process flow measures - isyesman/courses/2030/lecture2_materialflownor… · basic pattern of job...
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Process Flow Measures
Roadmap
• Flows and Processes• Capacity required to support flows
and processes• Amount of material in flows and
processes• Length of time material is in flows
and processes
How does an IE understand Norcen Industries?By focusing on the material
flows, and information flows.
Important Terminology(domain knowledge)
• Part (part number, part type, sku)• Customer order--one or more part types• Job -- the basic unit of material flow, one
or more parts• Process -- basic unit of conversion capacity• Operation -- particular conversion
performed at a particular process for a particular part
More Terminology
• Process sheet--sequence of conversion operations for a specific part
• Job sheet--history of a specific job• Time card--record of time charged by a
specific worker to specific jobs• Record card--history of orders for a
specific part type from a specific customer, with PO number for each order
Process SheetTechnical data Work standards
Process Sheet
• Tells us what conversion steps are required, and in what order– Q: is this order unique?
• Tells us how long each conversion operation should take
• Does not tell us how long it takes to complete the job!– Q: why not?
Turning
Grinding
Sawing
Milling
Drilling & Deburring
Prep
Inspect
Ship
Figure B7 in Tour B illustrates processes (conversions) for “typical” part
Prep Mill Grind Inspect& Ship
Turn
Turning
Grinding
Sawing
Milling
Drilling & Deburring
Prep
Inspect
Ship
Basic pattern of Job Shop Material Flow
Delay
Setup timeRun time
Transport Time
“Standards”
No “Standards”
Time at this operation = WaitIn + Setup + Run + WaitOut + Transport
Manufacturing Cycle Time(Job Flow Time)
MCT = Σ (WaitIn + Waitout) + Σ (Setup + Run)
+ Σ Transport
ReleaseTime + MCT = DeliveryTime
DeliveryTime - DueDate = Earliness/Lateness
Flow Process Chart
JobChart beginsChart endsChart byDate
Ope
ratio
n Details of Operation Present
Proposed
Ope
ratio
n
Tran
spor
t
Insp
ectio
n
Del
ay
Sto
rage
Dis
tanc
e (ft
)
Qua
ntity
Tim
e
Notes
Process Flow Chart*
* standard “IE” tool
Turning
Grinding
Sawing
Milling
Drilling & Deburring
Prep
Inspect
Ship
Flow Process ChartJobChart beginsChart endsChart byDate
Ope
ratio
n Details of Operation Present
Proposed
Ope
ratio
n
Tran
spor
t
Insp
ectio
n
Dela
y
Stor
age
Dist
ance
(ft)
Qua
ntity
Tim
e
Notes
Prep materials 100
Move to Turning Dept 75
100 2 hour setup time
Turnco Lathe #3
Supervisor inspection 100
Move to Milling Dept
80
Millco Mill #1
Move to Grinding Dept 65
See sheet b for rework process
Grindco Grinder A
Move to QC Department 30
QC sampling inspection
Move to Shipping 100
Pack
Ship
Process Flow Chart
• Documents all the transactionsinvolved in completing a job
• Allows computing the “theoretical” job time, from the standards
• Identifies the delays that must be accounted for
• Provides the basis for estimating actual MCT
Sample of 41 jobs from last week
P T M G I/S 32
P T M G I/S 3
P T M G I/S 3
P T M G I/S 3
What is the total material flow?
From/To Chart*F\T Prep Turn Mill Grind Ins/Ship OutsPrep 32 9 41Turn 32+3=35 3 38Mill 3 32+3+3+3=41 44Grind 3 32+3+3+3=41 44Insp/ShipIns 38 44 44 41 167
What do we learn from this?
* standard “IE” tool
Estimating Mover Capacity
• Suppose jobs moved one-at-a-time by lift truck
• How many “lift truck hours” per day were required?
• Note: lift trucks travel loaded and unloaded
• Visualize lift truck operations...
Estimating Mover Capacity
• Distance traveled unloaded (from last delivery)
• Distance traveled loaded (origin to destination)
• Time required to pick up and set down• Time required to travel, based on velocity
Requires “Standards”
Summary
• Process modeling– input, output, resources– process sheets– process flow charts
• Estimating mover capacity requirement