State-of-the-art machinery puts new Steelcase plant in context.
Nestled in a suburb of Grand Rapids, Mich., and spread over 18.1 acres of land, Steelcase's new Context plant integrates specially designed computer controlled machinery and human teamwork to create a new line of freestanding office furniture.
The office furniture system created in this mammoth complex consists of metal cabinetry and pedestals topped with the company's Silque desktops made of MDF substrate. These desktops are painted in any of seven colors. Buttresses, boundary walls, storage units, screens, and other accessories complete the systems produced at this nearly year old facility.
A key to the manufacture of these systems is the production line for the Silque desktops. The winding, automated line designed by Steelcase and Rapistan Corp., of Grand Rapids, is unique to the industry, said John Gruizenga, vice president of Manufacturing Support Groups. It can take a piece of raw MDF, apply a urethane liquid edge, rout it twice, finish and sand it, and monitor the accuracy of the work. In addition, using CAD/CAM and bar code technology, each panel can be a different size and shape without slowing production.
Gruizenga called the Context plant a "focus factory," containing three factories in one. The products from the three factories will eventually come together to produce the Context Freestanding Furniture. In one factory, the freestanding furniture is created; in a second, metal cabinetry such as pedestals are produced; and the third manufactures case goods such as vertical storage cabinets.
It took three years of planning, building and installing before the first product emerged from the Context plant in June of 1990. Even now the company is continuing to expand Context's production capabilities. Currently, the plant has one automated production line for its desktops, but by summer, Gruizenga said a second line for laminated desktops will be brought online.
The office furniture system created here is almost entirely done in-house. The Context plant is only dependent on raw materials purchased from outside vendors. Context workers will create the MDF desktops, cut and form rolled steel for assembly into metal cabinets, and construct each component of the system under one roof. According to Gruizenga, within two days of delivery, the raw MDF has been transformed into finished desktops, and by the third day the completed workstations are ready to be delivered to the customer.
"This is the most automated, most flexible system in the world," Gruizenga said. "At this end (of the plant) it is all numerically controlled equipment, and the main benefit of that is it allows us to make any size or shaped top without set-up time."
This is important because the company only constructs office furniture that has already been sold, he added, thereby eliminating inventory and its related costs.
From raw MDF to finished desktop In keeping with the no-inventory philosophy, cut-to-size MDF panels are shipped to the plant on a daily basis by a local vendor. The amount of MDF brought in is dependent upon the quantity required to fill customer orders, said Manufacturing Manager Jack Walker. Rolling in on Rapistan conveyors, the MDF is placed in stacks or "bunks" awaiting an automated vacuum suction cup system to grab the top panel and start it on its way through "Factory No. 1."
Each panel strip is labeled with a bar code. This code will subsequently be read by a series of AccuSort bar code readers positioned before each machine along the conveyorized line. This is the key that allows tops of any shape or size to be formed one right after the other, Gruizenga said.
"A key element to the system is having machines that are programmable so they can run programs stored in a remote computer memory," Gruizenga said.
These computer aided design programs are the desktop patterns which range from straight edge to curved tables. Each pattern program can be called from memory to instruct machining operations.
The first operation encountered by the MDF is a routing operation. The CNC router, specially designed and developed by C.M.S. North America Inc. and Steelcase, automatically machines a groove into the board in the pattern of the finished product.
At this point a second key to the operation occurs. Two round holes are bored into the bottom of the MDF using the C.M.S. router. A Renishaw probe device will later use these holes as reference points during subsequent routing operations. The probe communicates to the machine the location of the board on the router within 5,000th of an inch to ensure accuracy, Gruizenga said.
The board's journey continues to a urethane fill system designed and built by Max Machinery Co. and Miller-Moorehead Machinery. The urethane processing equipment then injects a liquid urethane edge into the groove on the board. Liquid urethane is a "hard and durable material that is mar resistant," said Gruizenga in explaining its use.
After the bar code reader scans the label, the liquid material is applied. This machine circles the board filling in the groove cut out by the C.M.S. router. The groove acts as a reservoir for the fast-drying liquid. The custom-built machine can work on a 5-foot by 10-foot surface, Gruizenga said. Details of how the liquid edge is kept in place, the thickness of the edge, and how long it takes for the edge to harden is a well-guarded company "secret," Gruizenga said.
After each board passes, the edge machine cleans itself by dipping its nozzle in solvent so that the urethane does not harden and clog the nozzle.
The next step is to cut away the excess board, and this is done by a second C.M.S. CNC router. The board is brought underneath the router by conveyor, and a second Renishaw probe extends down, searches for the reference holes and "rough routs" the board in the same pattern grooved by the first router.
The piece is then conveyed to the final routing station. As it exits the router, wood scraps fall off into a side conveyor which transports the offal into a disposal bin.
At the last routing operation, the final edge shape is profiled by a special CMS pod-style router. The workpiece is elevated from the bed while various bullnose tools shape the urethane edge, Walker said. "This operation ensures consistent, high-quality work surfaces for all sizes and shapes," he added.
The top is then finished in one of seven available colors. The board is physically taken off of the production line, and put on a monorail conveyorized finishing line, Gruizenga said. However, before this happens a verification step is performed. At the beginning of every rack, or 10 tops, the first top is taken off the line to verify that the cuts are accurate, Gruizenga said.
"When it comes to this point the board is taken off the line, and the rest of the process continues," Gruizenga said. "This verifies the whole system using the extremely accurate Coordinate Measurement Machine (CMM)."
The finish chamber
Steelcase designed and developed its finishing line, and it goes to great lengths to protect the finish of its tops. The finishing equipment is located in a "clean air room" where air is filtered twice to ensure a dirt-and dust-free finishing area.
To safeguard against contamination, a number of steps are taken to ensure that operators do not bring dust or static electricity into the finishing area. A person must first enter a room where a deionizing light breaks down any static electricity. He then enters a blow-off chamber in which air is forced through nozzles on opposite walls to blow off any dust or dirt that might contaminate the finished product. Each person entering the finishing area must wear protective jumpsuits.
On top of this, a computer monitors when someone enters the room. The reason for this is to help ensure cleanliness, Gruizenga said.
"Every little piece of dust magnifies itself 50 times," he said. "If dust gets into the wet paint, when it dries, there can be craters and bumps."
The paint applied in this step gives the top color, and not durability. That will come later, Gruizenga added.
Once painted, the top is baked in an Sunkiss Thermal Reactory infrared oven. An infrared oven is used rather than a convection oven or another oven so as to not bake the board too hot which could bubble the paint.
The painted top is then scuff sanded in a specially designed booth which draws all dust down. Riding on a conveyor, the top goes under a dust vacuum to remove some dust, and then under an ostrich feather duster which beats off the remaining dust.
An acrylic coat is applied to the board which will give it mar resistance. The desk-top is then transported to another room where an operator will apply the acrylic coat to the edges with a spraygun. A machine turns the workpiece 360 degrees allowing the operator to spray all four sides with an acrylic lacquer.
The finished top is then cured with UV light on a UV processing system from George Koch & Sons, Gruizenga said.
Meeting VOC emission requirements
When designing the finishing system Context designers kept one eye on future volatile organic compound (VOC) level requirements, and the amounts of VOCs their operation creates. In addition to the VOCs emitted by the painting of the Silque tops, the metal components of the office system are also painted. In fact, substantially more metal is painted than desktops, resulting in greater VOCs because of the higher numbers.
When deciding how to eliminate these VOCs from entering the atmosphere, Context planners asked themselves two things: How do we get rid of the most VOCs, and how do we do it at the lowest possible cost?
The first step involved identifying the areas representing the worst culprits - namely, the spray booth and the oven. They then set out to eliminate those VOCs. Currently, 96 to 98 percent of the VOCs are eliminated with the system they installed, said Automation Improvement Technician Mike Carter.
The system, known as the Flakt/Calgon Carbon Reclaiming System, designed by Flakt Inc. of Knoxville, Tenn., is monitored by a technician from a nearby enclosed computer room. On the wall are three computer screens which can call up computer images of any portion of the process and what is happening in the system at that particular moment.
The finishing room air is first funnelled into four vessels filled with activated carbon filters. These filters absorb the VOCs created by the finishing operation. When one of these filters is nearing saturation the computer alerts the operator, and the vessel can then be regenerated while the remaining vessels continue to operate.
With this system the incinerator does not work constantly, thus saving costs as well as natural gas.
To clean the vessels of VOCs, steam heated to between 285 and 300 F is introduced into the system. The super heated steam is pumped through the filter obtaining a mixture of steam and solvent. This mixture is then pumped to a natural gas burner that burns the VOC laden steam at 1400 F. Once the burning has started, the operator can cut down on the natural gas because the VOCs will burn keeping the heat up, Carter said.
In a ceiling-less room stand two dust collection vessels where the wood dust is stored. The room does not have a roof because it is less expensive and reduces fire risks, said Gruizenga. The containers are computer monitored, and when one container is full, the second goes into operation. Currently, trucks take the dust to an incinerator where it is burned, but long-term plans have the dust being used as fuel to heat the plant and for process fuel, he added.
The dust is brought to these containers in different ways. The C.M.S. routers have 125 horsepower vacuum lines attached that suck up the dust from the workpiece, and every room is equipped with a vacuum cleaner system that hangs along the wall. Larger pieces of wood are chewed up in a shredder, and sent to the vessels.
"Not only do the belt-style routers collect most of the dust and shavings," Gruizenga said, "but when the board goes down the conveyor it goes under a vacuum which gets the rest of the stuff off."
Together at last
While the top is being produced, the remainder of the office system is being made at the other end of the factory.
The steel is delivered to the plant in rolls, some weighing up to 40,000 pounds. It is then cut and formed. Computer programs can make whatever design the customer wants, said Gruizenga. Changing panel types takes approximately two minutes, he said.
Once all the panels are formed, two man teams actually put the product together, Gruizenga said.
Teamwork and personal responsibility
Many companies use the term teamwork as reasons for their success, but Steelcase embodies the idea. In designing the state-of-the-art Context plant, Steelcase, the world's largest office furniture manufacturer, put together a team of professionals from a range of perspectives. "It was a combined team effort between Steelcase engineers, operators of the equipment, and the equipment suppliers," said John Gruizenga.
Gruizenga said each person is responsible for their respective jobs, machines and workplace. When they need more parts, have a problem with a machine, or have other such situations the worker takes the initiative to get the parts, make the phone calls, or does whatever needs to be done, Gruizenga said.
"What makes it all work is the people and teamwork," Gruizenga added.
The team concept runs throughout the plant, Gruizenga said. There are 36 teams that meet to discuss everything from plant safety to what should go into the cafeteria.
"Plant teams are actually running the plant," Gruizenga said. "The things you would expect a supervisor to do the employees are doing themselves. This gives us flexibility and fast responsiveness, which is exactly what we are looking for."
PHOTO : Steelcase's new Context plant features a conveyorized line for applying liquid edges to desktops, like the one shown above.
PHOTO : Bunks of cut-to-size MDF are trucked in on an "as needed" basis. Within three days, the panels will be turned into finished desktops, ready for customer delivery.
PHOTO : Using bar codes, this CNC router, designed by C.M.S. North America Inc. and Steelcase, routs grooves into variably shaped and sized panels, one after the other.
PHOTO : The liquid edge applied by the machine built by Max Machinery and Miller-Moorehead is hard durable and mar resistant.
PHOTO : These two panels are illustrative of how the machinery in the Context plant can process panels of two different sizes and shapes back to back.
PHOTO : Steelcase management refers to the Context plant as a "focus factory." It houses three different factories, and is largely self-sufficient.
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|Title Annotation:||includes related article on an edgebanding machine|
|Publication:||Wood & Wood Products|
|Date:||Apr 1, 1991|
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