Spindle2.ppt

7/29/2019 Spindle2.ppt

1/9

Six Sigma Project Case Study:

Improved Productivity of Fans

through Reduction of

Defects/Defectives at Spindlemanufacturing


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Preamble/Project Selection

High Loss of Production of Fans due to short

supply of Critical Components Spindle was an important component. It was

not possible to augment the production of

However, it was observed that, rejection ofspindles was very high (6.5%)

If rejection is brought down, it will have greatimpact on business in the form of higher

productivity of fans and reduced losses atspindle manufacturing

Hence, management initiated a Six Sigmaproject at spindle manufacturing


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Define Phase : The Project Charter

Problem StatementHigh rejection of spindles due to various dimensions

was causing heavy losses and loss of production of

fans due to short supply of the component.

The TeamSponsor: GM, components Manufacturing

Leader : Manager (QC), a Black Belt

Team Members: Two Green Belts and one supervisorTrainer & Guide : Consultant

Scope:

All types of Spindles manufactured


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The process and CTQsThe entire manufacturing process for spindle. Various

dimensions of the spindle which may lead to rejections

A high level process map was drawn

Schedule for the project milestones was drawn

using a Gantt diagram.

Target

It was decided to achieve a five-fold improvement in

rejections. The current level being 6.5%, the target was

set at 1.3%


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DefectiveAny spindle which cannot be used in the assembly due

to one or more of the dimensions being high or low is a

defective product.

DefectAny dimension which is high or low is considered as a

defect. There were as many as 19 dimensions. Hence

number of opportunities is 19


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Measure Phase

Base line Data

Past 1 months go-no-go inspection data wasconsidered. The number of spindles inspected, the totalnumber of defective spindles and the number of defectsdue to each dimension were noted down.

Total no. inspected : 17,000

Number of defectives : 1130Total no. of defects : 1350

P = 0.065

Yield = 93.5%

dpmo = 4180

Sigma Rating for product: 3.01 (Z= 1.51 for p=0.065)Sigma for defects: 4.13 (based on dpmo)

Target p = 0.013

Target sigma rating for product: 3.72


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Analyze Phase

Pareto analysis was carried out with the Data on defects.

Four dimensions accounted for over 90% of the defects(A group). These were selected for further study. There

were 8 dimensions with negligible defects (C group).

Remaining 7 dimensions (B group) were average.

For each of the selected dimensions, data on actualmeasurement were collected for 150 components.

Histograms were drawn

The histograms suggested that the process capabilities

were good. However, there was severe lack of control in2 cases, improper setting in one case and shift in

average dimension due to tool wear out in the fourth

case.


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Improve Phase

1. Improvement suggestions for A group items:

For cases where lack of control was evident,control chart was recommended. ( )

For the case where there was improper setting, first

off inspection (approval inspection) was

recommended For the case where there was tool wear out,

statistical analysis (regression analysis) was carried

out and optimum tool grinding/ tool replacement

were recommended2. For B group items maintenance of p/np chart shift

wise were recommended

RX


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ControlPhase : Sustain the Gain

The control charts were designed and implemented for

all the 11 dimensions.

The manager of the spindle shop was assigned the task

of routine follow and feedback as a process owner.

1 month after implementation, the status was as under:

Overall rejection level: 2.1%dpmo : 1200

Sigma Rating for product: 3.54

Sigma Rating for defects: 4.54

The expected annual savings from increased productionand reduced losses is 35 lakhs of rupees.

Spindle2.ppt

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