Guidelines for Successful JIT Implementation

1)  Make the factory loadings uniform, linear, and stable.  Fluctuations in manufacturing loadings will result in bottlenecks.

2)  Reduce, if not eliminate, conversion and set-up times.

3)  Reduce lot sizes.  This will smoothen out the flow of inventories from one station to another, although this may necessitate more frequent deliveries or transfers.

4)  Reduce lead times by moving work stations closer together and streamlining the production floor lay-out, applying cellular manufacturing concepts, using technology to automate processes and improve coordination.

5)  Reduce equipment downtimes through good preventive maintenance.

6)  Cross-train personnel to achieve a very flexible work force.

7)  Require stringent supplier quality assurance since an operation under JIT can not afford to incur errors due to defects.

8)  Use a control system to convey lots between workstations efficiently; the use of a kanban system is an example of this

Kanban Systems

Kanban systems are often associated with JIT implementation. In fact, some people have the misimpression that JIT requires the use of a kanban system.  Having a kanban system is not a strict requirement of JIT implementation, but their use as a tool for practicing JIT has become quite popular owing to its simplicity.

A kanban is a card attached to the carrier or container of a lot used to match what needs to be produced in a work station and what needs to be delivered to the next station. As mentioned, a JIT system is basically a 'pull' system, which means that what needs to be produced in a particular station depends on what the next station needs. Ultimately the production is therefore modulated by end customer orders.  Kanbans, which contain information about the lots and quantities involved, are therefore used to facilitate the execution of this 'pull' system.  With this 'pull' system, no parts that can not be processed in succeeding stations will be produced.

There are two types of kanban assigned to every lot, namely, a production kanban (P-kanban) and a conveyance kanban (C-kanban). The P-kanban  denotes the need to produce more parts while the C-kanban denotes the need to deliver more parts to the next station. No parts can be produced unless authorized by a P-kanban. On the other hand, a C-kanban triggers the 'pulling' or 'withdrawal' of units from the preceding station. C-kanbans are also known as 'move' or 'withdrawal' kanbans.  <Back to Page 1>