Pengantar Perencanaan
Tata - Letak
D0052 Pengantar Sistem dan Teknik Industri
Universitas Bina Nusantara
Revised 2002
Brief History of Plant Layout
• Perusahaan – perusahaan masa lalu menggunakan
tenaga ‘draftsperson’ untuk melengkapi tata letak
pabrik.
• The general belief was that there was a void of
expertise in facility layout design.
• Problems could be overcome with an extra forklift or
conveyor length.
Plant Layout
QC
Raw Stock
Shear
Stamp
Screw
Machine
Lathe
Brake
Mill
Weld
Grind
Drill
Finish
Ship
Rec
QC
Assembly
Parts Stock
Impact of Poor Plant Layout
• Tingginya biaya ‘material handling’.
• Keterlambatan siklus waktu dan ‘lead
•
•
•
•
•
•
•
time’.
Persediaan WIP tinggi
Mutu rendah.
Kerusakan produk.
Masalah keamanan dan moral.
Utilitas peralatan rendah.
Congested aisles
Ruang yang tidak digunakan.
Bagaimana memperbaikinya?
Lean Manufacturing dan Cellular Flow
Sebelum:
6 Assemblers
Batch Assembly
C/T 4.5 days
How Can We Improve?
Lean Manufacturing dan Cellular Flow
Sesudah:
6 Assemblers
Flow / Pull
C/T 53 minutes
Facility Improvement Pitfalls
•
•
•
•
Poorly planned layout
Lack of employee involvement
Lack of management commitment
Budgetary constraints leading to a “piecemeal”
approach
• Focus on the almighty ROI versus the future of the
business
• Short term management focus
Manufacturing Savings
Where can we save costs in manufacturing?
Reduce or Eliminate• Work-in-process inventories (WIP)
• Non-value added activities
• Material handling costs
• Processing time
• Product defects
Manufacturing Savings
The largest components of factory labor and the
cost of materials purchased and used in a
factory are:
• Internal transportation costs
• Material handling costs
• Storage costs
This includes both our manufacturing plants
and those of our suppliers!
Facilities Layout Goals
• Goals should include:
– Minimize unit cost. Minimize project cost.
– Optimize quality.
– Promote the effective use of (a) people, (b) space,
(c) equipment, and (d) energy.
– Provide for (a) employee convenience, (b)
employee safety, and (c) employee comfort.
– Control project cost.
– Achieve the production start date.
– Build flexibility into the plan.
– Reduce or eliminate excessive inventory.
– Achieve miscellaneous goals.
Five Types of Facility Design Projects
1. New Facility – fewer restrictions and constraints on
the layout since it is new
2. New Product – integration of a new product into the
existing process and layout
3. Design Changes – incorporate the impact of design
changes into the manufacturing process
4. Cost Reduction – redesign the existing layout to
facilitate cost reduction programs and ideas
5. Retrofit – similar to a new facility layout except with
the constraints present
Cycle Times and Materials Handling
Old Adage:
“the smaller the lot size, the higher the materials handling
and setup costs”
“the faster the assembly line conveyor speed, the higher the
production output”
Response:
Ask the right answer and get the right question . . .
Focus on the true problems that prevent smaller lot
sizes and faster production speeds.
Cycle Times and Materials Handling
Getting the right answer to the right question. . .
Range
width
30 in.
30 in.
Typical
Speed
= 60 in. / 18 sec
= 200 in. / min
Units / shift:
60 sec / cycle time per unit = 60 / 18 = 3.33 units per minute
3.33 units per minute X 60 minutes X 7 hours = 1400 units / shift
Cycle Times and Materials Handling
Getting the right answer to the right question. . .
12 in.
Typical
Range
width
30 in.
Speed
= 42 in. / 15 sec
= 168 in. / min
Units / shift:
60 sec / cycle time per unit = 60 / 15 = 4 units per minute
4 units per minute X 60 minutes X 7 hours = 1680 units / shift
Cycle Times and Materials Handling
The right question was how to increasing production
while reducing cycle time. . .the wrong answer was
speeding up the line!
Results:
1,680 / 1,400 = 1.2 = 20% Production Increase
Materials Handling
• Materials handling is a non-value activity that your
customer is unwilling to pay for.
• Constantly question material handling methods and
manufacturing methods. . . your competitors do!
• Just because you “have always done it that way” does
not make it right.
Materials Handling Mistakes
A Local Company’s Materials Handling Process-
Step 1Begin
Assemblies
Step 2Move to WIP
Warehouse
Step 3Store in WIP
Warehouse
Step 4Move back to
Manufacturing
WAREHOUSE
Materials Handling Mistakes
Local Company’s Materials Handling ProcessStep 6Back to the
Warehouse
Step 5Begin
Assembly
Continue Until
Complete
36 Trailers / Day
WAREHOUSE
Materials Handling Mistakes
Company Results:
• Material was handled so much that damage was inevitable.
• Their customer began penalizing them $100 per damaged
part received due to the poor finished goods quality.
• The materials handling inefficiencies manifested
themselves in higher product costs, larger amounts of WIP,
poor product quality and longer lead times.
• The parts were inspected eight (8) times on average,
product yield was a dismal 60%.
• A reduction in two (2) inspections steps generated over $1M
in annual savings. . .the right question should have been
“Why are we moving these parts so much?”
Materials Handling Example
Electric Lift Hoist
Fabric Rolls in
Excess of 100#
Key Manufacturing Fundamentals
Four Fundamental Customer Expectations:
1. Product Quality
2. Delivery as scheduled / requested
3. Flexibility to handle change and service
4. Low $$$
One method to achieve this is by
implementing Lean Manufacturing principles
Benefits of Lean
Percentage of Benefits Achieved
0
Lead Time Reduction
Productivity Increase
WIP Reduction
Quality Improvement
Space Utilization
25
50
75
100