Page 244 - How To Implement Lean Manufacturing

222 Cha pte r F i f tee n

We inquired about the OEE (Overall Equipment Effectiveness) for this line, and
they did not know, but we were able to discover the following information.
• The production process consisted of two cells, operating in series.
• Nearly all steps were simple manual assembly, with no major equipment until
final test.
• They believed that line availability was well over 95 percent, close to 100
percent.
• Operators were highly cross trained.
• They had not had a stock out in over a month.
• They had recently conducted line time studies, and had both line balancing charts
and standard combination work tables posted at the line for the product.
• The entire plant had begun a lean initiative with some withdrawal kanbans and
had begun utilizing U-shaped manufacturing cells.
• On this line, which produced 11 different models, they had also made an effort
to go to small lot production.
• Within each cell they had a pull system in place, using kanban spaces, and the
operators would not forward the small lots unless the kanban spaces were
empty.
• All models were very similar, with over 90 percent of the component parts
being the same in all 11 models.
• They described a small lot as 50 units, which was a tray.
• Four trays were stacked in a small box and five small boxes were packed in a
larger box, for a total of 1000 units per box, and a typical shipping lot was 2000
units, or two large boxes on one pallet.
• The customer demand was 10,000 units per week of a model mix, but since
changeover time was minimal, product mix was not an issue. Their problems
were threefold:
• They could not produce to schedule and frequently missed shipments.
• It took nearly twice the time.
• It took nearly 70 percent extra labor to make a batch.

Implementing the Prescription
We did some preliminary calculations and could easily understand some of the prob-
lems with production times and missed shipments. We could not yet explain the mag-
nitude of the extra labor required, however. Nor could we explain the need to work
eight days to produce five days of product.
Our approach was simple: We used the prescription outlined in Chap. 7 and we
decided to:
• Synchronize supply to the customer, externally
• Synchronize production, internally