Lean Manufacturing

“A philosophy of production that emphasizes the minimization of the amount of all the resources (including time) used in the various activities of the enterprise.” - APICS Dictionary, 10th ed.

Sebuah filosofi produksi yang menekankan minimisasi jumlah semua sumber daya (termasuk waktu) yang digunakan didalam berbagai aktifitas perusahaan

“An enterprise with a focus on waste elimination and the customer’s needs in all parts of its operations, manufacturing and administration. Emphasis is given to lean structures and processes, flexibility of response and methods and techniques to continually seize new opportunities as they arise.”  -  APICS Lean SIG

Sebuah perusahaan yang berfokus pada penghilangan limbah dan kebutuhan konsumen pada semua operasi, pabrikasi dan admistrasi

History

Sakichi Toyoda, pendiri Toyota group memulai bisnis Toyota sebagai perusahaan mesin tekstil.

Kiichiro Toyoda, anak Sakichi dan pendiri perusahaan mobil Toyota, mengembangkan konsep JIT pada tahun 1930. Toyota tidak mengijinkan persediaan yang berlebih dan menjalin partneship dengan suplier sampai pada tingkat operasional. 

Taiichi Ohno dan Dr. Shigeo Shingo mengembangkanToyota Production System (TPS). 

Toyota Production System (TPS)

Definition: The production system developed by Toyota Motor Corporation to provide best quality, lowest cost, and shortest lead time through the elimination of waste. 

Sistem produksi yang dikembangkan oleh Toyota untuk menghasilkan kualitas terbaik, biaya terendah dan lead time lebih cepat melalui eliminasi limbah.

TPS dibangun dengan dua pilar yaitu, Just-in-Time and Jidoka (autonomation) , 
TPS dikelola dan diperbaiki melalui iterasi standart kerja dan kaizen  (continuous improvement), following Plan–Do-Check-Act (PDCA Cycle from Dr. Deming), or the scientific method.

How to make money?

Profit : Sales – Cost = Profit

Traditional pricing strategy: Cost + Profit = Selling price

Example: 

Jika biaya naik, harga jual akan naik yang menunjukkan biaya yang lebih tinggi dan keuntungan. 
Profit harus cukup besar untuk mengcover potensial kerugian jika penjualan produk jelek.

Toyota tidak dapat menerima kedua argumen tersebut.

Toyota’s philosophy

Selling price – Cost = Profit 
Konsumen menentukan harga jual.
Profit merupakan selisih antara harga jual dan cost.
Untuk meningkatkan profit maka harus menurunkan cost.
Consequently, pengurangan biaya melalui eliminasi limbah merupakan prioritas utama.
Mengurangi cost (waste), akan mengurangi lead time dan meningkatkan kualitas dan kepuasan pelanggan 

What is Lean?

It is NOT:
Collection of techniques or a methodology
Reduced staffing or low inventories

It IS:
A philosophy of manufacturing
Totally different way of thinking 
A different value system
Seeks to eliminate waste (non-value added activities to the customer)‏
Emphasis on flow manufacturing

Basic Lean Manufacturing Principles
Lean manufacturing mendefinisikan nilai (value) dari sebuah produk atau jasa dilihat dari sisi konsumen.
Konsumen akan menilai apakah produk yang dibeli dapat memenuhi kebutuhannya
Konsumen tidak peduli dengan proses membuat produk
Produk yang kita jual harus bagus dan murah

Lean Thinking Principles
Accurately specify the value of the products or services (applies to both factory and office areas, not just to manufacturing).
Identify the value stream for each product or service and remove wasted actions (muda).
Make the product or service value flow without interruptions.
Let customers pull products or services from the producer.
Pursue perfection and continuously improve.

Lean Characteristics
Focus is on the improvement of resource utilization:
―  Equipment setup time reduced (mengurangi waktu setup)‏
―  Scheduled machine maintenance (jadwal perawatan)‏
―  Orderly, clean workplace (tempat kerja yang bersih)‏
―  Pull production being used (sistem produksi tarik)‏
―  JIT inventory control 
―  Factory layout in work cell arrangement by products (Tata letak 
             pabrik)‏
―  Active error elimination (pengurangan kesalahan)‏
―  Improved quality, etc.(perbaikan kualitas)‏

The Importance of Waste Elimination
Lean deals with the elimination or reduction of many types of non-value-added activities, often referred to as waste

The driving force for waste elimination is improved value in the products and services customers buy

The Nature of Wastes

1. Overproduction
Target and achievement unclear (target tidak jelas)‏
Processes not statistically capable (kemampuan proses tidak bagus)‏

2. Waiting
Operators waiting (operator yang menunggu)‏
Operators slower than production line (kerja operator lebih lambat dari mesin)‏

3. Excessive Transportation
Widely spaced equipment waiting (jarak antar mesin jauh)‏
Forklifts not available when needed (alat angkut tidak tersedia)‏

4. Inappropriate Processing
Variability in operator’s performance (variabilitas kemampuan operator)‏
Processes not statistically capable (kemampuan proses tidak baik)‏

5. Inventory
Large safety stocks (stok terlalu banyak)‏
Variable procurement lead times (lead time tidak pasti)‏

6. Motion
Double handling 
Non-standard layouts (tata letak mesin tidak standart)‏
Equipment widely spaced from each other (jarak antar mesin jauh)‏

7. Defects
Low material yields (bahan baku tidak bagus)‏
Excessive process variability

Correcting Wastes

1. Overproduction
Eliminate by reducing setup times. (mengurangi waktu setup)‏
Synchronizing quantities and timing between processes.(jumlah produksi disesuaikan)‏
Make only what is needed now.(memproduksi sesuai dengan yang dibutuhkan)‏

2. Waiting
Eliminate through synchronizing work flow.(aliran kerja disesuaikan)‏
Balancing uneven loads with flexible workers and equipment.(seimbangkan beban keraj pekerja dan mesin)

3. Excessive Transportation
Establish layouts and locations to make transport and handling unnecessary, if possible.(susun ulang tata letak)‏

4. Inappropriate Processing
Why should this item be made?
Why is each process necessary?
Are any processes being performed that are not part of the work flow?

5. Inventory
Reduce by shortening setup times.(mempercepat setup time)‏
Improving work skills. (meningkatkakn ketrampilan kerja)‏
Smoothing fluctuations in demand for the product.(memperkecil fluktuasi permintaan)‏
Reducing all the other wastes reduces the waste in stocks.(mengurangi waste yang lain akan mengurangi inventory waste)‏

6. Motion
Study motion for economy and consistency.(studi gerakan)‏
Economy improves productivity, and consistency improves quality. 
Improve the motions, then mechanize or automate. Otherwise, there is a danger of automating waste.

7. Defects
Develop the production process to prevent defects.(kembangkan proses produksi yang mencegah cacat)‏
Eliminate the need for inspection. At each process, produce no defects. (minimasi inspeksi)‏
Design processes to be failsafe (Poka yoke).
Quality processes yields quality products – automatically (proses baik hasil baik).

Seven Additional Wastes within Manufacturing
Wasted power and energy
Wasted human potential
Environmental pollution
Unnecessary overhead
Inappropriate design
Departmental culture
Inappropriate information


Sumber : Pertemuan Surabaya Study Group