Business is changing even for one of the newer particleboard mills in the US; Temple Inland’s, in the optimistically named town of Hope, Arkansas, in the US Southeast. And Hope has another claim to fame, as the ubiquitous signs emphasise. It is one of the former home towns of ex US President Bill Clinton.
Temple, a Texas-based company with four other particleboard plants, built the mill in 1996. Mid-South Engineering designed the mill and was the main construction contractor.
Temstock is the industrial grade product’s trade name.
This was based a good deal on purchased 15% moisture content southern yellow pine planer shavings. “But with the supplying mills focusing on yield in their processes, we’re seeing smaller fibre size to work with,” said Ron Tews, plant manager.
He continued: “Our supply is somewhat seasonal. During the wet winter months the supply side falls short of the demand curve. This time of year there is more material than we need.”
Temple has covered storage for 10,000 tons of material at 16% moisture content.
The mix is made mostly of dry planer shavings with a maximum of 30% green sawdust. A pre-dryer brings the sawdust down to 15% to 18%, according to Mr Tews, who explained that sawdust is limited mainly because of bark contamination. He doesn’t see the bark as a physical problem, more a cosmetic one.
He went on: “Other sources of wood fibre are a possibility, although we haven’t come to any definite alternatives. We’re evaluating, analysing, and using our applied research centre in Diboll, Texas. We have small scale prototypes of different material mixes.”
The bulk of Hope’s raw material comes from a 50-mile radius, delivered from such company sawmills as Weyerhaeuser, International Paper and Potlatch. Their mills generate more than they can use internally. The Hope mill also buys from other companies and private sawmill operators.
Production manager Wayne Hargraves, a 25-year particleboard veteran, leads us through the process.
The raw material is all southern yellow pine shavings with a 15% moisture content maximum. Trucks are weighed in and out with gross, net, and tare weight recorded. Payment is by tonnage.
From twin Phelps truck dumps the material is moved into the raw materials storage building with a capacity of 10,000 to 12,000 tons. A Volvo front-end loader moves it to Acrowood shaker screens. Overs, of more than 5/8in, go to a Bliss hog and back to a shaker screen. From there, core and face material is segregated. A metal detector is also installed in this flow.
From the milling area, the raw material goes to the green and dry SHW silos, which provide a surge capacity of 40 to 50 tons. Face stock goes to six Bliss hammer-mills and four Sprout-Waldron 1,250hp refiners from where it is blown to dry metering bins ahead of the dryers. The dry silo holds 40 to 50 tons – about 45 minutes of operating material.
Temple has conventional three-pass M-E-C dryers, a face dryer, core dryer, and a swing dryer that can handle either, but is mainly used for core. A McConnell sander dust burner is used as a heat source.
The dried material is conveyed to SHW dry silos from where it is conveyed to an Imal blending system, introducing Borden resin and wax, and to the Schenck forming line.
An air former lays the faces while a mechanical former lays down the core.
The mat proceeds to an hydraulic hot oil heated Washington Iron Works 10-opening 9ft x 25ft screen caul press where, for example, 3/4in panels are pressed for 310 seconds at 325°F. The big press produces 2,250ft2 in a single charge. The oil is heated in an M-E-C McConnell wood burner. “At the right moisture content, it doesn’t take much wood dust to make a good fire,” said Mr Hargraves.
Average thickness produced is 5/8in with a 11/8in maximum, but 1/2in production is increasing.
Offbearing panels spend 20 to 30 minutes in an 80-board cooler. The company sands before sawing and the panels proceed directly to the Steinemann eight-head, 9ft sander. The panels can be rough-stacked ahead of the sander.
Next comes the extensive Schelling book saw installation. The 9ft line provides the versatility to produce both 5ft- and 4ftwide stock and Temple is producing about an even mix between the two. Mr Tews sees a significant advantage in this, saying: “So far this year we have not experienced market down time like a number of 4ft plants.”
A Globe jumbo stacker handles large panel storage.
Allen Bradley PLCs are used throughout the mill. Direct computer communication is available to most of the equipment suppliers for remote troubleshooting.
There is an increasing amount of production to order. The mill ships (evenly divided between truck and rail) mainly to a 300 mile radius for such products as RTA (ready to assemble) furniture and kitchen cabinet products. Some goes to laminated products.
The mill operates four shifts, seven days a week, with 129 employees, all salaried. Employment policies guarantee a high-quality workforce. They have a quite strong testing regimen in basic maths, reading skills, and mechanical aptitude.
Mr Hargraves said: “The more jobs that you know and can demonstrate, the higher the opportunity for more income. We are definitely one of the higher paying employers in this area. We pay more, but we expect more.”
The company has on-the-job training for advancement.
“We operate with what we call CPI, continuous process improvement,” said Mr Tews. All employees are in one team or another pursuing improvement in their processes. It’s part of our daily routine.
The plant occupies 52 acres on a 142-acre site with 290,000ft2 under roof. It’s an interesting site, a World War II ammunition storage area that was thoroughly checked before construction. A few ammunition bunkers have been left intact.
The plant’s design capacity is 208 million ft2, 3/4in basis with a state air quality permit for 220 million. “Proactively, we gained the best technology,” Mr Tews said, We have RTO and wet ESP lines.”