PEMILIHAN PROSES MANUFAKTUR (From Design to Manufacture)

PEMILIHAN PROSES

MANUFAKTUR

(From Design to Manufacture)

Dr. M.K. Herliansyah, ST. MT.

Program Studi Teknik Industri Jurusan Teknik Mesin dan Industri Fakultas Teknik Universitas Gadjah Mada 2010

Alasan Pemilihan Proses Manufaktur:

♦ Hasil sesuai Yang Diinginkan

♦ Efisien

♦ Murah

♦ Cepat

Permasalahan :

• Kompetisi / persaingan ketat • Harapan konsumen yang

semakin tinggi

Bisnis Manufaktur

• Memperbaiki kualitas • Harga jual murah

• Penyediaan yang cepat

¾ Menaikkan efisiensi

¾ Perbaikan kualitas ¾ Investasi/otomatisasi ¾ Penurunan cost

¾ Mesin-mesin yang advance

¾ Pemilihan proses yang tepat (efisien + ekonomis) ¾ Teknologi dan biaya perancangan

MANUFACTURING INFORMATION FOR DESIGN

♦Produk mengalami perubahan sebelum sampai ke konsumen

♦ Faktor-faktor Pertimbangan Dalam Pemilihan Proses Manufaktur :

a. Jumlah produk

b. Biaya peralatan (equipment) c. Biaya tooling

d. Waktu proses

e. Intensitas pekerja f. Supervisi – proses g. Perawatan

Cont’

i. Biaya material + ketersediaannya j. Bentuk dan dimensi komponen k. Toleransi yang diperlukan

l. Surface finish m. Bulk treatment

n. Keragaman komponen o. Limbah/sisa

♦ Agar produk yang dihasilkan kompetitif, identifikasi fisibilitas teknologi dan ekonomi dari kombinasi proses manufaktur dan bahan, E X A M P L E

A PROCESS SELECTION STRATEGY

♦ diperlukan suatu metode atau alat untuk memilih

proses yang sesuai dan mengestimasi biaya se-awal mungkin.

♦ PRIMA (Process Information Maps) bertujuan : – memberikan informasi mengenai proses yang

Strategi

!!!

a. Tentukan atau perkirakan kuantitas produk dalam setahun

b. Pilihlah bahan yang sesuai dengan spesifikasi desain c. Pilihlah alternative proses yang sesuai menurut PRIMAs

d. Pertimbangkan setiap alternative tersebut berdasarkan persyaratan engineering dan ekonomi:

i. Mengerti proses dan variasinya

ii. Mempertimbangkan kesesuaian bahan dan proses

iii. Assess conformance of component concept with design rules

iv. Compare tolerance and surface finish requirements with process capability data

Cont’

e. Mempertimbangkan posisi ekonomi dari proses

dan dapatkan estimasi biaya komponen dari setiap alternative

f. Sesuaikan proses manufaktur yang telah dipilih

Design for X Topics

♦ Design for Manufacturing

♦ Design for Assembly

♦ Design for Production

♦ Design for Recycling/Disposal

♦ Design for Life Cycle

♦ Prototyping

Gathering DFM Information

♦ Design documents:

– Sketches, – Drawings,

– Spesifikasi produk, dan

– Alternatif-alternatif desain.

♦ Pemahaman dan informasi detil mengenai proses produksi dan perakitan/assembly

♦ Perkiraan:

– manufacturing costs, – production volumes, dan – ramp-up timing.

DFM Method

♦ Memperkirakan manufacturing costs.

♦ Mengurangi biaya-biaya untuk

mempersiapkan/pembuatan components.

♦ Mengurangi biaya-biaya untuk proses perakitan/assembly.

♦ Mengurangi biaya-biaya pendukung proses production.

♦ Mempertimbangkan dampak/pengaruh DFM decisions pada faktor-faktor yang lain.

DFM Method

Reduce the Cost of Supporting Production

Consider the Impact of DFM Decisions on Other Factors Proposed Design

Estimate The Manufacturing Cost

Reduce the Cost of Components

Reduce the Cost of Assembly

Recompute the Manufacturing Costs

Good Enough ?

N

Y

Estimate the Manufacturing Costs

Finished Goods

Manufacturing System

Equipment Information Tooling

Waste Services Supplies Energy Raw Materials Labor Purchased Components

Manufacturing Costs Defined

• Menghitung seluruh pengeluaran untuk

input system (sebagai contoh: pembelian

komponen-komponen, energi, raw materials, dan lain-lain) dan pengeluaran untuk

penanganan limbah yang dihasilkan oleh sistem.

Elements of the Manufacturing Cost

of a Product

Manufacturing Cost Overhead Assembly Components

Standard Custom Labor Equipment

and Tooling Support

Indirect Allocation

Raw

Manufacturing Cost of a Product

♦ Component Costs (komponen-komponen dari produk yang dibuat)

– Komponen-komponen yang dibeli dari supplier

– Custom parts yang dibuat didalam shop floor-nya sendiri atau shop floor para supplier sesuai dengan spesifikasi desain dari manufacturer’s

♦ Assembly Costs (labor, equipment, & tooling)

♦ Overhead Costs (all other costs)

– Support Costs (material handling, quality assurance, purchasing, shipping, receiving, facilities, etc.)

– Indirect Allocations (tidak berhubungan secara langsung dengan suatu particular product tetapi harus dibayar

Fixed Costs vs. Variable Costs

♦ Fixed Costs – ditentukan terlebih dahulu dalam suatu jumlah tertentu tanpa

memperhatikan jumlah unit yang diproduksi (i.e. setting up the factory work area or cost of an injection mold)

♦ Variable Costs – ditentukan secara

langsung dalam jumlah yang proporsional dengan jumlah unit yang diproduksi (i.e. cost of raw materials)

Reduce the Cost of Components

1. Understand the Process Constraints and

Cost Drivers

2. Redesign Components to Eliminate

Processing Steps

3. Choose the Appropriate Economic Scale

for the Part Process

4. Standardize Components and Processes 5. Adhere to “Black Box” Component

Redesign costly parts with the same performance while avoiding high

manufacturing costs.

Work closely with design engineers—raise awareness of difficult operations and high costs.

1. Understand the Process Constraints

and Cost Drivers

2. Redesign Components to Eliminate

Processing Steps

♦ Reduce the number of steps of the production process

– Will usually result in reduce costs

♦ Eliminate unnecessary steps.

♦ Use substitution steps, where applicable.

♦ Analysis Tool – Process Flow Chart and Value Stream Mapping

3. Choose the Appropriate Economic

Scale for the Part Process

Economies of Scale – As production volume increases, manufacturing costs usually

decrease.

♦ Fixed costs divided among more units.

♦ Variable costs are lower since the firm can use more efficient processes and equipment.

4. Standardize Components and

Processes

♦ Economies of Scale – The unit cost of a component decreases as the production volume increases.

♦ Standard Components—common to more than one product

♦ Analysis tools – group technology and mass customization

5. Adhere to “Black Box” Component

Procurement

♦ Black box—only give a description of what the component has to do, not how to

achieve it

♦ Successful black box design requires clear definitions of the functions, interfaces, and interactions of each component.

DFM Tools and Methodology

ƒ Tools and Methodologies

ƒ Design For Assembly (DFA), (IBM experience) ƒ Failure Mode and Effect Analysis (FMEA), (Sun

example)

ƒ Taguchi Method, (Hitachi experience)

ƒ Value Analysis--”Value Engineering” (HP example) ƒ Quality Function Deployment (QFD), Going to the

Gemba (Hitachi)

ƒ Group Technology, (IBM example)

ƒ Cost management and optimization, SPC, Six-Sigma (Motorola), TQC, etc

DFA Systems

♦ Boothroyd Dewhurst DFM & A

♦ Munro & Assoc. (Design Prophet/Profit)

Commercial Airplanes - Military Aircraft & Missiles - Space & Communications - Air Traffic Management - Boeing Capital Corporation - Shared Services Group - Phantom Works

DFM Tools: DFA Guidelines

- Standard parts (one screw type)

- Parts are self-guiding

-Die cast with minimal amount of

holes (debris chip)

-Standard cutters -Guide features

- Common datum’s for all fixtures

-One common plane for assembly - Tabs for robotic lift

- One assembly direction “tops down”

-No adjustments required -No hidden features

- bottom rails for conveyor - Test direction access from top

- Easy to fabricate parts

- Sub-assemblies reduce handling of small hard to grip

parts - Symmetry in two axis

- Holes large enough

(straightness issues if too deep)

- Avoid tangle with use of fixtures

DFM Tools: DFA Guidelines

ƒ Summary of DFA Guidelines

1. Minimize the number of parts

2. Standardize and use as many common parts as possible

3. Design parts for ease of fabrication (use castings without machining and stampings without bend) 4. Minimize the number of assembly planes (Z-axis) 5. Use standard cutters, drills, tools

6. Avoid small holes (chips, straightness, debris) 7. Use common datum’s for tooling fixtures

8. Minimize assembly directions

DFM Tools: DFA Guidelines

ƒ

Summary of DFA Guidelines

10. Minimize handling 11. Eliminate adjustments

12. Use repeatable, well understood processes 13. Design parts for efficient testing

14. Avoid hidden features 15. Use Guide features

16. Incorporate symmetry in both axis 17. Avoid designs that will tangle.

DFM Tools and Methodology

ƒ FMEA (Failure Mode and Effects Analysis)

ƒ Method for analyzing the causes and effects of failures.

ƒ Highlights designs and assemblies most likely to cause failures.

ƒ Helps identify and prioritize corrective action

ƒ Indicates where the most improvement in terms of severity, frequency, and detectability can be made. ƒ Widely used manufacturing technique (Mil

Reduce the Costs of Assembly

1. Design for Assembly (DFA) index

2. Integrated Parts (Advantages and

Disadvantages)

3. Maximize Ease of Assembly 4. Consider Customer Assembly

1. Design for Assembly Index

DFA index =

(Theoretical minimum number of parts) x (3 seconds)

Determining the Theoretical Minimum

Number of Parts

♦ Does the part need to move relative to the rest of the assembly?

♦ Must the part be made of a different

material from the rest of the assembly for fundamental physical reasons?

♦ Does the part have to be separated from the assembly for assembly access, replacement, or repair?

2. Advantages of Integrated Parts

♦ Do not have to be assembled

♦ Often less expensive to fabricate rather than the sum of each individual part

♦ Allows critical geometric features to be controlled by the part fabrication process versus a similar assembly process

2. Disadvantages of Integrated Parts

♦ Conflict with other sound approaches to minimize costs

3. Maximize Ease of Assembly

♦ Part is inserted from the top of the assembly

♦ Part is self-aligning

♦ Part does not need to be oriented

♦ Part requires only one hand for assembly

♦ Part requires no tools

♦ Part is assembled in a single, linear motion

4. Consider Customer Assembly

♦ Customers will tolerate some assembly

♦ Design product so that customers can easily and assemble correctly

Reduce the Costs of Supporting

Production

♦ Minimize Systemic Complexity (inputs, outputs, and transforming processes)

– Use smart design decisions

♦ Error Proofing (Poka Yoke)

– Anticipate possible failure modes

– Take appropriate corrective actions in the early stages

– Use color coding to easily identify similar looking, but different parts

Consider the Impact of DFM

Decisions on Other Factors

♦ Development Time

♦ Development Cost

♦ Product Quality

♦ External Factors

– Component reuse – Life cycle costs

DFM&A Road Map

♦ Membentuk sebuah multifunctional team

♦ Menetapkan sasaran produk melalui competitive

benchmarking

♦ Melakukan DFA analysis

♦ Melakukan segmentasi produk hingga mencapai

manageable subassemblies atau levels of assembly

♦ Sebagai sebuah team, menggunakan prinsip-prinsip DFA

♦ Menggunakan teknik-teknik kreatif untuk meningkatkan

desain yang dihasilkan

♦ Sebagai sebuah team, melakukan evaluasi dan memilih ide

rancangan yang terbaik

♦ Memastikan bahwa setiap bagian komponen diproduksi

pada level yang ekonomis

♦ Menentukan target cost untuk setiap komponen dalam

TERIMA KASIH

ATAS PERHATIAN DAN KERJASAMANYA

Dr. Muhammad K. Herliansyah, ST. MT.

mkherliansyah@gadjahmada.edu herliansyah@ugm.ac.id http://herliansyah.staff.ugm.ac.id