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Models Aren’t Meant to Be Rigid!
A Case New Holland Combine Case Study
Epicenterwww.epicentergroup.com 216.702.0952
Epicenter Development Group Client ListAutomotive/Trucking
• Amtex Corporation – Ohio
• Bellemar Parts – Ohio
• Case New Holland – Nebraska
• Chrysler Motors/Jeep – Ohio
• Eaton Corporation - Kentucky, Michigan
• Essex Specialty Products – Michigan
• G.M. - Packard Electric (Ohio), Hydra-matic (Michigan)
• Manchester Plastics - Michigan, Ontario
• Monroe Auto – Michigan
• PACCAR Truck Assembly Plant – Washington
• Schlegel, Inc – Iowa
• Ternes Packaging – Michigan
• Toth Industries – Ohio
• United Technologies Automotive - OH, MI, IN, IA, IL, TN
• Volvo/GM Heavy Truck -Ohio
Food/Pharm
• Biery Cheese – Ohio
• Ernst and Young (Boston Chicken) – Illinois
• Frozen Specialties – Ohio
• Great Lakes Brewing Company – Ohio
• Hickory Farms – Ohio
• Mallinckrodt Inc. – Missouri
• Miller Brewing – Ohio
• Ross Laboratories - Ohio, Michigan, Arizona
Chemical/Plastics
• GOJO Industries – Ohio
• Johnson Wax Professional – Wisconsin
• Master Chemical – Ohio
• Mueller Plastics - Michigan, Ohio
• Occidental Chemical – Ohio
• Phillips Plastics – Wisconsin
• PPG Industries
• Spartan Chemical – Ohio
• Struktol Company of America – Ohio
• Sunbeam Plastics – Indiana
• The Sherwin Williams Company - Ohio
Construction
• Owens-Corning - WI, Ohio, TN
• Ryland Homes - Michigan
Electronics
• Proto-Circuits – Ohio
• Thompson Consumer Electronics – Ohio
• Tosoh, SMD – Ohio
• Union Carbide – Ohio
• Westinghouse Electric - Ohio
Steel/Casting
• American Spring Wire – Ohio
• Doehler Jarvis - Tennessee, Ohio
• North America Wire Products – Ohio
• Pre-Finish Metals – Ohio
• Rouge Steel - Michigan
Other
• Aeroquip/Trinova – Ohio
• American Red Cross - Ohio
• American Way Manufacturing – Ohio
• Applied Material Sciences – Massachusetts
• Checker Distribution – Ohio
• Commercial Aluminum Cookware – Ohio
• Davidson Plyforms - Michigan
• Ecodyne – Ohio
• FFr, Inc. – Ohio
• Godfrey & Wing – Ohio
• Goody Products - Georgia, Florida
• Greenville Utilities – North Carolina
• Harley-Davidson – Pennsylvania
• I.D. Images – Ohio
• Junior Achievement - Ohio
• Kalb, O’Keefe and Sullivan – Ohio
• Lott Industries – Ohio
• Meyer Products – Ohio
• OfficeMax Corporation – Ohio
• Quickdraft – Ohio
• Sonopress, Inc. – North Carolina
• The Lincoln Electric Company
• Weiss Industries, Inc. – Ohio
• Weldon Pump
• Whirlpool Corporation – Ohio
Epicenterwww.epicentergroup.com 216.702.0952
Simulation is Part of a Group Process at Epicenter
Determine Project
Objectives
Interview “Stakeholders”
Collect and Analyze “Field”
Information
Create Collaborative
Tool(s)
Team Event with
Stakeholders
Manage Transitional
Activities
On-Going Support until
Objectives are Met
Technical/Process
Information
People/Process
Information
Build Relationships /
Understand Culture
Review Operation / Understand
Systems
Multiple Events
• Simulation• Process Maps• Value-Stream Mapping• Etc.
The GreenRoom Engineering Process
Epicenterwww.epicentergroup.com 216.702.0952
The BIG Takeaways!
• Model flexibility is important.
• You can build flexibility through:– Spreadsheets
– Toggles
– Rules-of-Thumbs
– Subroutines
– KISS Principle
Epicenterwww.epicentergroup.com 216.702.0952
Why is Flexibility Important?
• Every once in a while a model needs to be built without all of the information…
• People occasionally change their minds…
• Regrettably the first design isn’t always the best…
Epicenterwww.epicentergroup.com 216.702.0952
Considerations for a Flexible Model
1. Put as many of the calculations and variables in a spreadsheet as possible (spreadsheets are “user-friendly” to people)
2. Create “toggles” in the model to turn on and off elements “on the fly”
3. Use Rules-of-Thumb that govern how information is used
4. Use subroutines so changes can be made more globally when necessary.
5. Keep things simple! (K.I.S.S. Principle)
Epicenterwww.epicentergroup.com 216.702.0952
Our Story Begins…• CNH was planning to invest in expanding their
current paint system for planned production increases and to address current design capacity bottlenecks .
• They had to redesign and modify the system within a short period of time to accommodate a planned volume increase. This would be a significant investment in time and money.
• It was critical that the paint system handle the required production volume – “do or die” time!
• CNH decided to model the new system and use the model to validate the design before making any modifications. There were lots of expensive design modifications to consider.
Epicenterwww.epicentergroup.com 216.702.0952
Existing Paint SystemLayout (simplified)Layout (simplified)
1 2 3 4 5a 5 6 7 8 9a 9 10 11
E Coat Oven Bottom - Top coat Oven Top
Large
Small
Spray Booths
E Coat System
Load/Unload
#1
Load/Unload
#2
Bare Carrier Storage
Unpainted E Coated Top Coated Bare Carrier
or
Small Large
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System Definitions• Carrier - Orange Trolley Device
Permanently fixed to the Power & Free Conveyor.– Bare Carrier - Carrier with no
Load Bar attached.
– Empty Carrier - Carrier with Load Bar attached but no parts hanging.
• Load Bar - The device attached below to the “carrier” where parts are hung. Load Bars are separated from the carrier for processing through E-Coat.
PartsParts
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The Power & Free Conveyor Design…
• Every position on the Power & Free Conveyor was modeled as a unique location
• When one carrier moves to the next location, it can start a “waterfall” of carrier movements downstream.
• Delays for carrier movements were calculated based upon user-defined formulas. This was tricky!
Epicenterwww.epicentergroup.com 216.702.0952
The E-Coat Dip Tank Design…
• This was a series of tanks where parts were transferred by a number of automated cranes
• We wanted to be able to easily modify the crane/tank assignments and sequence and timing of crane movements.
Epicenterwww.epicentergroup.com 216.702.0952
Flex Design Principle #1
Put as many of the calculations and variables in a linked spreadsheet as possible. Spreadsheets are “user-friendly” to people.
Before we built our model, we identified several variables that had the potential to change. We put these variables into spreadsheet tables.
Epicenterwww.epicentergroup.com 216.702.0952
Spreadsheet – P&F System Variables
Every Variable that could be put into the spreadsheet – was!
Element Value Description Model VariableLarge Carriers in system 18 Preloaded carriers LcarriersSmall Carriers in system 91 Preloaded carriers ScarriersBare Carriers in system 4 Preloaded carriers Bcarriers
Chain Speed Transport (ft/min): 55
Speed of the power and free transport chain Only used in spreadsheet
Chain Speed Oven (ft/min): 16.8Speed of the paint oven Ovenspeed
Ecoat Oven Pulse (minutes): 4.286 Pulse of ecoat oven eoven_pulseChain Speed Booth - Paint 1 (ft/min): 9
Speed of the paint line #1 chain Sppaint1
Chain Speed Booth - Paint 2 (ft/min): 9
Speed of the paint line #2 chain Sppaint2
Chain Delay Max (minutes): 0.18
Maximum time to transfer to another chain Std_Chain_Delay_Max
Stop Delay Max (minutes): 0.18
Maximum time to restart on a chain at a stop point Std_Stop_Delay_Max
Queue Delay Max (minutes): 0.05
Standard time to restart when advancing in a queuing location Std_Queue_Delay_Max
Load Area Maximum Carriers 36
Maximum number of carriers in the Load/unload area Load_area_target
Carrier Overflow Maximum Queue 10
Maximum queue during shift. Paint_overflow_target
Crane down % 0Overtime time a crane is down crane_down_percent
Crane down (per hour) 1.5Frequency of crane downtime crane_down_perhour
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Spreadsheet - Segment Travel Times
• Each segment of the Power & Free conveyor was given a model name, index number and length in feet.
• The spreadsheet calculated the travel time based upon the chain speed of the segment.
Conveyor Segment
Index Number
Length (ft)
Travel Time (min)
l_Carrier_Entry 1 22 0.400l_Stop_02 2 22 0.400l_Stop_03_Q_1 3 22 0.400
l_Stop_03 4 22 0.400
l_Stop_04_Q_1 5 22 0.400l_Stop_04 6 22 0.400
l_Stop_05 7 22 0.400
l_Stop_06 8 22 0.400
l_Stop_07_Q_1 9 22 0.400
l_Stop_07 10 22 0.400
l_Stop_08_Q_3 11 50 0.909
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Spreadsheet - Load Information
Min Avg. MaxLarge Carriers - Load - minutes 2.5 3 3.5Large Carriers - Unload - minutes 2.5 3 3.5Small Carriers - Unload/Load 3.0 3.5 4.5E-coat Only (% of mix) 10.0 12.5 15.0 Sanding Required (% of mix) 15.0 20.0 25.0
Paint Color for Carrier PercentColor - Red 50 Color - Dark Grey 35 Color - Yellow 10 Topcoat Only 5
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Spreadsheet - Crane Routes
A spreadsheet system was developed to create crane routings for the model.
Cycle Step
DestinationTime to
Destination (sec)
Action at DESTINATION:
1) Pick only, 2) Drop Only, 3) Drop, Wait,
Pick
DestinationTime to
Destination (sec)
Action at DESTINATION:
1) Pick only, 2) Drop Only, 3) Drop, Wait,
Pick
DestinationTime to
Destination (sec)
Action at DESTINATIO
N: 1) Pick only, 2) Drop Only, 3) Drop, Wait,
Pick
Scenario 01 1 Tank 01 10 3 Tank 04 10 1 Tank 08 10 22 Tank 02 10 2 Tank 05 10 2 Tank 06 10 13 Tank 01 10 4 Tank 03 10 1 Tank 07 10 24 Stage 10 1 Tank 04 10 2 Tank 06 10 45 Tank 02 10 1 Tank 05 10 16 Tank 03 10 2 Tank 06 10 27 Tank 07 10 18
9
10
Crane 1 Crane 2 Crane 3
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Spreadsheet - Crane Timing
The spreadsheet also identified the crane movement and processing times for the model.
Operation Stage PreClean Clean RinseRinse & Activator
Zinc Phosphate Rinse Rinse DI Rinse E-Coat Rinse 1 Rinse 2 Transfer
Tank - 1 2 3 4 5a 5 6 7 8 9a 9 10 11 -
for simulation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Down 0 30 30 30 25 0 25 25 25 25 0 25 24 24 13
In Tank 0 100 100 58 100 0 108 58 88 100 0 120 30 30 0
Up 12 12 12 12 12 0 12 12 12 12 0 12 12 12 0
Drain 0 10 10 10 10 0 10 10 10 10 0 20 15 30 0
Transfer 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
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Flex Design Principle #2
Create “toggles” in the model to turn on and off elements “on the fly”
In our model, we could manually turn off paint booths during the model run by manually setting certain key variables. This allowed us to rapidly experiment with how the system reacted to downtime or less available stations.
Example: “wait until stop_paint2=0 #for manual shutdown of paint line”
Epicenterwww.epicentergroup.com 216.702.0952
Flex Design Principle #3
Use “rules-of-thumb” that govern how information is used
Instead of hard-coding the model to handle every scenario, we used “rules-of-thumb” logic. This allowed the model to adjust to most scenarios (ex: rules to handle “traffic control” for carriers in the system)
Epicenterwww.epicentergroup.com 216.702.0952
Flex Design Principle #3#part is e-coat only and zone is free and Stop19 queue is open
If zlock[3,1]=0 and color=0 and size<3 and partcounter[(loc(l_Stop_19_Q_1))]+partcounter[(loc(l_Stop_19))]<2 then
Begin
zlock[3,1]=1
Nextroute=1
Route 1
Goto L2
End
#part is e-coat only and zone is free and Stop19 queue is not open - send through topcoat
If zlock[3,1]=0 and color=0 and size<3 and partcounter[loc((l_Stop_20_Q_1))]+partcounter[loc((l_Stop_20))]<2 then
Begin
zlock[3,1]=1
Nextroute=3 #send through topcoat
Route 1
Goto L2
End
#part is e-coat only and zone is free and Stop19 queue is not open and paint is backed up - send to paint overflow queue
If zlock[3,1]=0 and color=0 and size<3 and partcounter[(loc(l_Stop_07_Q_1))]+partcounter[(loc(l_Stop_07))]<2 and size<3 and (paintoverflow_counter<paintoverflow_target or offshift>0) then
Begin
zlock[3,1]=1
Nextroute=4 #to paint queue
Route 1
Goto L2
End
Epicenterwww.epicentergroup.com 216.702.0952
Flex Design Principle #4
Use subroutines so changes can be made more globally when necessary.
Subroutines give you single point control over general model functions.
Epicenterwww.epicentergroup.com 216.702.0952
Flex Design Principle #4#####This is a multi-purpose subroutine for chain delays
##s_stop_delay(stopped, queue_index, chain_trans, stop_point)
# "stopped" is whether the unit stopped due to non-queue backups.
# "queue_index" is the index of the next conveyor to consider for queue delays
# "chain_trans" is whether there is a chain transfer involved in the move. This will always happen
# "stop_point" says that this is a stop point - if there is a queue delay then we need to do a full start
###########start with whether we need to chain delay or not
L1:
If queue_index=0 then goto L2 #skip conveyor release delay step
If clock(min)-Zone_Delay[queue_index,1]<Std_queue_delay then #wait if turned on(queue_index>0) or part is in next zone
Begin
wait .03 #wait 2 seconds and check again
If stop_point=1 then stopped=1 #if we had to wait, then there is a stop delay
Goto L1
end
##########
L2:
If stopped=1 then wait rand(STD_Stop_Delay_Max) min #we must do a chain start
If chain_trans=1 then wait rand(STD_Chain_Delay_Max) min #we must do a chain to chain wait
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Flex Design Principle #5
Keep things simple! (K.I.S.S. Principle)
Our goal is always to use the simplest logic necessary to “get the job done”. Although we have several model locations, most P&F locations used the same operation logic with minor variations.
#Index 20, next index 21s_stop_delay(0,21,0,0) #forced to stop, next index, chain trans?, stop point?
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Project Results
1. The model was used by the material handling engineers to redesign and validate the new paint system. The model logic was used as the basis for the new PLC logic
2. The new paint system was installed on time to handle the planned volume increase (and works!)
3. The model avoided the cost of a $500,000 crane upgrade.
4. Case New Holland has a model that can be used to experiment on the paint system for future improvements.