Corban Industries , Orion, MI, wanted a safer, more comfortable working environment for its employees. Outfitting three robotic welding with self-contained air filtration units boosted air quality to levels that exceeded OSHA standards.

A maintenance program eliminates concerns associated with risk of fire and disposal of particulate matter, regulated by the EPA.

Floor-mounted units offer the dollar saving ability to duct two welding cells to a single self-contained collector unit. They also come with an automatic on/off switch that senses when a welder strikes an arc, and shuts off after five minutes of inactivity saving power and extending filter life.

The Air Filtration Process

Vertical filters, which allow collected dust and debris to fall into a containment area, are more efficient and offer a longer service life than horizontal models.

All blowers use an air foil design and a direct drive, 3,600 RPM motor. The motor and blower wheel are assembled as a separate module and can be removed for maintenance and alignment.

Self-contained filtration units mount on top of the welding cell to conserve valuable shop floor space.

Nine years ago, Mike Cain, welding engineer at Corban Industries in Orion, MI, did not believe air filtration could be successful in a welding plant.

"As far as I was concerned, it was a waste of money," he recalls saying in a meeting at a former employer's office.

Today, Cain, now a 32-year veteran of the welding industry, not only believes air filtration can be successful, but that it is a truly a necessity in the welding environment.

Cain uses RoboVent air filtration products from Great Lakes Air Systems of Clawson, MI, at Corban's Orion manufacturing plant, a tier 1, 2, and 3 supplier to the automotive industry. Corban Industries has 230 employees operating three plants where they produce stampings, assemblies, conduct tool and die manufacturing, and perform engineering and product and tool design.

Major Automotive Supplier
Corban is a major supplier to the Lear Corporation, manufacturing seat components including armrest frames for seat assemblies that go into GM and Daimler Chrysler automobiles. The armrest frames go in the General Motors' GMT 800 product line, which includes nearly all GM trucks, and the GMT 820 product line, which includes the Cadillac Escalade and other SUV models. They also manufacture for a Daimler-Chrysler product line, which includes the Dodge Dakota and other models.

Within each armrest assembly, Corban manufactures several basic parts. The stamping, or main body of the armrest, is the skeleton of the armrest in which the foam and fabric is fitted over and around. Corban also manufactures a rod reinforcement that provides form and support for the arm-rest and fits into a pivot bracket (also manufactured by Corban) that allows the armrest to move up and down.

Precision Welding Required
Each of these components requires precision welding and Corban uses three Fanuc ARC Mate robotic welding cells with Lincoln Electric Power-Wave inverters. They use gas metal arc welding with a 90 Ar - 10 CO2 mix. Most of the welds are ³ /16 in. fillet welds that are less than 25 mm long.

Cain said they use ER-70-S6 0.035 in. wire in their welds and go through about 3,000 lbs. a month.

Cain credits John Reid of Great Lakes Air Systems for changing his mind on the issue of air filtration. Reid offered to install six RoboVent systems on a trial basis at Cain's former employer to prove that the systems can effectively clean the air. After 90 days, Cain said he changed his mind. "I've been a supporter of the systems ever since," he said.

Safety,Comfort, Compliance
Recently, Cain asked Great Lakes to install a system to help create a safer, more comfortable working environment for employees with air quality that exceeded OSHA standards. Additionally, he wanted the system to collect the smoke and air, filter it and return it to the plant, to save money on heating in the winter months by returning heated air to the plant. Corban's three robotic welding cells were fitted with self-contained air filtration units.

The floor-mounted units use a hood mounted over the welding cell equipped with a specially engineered spark arrester to prevent fires as it sucks air laden with smoke, welding dust, and debris from the cell. Air travels through a duct to a self-contained collection unit consisting of a housing with a blower, motor, silencer, filter cartridges, and a unique compressed air pulsing system that keeps filters clean.

The collection unit uses a patented filtration process in which air flows in a downward path as it comes into the unit, then passes through vertical filters that clean the air. As the collection unit receives air from the hood, it immediately shifts the airflow 90° downward through the filter elements. This causes separation and deposition of the larger, heavier smoke and welding dust particles, reducing the load on the filter cartridges.

The down flow of air within the containment unit reduces turbulence and virtually eliminates re-entrainment, or re-blowing dust within the unit that has already been cleaned off of the filter back onto the filter. Re-entrainment is the primary cause of short filter life. The down flow of air also travels in the same direction as debris that has been cleaned off the filters by the unit's pulsed air cleaning system, helping to keep the debris in the collection tray and off the filters.

Vertical Filters
The units use vertical filters, which are more efficient and have much more filter life than the horizontal filters used in most air filtration units. Vertical filters allow collected dust and debris to shed off of the filter and fall directly down, with the direction of the airflow, into the containment or collection system when the filters are pulsed by the cleaning system.

Horizontal filters are inefficient, according to Reid. "We've found that dirt and debris tends to fall off only the bottom two-thirds of a horizontal filter, rendering the top of the filter ineffective as it becomes clogged with debris," he said. "This results in a 30-40 percent loss in filter area and a substantial reduction in filter life."

The entire unit is engineered for a heavy manufacturing environment and for easy, minimal maintenance. The unit is constructed of heavy gauge steel and all seams are 100 percent welded. All blowers use the efficient air foil design and a direct drive, 3,600 RPM motor. The entire motor and blower wheel are assembled as a separate module and can be removed for maintenance and alignment when needed. The blower compartment is lined with 1 in. coated acoustical foam for quiet operation.

Pre-coating Extends Filter Life
Great Lakes developed a proprietary blend of non-woven filter media for these units. The filter media is precoated to extend service life and filter cartridges are supplied with a securely attached gasket for an airtight seal. No special tools are required to change or service the filters.

Corban was looking for cost savings and the floor-mounted units had two dollar saving features. One was the ability to duct two welding cells to a single self-contained collector unit.

In addition, each floor-mounted unit comes with an innovative automatic on/off switch that turns the unit on when it senses that the welder strikes an arc, and automatically turns the unit off after five minutes of inactivity resulting in tremendous savings on power consumption and filter life.

Great Lakes also manufactures a self-contained system in which all components, including the collection unit, mount above the welding cell to conserve valuable floor space and provide maximum flexibility for easy movement within the plant.

Cain says that employees noticed the difference once the units were installed. "If the units are shut off, the operator tells us immediately. They notice an immediate change in the air quality."

Maintenance Pays Off
Cain knows from experience that proper maintenance is the key to effective air filtration and productive employees. "I believe that one of the biggest things that is critical to these systems is the maintenance," Cain said.

Cain elected to have the manufacturer maintain its air filtration systems to ensure units continued to operate at peak efficiency.

As part of the program, the firm visits the plant regularly, changes filters as needed, performs routine maintenance on each unit and its spark arresters, and disposes of the filtered particulate in the proper, regulated manner. Most maintenance activities are performed while machines are running. If they do need to change the filters, that requires only a 15-minute shutdown.

Corban has had no issues with fires or disposal of particulate matter, regulated by the EPA as a result of the maintenance program.

Edited from information provided by Great Lakes Air Systems, Clawson, MI.