There are several problems which are connected within JIT concept. Maybe the
major problem with JIT operation is that it leaves the supplier and downstream
consumers open to supply shocks. With shipments coming in sometimes several
times per day, the company is especially susceptible to an interruption in the flow.
For that reason, some companies are careful to use two or more suppliers for most of
theirs assemblies. The hidden costs are present and they include labour union
leverage, problems with flexible manufacturing systems (FMS), problems developing
for the flexible workforce, difficulties with supplying commodities using JIT, increased
expenses for suppliers.