent years to re-work  the green end of its OSB plant in  Edson, Alberta, part of a continuous  improvement program that has  delivered results—in the form of  increased OSB production. 

By Tony Kryzanowski   

Two new Carmanah stranders were installed as part of  Weyerhaeuser’s $24 million investment in the green line  at its Edson, Alberta OSB plant. One new strander produces  almost as much strands as two of the plant’s older stranders.

A $24-million investment by Weyerhaeuser over the past  several years to replace the green line at its OSB plant  in Edson, Alberta is part of a continuous improvement  program at the mill. This ongoing program has resulted in the  plant producing nearly double the amount of OSB compared to  its original design when the mill opened in 1983. The plant now  has rated annual production capacity of 440 million square feet  of OSB on a 3/8ths inch basis, compared to the original design  production of about 230 million square feet.    

The latest capital investment included a building addition,  installation of two Carmanah stranders and a variety of  conveying systems provided by Tri-Tech Machine Ltd.                        Weyerhaeuser handled the engineering services for the project  while the prime contractor was Eugene Forest Systems.                                     

“All of the money was spent on the green end of the plant,”  says plant manager Mitch Gregoire. A good deal of the money  went to replace old strander technology from the early 1980s.  “One of our new stranders is almost as productive as two of our  older standers.”               

A combination of specially oriented aspen OSB strands and resin heads into one of the openings on the Dieffenbacher press at the Edson OSB plant            

Gregoire says Weyerhaeuser was able to build the addition  and install the new stranders and conveyance system while the  older green line continued to feed the plant. A wall was literally  knocked out to connect the new green line with the existing  plant, and the new line was integrated without any major  disruption in production.   

Like so many other OSB plants,  Weyerhaeuser’s Edson facility is riding out  a down cycle, with reduced OSB demand  due to the reduction of housing starts in  the United States. Gregoire says the Edson  facility produces flooring and sheathing  and a significant portion of its production  is exported to the United States.                                  

Historically, the State of California  alone has housing starts equal to or more  than all of Canada, noted Gregoire,  explaining why the US market has such an  impact on Canadian OSB manufacturers.                      

Gregoire says there are several  reasons why the Edson OSB plant has  become so much more productive over  its lifetime, including improvements in  both production techniques as well as  materials, such as resins. Weyerhaeuser  has also worked hard over the years  to overcome whatever production  bottlenecks may have existed in the  system, which has had a further positive  impact on overall production.

Upgrade tour: Weyerhaeuser Edson OSB plant manager Mitch Gregoire (left in photo) recently led a tour of Forest Industry Suppliers and Loggers Association (FISLA) members— including FISLA forestry business advisor Darrell Latimer (right)—through the refurbished plant.

Handling and conditioning of logs  has improved operations. Wood arriving  in the yard has been merchandized to  eight-foot lengths in the bush. Typically  during the winter log haul, loads from  arriving log trucks are fed directly into the  conditioning ponds at the infeed using  Komatsu PC400 log loaders equipped  with Weldco-Beales short-wood grapples.   

Once properly conditioned, logs  proceed to the green line where they  encounter two Nicholson debarkers and  the new Carmanah stranders that create  the strands used in OSB production. The  strands are dried using three triple-pass  MEC dryers before being placed in storage  bins. Before the strands are dropped  from the storage bins and placed on the  Schenck forming line, they are mixed with  resin. Their placement, or  orientation, on the forming  line mat depends on  whether they will end up as  the surface or core of the  OSB panel, and the amount  of raw material and resin is determined by  the panel thickness.                                   

The Dieffenbacher press has a series  of openings like a baker’s oven, which are  filled in sequence with specific lengths  of mat material from the forming line.  Once filled, the press clamps down on  the strand/resin mixture in each opening  using heat and a specified cycle time to  produce raw OSB panels.                                     

When the cycle is complete, the OSB  panels exit the press on a conveyor and  proceed through a Globe trim saw line  that creates the four-foot by eight-foot  OSB panels. The panels are stacked,  strapped, packed and then allowed to  cure in the warehouse for about 24 hours.  Samples of the product are tested on  a regular basis to ensure that they meet  the required performance standards for  building construction applications.  Weyerhaeuser’s Edson facility employs  about 150 people to meet its round-theclock  operating schedule.  

Earlier this year, Weyerhaeuser  announced reduced operations at  three of its OSB mills, including the  facility in Drayton Valley, Alberta as  part of a strategy to align its production  with current demand. According to  Weyerhaeuser’s 2005 Investor Guide,  the company has capacity to produce  about 4.3 billion square feet of OSB per  year. The curtailed production at the  three plants, the others being in Hudson  Bay, Saskatchewan and Sutton, West  Virginia, could reduce overall production  by between 500 million and 600 million  square feet on an annual basis.     

A successful—and quick—chipper install at Weyerhaeuser with 3D modeling  

Last September, the  Weyerhaeuser sawmill in  Drayton Valley, Alberta, was  given a last-minute opportunity to  replace the main mill chipper—but it  had to be done by year end.                         

The intake of the old CAE 55-  inch chipper, installed shortly after  the original mill was built, could not  handle the flow of trim blocks from  the sawmill and planer mill, resulting  in multiple jam-ups per shift. The  blocks had to be diverted to the  refuse system—thereby  losing chip revenue for the  mill and adding the daily  cost of labour to clear the  blocked intake.                        

The feasibility study  was given to McGregor  Consulting of Spruce  Grove, Alberta—the  contract project managers  for the plant—with the  following demanding  scope criteria:      

• The new chipper had  to have a capacity large  enough to handle all of  the trim blocks produced  by both the sawmill and  the planer mill. 

• The existing infeed vibrating  conveyor had to be replaced by a  larger conveyor with a wider intake. 

• The new equipment had to  be specified, ordered, delivered,  installed and commissioned before  the end of 2006 in order to get  project approval.                         

The first challenge was delivery:  Could a left-handed chipper be  delivered to the site by December  21 at the latest? Carmanah Design  (formerly CAE) said it would be  “impossible.” However, the supply  of a right handed chipper was just  “nearly impossible.”                     

The second challenge was  would the larger chipper fit into  the extremely restricted area that  the old chipper occupied? Rough  measurements from the Carmanah  drawing delivered the same answer:  “nearly impossible.” As space  restrictions were severe, McGregor  Consulting decided to make a  3D computer model of the area,  including all the existing equipment,  and to position a 3D model of the  chipper inside the model.                      

The model revealed that the  motor support frame would not fit  with the existing refuse conveyor—  Carmanah agreed to lift the frame to  clear. It also revealed that the chipper  lid, in the open position, would not  fit with the “Superflow” conveyor  above it—Carmanah agreed to alter  the lid to clear.                    

The vibrating conveyor posed  the next problem as the existing  conveyor had a downward slope of  about five degrees from its infeed to  the chipper infeed, with a concrete  footing that went under floor level  at the chipper end. As the company  had never seen or heard of a sloping  vibe conveyor, McGregor Consulting  decided not to copy it with the new  one. Due to height limitations they  decided on a “balanced” vibrating  conveyor from Edem that does not  require a concrete base and can be  anchored to the floor.                    

“The biggest problem, however,  was that the existing chipper had a  left-hand feed and the new one had  a right hand feed.” explained Alan  McGregor vice-president, design, of  McGregor Consulting. “That meant  the new chipper had to sit at approx.  90 degrees to the existing rectangular  foundation—directly across the old  foundation width.” The question  was: Should concrete be added to  the base? McGregor concluded  that was a non-starter—a sixfoot  deep excavation in the  area was impossible given the  allotted shutdown duration.  Another call to Carmanah  revealed that the company  had actually replaced 55-inch  chippers with 65-inch chippers  using the same concrete bases.                         

However, they had never  switched a 55-inch left to a 65-  inch right on the same base.  McGregor Consulting went  back to the 3D model for  another look. They could  pick up about 75 per cent of  the footing area. They also  found that the chipper had to  be raised 8-3/4-inch to match the  chipper bed plate with the bottom of  the vibe trough. They then designed  an adapter structure that was held  down by all (seven) of the existing  anchor bolts and supported the  overhanging parts of the new chipper  base.  The upshot? The new chipper  replacement project was completed  ahead of schedule and under  budget, says company president  Davis McGregor. “What started  out as nearly impossible turned  out to be relatively easy after first  being completely assembled in  3D cyberspace in our computers,”  McGregor says.   

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