Making hotplates case study answers

I need an explanation for this Management question to help me study.

For this case analysis, a group of ten workers are responsible for assembling hotplates for hospital and medical laboratory use. There are many different models of hotplates being manufactured. After management discussed some problems in the factory, they decided to try something new.

Making Hotplates

A group of ten workers were responsible for assembling hotplates (instruments for heating solutions to a given temperature) for hospital and medical laboratory use. A number of different models of hotplates were being manufactured. Some hotplates had a vibrating device, so that the solution could be mixed while being heated. Other hotplates heated only test tubes, while some hotplates could heat solutions in a variety of different containers.

With the appropriate small tools, each worker assembled part of a hotplate. The partially completed hotplate was placed on a moving belt and carried from one assembly station to the next. When the hotplate was completed, an inspector would check it over to ensure that it was working properly. Then, the last worker would place it in a specially prepared cardboard box for shipping.

The assembly line had been carefully balanced by industrial engineers, who had used a time and motion study to break the job down into subassembly tasks, each task requiring about three minutes to accomplish. The amount of time calculated for each subassembly had also been “balanced,” so that the task performed by each worker was supposed to take almost exactly the same amount of time. The workers were paid a straight hourly rate.

However, there were some problems. Morale seemed to be low, and the inspector was finding a relatively high percentage of badly assembled hotplates. Controllable rejects, those “caused” by the operator rather than by faulty materials, were running about 23%.

After discussing the situation, management decided to try something new. The workers were brought together and asked if they would like to build the hotplates individually. The workers decided they would like to try this approach, provided they could go back to the old program, if the new one did not work well. After several days of training, each worker began to assemble the entire hotplate.