1. Stabilize
and level the MPS with uniform plant loading (heijunka in Japanese): create a uniform load on all work centers through
constant daily production (establish freeze windows to prevent changes in the production plan for some period of time) and
mixed model assembly (produce roughly the same mix of products each day, using a repeating sequence if several products are
produced on the same line). Meet demand fluctuations through end item inventory rather than through fluctuations in
production level. Use of a stable production schedule also permits the use of backflushing to manage inventory: an end
item’s bill of materials is periodically exploded to calculate the usage quantities of the various components that were
used to make the item, eliminating the need to collect detailed usage information on the shop floor.
2. Reduce or eliminate setup times: aim for single digit setup times (less than 10
minutes) or "one touch" setup. This can be done through better planning, process redesign, and product redesign.
3. Reduce lot sizes (manufacturing and purchase): reducing setup times allows economical
production of smaller lots; close cooperation with suppliers is necessary to achieve reductions in order lot sizes for purchased
items, since this will require more frequent deliveries.
4. Reduce lead times (production and delivery): production lead times can be reduced
by moving work stations closer together, applying group technology and cellular manufacturing concepts, reducing queue length
(reducing the number of jobs waiting to be processed at a given machine), and improving the coordination and cooperation between
successive processes; delivery lead times can be reduced through close cooperation with suppliers, possibly by inducing suppliers
to locate closer to the factory, as Toyota has done in Japan and Honda has done in Ohio.
5. Preventive maintenance: use machine and worker idle time to maintain equipment
and prevent breakdowns.
6. Flexible work force: workers should be trained to operate several machines, to
perform maintenance tasks, and to perform quality inspections. In general, JIT requires teams of competent, empowered
employees who have more responsibility for their own work. The Toyota Production System concept of “respect for
people” contributes to a good relationship between workers and management.
7. Require supplier quality assurance and implement a zero defects quality program:
errors leading to defective items must be eliminated, since there are no buffers of excess parts. A quality at the source
(jidoka) program must be implemented to give workers the personal responsibility for the quality of the work they do, and
the authority to stop production when something goes wrong. Techniques such as "JIT lights" (to indicate line slowdowns
or stoppages) and "tally boards" (to record and analyze causes of production stoppages and slowdowns to facilitate correcting
them later) may be used.
8. Small lot (single unit) conveyance: use a control system such as a kanban (card)
system (or other signaling system) to convey parts between work stations in small quantities (ideally, one unit at a time).
In its largest sense, JIT is not the same thing as a kanban system, and a kanban system is not required to implement JIT (some
companies have instituted a JIT program along with a MRP system), although JIT is required to implement a kanban system and
the two concepts are frequently equated with one another.