The Lean 6 Concept
Lean 6 Road mapWhat is your Problem ??
Is it really .
Why is that important
How is it related to Business Objectives?
What factors contribute to those Objectives?
Solution to the problem to meet those objectives
Rework in components
A large number of components had to be reworked.
Majority of the time is spent in non value added process such as personnel movement, Photostat copying, etc.
Data CollectionRework in components
In the month of June, 1695 components were inspected Of the 1695 components, 98 components were reworked.
A value stream map revealed that on an average, a component requires 135 min for inspection of which 25 minutes is the value added time required while the remaining non-value added time was spent on movement of inspection personnel, arranging the component, cleaning the component etcIf an error is made in measurement, the entire time is wasted.
Analysis of the Problem
Analysis of the ProblemRework in components
Error in reading the value on the micrometer scale
Usually the error is 0.5mm or 5mm
0.5mm is interpreted wrongly based on the position of the thimble scale on the main scale (E.g. 5.78mm is interpreted as 5.28mm)
5mm is interpreted wrongly based on the anvils chosen for the measurement (E.g. 195mm is interpreted as 190mm because of the operator making the mistake of adding up the reading)
Analysis of the Problem
VSM of Inspection process
Poka-Yoke for Measurement
An ideal mistake-proofing method is to cross check the reading with a Vernier caliper to ensure that a reading error was not made
It is not time consuming and avoids any repeatability of inspecting the component once again
Controlling error in Measurement & Managing time
To prevent recurrence of errors, a separate column in the inspection report is made where the Vernier caliper/pie-tape readings can be noted adjacent to the micrometer reading.
To Manage time, during any process, say for example dismantling of any equipment, the assembly section can offer the equipment for inspection so that inspection and dismantling can be carried out parallel rather than in series.
Using formats (with drawing readings/tolerances)for commonly dismantled assemblies and keeping instruments ready can reduce time by 25%
Cost AnalysisCost of inspection/ hr (average)
Previously , cost incurred is Rs. 157 per hour (considering a M10 employee earning Rs.450000 PA) i.e Rs 354 for Inspecting (for 135 min)
After Poka-yoke, a 25% of cost is reduced i.e, Rs 265 per hour