K-TEC WHITE PAPER November
2007
John Neumann, Larry Tyler, Carol Lazerick Kinetic
Technologies, Inc. Phone: 440-973-4111 | Website: http://www.ktecinc.com |
Email: info@KtecInc.com
Increasingly,
companies are mandating that the use of forklifts be limited to designated
loading and unloading zones or “Red Zones.” This movement is based on the
concern for employee safety as well as the desire to reduce forklift lease and
maintenance costs.
Realistically,
factories will not operate completely forklift free. The challenge for Six Sigma
managers, lean managers and material handling specialists is to intelligently
mix tuggers, non-powered manual material handling equipment and forklifts in order
to benefit the bottom line and satisfy safety concerns. While safety and cost
reduction are macro benefits, there are many other less visible advantages that
may play an important role in reducing costs and improving customer response.
Identifying these benefits requires a big picture overview of the project as
well as an understanding of how each department and suppliers, both internal
and external, will be impacted.
Balancing
the mix of forklifts, carts and tuggers can be extremely challenging and at
times frustrating. Many familiar habits of both the material handling support
and production assembly personnel will be changed. Physical plant, assembly
line and storage constraints, packaging changes, budget limits, ergonomic
issues and project completion time add additional complexity. Working through
these difficult problems will require unabridged input from top management, the
affected departments and suppliers who will share ownership of the plan.
The Case for Restricting Forklift Usage
There is no
question human loss and liability cost relative to forklift injuries has been
the number one driver for initiating forklift control programs. Each year in
the United States, nearly 100 workers are killed and another 20,000 are
seriously injured in forklift-related incidents. Forklift overturns are the
leading cause of fatalities involving forklifts; they represent about 25% of
all forklift-related deaths1.
The Hyster
Company estimates that businesses waste over $1 billion in unnecessary
operating costs associated with material handling equipment. A recent study
suggested that unfortunately, only 6% of end-users actually know their real
maintenance costs. Even fewer have programs in place to reduce these expenses2.
An old industry axiom states that on the average over the life of a forklift,
only 20% of its cost is ownership. Approximately 80% of total forklift costs
are operating costs3.
On the flip
side, forklift control programs can contribute value in areas relating to reduction
of inventory, improvement of material flow, reduction of line-side handling
equipment and floor space, improved operator ergonomics, cycle efficiency and
reduced need for coordination between forklifts and operators for
replenishment. Benefits of forklift control programs include:
1. Cost avoidance due to fewer and
less expensive line-side handling equipment.
2. Cost avoidance of extra line space
required for forklift replenishment.
3. Improved scheduling flexibility by
not needing tight coordination between line operators and production floor
material handlers (built-in system using RF, Kanban, etc.).
4. Decreased total WIP
(work-in-process) inventory.
5. Improved control of FIFO (first in,
first out) products delivered line-side.
6. Reduced coordination time between
forklift operators and production floor material handlers.
7. Improved personnel morale as
forklift activity is reduced in response to a serious injury or fatality
involving forklift operation.
8. Decreased loss in worker
production, lower insurance rates, fewer worker compensation claims and
litigation costs associated with less forklift injury claims by going to a
forklift controlled environment.
9. Reduced costs for forklift leasing,
purchase, maintenance.
10. Reduced
forklift operator costs (direct labor, benefits and operator
certification).
Macro Issues
Building a
forklift control program requires that a significant amount of time be spent on
the front end of the process clarifying plan targets, goals, identifying waste,
ergonomic and safety threats. At the start of the project, a framework can be
established by asking probing questions about how changes might impact
operations and the supply chain. Manufacturing / industrial engineers and
material logistics personnel are the typical project leaders who would ask
questions and make decisions with input from safety and ergonomic teams,
production managers, line operators, proposed tug drivers, market supply teams,
purchasing and suppliers. Poor communication is the root cause of
ineffective forklift control programs that add waste, increase costs and create
the “tried it once, not going to try again” mind set on future programs.
The
following questions are samples of those that should be asked to help uncover
possible problems and define the foundation / framework of the plan. At the end
of the exercise, all affected personnel and departments should have a clear
picture of any changes to past procedures and new responsibilities that may be
required under a forklift control plan.
Objectives
1. What are the goals of the
program? Can they be clearly defined, measured and shared with all personnel?
2. Do proposed plans and actions
support the goals or stray from the target?
3. What will be the impact on the
company’s bottom line?
Parts Presentation
1. Are mixed product lines with
complex parts change outs being used?
2. Will they be handled with
sequencing or kitting part configurations?
3. What criteria will determine
where containers will be “pushed” to/from conveyors or containers on carts will
be “exchanged” in work cells?
4. Will suppliers
(internal/external) support different container configurations and more
frequent deliveries? What are the costs?
Logistics
1. Where in the plant will forklifts
continue to be used?
2. Will there be one market area
and/or multiple smaller staging areas?
3. How much inventory can be removed
from the floor?
4. How much can be removed from the
market?
5. Will forklifts be used to load
line-side supply carts in the market areas?
6. What kind of tugs will be
acceptable to the drivers, maintenance personnel and be suitable for the loads
handled?
Personnel
1. How many material handling
support personnel are needed for a cart/tugger replenishment plan? Is this
better or worse than present forklift manpower? Why?
2. How closely will ergonomic
guidelines be followed?
3. Will material handling (MH)
operators be loading/unloading any carts to conveyors?
4. What maximum weights will MH
operators need to push, pull? What frequency, distance?
5. Will assembly operators be
expected to move containers or carts?
6. Will MH operators be required to
get in and out of tuggers repeatedly? Stand up vs. sit down designs? Ergo
impact?
7. What are the Union regulations
and issues related to the changes?
Micro Issues
Tracing the flow of material (and containers)
from the supplier to receiving dock through the assembly station and back to
the shipping dock for each part or part group can provide the insight
into troublesome details that might otherwise not surface until the first
run-off. These handling problems can be avoided if the forklift control system
designer accounts for all of the plant clients who must touch material in some
way. In example 1.1 that follows, the traditional forklift movement of one part
(and its container) used in one production cell location is compared to a
forklift control strategy. As the details unfold, note the number of
operational issues, personnel and supplier changes that must be put in place.
Example 1.1
INJECTION MOLDED HOUSING FORKLIFT CONTROL ANALYSIS
Receiving
Standard Forklifts
Original
part is delivered from an outside supplier two times a week in 96” long x 45”
wide containers. Parts are in 10 stacks of 50 each/container, 5 - 6 containers
per/delivery. Production uses approximately 10 containers/week. Maximum market
inventory: 3000 units.
Forklift Control Approach
10
stackable, gravity slide tube racks that hold 125 units each are delivered four
times a week from the supplier. Racks are forklift loaded in the receiving area
onto low push / pull force, towable carts and staged in the market area.
Maximum market inventory: 1250 units.
Line-Side Delivery
Standard Forklifts
Forklift
operator delivers one container to the line at the start of each shift for two
shifts. Assembly operator places any remaining parts in new container, forklift
driver removes empty container, loads new container on a lift and tilt device.
Load time: 10 minutes.
Forklift Control Approach
Every two
hours the tug operator tows one rack to the line. Tug operator rolls out empty
rack (placing any remaining parts on the new rack) and pushes new rack over a
small footprint lift. Maximum inertial push / pull forces are not exceed 40
lbs. Load time: 4 minutes.
Assembly Operator Actions
Standard Forklifts
Operator
works from one side of the tilted container walking the length (96”) of the
unit to unload. Line space required: 81” linear (36” for operator and 45”
for container width), plus 96” depth. Av. operator cycle: 45 seconds
retrieve/install, 12 seconds rest.
Forklift Control Approach
Operator
works from the back of the cart rack (end facing the line). As parts are
removed, gravity slide rack feeds new parts to the operators allowing them to
stay (sit or stand) in one area. Line space required: 42” for operator / rack
width, plus 75” depth. Cart rack has double slides to accommodate required part
volume. Av. operator cycle: 20 seconds retrieve/install, 37 seconds rest
(opportunity to increase line speed or add second operation).
Return
Standard Forklifts
Forklift
picks up empty container line-side, moves it to shipping and stacks it on the
floor (stacked two high) until next vendor pickup.
Forklift Control Approach
Empty rack
is towed to shipping and forklift separates the base from the rack assembly and
stacks the rack on the floor (stacked two high) until next vendor pickup.
Plant Considerations
Controlling the use of forklifts in an existing plant (Brownfield)
is more difficult than in new or remodeled facilities (Greenfield) where
constraints can be adjusted on the drawing board. Even when approached
carefully, existing plant constraints may make the best forklift control
strategy less than optimal. Narrow aisle widths, blind aisles, poor floors,
variable conveyor heights and set backs from the aisles, limited linear line
space, ceiling height and poor market (inventory stores) locations are just a
few of the basic challenges. Table 2.1 lists more examples of micro issues that
would need to be addressed.
Area
|
Issues
|
Operator
Ergonomics/Safety
|
Push/pull
forces, rotational forces, reaching distance, lift height, bending/twisting
needs, pedal forces, tripping, pinching, crushing or impact hazards
|
Part
Picking, Sequencing, Presentation
|
Line-side
configuration (cart exchange vs. push) relative to high density/low density
parts, dunnage type, weight, size, and line space
|
Operator
Efficiency (prod.)
|
Cycle time
targets, eliminate wasted motion or action
|
Zero Line
Stops
|
Simulation
models, real variable assumptions
|
Line Space
Required
|
See part
presentation
|
Operator
Efficiency (MH)
|
Market:
loading/unloading dunnage, conveyor vs. forklift, tug speeds, market to line
cycle times
|
Plant
Constraints
|
Floor
types/condition/flatness, column locations, aisle widths, production line set
backs, turn around areas, market areas vs. high volume assembly locations
|
Equipment
Constraints
|
Existing
conveyors, lifts, tilters, etc. that compromise ergonomics, cart loading,
cart geometry/alignment (to conveyors), number of carts/train
|
Financial
Constraints
|
Poor
planning/business case, cost overruns, budget cutbacks (at expense of long
term gains)
|
Replenishment
Signals
|
Determining
the appropriate type of pull signals such as Kanban cards, electronic RF
calls, etc.
|
Visual
Factory/Error Reducing
|
Color
coded inventory containers, open racking for easy identification of
inventory, color coded delivery locations
|
1 National Institute for Occupational Safety and Health
(NIOSH) at www.cdc.gov/niosh/2001-109.html
2 The Hyster
Company, www.hysterusa.com/fleetsvc.html 3 Materials Handling Equipment Co.,
materials-handling-eqp.com/forklift/significantly-reduce-forklift-operating-costs.htm
3 Materials Handling Equipment Co.,
materials-handling-eqp.com/forklift/significantly-reduce-forklift-operating-costs.htm
