Finished wood products such as cabinets, floors, or furniture, plywood,
particle board, fiberboard, or even paper do not present an obvious environmental
hazard. Wood is plentiful at our homes and workplaces, provides us with warmth
and stability, and can be highly useful in several industries. However, wood
manufacturers must embrace extreme methods to make wood product manufacturing
less harmful for their employees and prevent accidents. In October of 2005,
a wood products plant
exploded in Schofield, WI killing one worker. According to OSHA statistics
in 2009, 21 fatalities occurred in the Wood Industry alone. OSHA also reports that “since 1980, more than 130 workers have
been killed and more than 780 injured in combustible dust explosions.”
Using robots in the wood industry allows wood manufacturers to remove their
employees from these dangerous environments and utilize them more effectively,
while at the same time trim production costs.
Wood manufacturing hazards include dust inhalation during sanding and
cutting, chemical inhalation caused by chemical wood treatments, as well as
the dangers of eye or skin injuries from thrown wood particles. Metal injuries
from staples, or fire or explosion hazards if wood dust accumulates in machinery
are also a risk. In addition to these, biological organisms such as mold and
fungi which can grow on wood, and chemicals such as formaldehyde, which is
used in some wood processing methods, can be hazardous. Expensive respirators
are used to minimize worker exposure and injury, and stringent cleaning methods
must be maintained to minimize risks. However, these are not foolproof methods
and require frequent surveillance to make sure machines are clean and running
properly, and that workers are following the best safety practices in order
to reduce life-threatening risks.
Under the Occupational Safety and Health Act of 1970, employers are
responsible for providing safe and healthful workplaces for their employees.
According to the OSHA
website, “OSHA's role is to assure these conditions for America's
working men and women by setting and enforcing standards, and providing training,
education and assistance.” Even if these standards are in place, accidents
can happen and workers can be injured. For example according to the Workers'
Compensation Board of British Columbia, a worker in a lumber processing
plant died while feeding rough lumber planks into a stripsaw. Standard practice
was to feed the lumber from the side however, in order to feed the lumber
with enough force, the lumber was fed manually from the end. When the saw
kicked-back, one plank hit another and struck and killed the worker. Programmable,
highly reliable, and predictable robots can be used in situations such as
this to remove workers and inherently force safer methods. The manufacturing
costs from removing the liability alone can be recovered with just one robot
Placing robots into previously dangerous, traditionally manual situations
can provide other benefits as well. For example, a large manufacturer of wood
boxes for various packaging products historically hand-produced boxes using
a special self-produced tacker head for the metal staples fastening the box.
The tacker is actually very unique as the staples are directly produced from
a metal line just before being stapled on the wood ~ with an astonishing speed
of 2 seconds for 12 staples. This extremely innovative continuous flow stapling
has been patented. However, box production heavily relied on manpower, thus
preventing the workers from making more complex products. Also, the tacker
head produces a blowback when stapling the agraffes (a hook and loop fastener)
on the box, which could injure workers. In addition, the demand for boxes
was increasing at such a rate that the production needed to be pursued at
night and on weekends. This became a perfect entry point for robotic automation.
With a new robotic system installed, the robots build wood boxes quickly for
the metal parts holding the slates on roofs. The plant workers are now working
on more complex boxes. In this installation, one robot takes the boxes from
the pallet (4 sides plus bottom at one time with one gripper). The wooden
parts are simply laying on the pallet without high precision, and are then
sliced one by one in a special part holder system on a turning table. The
holder system allows the sides and bottom to be placed correctly before being
stapled. The box is moved on the turning table to the second robot which
then staples the sides and the bottom, and then puts it on a pallet. This
solution has been running 24 hours a day and 7 days a week for 6 years, without
special supervision or maintenance.
In another successful application PRE-TEC, a Division of the Willamette
Valley Company, has implemented a system in which four FANUC robots apply
protective wrapping and end sealant to I-Joist Beams or Stacked Laminated
Veneer Lumber (LVL). In this system, robots replaced an operation that presented
stapling hazards as well as those that come with handling large pieces of
engineered wood products. Previously, the made-to-order wood products of
varying sizes were loaded, hand-sealed, wrapped, stapled, and labeled manually
in this steady production process.
In the previous system, there was
concern for worker safety when climbing on the wood to stretch the wrapping.
In the new system, robots bring in each piece, accurately measure and stretch
the wrapping to match the piece size, apply the sealant, and stack the wood
for distribution. The beams are measured continuously on the carousel to be
sure the correct size wrapping is loaded. The robots then wrap and staple
the wood automatically. According to Rufus Burton, PRE-TEC Robotics Sales
Manager, “This new process effectively eliminates any human stapling
hazards, as well as the cumbersome process of cutting and stretching the wrapping
to size making the process more efficient.”
This system uses one FANUC
Robotics M–710 iC/70 robot, two M–16 iB/10L
robots, and one M–20iA/10L robot to complete the process. Previously,
4–5 people worked on the manual system. While one worker remains in
place providing system maintenance, the remaining workers have been moved
to more value-added, non-hazardous, maintenance positions. “FANUC Robotics
has always provided great support on our projects ~ from the District Manager
to the Support Staff,” says Burton. “We at PRE-TEC are pleased
with their efforts as they are constantly helping us look for ways to innovative,
apply the latest technology, improve methods, and build better systems.”
In addition to safety, wood manufacturers can realize other cost saving
advantages in moving workers away from environmental hazards and into safer,
more critical positions. Robots are cost effective and, when using highly
sophisticated imbedded robotic vision
systems, can be trained to handle the distinct characteristics of
wood. Depending on the kind of wood being processed, knots must be avoided
or placed in certain locations, and wood density or softness must be taken
into account so as not to damage the product. In these situations, iRVision
sensing equipment can be used to monitor and control output quality.
FANUC robots use integrated (or built-in) iRVision® for part location and evaluation. iRVision® is Integrated Robot Machine Vision
which is the integration of a camera interface built into the robot controller.
One or more cameras can be attached to the robot, or they can be in a remote
location. In traditional processes, if you want the robot to manipulate every
workpiece in the same way, you need to place every workpiece at exactly the
same position. iRVision® is a visual
sensor system designed to eliminate such restrictions. iRVision®
measures the position of each workpiece by using cameras, and it adjusts the
robot motion so that the robot can manipulate the workpiece in the same way
as programmed even if the position of the workpiece is different from the
workpiece position set when the robot program was taught. All of the application-specific
tools developed to simplify the use of the camera as a guidance, identification,
or inspection tool are integrated with the robot.
Handles multiple parts at one time.
Reduces floor space.
Makes part changeovers a breeze.
Identifies parts in multiple orientations.
Locates parts in 2D or 3D.
Error proofs the parts as they enter assembly, as well as
the assembly itself.
Reduces or eliminates fixturing costs.
Off-line programming can also be beneficial in wood applications. For
example, a FANUC
M-710iC robot mills complex patterns
into a stair case rail. A user can work off-line to create the program and
run simulation tests. The robot runs a series of passes from rough to finish
taking off lots of material during rough passes and very little material during
finish passes. The end result is shown after light sanding and staining.
In the previously discussed PRE-TEC application, ROBOGUIDE was used
to simulate the complex process before production to save time, maximize process
efficiencies, and optimize cycle time.
ROBOGUIDE Wood Wrapping Application
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