FTA (изд-во). Flexography: Principles And Practices. Vol.1-6

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CHAPTER 3

Quality Control

FLEXOGRAPHY: PRINCIPLES & PRACTICES

ACKNOWLEDGEMENTS

Author/Editor: Professor Hank Apfelberg, California Polytechnic State University

Contributors: Dave Argent, Progressive Ink Co.

Lorraine Bowles-Tracy, Lord Label

Bob Bowen, Cryovac Division, Sealed Air Corp.

Steve Cushner, DuPont

Stephen Long, Schiffenhaus Packaging Corp.

Tom Thackeray, Willamette Industries

he American Society for Quality

Control defines quality as “the

characteristics of a product or

service that bear on its ability to

satisfy stated or implied needs

or a product or service free of

deficiencies.” Other definitions of quality

may include meeting customer expectations

or even exceeding customer expectations.

First and foremost, the supplier must under-

stand the customer and what he or she will

be doing with the product after delivery. This

can be done in many ways, depending on

what the customer most values and what the

supplier is capable of delivering. In the flexo-

graphic industry, meeting customer expecta-

tions might require that the price be consis-

tent or lower than the competition or that the

service received by the customer includes

expert advice on the type of substrate to use

or design elements that will work effectively

in flexography. This implies that the flexo-

graphic printer must understand which char-

acteristics are necessary to satisfy the cus-

tomer as well as what defects must be avoid-

ed in the printed product. These defects

might include more than misregistration or

poor color consistency or die cut. They might

include such items as late delivery and

improper product count.

There is much confusion between features

and quality. Features are those characteris-

tics that describe a product. Quality is the

continual meeting of whatever specifica-

tions have been agreed upon to achieve a

satisfactory end result, and requires that

you, the supplier, have an understanding of

what the customer wants, a knowledge of

what you are capable of delivering and the

agreement in place between you and the cus-

tomer on the specifications of the product or

service provided. Saying that four-color

process is of higher quality than spot colors

and line art is not an adequate definition of

quality. Because one printed product may be

harder to produce or have some attribute

such as an over-varnish does not make it

more of a quality product than one that is

easy to produce and has few attributes.

Quality is, first and foremost, meeting cus-

tomer expectations on a continuous basis no

matter what the desired feature may be.

For flexographic printers to consider

themselves quality manufacturers they need

to look at their entire system. The questions

that they must answer are:

• Do they know what they are capable of

doing?

• Do they know the customer’s expecta-

tions?

• Do they have the critical variables ade-

quately defined?

• Do they have specifications that they

and the customer have agreed upon?

• Can they consistently meet these specifi-

cations and customer expectations?

• Do they have a system in place that will

answer the above questions?

QUALITY CONTROL VS.

QUALITY ASSURANCE

Quality control encompasses those opera-

tional techniques and activities used to fulfill

the requirements for quality. Armand

Feigenbaum expands on this statement in

his book “Total Quality Control” where he

states that quality control is “an effective

QUALITY CONTROL 79

Introduction

The indiviual doing

the work is ultimately

responsible for its

quality, but the quality

control department is

there to act as an extra

set of eyes.

80 FLEXOGRAPHY: PRINCIPLES & PRACTICES

system for integrating the quality-develop-

ment, quality-maintenance, and quality-

improvement efforts of the various groups

in an organization so as to enable market-

ing, engineering, production, and services at

the most economical levels which allow for

full customer satisfaction.” Quality in this

definition does not mean best overall, but

best for this particular customer for a spe-

cific set of conditions and at a given price.

Control means maintaining a given set of

specifications and reacting when the stan-

dards are not met. Generally, the person,

persons or department doing the specific

work are given the responsibility for main-

taining the quality outcome of their efforts.

Quality assurance refers to all these plan-

ning and systematic actions which will pro-

vide confidence that a product or service is

free of deficiencies. This includes assisting in

developing workable specifications, meth-

ods for evaluating conformance to these

specifications, monitoring methods, an eval-

uation process of overall quality, working

with suppliers in determining specifications

and working on the procedures to improve

the overall quality of the organization. The

quality control department should be in-

volved with the following:

• planning the quality system;

• determining the company’s capabilities;

• coordinating the qualifications of suppli-

ers on quality issues;

• assisting in the development of product

specifications;

• developing test and inspection equip-

ment;

• planning inspection and test procedures;

• performing in-process quality measure-

ments;

• performing in-process quality audits;

• analyzing and sharing quality costs;

• analyzing complaint data;

• facilitating corrective action;

• feedback quality information; and

• facilitating strategies for process

improvement .

WHO IS RESPONSIBLE

FOR QUALITY?

There can be only one answer to that:

Everyone in the organization is responsible

for quality. Traditionally, when a quality con-

trol department is in place in a flexo printing

company, then the responsibility for quality

seems to rest with that group. However, no

quality control department can be responsible

for quality. The best that can be done by this

department is to monitor and reinforce the

quality effort. Quality must be maintained by

the people doing the actual work. If the ink

department makes up a specific spot-color

ink, then it becomes their responsibility to

match that ink to customer and press specifi-

cations. The quality department may be able

to monitor the end results, but this would be

after the fact. If the ink department has made

a mistake in the ink color a major portion of a

job could be run before the quality depart-

ment could catch it. The quality control de-

partment is there to act as an extra set of eyes,

not to be the first line of defense against qual-

ity mistakes (Figure

). The individual or

individuals doing the actual work are the ones

who must be held accountable for their work.

he printed packaging product

acts as a communication vehi-

cle to give information on what

the product is and how to use it,

and acts as a silent salesperson

in encouraging the customer to

purchase the product. If the flexo product is

a directory or a flexible package it is con-

veying information and must be printed

accurately and give a realistic portrayal of

what needs to be conveyed be it words or

pictorials. The result of a quality effort is to

satisfy the needs of the end user. If there is

an error, it really doesn’t matter to the end

user where in the production cycle a quality

error is made. All the end user cares about is

“does the product work satisfactorily.” When

buying a bottle of wine, the label (Figure

)

serves the purpose of identifying the product

and influencing the customer to buy and is

part of the presentation of a quality product.

The best wine with a poorly designed and

printed label can leave an excellent wine sit-

ting on the shelf without a purchaser. If the

label falls off the bottle or is applied in a

crooked manner or the colors bleed when

refrigerated, the end result is that the cus-

tomer may not purchase that wine again.

CUSTOMER

The purchaser of converting and printing

products generally uses the printing to

enhance the product. The manufacturer of

the product (Figure

) may wish to have a

corrugated container with a point of pur-

chase graphic printed directly on the pack-

age. What are the concerns? Do the graphics

and words accurately portray the product?

Will the ink rub off when shipped or handled?

Are the colors consistent from one package

to another? How consistent does the color

have to be so it is not being noticed by the

end user? Are the die cuts and scores accu-

QUALITY CONTROL 81

Characteristics

of Quality

2^A label not only

identifies a product,

but also influences the

purchasing decision.

In an effort to influence

sales, a manufacturer

may choose to print

graphics right on the

package.

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82 FLEXOGRAPHY: PRINCIPLES & PRACTICES

rate so that they work well in the converting

process? Is the register accurate from color

to color and from the print to the die cut and

scores? Will the printing and converting

process crush the flutes and cause damage to

the product? Will the packages be delivered

on time and in the right quantity? And, lastly

is the price within the area that is affordable

for the product that it will contain? These

quality issues must be addressed and han-

dled between the converter and the cus-

tomer to fully accomplish what is required

for the particular package.

PRINTER

One of the biggest problems faced by the

flexo printer is that sometimes customers

and end users have not thought out what

they really need and only recognize these

needs when they see them pop up as quality

defects. The flexographic printer needs to

understand what the requirements of the end

user and the customer are in order to fully

satisfy the demands necessary to meet the

quality requirements. This can be addressed

by sales and customer service. Exceeding

customer expectations means being able to

ask questions that the customer and end user

may not have thought about. This is truly a

value-added activity on the part of the flexo

printer. Developing and working with a

checklist is an excellent way of heading off a

problem before it becomes one. Table 13 is a

sample of a checklist that can be used for

determining customer and end user needs.

SUPPLIER

In the printing industry, the supplier is

sometimes expected to do too much. More

and more, the supplier is expected to offer

the training, research and technical assis-

tance that goes along with the product. The

printer also expects that the supplier will

provide the specifications necessary for

the product. This can create a problem as

the supplier may not know the printer’s

capability or the many uses that the mate-

rial will go through. It is therefore incum-

bent upon the printer to make the supplier

understand what the specification needs

are. This requires that a partnership be ini-

tiated between the supplier and printer to

facilitate product specifications. Price

alone will not satisfy this need. Price is

very important, but the specifications must

also include such items as on-time delivery,

service, training and technical support.

Table 13

1.Who will use the printed product?

2.What are the product needs for protection?

3.Will the product be adversely affected by

the ink or substrate?

4.What is the shelf life of the package

before use?

5.How many times will the product be used

before graphics are no longer important?

6.How will the product be placed into the

package?

7.How will the graphic be applied to the

package or product?

8.What type of climatic changes will the

package or product undergo?

9.Where will the flexo printed product be

used?

CHECKLIST FOR SALES

AND/OR CUSTOMER SERVICE

ommitment to quality needs to

be present at all levels of the

organization. It is particularly

important to have management

committed to quality through-

out the organization. This com-

mitment includes all products and services

provided by the organization. In addition to

management, each and every individual in

the organization must share this commit-

ment to quality.

TOP MANAGEMENT

Quality starts at the top. In W. Edwards

Deming’s book “Out of the Crises” (p. 248) he

states, “The aim of leadership should be to

improve the performance of man and

machine, to improve quality, to increase out-

put, and simultaneously to bring pride of

workmanship to people. The aim of leader-

ship is not merely to find and record failures

of people, but to remove the causes of failure:

to help people to do a better job with less

effort.” This has to be the mission of top man-

agement. Without a clearly defined and under-

stood quality effort from top management, it is

very unlikely that the organization can be a

quality organization. Top management must

balance quality, productivity and price, not

choose one or two of these.

Top management must set the quality

goals and provide time, money and effort to

back up their words. Some managers feel

that if people are honest and hard working

they will, by these attributes, produce quali-

ty work. This is, of course, not true. Quality

needs to be planned and cannot be left to

subjective forces. Planning has to go into the

materials used, the equipment chosen and

the training given to employees.

MIDDLE MANAGEMENT

Middle management is generally assigned

the task of implementing the quality com-

mitment of the company. In this regard they

are given the responsibility for implement-

ing, training and monitoring the effort, but

they may not be given the time or money to

do the job adequately. The first objective

should be to train middle managers in what

they need to know and how to go about

implementing a quality process.

One area in which middle managers fre-

quently need training is the development of

the team process. This means that middle

managers must be taught how to delegate

and work with project-oriented teams to

improve the process or resolve problems.

This is a new concept, as middle managers

have usually been trained to do this work

themselves. However, if the company has

decided to empower its employees it is

important that this be done (Table 14).

Middle managers need to be trained in

how to be coaches and facilitators and a cen-

tral resource of information, rather than

direct supervisors of the quality process.

Quality is maintained by those actually doing

the job and the supervisor must make this

possible by offering methods, supplies and

QUALITY CONTROL 83

Commitment

To Quality

84 FLEXOGRAPHY: PRINCIPLES & PRACTICES

equipment that will enable the operating per-

sonnel to perform in a quality manner.

OPERATING PERSONNEL

The responsibility for first-line quality is

always that of the person doing the job.

While it is important to have checkpoints so

that the quality of the end product is not

jeopardized, this occurs only after the fact. It

takes time and effort and does not add value

to the process. The more that individuals are

allowed to take responsibility for their own

work, the less expensive it is to produce a

quality flexo job.

For operating personnel to produce a qual-

ity job, it is important that they be given ade-

quate tools, training and reinforcement so

that they understand thoroughly what has to

be accomplished (Table 15). Understanding

the specifications of the work they do in

relationship to the various steps in the

process and end-use requirements is para-

mount to the quality process.

For lack of the right tool, many operations

are done poorly and end up causing quality

defects in the finished work. Inadequate,

inappropriate or improperly maintained

tools can lead to downtime and frustrations

– all which could have been avoided. It is up

to management to work with and craft peo-

ple to ensure that the appropriate tools are

chosen, maintained and used.

The materials used by operating personnel

must be within specification to what is need-

ed to do a quality job. Operating personnel

must not be put in a situation in which they

have to make do in order to get their job done.

This will impede their efforts toward doing

quality work. Middle and upper management

must understand the capability of the materi-

als in relationship to the equipment and cus-

tomer needs, and supply operating personnel

with materials that meet these needs.

The equipment must be maintained and

optimized to perform at or above the original

manufacturer’s specifications. Optimizing is

accomplished by matching the original manu-

facturer’s specifications to the way a machine

is presently functioning and repairing or

replacing any component which does not con-

form. Some of the items one would look at in

the case of a press would include gear wear,

repeatability of printing units, runout and par-

allelism of the anilox print-impression cylin-

der, dryer capacity and tension variations.

After optimization the press can be character-

ized (fingerprinted). This fingerprint would

include such characteristics as registration,

slur, dot gain and trap of inks. This needs to be

done for each set of conditions, including

anilox rollers, ink types and substrates.

Operating personnel cannot be held

responsible for anything more than how

they use the equipment, methods and mate-

rials given to them by middle and upper

management. It has been claimed that oper-

ating personnel have control of only 15% of

the output, while middle and upper manage-

ment have control of 85%.

Table 14

Table 15

■ Methods ■ Skills ■ Tools

■ Materials ■ Equipment

ENABLING OPERATING PERSONNEL

TO PERFORM QUALITY WORK

■ How to delegate the responsibility

to the team.

■ How to choose team members.

■ How to develop a team problem

statement.

■ How to develop a team mission

statement.

■ How to train a team to work

effectively and efficiently.

MIDDLE MANAGER

TEAM TRAINING

QUALITY CONTROL 85

Responsibilities of a

Quality Control Department

raditionally, quality control de-

partments were set up to in-

spect work in progress and do

laboratory testing to ensure

that the end product met cus-

tomer specifications. Quality

control department members were also used

to collect samples that were given to cus-

tomers to verify that the product was within

specification. As a general rule, quality con-

trol had little to do with training operating

personnel on how to evaluate the quality of

their work and record these procedures.

Quality control departments were not used

to assist in optimizing, characterizing or

developing strategies for implementing

capability studies. Very little emphasis was

placed upon the use of statistical process

control.

The quality control function was only for

the production process with little to no inter-

action or responsibility for working with cus-

tomers, marketing, sales or customer service.

Most significantly, the quality function did not

include reviewing the product before manu-

facturing to be sure that the specifications

could be met. Two attitudes were prevalent

concerning quality control departments and

their people. The first was that they were a

form of police unit, functioning to catch peo-

ple doing things wrong and were dreaded

when seen heading for your department.

Second was that you as an operator were not

responsible for your quality because the qual-

ity department was there to catch all your mis-

takes. Operating personnel were not responsi-

ble for quality, that was the responsibility of

quality inspectors and the quality department.

There are a number of things wrong with

this traditional approach to a quality control

department. The first is that if operating per-

sonnel feel the quality department is a police

unit they will try and hide mistakes and the

quality inspector will not get cooperation from

operating personnel to review quality from an

objective posture. The other major problem is

that if the quality department is seen as the

only group responsible for quality the end

result might very well be out of specification

for flexo products, thus becoming waste in the

inspection process or, worse, ending up as

unsatisfactory product in the customers’

hands. Either of these scenarios is very expen-

sive to the flexo printing company.

BASIC GOALS

The modern quality department needs to

focus upon the needs of the customer and

translate these into operational specifica-

tions and procedures that will satisfy these

needs. To accomplish these goals the quality

department and its manager must be

involved in new design control, capability

analysis, incoming raw material control,

printing process control and process

improvement strategies (Table 16).

This does not mean that the modern quali-

ty department does not do inspections and

quality testing or take samples for customers.

This remains a part of their job, but the job of

quality control is expanded to become more

86 FLEXOGRAPHY: PRINCIPLES & PRACTICES

proactive rather than reactive in assisting the

entire organization in its quality effort.

NEW DESIGN CONTROL

The quality department must be involved in

reviewing printing job specifications includ-

ing type families and sizes, trap considera-

tions, type of inks, number of colors, die cut

and scoring feasibility, substrates and ship-

ping parameters. The development of work-

able specifications is the first step in being

able to produce a flexo product that meets

customers’ needs and expectations. Some of

the quality measures of the output are shown

in Figure

. It is important that all specifica-

tion reviews involve the quality department

as it is their function to assist in evaluating

the quality output. In order to do so they need

to be involved with the quality input.

CAPABILITY ANALYSIS

It is extremely important for the printer to

understand the capabilities of the manufac-

turing process in order to assure that the

process is capable of producing the work

that the sales department has sold and that

the package and graphic designers have

developed. A capable process is a process

that will produce virtually all of its product

within designated specifications.

The capability of the process can be dis-

covered using a statistical technique such as

a simple histogram (Figure

). A minimum

of 30 samples needs to be taken to be statis-

tically sound. In the figure, the deviations

from the print to die are measured and the

frequency of each deviation is plotted.

Putting in the acceptable limits (customer

specifications) shows whether the process

is capable of producing product within those

limits.

INCOMING RAW

MATERIAL CONTROL

It is important that all supplies that are

used in each and every process be within the

specifications designated by agreement with

the customer, whether they are internal

(produced in-house), or external (purchased

from an outside supplier). The quality con-

Flexo output measures.

Flexo Output Measures

Output Measures

Stability/

Robustness

• Within Run

• Run to Run

• Press to Press

• FDA

• EPA

• Energy

• Waste/Recycle

• Cost/Unit

• Cost of Use

• Effect in Use

• Adhesion

• Gloss

• COF

• Machineability

• Odor

• Retains

• Product

Resistance

• Lightfastness

• Abrasion

Resistance

• Solids

• Color

• Uniformity

• Trap

• Reverses

• Type

• Halftones

• Gain

• Linearity

• Contrast

Environmental/

Regulatory

Value/

Performance Physical Quality Image Quality

Table 16

■ New Design Control

■ Capability Analysis

■ Incoming Raw Material Control

■ Process Improvement Strategies

THE MODERN QUALITY

CONTROL DEPARTMENT