Just In Time

Just In Time

Prinsip dari JIT sangat sederhana, yaitu produksi hanya apabila ada permintaan (pull system) atau dengan kata lain hanya memproduksi sesuatu yang diminta dan hanya sebesar kuatitas yang diminta. Filosofi JIT digunakan pertama kali oleh Toyota dan kemudian diadopsi oleh banyak perusahaan manufaktur dijepang .

Bila JIT merupakan suatau filosofi manajemen operasi yang berusaha untuk menghilangkan pemborosan pada semua aspek dari kegiatan-kegiatan produksi perusahaan. Sasaran utama JIT adalah menngkatkan produktivitas system produksi atau opersi dengan cara nenghilangkan semua macam kegiatan yang tidak menembah nilai bagi suatui produk.

Dengan system ini diharapkan mendapatkan kualitas, menekan biaya, dan mencapai waktu penyerahan seefisien mungkin dengan menghapus seluruh jenis pemborosan yang terdapat dalam proses produksi sehingga perusahaan mampu menyerahkan produknya (baik barang maupun jasa) sesuai kehendak konsumen tepat waktu.Untuk mencapai sasaran dari sistem ini, perusahaan memproduksi hanya sebanyak jumlah yang dibutuhkan/diminta konsumen dan pada saat dibutuhkan sehingga dapat mengurangi biaya pemeliharaan maupun menekan kemungkinan kerusakan atau kerugian akibat menimbun barang.

Sistem ini dirintis oleh Toyota Motor Corporation dan dikenal juga dengan Sistem Produksi Toyota, yang kemudian dikenal juga dengan istilah Sistem Produksi Ramping (Lean Production System) dan sistem kanban.

Konsep Just In Ti me (JIT) adalah sistem manajemen fabrikasi modern yang dikembangkan oleh perusahaan-perusahaan terbaik yang ada di Jepang, sejak awal tahun 1970an, JIT pertama kali dikembangkan dan disempurnakan di pabrik Toyota Manufacturing oleh Taiichi Ohno, oleh karena itu Taiichi Ohno sering disebut sebagai bapak JIT, Konsep JIT berprinsip hanya memproduksi  jenis-jenis barang yang diminta (what) sejumlah yang diperlukan (How much) dan pada saat dibutuhkan (When) oleh konsumen.

Prinsip dasar Just In Time adalah peningkatan kemampuan perusahaan secara terus menerus untuk merespon perubahan dengan minimisasi pemborosan. Terdapat empat aspek pokok dalam konsep Just In Time yaitu:
1. Menghilangkan semua aktifitas atau sumber-sumber yang tidak memberikan nilai tambah terhadap produk atau jasa.
2. Komitmen terhadap kualitas prima.
3. Mendorong perbaikan berkesinambungan untuk meningkatkan efisiensi.
4. Memberikan tekanan pada penyederhanaan aktivitas dan peningkatan visibilitas aktivitas yang memberikan nilai tambah.

Just In Time (JIT)

Reducing Inventory, Minimizing Waste, and Responding to Your Customers

When is the best time to have an inventory part ready for production?

– Just in time.

When is the best time to have an item ready for the next step in production?

– Just in time.

When is the best time to have a product ready for delivery to a customer?

– Just in time.

So why do manufacturers build inventory of both finished goods and raw materials?

– Just in case!

A buffer of inventory on hand is comforting – and costly.

If you hold a lot of items in inventory, you're locking away a huge amount of cash unnecessarily. These items can be lost, stolen, or damaged, or they can deteriorate. They occupy space, which could otherwise be devoted to operations. And they can become obsolete, particularly when products are improved or changed often (many of us can remember images of airfields full of unwanted, obsolete cars from the 1970s and 1980s.) All of this represents financial loss to the business.

In the 1970s, when Japanese manufacturing companies were trying to perfect their systems, Taiichi Ohno of Toyota developed a guiding philosophy for manufacturing that minimized waste and improved quality. Called Just In Time (JIT), this philosophy advocates a lean approach to production, and uses many tools to achieve this overall goal.

When items are ready just in time, they aren't sitting idle and taking up space. This means that they aren't costing you anything to hold onto them, and they're not becoming obsolete or deteriorating. However, without the buffer of having items in stock, you must tightly control your manufacturing process so that parts are ready when you need them.

When you do (and JIT helps you do this) you can be very responsive to customer orders – after all, you have no stake in "forcing" customers to have one particular product, just because you have a warehouse full of parts that need to be used up. And you have no stake in trying to persuade customers to take an obsolete model just because it's sitting in stock.

The key benefits of JIT are:

• Low inventory
• Low wastage
• High quality production
• High customer responsiveness.

The JIT Strategy

By taking a JIT approach to inventory and product handling, companies can often cut costs significantly. Inventory costs contribute heavily to the company expenses, especially in manufacturing organizations. By minimizing the amount of inventory you hold, you save space, free up cash resources, and reduce the waste that comes from obsolescence.

JIT Systems

To facilitate a JIT approach, you need a variety of systems in place. The most notable is a kanban  . This is a Japanese approach to ensuring a continuous supply of inventory or product. Kanbans were designed to support the JIT philosophy.

A kanban is a visual signal that indicates it is time to replenish stock and possibly reorder. For instance, as the supply of bolts in a bin on the assembly line falls below a certain number, it may uncover a yellow line painted around the inside of the storage bin. This yellow line indicates to the foreman that he needs to prepare a requisition for more bolts. That requisition is given to the purchasing department, which processes the order. This prevents the supply of bolts from dropping below a critical amount and allows production continues to flow smoothly. To read more on kanban, click here   for the Mind Tools article on it.

JIT also exists in concert with continuous improvement systems. Total Quality Management   and Six Sigma are overarching programs that help you take a detailed look at every point of the production process and identify ways to make improvements. By applying JIT, you are continuously monitoring the production process. This gives you opportunities for making the production process smoother and more efficient.

Because JIT is intended to spread throughout the organization, it can have an impact on many areas through improvements in processes. When the emphasis is on lean production, systems tend to be made simpler and more predictable. From how a product moves through the building to ways to increase worker involvement in system design, JIT improves efficiency.

JIT and Stakeholder Relationships

With JIT, it is necessary that you build strong ties with your supply chain. This will ensure that you have access to the supplies you need when you need them. (A side benefit of this is that you're more likely to receive forewarning of shifts in supply that may have an impact on your business.)

With a secure source of supplies, you can continue to make improvements in your production and inventory systems. This helps you to increase your responsiveness to customer demand. If you need to ramp up production, you can be confident knowing your suppliers will help you.

If your customers demand a newer technology, you can switch product quite easily, without worrying about writing off a large stock of obsolete supplies and finished goods. This means that you can meet changing customer needs more quickly.

Custom orders are simpler with a JIT system. Instead of the customer's widget being built six months in advance and waiting on a shelf, it is built when it's ordered. By delivering product "just in time," you allow for last-minute changes.

Essentially, JIT allows your company to get the right products to the right customers at the right time. In many industries, this can give you a huge competitive advantage, at the same time that it helps you save a large amount of money.

Note:

A key drawback of JIT is that it only works if you can rely on your suppliers to deliver when they promise to – otherwise your whole operation may grind to a halt.

What's more, if material costs suddenly increase, then storing them at a lower rate might have been a more economic option. And JIT is also based on historical patterns of need: If orders increase sharply, adjusting to the increased need for supplies may not be easy for you or your suppliers.

Key Points

Just In Time is a way of managing operations so that they run leanly and efficiently. JIT requires giving up your "Just In Case" safety net, and controlling supplies and inventory to levels that just support production. The main emphasis of JIT is on cost reduction and minimal waste.

The process of implementation requires you to take a very close look at every stage of your production and inventory carrying points. This alone is a useful exercise that will highlight some areas for improvement. Ultimately, the more efficient you are and the higher quality product you provide, the more appealing you will be to customers and clients.

Sumber: http://www.mindtools.com/pages/article/newSTR_78.htm

Just-In-Time Manufacturing (JIT)

Introduction

Just-in-time manufacturing was a concept introduced to the United States by the Ford motor company. It works on a demand-pull basis, contrary to hitherto used techniques, which worked on a production-push basis.

To elaborate further, under just-in-time manufacturing (colloquially referred to as JIT production systems), actual orders dictate what should be manufactured, so that the exact quantity is produced at the exact time that is required.

Just-in-time manufacturing goes hand in hand with concepts such as Kanban, continuous improvement and total quality management (TQM).

Just-in-time production requires intricate planning in terms of procurement policies and the manufacturing process if its implementation is to be a success.

Highly advanced technological support systems provide the necessary back-up that Just-in-time manufacturing demands with production scheduling software and electronic data interchange being the most sought after.

Advantages Just-In-Time Systems

Following are the advantages of Adopting Just-In-Time Manufacturing Systems:

• Just-in-time manufacturing keeps stock holding costs to a bare minimum. The release of storage space results in better utilization of space and thereby bears a favorable impact on the rent paid and on any insurance premiums that would otherwise need to be made.
• Just-in-time manufacturing eliminates waste, as out-of-date or expired products; do not enter into this equation at all.
• As under this technique, only essential stocks are obtained, less working capital is required to finance procurement. Here, a minimum re-order level is set, and only once that mark is reached, fresh stocks are ordered making this a boon to inventory management too.
• Due to the aforementioned low level of stocks held, the organizations return on investment (referred to as ROI, in management parlance) would generally be high.
• As just-in-time production works on a demand-pull basis, all goods made would be sold, and thus it incorporates changes in demand with surprising ease. This makes it especially appealing today, where the market demand is volatile and somewhat unpredictable.
• Just-in-time manufacturing encourages the 'right first time' concept, so that inspection costs and cost of rework is minimized.
• High quality products and greater efficiency can be derived from following a just-in-time production system.
• Close relationships are fostered along the production chain under a just-in-time manufacturing system.
• Constant communication with the customer results in high customer satisfaction.
• Overproduction is eliminated when just-in-time manufacturing is adopted.

Disadvantages:

Following are the disadvantages of Adopting Just-In-Time Manufacturing Systems:

• Just-in-time manufacturing provides zero tolerance for mistakes, as it makes re-working very difficult in practice, as inventory is kept to a bare minimum.
• There is a high reliance on suppliers, whose performance is generally outside the purview of the manufacturer.
• Due to there being no buffers for delays, production downtime and line idling can occur which would bear a detrimental effect on finances and on the equilibrium of the production process.
• The organization would not be able to meet an unexpected increase in orders due to the fact that there are no excess finish goods.
• Transaction costs would be relatively high as frequent transactions would be made.
• Just-in-time manufacturing may have certain detrimental effects on the environment due to the frequent deliveries that would result in increased use of transportation, which in turn would consume more fossil fuels.

Precautions:

Following are the things to Remember When Implementing a Just-In-Time Manufacturing System:

• Management buy-in and support at all levels of the organization are required; if a just-in-time manufacturing system is to be successfully adopted.
• Adequate resources should be allocated, so as to obtain technologically advanced software that is generally required if a just-in-time system is to be a success.
• Building a close, trusting relationship with reputed and time-tested suppliers will minimize unexpected delays in the receipt of inventory.
• Just-in-time manufacturing cannot be adopted overnight. It requires commitment in terms of time and adjustments to corporate culture would be required, as it is starkly different to traditional production processes.
• The design flow process needs to be redesigned and layouts need to be re-formatted, so as to incorporate just-in-time manufacturing.
• Lot sizes need to be minimized.
• Workstation capacity should be balanced whenever possible.
• Preventive maintenance should be carried out, so as to minimize machine breakdowns.
• Set-up times should be reduced wherever possible.
• Quality enhancement programs should be adopted, so that total quality control practices can be adopted.
• Reduction in lead times and frequent deliveries should be incorporated.
• Motion waste should be minimized, so the incorporation of conveyor belts might prove to be a good idea when implementing a just-in-time manufacturing system.

Conclusion

Just-in-time manufacturing is a philosophy that has been successfully implemented in many manufacturing organizations.

It is an optimal system that reduces inventory whilst being increasingly responsive to customer needs, this is not to say that it is not without its pitfalls.

However, these disadvantages can be overcome with a little forethought and a lot of commitment at all levels of the organization.

Sumber : http://www.tutorialspoint.com/management_concepts/just_in_time_manufacturing.htm

JIT Just-in-Time manufacturing

`Just-in-time' is a management philosophy and not a technique.

It originally referred to the production of goods to meet customer demand exactly, in time, quality and quantity, whether the `customer' is the final purchaser of the product or another process further along the production line.

It has now come to mean producing with minimum waste. "Waste" is taken in its most general sense and includes time and resources as well as materials. Elements of JIT include:

• Continuous improvement.
• Attacking fundamental problems - anything that does not add value to the product.
• Devising systems to identify problems.
• Striving for simplicity - simpler systems may be easier to understand, easier to manage and less likely to go wrong.
• A product oriented layout - produces less time spent moving of materials and parts.
• Quality control at source - each worker is responsible for the quality of their own output.
• Poka-yoke - `foolproof' tools, methods, jigs etc. prevent mistakes
• Preventative maintenance, Total productive maintenance - ensuring machinery and equipment functions perfectly when it is required, and continually improving it.
• Eliminating waste. There are seven types of waste:
• waste from overproduction.
• waste of waiting time.
• transportation waste.
• processing waste.
• inventory waste.
• waste of motion.
• waste from product defects.
• Good housekeeping - workplace cleanliness and organisation.
• Set-up time reduction - increases flexibility and allows smaller batches. Ideal batch size is 1item. Multi-process handling - a multi-skilled workforce has greater productivity, flexibility and job satisfaction.
• Levelled / mixed production - to smooth the flow of products through the factory.
• Kanbans  - simple tools to `pull' products and components through the process.
• Jidoka (Autonomation) - providing machines with the autonomous capability to use judgement, so workers can do more useful things than standing watching them work.
• Andon (trouble lights) - to signal problems to initiate corrective action.

JIT - Background and History

JIT is a Japanese management philosophy which has been applied in practice since the early 1970s in many Japanese manufacturing organisations. It was first developed and perfected within the Toyota manufacturing plants by Taiichi Ohno as a means of meeting consumer demands with minimum delays . Taiichi Ohno is frequently referred to as the father of JIT.
Toyota was able to meet the increasing challenges for survival through an approach that focused on people, plants and systems. Toyota realised that JIT would only be successful if every individual within the organisation was involved and committed to it, if the plant and processes were arranged for maximum output and efficiency, and if quality and production programs were scheduled to meet demands exactly.

JIT manufacturing has the capacity, when properly adapted to the organisation, to strengthen the organisation's competitiveness in the marketplace substantially by reducing wastes and improving product quality and efficiency of production.

There are strong cultural aspects associated with the emergence of JIT in Japan. The Japanese work ethic involves the following concepts.

• Workers are highly motivated to seek constant improvement upon that which already exists. Although high standards are currently being met, there exist even higher standards to achieve.
• Companies focus on group effort which involves the combining of talents and sharing knowledge, problem-solving skills, ideas and the achievement of a common goal.
• Work itself takes precedence over leisure. It is not unusual for a Japanese employee to work 14-hour days.
• Employees tend to remain with one company throughout the course of their career span. This allows the opportunity for them to hone their skills and abilities at a constant rate while offering numerous benefits to the company.

These benefits manifest themselves in employee loyalty, low turnover costs and fulfilment of company goals.

References

• Kiyoshi Suzaki, 1987, The New Manufacturing Challenge: techniques for continuous improvement, the Free Press, London.
• Yasuhiro Monden, 1993, Toyota Production System: an integrated approach to Just-In Time. Second edition, Industrial Engineering and Management Press, Institute of Industrial Engineers, Norcross, Georgia.
• Cheng TCE and Podolsky S, 1993, Just-in-Time Manufacturing - an introduction, Chapman and Hall, London.

Sumber: http://www.ifm.eng.cam.ac.uk/research/dstools/jit-just-in-time-manufacturing/