What are the problems and benefits from an employee's point of view if
a company is going to implement a just in time manufacturing program?

Transitioning from a traditional manufacturing approach to a
just-in-time manufacturing approach has a number of problems and
benefits for employees.

First, there is usually a need to change policies and procedures. 
Because many people do not like to change, this can be stressful to
employees.

Second, in many respects, just-in-time manufacturing is far more
demanding of employees than the conventional approach.  "Just-in-time
as a production planning philosophy aimed at reducing work in process
inventories to the bare minimum."  (Page 594) One implication of this
is that production lot sizes must be made as small as possible.  In
order to accomplish this economically, that means that setup times and
costs must be greatly reduced.  This requires employees to come up
with new approaches to setups.

Also, because of the reduced inventories, the manufacturing system is
much more vulnerable to breakdowns and quality problems.  Employees
have to be capable of troubleshooting and correcting problems very
rapidly because very little inventory exists to buffer disturbances in
the manufacturing process.  When breakdowns do occur, employees
elsewhere in the process may be idled.  While in some cases the
employees may be crosstrained to perform other tasks, that may not be
permitted in a unionized environment.  Keeping the employees engaged
when they are idled is a challenge.

In addition, "because items are moved through the system in small
batches, 100% inspection is feasible."  (Page 608) Rapid discovery of
quality problems is critical for success of the overall system. 
However, this puts more pressure on employees to produce perfect
quality products each time.

Finally, suppliers become even more important to the process, and
employees must become adept at communicating frequently with suppliers
so that materials arrive as needed throughout the day.

The benefits for employees are that they have the potential to become
much more involved in their jobs and have the opportunity to problem
solve.  Over time, assuming a successful implementation, the quality
of the products produced should increase and the reliability of the
manufacturing processes should also increase.  However, when problems
are exposed during the early stages of implementation, employees can
be under a great deal of stress to maintain production.

I hope you find the above information helpful.  Please request
clarification if needed.

Sincerely,

Wonko

Source: "Production and Operations Analysis" by Stephen Nahmias,
Irwin, 1989