Question

Calculate Lead Time

Flint Fabricators Inc. machines metal parts for the automotive industry. Under the traditional manufacturing approach, the parts are machined through two processes: milling and finishing. Parts are produced in batch sizes of 85 parts. A part requires 3 minutes in milling and 7 minutes in finishing. The move time between the two operations for a complete batch is 8 minutes.

Under the lean philosophy, the part is produced in a cell that includes both the milling and finishing operations. The operating time is unchanged; however, the batch size is reduced to 5 parts and the move time is eliminated.

Determine the value-added, non-value-added, and total lead times, and the value-added ratio under the traditional and lean manufacturing methods. If required, round percentages to one decimal place.

	Traditional Philosophy		Lean Manufacturing Philosophy
Value-added time		min		min
Non-value-added time		min		min
Total lead time		min		min
Value-added ratio (as a percent)		%		%

Answer 1

	Traditional Philosophy		Lean Manufacturing Philosophy
Value-added time	10	min	10	min
Non-value-added time	848	min	40	min
Total lead time	858	min	50	min
Value-added ratio (as a percent)	1.2	%	20	%

Explanations :-

Value Added Time :-

3 min (milling) + 7 min (finishing) = 10 minutes

Non Value added time :-

Traditional :-

8 min + 10 min(85 – 1) = 848 min

Lean :-

10 min (5 – 1) = 40 min

Total Lead Time :-

Traditional:-

Value added + Non value added

10+848 = 858 min

Lean :-

10+40 = 50 min

Value Added Ratio :-

Traditional :-

Value added time / Total Lead Time

= 10/858 = 1.2%

Lean :-

= 10/50 = 20%