Johnston Products
Johnston Products Case Study
No matter how many times Justin Wang, the master scheduler for Johnston Products,
tried, he couldn’t seem to get it through people’s minds. They kept trying to “front
load” the production schedule, and the problem appeared to be getting worse.
By “front loading” Justin meant that production supervisors would attempt to
catch up with production they failed to make the previous week. It seemed to happen
every week, and the only way Justin could get things back to a realistic position was to
completely reconstruct the entire master schedule—usually about every three weeks.
Last month could serve as an example. The first week of the month Justin had
scheduled production equal to 320 standard hours in the assembly area. The assembly
area managed to complete only 291 hours that week because of some equipment
maintenance and a few unexpected part shortages. The assembly supervisor then had
the workers complete the remaining 29 hours from week 1 at the start of week 2.
Since week 2 already had 330 standard hours scheduled, the additional 29 hours
really put them in a position of attempting to complete 359 hours. The workers actually
completed 302 hours in week 2, leaving 57 hours to front load into week 3, and so
forth. Usually by the time Justin came to his three-week review of the master schedule,
it was not uncommon for the assembly area to be more than 100 standard hours
behind schedule.
Clearly something needed to be done. Justin decided to review some of the
areas that could be causing the problem:
- Job standards—Although it had been at least four years since any job standards had
been reviewed or changed, Jason felt the standards could not be the problem—
quite the opposite. His operations course had taught him about the concept of
the learning curve, implying that if anything the standards should be too large,
allowing the average worker to complete even more production than implied by
the job standard.
- Utilization—The general manager was very insistent on high utilization of the
area. He felt that it would help control costs, and consequently used utilization
as a major performance measure for the assembly area. The problem was that
customer service was also extremely important. With the problems Justin was
having with the master schedule, it was difficult to promise order delivery accurately,
and equally difficult to deliver the product on time once the order
promise was made.
- The workers—In an effort to control costs, the hourly wage for the workers was
not very high. This caused a turnover in the workforce of almost 70% per year.
In spite of this, the facility was located in an area where replacement workers
were fairly easy to hire. They were assigned to the production area after they
had a minimum of one week’s worth of training on the equipment. In the meantime,
the company filled vacant positions with temporary workers brought in by
a local temporary employment service.
- Engineering changes—The design of virtually all the products was changing, with
the average product changing some aspect of the design about every two months.
Usually this resulted in an improvement to the products, however, so Justin
quickly dismissed the changes as a problem. There were also some engineering
changes on the equipment, but in general little in the way of process change had
been made. The setup time for a batch of a specific design had remained at
about 15 minutes. That forced a batch size of about from 50 to 300 units,
depending on the design. The equipment was getting rather old, however, forcing
regular maintenance as well as causing an occasional breakdown. Each piece
of equipment generally required about three hours of maintenance per week.
Since the computer had done most of his calculations in the past, Justin decided to
check to see if the computer was the source of the problem. He gathered information
to conduct a manual calculation on a week when there were eight people assigned of
the assembly area (one person for each of eight machines) for one shift per day. With
no overtime, that would allow 320 hours of production.
Standard Assembly Time
Product Batch Size (minutes per item)
A174 50 17
G820 100 9
H221 50 19.5
B327 200 11.7
C803 100 21.2
P932 300 14.1
F732 200 15.8
J513 150 17.3
L683 150 12.8
Case Analysis
- With this information, Justin calculated the total standard time required to be within the
320 hours available. Is he correct? Calculate the time required and check the accuracy of
his calculation.
- List the areas you think are causing trouble in this facility.
- Develop a plan to deal with the situation and try to get the production schedule back
under control under the constraints listed.
……………………Answer preview………………………………
With this information, Justin calculated the total standard time required to be within the
320 hours available. Is he correct? Calculate the time required and check the accuracy ofhis calculation.
The time needed for each order is the total of the run time and the setup time. The standard time needed to process a single piece by every operation is called run time.
JW has approximated the total time needed as 320 hours for week one in the area of assembly. But in practice, as a result of the maintenance…………………….
APA
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