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Charts, and defect concentration diagrams, the basic SPC problem solving

tools must become widely known and widely used throught the organization.

Ongoing education of personnel about SPC and other methods for reducingvariability are necessary to achive this widespread knowledge of the tools.

The objective of an SPC based variability reduction program is continuous

improvement on a weekly, quarterly, and annual basic. SPC is not a one timeprogram to be applied when the business is in trouble and later abandoned. Quality

improvement that is focused on reduction of variability must become part of the

culture of the organization.The control chart is in important tool for process improvement. Process do

not naturally operate in an in control state, and the use of control charts is an

important step that must be taken early is an SPC program to eliminate assignable

causes, reduce process variability, and stabilize process performance. To improvequality and productivity, we must begin to manage with facts and data, and not

simply rely on judgment. Control charts are an important parts of this change in

management approach.

In implementing a company-wide effort to reduce variability and improvequality, we have found that several elements are usually in all successful efforts.

These elements are as follws:

Elements of a successful SPC Program1. Management leadership2. A team approach

3. Education of employee at all levels4. Emphasis on reducing variability5. Measuring success in quantitative (economic) terms6. A mechanism for communicating successful results throught the

organizationWe cannot overemphasize the importance ofmanagement leadership and

the team approach. Succesful quality improvement is a top-down management-

driven activity. It is also important to measure progress throught and success inquantitative (economic) terms and to spread knowledge of this success throughout

the organization. When successful improvements are communicated throughout the

company, this can provide motivation and incentive to improve other processes and

to make continous improvement a normal part of the way of doing business.

4-6 AN APPLICATION OF SPC

In this section, we give an account of applying SPC methods to improvequality and productivity in a copper plating aperation at a printed circuit board

fabrication facility. This process was characterized by high levels of defects such as

brittle copper and copper voids and by long cycle time. The long cycle time was

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particularly troublesome, as it had led to an extensive work backlog and was a major

contributor to poor to the factory production schedule.

Gambar..

Management chodse this process area for an initial implementation of SPC.An improvement tean was formed. Consisting of the plating tank operator, the

manufacturing engineer responsible for the process, and quality engineer. All

members of the team had been exposed to the magnificent seven in a companysponsored SPC seminar. During the first team meeting, it was decided to concentrate

on reducing the flow time throughthe process, as the missed delivery targets were

considered to be the most serious obstacle to improving productivity. The teamquickly determined (based on operator experience) that excessive downtime on the

controller that regulated the copper concentration in the plating tank was a major

factor in the excessive flow time, as controller downtime translated directly into lost

production.

The team decided to use a cause and effects analysis to begin to isolate thepotential causes of controller downtime. Figure 4-23 shows the causes and effect

diagram that was produced during a brainstorming session focused on controllerdowntime. The team was able to quickly identifity 11 major potential causes of

controller downtime. However, when they examined the equipment logbook to make

a more definitive diagnosis of the causes of downtime based on actual processperformance, the results were disappointing. The logbook contained little usefull

information about causes of downtime, instead, it contained only a chronological

record of when the machine was up and when it was down.

The time then decided that it would be necessary to collect valid data aboutthe causes of controller downtime. They designed the check sheet shown in Fig, 4-24

as a supplemental page for the logbook. The team agreed that whenever theequipment was down, one team member would assume responsibility for filling outthe check sheet. Note that the major causes of controller downtime identified on the

cause and effect diagram have been used to structure the headings and subheadings

on the check sheet. The team agreed that data would be collected over a four to sixweek period.