Ellis Developments Limited
Nottinghamshire United Kingdom
QUALITY SYSTEMS FOR GARMENT
ACHIEVING THE RIGHT FINAL PRODUCT ON TIME
- PLAN OF THE OVERALL FUNCTION OF QUALITY CONTROL The cost of quality
Functions of Quality
Assurance
Commercial advantages form effective control systems
Economic aspects of
quality assurance
The role of quality control - THE ROLE OF QUALITY CONTROL IN THE CONTEXT OF QUALITY MANAGEMENT Outline of quality
control systems requirements
Data generated
British Standard 5750 - FINAL PRODUCT SPECIFICATIONS Quality control in the sampling/development department
From
sample to full production
The Specification layout
Product specification examples
Process
specification examples
Example garment specification
Seam specification examples
Performance
specification examples - THE MAIN RAW MATERIAL - FABRIC Fabric and garment dimensions - fabric stability and
finished width
Fabric inspection - examination of fabric on receipt - BASIC SEAMING TECHNOLOGY Basic technology of seams
Stitch forming action
Quality checks
on seams - LAYING-UP AND CUTTING
- QUALITY MONITORING THROUGH CUTTING AND GARMENT ASSEMBLY 7.1 Recording
Recording systems
- making up
Supervisors check list
Analysis of results
7.2 Tolerances
Tolerance limits
7.3
The threshold of faults
Training quality standards and faults analysis
7.4 Sampling
techniques
Checking levels of faults and seconds
7.5 Technology if Inspection
Garment
examination
Seeing colour and the effect of type of illuminant on the apparent shade
of a sample
Effects of intensity, angle of illumination and type on the apparent shade
of a sample
Effects on shade of other colours in adjacent areas
Mounting and displaying
for viewing
Colour vision
7.6 checking operatives and examiners
Assessment of operative
effectiveness from records
The supervisor and quality control
Weather trials
7.7 Auditing
Boxed Stock
Boxed Stock Quality Audit - QUALITY COMMUNICATIONS
Control of quality in garment assembly
Example of quality feedback - marks and stains
Action checklist to improve garment cleanliness
Fault cost assessment record
Quality Control Requirements - Order of Priorities
A manufacturer stays in business only as long as his product quality satisfies his
customers at the price they are prepared to pay.
Failure to maintain an adequate quality standard can therefore be disastrous. But
maintaining an adequate standard of quality also costs effort. From the first investigation
to find out what the potential customer for a new product really wants, through the
processes of design, specification, controlled manufacture and sale, to the arrangements
for aftersales service to the customer, effort is being spent on ensuring that the
company's product - and reputation - are good. If it is spent wisely, it can result
in savings greater than the increase in costs, and hence in an improvement to profits.
As products become more and more complex, and as customers - both Government Departments
and individuals - become more conscious of the effects on their own economics of
receiving a proportion of defective items, the effort required must continually increase.
The costs represented by this effort can be a significant proportion of the products
sales value (Do you know what the total is in your Company? In some instances the
cost of scrap, rework and inspection costs alone has been found to be as high as
20% of turn-over) and any manufacturer should be interested in making sure that he
is getting good value for his expenditure. He cannot feel sure unless he has studied
what the costs are, how they are incurred and what they ought to be. If they are
higher than they should be, he must consider ways in which they can be reduced.
Here we describe the nature of the costs incurred in ring product quality and reliability
and shows how costs can be reduced whilst quality and reliability are maintained
or improved.
THE NATURE OF QUALITY COSTS
Quality costs fall naturally into three main groups. First there are Costs associated
with attaining or setting an adequate quality standard, sometimes called Prevention
Costs. They are incurred largely in advance of production, when the quality standard
is set. Insufficient money spent at this stage on, for example, design and development
may well give rise to unnecessarily high costs later.
The second group is costs associated with maintaining an adequate quality standard,
sometimes called Appraisal Costs. These are the costs associated with keeping the
work manufacturing and buying functions up to the quality specified in the design.
The third category covers Failure Costs, or the costs associated with putting right
any departure from standard. These include the costs of scrap, reprocessing, and
guarantee claims. They are the costs, which arise as a result of shortcomings in,
or insufficient expenditure on, the other two phases. They may be caused on the one
hand by poor design, poor product engineering, poor operative training or, on the
other, by bad workmanship, or slipshod inspection at the appraisal stage.
A list of the types of cost connected with quality and reliability will be found
in the Appendix. Some difficulty may well be experienced in separating costs associated
with quality and reliability from those more directly concerned with achieving the
function of the product, for example, design and development. It is more important
to recognise the changes deliberately made in these costs as action is taken to bring
quality under control.
Obviously, the most significant improvements will usually be achieved by concentrating
effort on the areas of high cost. For this purpose an analysis of the principal costs
is required. Studies have shown that a fairly typical ratio between the three main
groups of costs in a manufacturing company is: -
Failure Costs, because they are typically the largest, will usually give the largest
return for the effort involved in reducing them. An effective way of attacking Failure
Costs is through a temporary increase in prevention and appraisal costs.
Appraisal Costs - for example, the cost of production and inspection - might be reduced
by more attention to Value Engineering, which would to some extent increase prevention
costs, and a closer control of the manufacturing process, which would increase appraisal
costs.
Appraisal Costs will usually be the next to come under attack. An analysis of all
essential quality control operations will often show opportunities for reducing expenditure
without reducing effectiveness. For example, statistical sampling techniques may
be used as a means of control, indicating trends in performance and assisting to
maintain quality. By improving the control of the process, 100 per cent inspection
may no longer be necessary.
Total costs will be lowest when design staff are aware of the cost implications of
their work. Good design saves cost not only at the design stage itself but throughout
production and testing: products become easier to make "right first time". Good design
is needed not only when conceiving the product but also when conceiving systems for
production and quality control. After failure and appraisal costs have been reduced
by attention to the prevention aspect, it may be possible to reduce prevention costs
as well.
We have seen that the process of reducing failure costs may well involve increasing
expenditure on the design, developing, testing, manufacturing and inspecting processes.
However, there must clearly be a point beyond which it would be uneconomic to incur
additional expense. Failure costs might possibly be eliminated but at considerable,
possibly prohibitive, costs in other areas. There is a point at which the aggregate
of all costs is at a minimum for the intended selling price. Achieving this minimum
cost will involve reviewing product designs, and improving planning processes, facilities
and methods.
When the initial attack on costs has been successful, it will be logical to provide
a means for analysing costs and for reporting on them in order to keep a close watch
on progress so that, firstly, a worthwhile reduction in the attacked cost is achieved;
and secondly, the expected increase in other costs is not exceeded.
SETTING STANDARDS OF COST
This can be done by setting a standard or budget for each cost item affected by the
action, and by comparing periodically the actual cost with the standard. Differences
between standard and actual cost are then notified to appropriate executives who
can modify the tactics of the attack as necessary to ensure that the differences
are reduced or eliminated.
Standards may be of two kinds: -
- They may be set on the basis of the calculations made during the preliminary study.
In this case, they will be agreed, by the quality controller, with all the executives
responsible for ensuring that the study expectations will be realised.
- They may be set by the more-or-less arbitrary decision of top management to reduce
overall quality costs by - say - 5% or 10%.
In a company where executives are properly trained and motivated, the first type
of standard is likely to be the more effective. Once the initial expectations have
been met, further efforts can be planned and new standards set to correspond.
Improvement comes to be regarded as a normal and continuing process.
In companies where executives lack these qualities it may be preferable to adopt
the second type of standard, in which a programme for improvement is autocratically
imposed. Active follow-up by a strong personality is characteristically necessary
in this situation, to see that executives really do all that is needful.
Standards will usually be set under conditions, which assume a certain volume of
throughput and a certain level of incoming quality. If either of these factors changes
significantly, the level and balance of costs will probably change also, and standards
will need to be adjusted to suit the new conditions.
ASCERTAINING QUALITY COSTS
Cost data will have been required when the first study was made to determine the
cost items most open to attack. These data will probably have been derived by ad
hoc investigation and analysis. The same figures will have been used to derive standards
or budgets.
When costs are to be ascertained regularly for comparison with standards, however,
a number of steps are involved. First, it is necessary to decide which costs are
to be analysed on a regular routine basis, which are to be analysed less frequently,
and which will continue to be derived by special cost studies, or sampling cost methods.
The second step is to decide who is to make each analysis. The preference depends
largely upon the source of the information. If the details can be made available
from the accounting system the Cost Accountant will logically take on the task. However,
if the information is of a technical nature or requires to be extracted from the
records of Quality Control or other staff, it may be convenient to have it done by
these departments.
Next a system of cost coding to simplify analysis must be provided. Where a code
system is already in use it may require modifying to enable quality control costs
to be collected in the most meaningful form. It is important that the causes of faults
should be revealed and this may necessitate identification of the machine, operator
or process where the loss arose.
Finally, one must define the procedure to be followed and the responsibilities of
all the affected staff.
The only purpose of reporting costs is to provoke action. Without action the money
spent on deriving and reporting data is wasted.
Action is required whenever there is a significant difference between an actual cost
and the budget set for it. Action is also required to discover the reason for the
difference and to eliminate it. If cost reports are to be effective in provoking
this type of action they must be: -
- presented at suitably short intervals
- presented quickly following the period they represent
- presented in simple, direct, intelligible form
- presented to the people who have the authority and knowledge to act effectively.
It is often effective for reports to be sent both to the person who is expected to
take action and also to his immediate superior.
It is important to remember that the actual costs revealed by control reports are
the result of joint action by quality control staff and by the design or manufacturing
functions. Action to correct undesirable trends may therefore have to be taken by
all these groups in co-operation. Action by any one group may well be fruitless.
Effective quality cost control depends upon good cost reporting.
The cost reporting system should:
- identify the areas of expense, which are being reported
- show actual expenditure compared with that planned
- facilitate the comparison of benefits with the price that is being paid for them
- indicate the causes of excessive costs so that further investigations can be made
and corrective action taken.
The data from which the Cost Reports are compiled should be so organised that such
further investigations into specific excesses can proceed logically and without the
need for too much re-analysis of basic documents.
Reports commonly take one of three main forms, corresponding to the main divisions
of Quality Costs. The first is the Failure Cost Report. It is not usually difficult
to produce adequate regular reports showing the level of failure costs - scrap, repairs,
test rejections, after-sales service, customer returns etc. The essential data they
should show includes the cause of failure, the value lost, and the department or
process responsible (not necessarily the same, of course, as the department or process
at which the failure was discovered and reported).
Supporting data for this report may include reporting point, description of product,
part etc., and the responsible machine group or operative. Such supporting data is,
however, probably best left out of reports for executive action. It may be more valuable
in daily, un-costed, reports for information and action at "shop-floor" level.
The second type is the Appraisal Cost Report. This reflects the cost of operating
the quality and reliability surveillance, as compared with budgeted expenditure.
The division of account headings may sometimes make it difficult to include the cost
of quality appraisal costs incurred by production operatives carrying out additional
operations such as the inspection, testing, or grading of pieceparts, but such costs
can sometimes be derived from a comparison of actual and standard times for the tasks,
and included in a separate section of the report.
Finally, a Prevention Cost Report is required. So many functions of the typical business
can be interpreted as contributing to Prevention Costs that it is normally wise to
restrict reports to those areas which are being deliberately varied as part of the
overall cost reduction project. The scope of such ad hoc reports can be enlarged
to include data from which changes in Quality tactics can be planned. Such reports
might include: an analysis of the effects on profits of changes in the system of
setting manufacturing tolerances; the probable cost effects of introducing a Vendor
Rating scheme; recommendations on the most economical points for inspection in a
sequence of operations; and an investigation into the economics of buying new testing
facilities.
Note that in studies involving a choice of methods we are concerned with the change
in profit resulting from the decision - that is the difference in the profit-and-loss
accounts before and after adopting the change. The costs which we use for studies
of this nature are not likely to be the same as those used for normal cost accounting,
for which purpose we have become used to the convention of expressing overheads as
a percentage of - say - direct labour. This approach is unsuitable for finding the
real cost, or change in cost, since in most cases the choice will cause little change
in the fixed part of overhead costs, such as establishment and management expenses.
Here are ten steps that can be taken to reduce Quality Costs in your company:
- Find out what Failure Costs are. The cost headings to include are listed in the Appendix
- Decide, from the size of these preventable Failure Costs, the scale of extra quality
control effort devoted to prevention and Appraisal which can be justified.
- Nominate a senior member of the organisation to have responsibility for quality control.
He should be familiar with and able to lead and train his staff in all aspects of
quality control
- Obtain from this manager a list of actions which can be taken, in the particular
circumstances of your organisation, to reduce systematically your Failure Costs
- Evaluate the approximate probable benefit of each action in reducing Failure Costs
e.g. by how much will the customer guarantee claims be reduced? How large a reduction
in scrap can be expected from Room "X"?
- Evaluate the approximate probable cost of each of these actions separately, e.g.
what will extra design administration cost? How much will have to be spent on new
test gear?
- Choose the one or two actions which are seen to offer the probability of largest
return for the cost to be incurred
- Make the quality controller responsible for seeing that these actions are taken and
that the forecast benefits are actually secured:-
- Don't give him too much to do at one time
- Give him a firm date for completion: make it tight but not impossible
- Make sure he follows up each action and keeps it going
- Insist on regular reporting of progress in cost terms - but don't interfere with
the authority that you have delegated to him
- As benefits are seen to flow from the first few - actions, initiate a few more from
the original list - and insist that extra possibilities are constantly added to the
list so that the process never comes to an end
- Find out what the Appraisal Costs are and, in an exactly similar way, initiate actions
designed to reduce specific Appraisal Costs by improving Prevention activities.
The precise contribution to profit made by the control of the quality costs will
naturally vary with the size, type, and technology of each individual company. However,
these suggestions can be regarded as the typical requirements for any programme.
Because almost all operations of a manufacturing company have some influence on Quality
Costs, a full and accurate analysis of costs can become very complex and may itself
be costly to produce. Approximations and estimates will often therefore be adequate.
Finally it will always be desirable to keep cost calculations and presentations-
simple- so that they can be understood readily by those who will be required to take
action upon them. -
- "Prevention Costs", i.e. Costs of Attaining Reliability Quality engineering, and
testing through pre-production stages; material specifications and design tolerance.
Training Quality and Production personnel in quality attainment.
Preparing test specifications
and quality standards.
Specifying test and inspection equipment.
Advising on specifications
of the production facilities needed to maintain quality standards.
Testing and calibrating
inspection and production facilities.
Quality administration.
Replacement of hand
by machine operations.
Replacement of hand operated by automatic machines.
Providing
mechanical handling facilities.
Providing adequate protective packing.
Providing
adequate protective storage.
Providing bins etc. to protect components during process.
- "Appraisal Costs", i.e. Costs of Maintaining Reliability Vendor and incoming inspections.
Inspecting and testing products and facilities.
Field testing.
Maintaining, re-testing
and calibrating inspection and production facilities. - "Failure Costs" (whether through faulty- -workmanship, design, acceptance standards,
machinery, packing, transport etc.)
Work scrapped: material and labour costs.
Re-inspection and re-testing.
Technical and clerical effort spent investigating faults and complaints.
Warranty claims, and gratuitous after-sales service.
Loss due to sale as second-grade product.
Delay in payment by customer - interest on outstanding money.
Double transport charges.
From: "The Cost of Quality"
British Institute of Management 1965
THE FUNCTIONS OF QUALITY ASSURANCE AND QUALITY CONTROL
"Quality" is defined as that combination of design and properties of materials of
a product which are needed for the intended end use and level of the market in which
it is sold.
"Requisite Quality" is defined as the design and composition of a product, which
has been thoroughly proved by adequate development work, in order to establish its
reliability under the conditions to which it will be subjected in use and to avoid
producing too high a grade of product for the intended market.
AIMS OF QUALITY CONTROL AS THE INSTRUMENT OF QUALITY ASSURANCE OR TOTAL QUALITY CONTROL
"To ensure that the requisite quality of product is achieved"
This ensures customer satisfaction, but it leaves quality control as a necessary
but expensive evil
"TO ENSURE, AT MINIMUM PRACTICABLE COST, THAT THE REQUISITE QUALITY OF PRODUCT IS
BEING ACHIEVED AT EVERY STAGE OF MANUFACTURE FROM RAW MATERIALS TO BOXED STOCK.
- Checking the suitability of raw materials,
- checking the manufacturing capability of the production undertaking
- monitoring production; feeding back information; responding to that information;
and so getting defects removed at source
- reduction of the fault rate
- saving costs
- maintenance of product consistency
All of these factors increase the possibility of developing further business and
the competitiveness of the company, and is therefore to the benefit of the company;
Quality control thus becomes a positive -benefit.
A further point stems from one aspect of Q.C: continually monitoring production and
deciding whether, in any part of the manufacturing chain, materials, machines or
workmanship need attention to effect a reduction in the fault rate. It is very easy
to "pass the buck" that is for production personnel to blame materials or to say
that it is the responsibility of QC, and so relax any endeavour on their part to
avoid faults. In fact, quality cannot be inspected into goods; it is to direct attention
and effort towards the most effective areas for avoiding faults and to maintain product
consistency.
"The establishment and maintenance of ALL activities and functions concerned with
the attainment of requisite quality"
"The systems required for programming and co-ordinating the efforts of the various
groups in an organisation to maintain the requisite quality" As such Quality Control
is seen as the agent of Quality Assurance or Total Quality Control
Quality Control requires the establishment of adequate specifications with proper
tolerances
To maximise the production of goods within the specified tolerances correctly the
first time.
By considering such information it can be decided what requires to be monitored.
Monitoring the process is the essence of quality control.
We now know where we wish to go and what is possible. -
The next stage after planning is to extract and expand along the guidelines established
in the planning stage the technology or the basic know-how for each projected line.
These technologies are;
Engineering - fabric, seams, garment
Communications and feedback sequences - without which there can be no control
Parameters - measurements and tolerances
Staffing decisions and the development of job specifications
This is the practical control application to the day-to-day running of the factory
- and extends from the basic concept of a style right through to the despatch of
the correct boxed stock.
INSTALLATION OF THE OVERALL PLAN
The above plan is a continuing procedure in the sense that if starting from scratch
one might have to begin with monitoring to get immediate results. This is then followed
by a continuing process of refinement along the lines of adding the checking of raw
materials and improving feedback routines.
The requisite quality is the standard required to meet the needs of the customer:
this must be determined and specified.
The specification must be clear and complete so that everybody from designer to production
operative has a clear idea as to what is needed. Individuals within an organisation
need only have parts of the specification that relates to their function. -
To achieve a satisfactory design of the fabric or garment in relation to the level
of choice in design, styles, colours, suitability of components and fitness of product
for the market. This must be viewed in the context of overriding market considerations
and production capabilities
- Itemise the variables that occur in fabric and garment production in order to provide
a complete specification.
- Develop a specification in a number of parts or sections to ensure that all design
and production staff have a clear idea as to what is needed
- Establish acceptable working tolerances in relation to all values on the specification.
- Establish fault rate recording systems
- Improve technical understanding of the product including
- fabric geometry and the interrelationship of yarn count, loop length, pick count,
relaxation and fabric properties.
- sewing problems
- causes and prevention of seam breakdown
- the effects of various factors on the apparent shade of goods affecting shade matching
- Check consistency of incoming raw materials
- Select suitable instrumentation for determining specified manufacturing values
- Choose recording systems to provide a history of control
- Select a method to assess operator effectiveness
- Make periodic checks on: Fault level
Waste
Seconds
Losses
Delivery weight of yarn and
record results - Commence testing of fabric and garments and record results
- Analyse results
- Check colour vision of personnel
- Examine fabric on receipt
- Consider fabric storage facilities
- Examine fabric cutting quality
- Cost the design quality in terms of: Cost of failure
Cost of appraisal
Cost of prevention - Introduce wearer trials and product testing
- Develop through recording systems in the sampling department
- Consider computer aids to development of specification
- Prepare working standards and samples for shade matching
- Examine potential for instrumental colour matching
- Integrate techniques into a coherent GC scheme
- Develop effective colour matching routines
- Examine economics of cleanliness
- Monitor cost levels at all stages
Control must be applied to make sure that all goods passed to the customer reach
the satisfactory level Planning procedures must be reviewed periodically -
Cost of achieving the required standard of quality must be targeted at all stages
-
PRINCIPLES OF QUALITY CONTROL
The essential requirements for producing a reliable product has been stated as follows:-
- A satisfactory design of product, thoroughly proved by adequate development testing
in order to establish its reliability under the conditions to which it will be subjected
in use. This is the Requisite Quality of the product.
- A full specification of the requirements of this quality, which must be clearly understood
by everyone concerned with the production of the constituent parts and of the complete
end product.
- Confirmation that the manufacturing processes are capable of meeting these requirements.
- Full acceptance, by all those concerned with production, of the responsibility for
meeting the standards set by the specification.
- Checks on the product at every stage of manufacture to detect any departures from
the specification.
- Record essential information derived from these checks to provide accurate evidence
for action.
- Establishment of lines of communication, - i.e. Feedback to Production, - to ensure
that this action is taken to effect the appropriate adjustments to materials, process
and operatives to maintain FUTURE production within the specification.
- Instruction in the use, applications and limitations of the product.
- A study of user experience, feedback to the department's concerned, and rapid remedial
action.
An important feature to realise in the establishment of these principles is that,
whilst tolerances and quality standards for goods going for despatch may often vary
rapidly, depending on the urgency of call-off, it is the duty of Quality Control
in enacting items 4-7 above, to stabilise the tolerances and quality standards for
goods IN PRODUCTION, based on the recognised Requisite Quality and this largely established
from the continual experience gained from item 9 above. Only by production personnel
knowing exactly what is expected can they respond to the requirements of Quality
Control.
ECONOMIC ASPECTS OF QUALITY ASSURANCE
The ideal situation is to keep the cost of conforming to the requisite quality as
low as possible, whilst at the same time achieving the highest percentage of acceptable
production.
To find if a company is approaching the optimum total cost trials need to be made
to establish the costs of quality control and the cost of defectives.
As a first approximation and as a guide, this total cost is usually achieved when
prevention costs = failure costs + appraisal costs, as illustrated in the above diagram,
and in the diagram below:-
In this firm the total quality costs were approximately 10% of turnover (very low).
By increasing appraisal and prevention a saving on total costs of 15% was effected.
This is 15% on 10% of turnover, say 1.5% of £2,000,000 i.e. £30,000 saving in cost,
improved product, improved delivery times, and improved customer satisfaction.
Quality Costs Sources of Cost information
Losses due to faulty and spoilt work
- additional materials
- extra labour
- disruption of production
- reaching agreement with customers
- replacing defectives or complaint adjustments
- office administration
Penalties of not meeting delivery dates, e.g. failure to meet export arrangements,
shipping. -
- Control of outside supplies, salaries and equipment less reclaims from suppliers
e.g. testing incoming materials etc
- Inspection e.g. 1st examination and final examination.
- Fabric or garment tests, e.g. wash tests, yield tests, and appearance checks, any
other checks
- Maintenance of test or inspection equipment
- Product value destroyed in testing materials consumed
- Cutting Department - cutting losses
- Services, e.g. electricity, steam, compressed air
- QC outside endorsements, e.g. Woolmark
- QC records & admin charges
Preparation and development of specifications
Time of personnel related to salaries
Developing consistency controls, e.g. use of stitch length
Operating consistency controls
Costs and salaries of department personnel
Evolving more effective processes
Quality awareness training Wages, account, and training costs
Maintenance of machinery to maintain product quality, e.g. re-needling knitting machines
Production records, wages and equipment costs.
THE BALANCE OF COSTS VERSUS SAVINGS - ASSESSMENT OF INNOVATIONS
The necessity of making conciliation occurs every time an idea or innovation needs
to be assessed.
Suppose a new system has been thought up to meet a problem or situation which needs
to be improved. The question before getting too involved in detailed planning of
such a system, will be does it pay off? This question needs answering before much
time, effort and money are spent.
- Look at the present situation. Ascertain the cost of failure in the area where the
innovation could be expected to have some effect. Analyse available records. If these
are inadequate consider making records for a trial period. The resultant cost gives
the potential saving and the scale of costs involved.
- Make an assessment of the cost of carrying out the innovation - not so much the costs
of installation as the continuing running and updating costs.
- Next consider what degree of potential saving is likely to be achieved as a result
of implementing the innovation. In the absence of any guidelines assume 50% achievement.
This will at least give a guide to what savings realistically might be achieved.
- Armed with this information a decision can be made, based on this assessment and
the relevant recorded information. Keep notes as ideas and evidence develops. If
the idea is worthwhile it is worth being persistent, but does not spoil a case by
pressing for it before you are too sure, since time and credibility can easily be
lost.
It is wise to seek a trial first, then the idea can justify itself on its own merits,
or can easily be dropped if for any reason it proves to be unsuccessful.
THE ROLE OF QUALITY CONTROL
- In a total quality control scheme, the total involvement of all personnel is required
as a philosophy.
- The staff concerned in all duties must be given authority to carry out their functions.
These functions should be defined.
- Lines of communication and responsibility should be established to carry out an effective
policy. Horizontal communication at all levels of personnel between Quality Control,
Production and other departments is needed. Also there must be vertical lines, which
follow the lines of responsibility and authority. In order to achieve this aim, the
terms of reference under which staff work, must be established. This is, perhaps,
best accomplished by job descriptions.
- It is the job of Quality Control to establish the correct information concerning
a quality situation, and present this clearly to their colleagues.
- Persons outside Quality Control must be authorised to make the commercial decisions
involved from a pre-established series of options, the consequences of each being
fully understood.
- Payment schemes should be re-examined where necessary to reward quality as well as
production, in a balanced way, since both are commercially important.
QUALITY CONTROL DATA GENERATED
Data is generated at each QC point. This must be recorded in simple systems to provide
visual on-going checks. These records provide the means for personnel accountability
and for rapid feedback for management action. -
- Shade - checked to be within tolerance of standard pattern.
- Delivery weights - checked and any shortfall claimed.
Knitting Machine Settings
- Yarn tension - levelled and to knitting specification.
- Distribution - K.O. Depth, dials height - set to specification.
- Loop/course length - Run-in levelled and to specification, positive feed checked.
- Take-down tensions - checked for consistency. -
Fabric Parameters, Fabric or Garment Blank Checks
- Shade and appearance correct jacquard pattern correct, absence of barrenness.
- Width normal - (this is only a guide with grey fabric).
- Fabric weights per square metre (or preferably weight per predetermined revs) - checked
to within tolerance of specification.
- Blank weight per dozen to be within tolerance of specification.
- Check fabric for faults and stains.
- Finishing loss - on-going record of losses on scouring etc.
- Accountability of knitters.
- Stitches per cm. and thread run-in ratio checked to be within tolerance of specification.
- Evenness, balance and correct bight, no stitching missed
- Extensibility and security correct (i.e. no cracking or laddering).
- Absence of skip stitching.
- Accountability of machinist.
- Shade correct and not varying from one part of garment to another.
- Cut is correct - e.g. neck, collar and sleeves balanced, pockets correct.
- Measurements within tolerance of specification, weight correct.
- Appearance correct, patterns matching.
- Seams finished correctly, absence of miss stitching, cracking and laddering.
- Accessories correctly applied and working.
- Absence of fabric faults and stains.
- Correct labelling.
- Accountability of making-up (volume of work unsatisfactory; break-down under various
fault categories.)
- Check whether remedial works satisfactory.
- Check on volume of work successfully recovered.
- Avoidance of work recycling.
- Count Tests on Staple Fibre Yarns: Check on count variability, within cones and between
deliveries: to be within tolerance of specification. If coarse, yarn utilisation
impaired. Check on running average.
- Bulking Tests on Continuous Filament Textured Yarns: Check on consistency, and on
filamentation
- Condition Checks: Check on incorrect condition
- Yarn wrapping:
Levelness of yarn (also User levelness).
- Colour fastness to agreed agencies: (e.g. washing, rubbing, perspiration, lights)
- checked and on-going continuity cards generated, showing rating, checked against
specification.
- Stability: Shrinkage, and extension recovery where needed - to be within tolerance
of specification
- Endurance: Abrasion, pilling or snagging - tested where needed. Rating checked against
specification
- Flammability:
Performance rating in appropriate test checked against specification. -
Further Yarn Checks (2nd order priority)
- Fibre analysis: As specified for correct labelling
- Fibre quality: As required
- Yarn twist: On new deliveries and on demand for fault diagnosis. To be within specified
tolerance
- Co-efficient of friction: Test and compare to specification
- Oil content: When records of finishing loss, yarn utilisation, count, grey weights,
or finished weights abnormal, oil content checked; and also if yarn running abnormally.
Content figure to be within tolerance of specification.
- Accessories Checks: Shade and size checked to be correct (e.g. buttons)
Stability
(e.g. linings and trims and zip tapes) within tolerance of specification. Extensibility
and modulus (e.g. binding and elastic) within tolerance of specification. Items work
properly (e.g. zips)
Sewing threads, correct shade, ticket number and sews normally
- Boxed Stock Audits Goods in warehouse - sample checked for quality and faults.
Goods
rejected - check to see if correctly rejected. - Machine Efficiency Ratio of knitting time or goods produced compared with basis if
no down-time. Provides measure of machine performance - analysed against knitter,
machinist, fabric quality, garment style and yarn. -
- Yarn Utilisation
- Fabric Utilisation
As with machine efficiency, checks on process performance.
Analysed against operation section, style, fabric or yarn.
The above data, immediately on being generated, is automatically entered on records
as continuity charts, either in tabular, graphical or computerised form. This action
takes very little time, and enables the current data to be compared with previous
data and with other related Q. C. data. The visual impact of the presentation is
immediate and creates rapid feed-back of vital information to production and other
interested management personnel.
British Standard 5750 Part 2 specifies a quality system, which is designed to provide
a comprehensive, concise and logical approach to total Quality Assurance.
It relates to a method of working and not to any specific performance standard of
a product. In principle it can therefore be applied to the manufacture of any product.
The essential features of the standard are contained in the following basic requirements:-
- Quality System
- Organisation
- Review of Quality System
- Documentation/Records
- Equipment
- Purchased Materials and Services
- Manufacturing Control
- Work Instructions/Workmanship
- Corrective Action
- Completed Item and Inspection and Test
- Sampling Procedures
- Control on Non-conforming Material
- Alternative Inspection Procedures and Equipment
- Indication of Inspection Status
- Protection and Preservation of Product Handling, Storage and Delivery
- Training.
To be of value each and every requirement requires individual manufacturer interpretation
and implementation relating to the product being produced
This Quality Management Scheme has proven success in many UK industries. At first
sight it appears complex and the first reaction is that it will add extra cost to
implement. In truth it is a straightforward logical system which gives total control
of quality which when implemented will prove fully cost effective.
- Quality System To achieve the overall objective you will need to establish, document
and maintain a system capable of ensuring that products conform in total to standards,
specifications and sealed samples. This will be required at every stage of manufacture.
Records must be maintained to give objective evidence that the specified requirements
have been met.
- Organisation You will need to appoint a management representative preferably independent
of other functions to be responsible to oversee the total control system and inspection
at each stage of manufacture. The person appointed should have the necessary authority
to execute any action related to achieving the desired standard of product.
- Review of the Quality System To be effective the system requires planned periodic
review by Senior Management to ensure its effectiveness is maintained. This will
entail internal audits, which must be positive and not conducted solely as a matter
of expediency resulting from a quality problem.
- Documentation
To be effective it is essential to establish and maintain clear, complete and current
written records of inspection and test procedures for each operation.
These records should identify: -
- Criteria for acceptance/rejection.
- Action to be taken and by whom.
- Essential information and data to identify item and batch.
- Details of equipment and calibration.
Records must be kept up to date and be stored for easy access and retrieval and be
available for examination.
- Equipment All inspection, measuring and test equipment requires effective maintenance
and calibration.
- Purchased Materials and Services The quality system must be capable of controlling
the standards of materials and services supplied by third party suppliers.
Your purchasing
documents must clearly define any desired standards or specification requirements.
All incoming goods from third party suppliers must be inspected and tested as appropriate
and records maintained. - Manufacturing Control In-work inspection should be conducted during manufacture on
all characteristics, which cannot be left until final inspection to prevent subsequent
sub-standard products. This type of inspection to be effective must act as a process
control.
- Work Instructions/Workmanship The supplier must establish satisfactory written standards
and representative samples or workmanship which must equate to standards and specifications
laid down in Data Sheets, Make-up Specifications and Sealed Samples. These standards
must provide an objective base on which decisions are made by skilled personnel.
- Corrective Action
Documented procedures must be established and maintained to cover: -
- The prompt detection and correction of inferior quality
- A continual monitor of processes and work operations including performance testing
- The action to be taken with third party suppliers on receipt of sub-standard materials.
- The review of any corrective actions taken.
- Completed Item Inspection and Test All finished products must be inspected and tested
to ensure conformity against any relevant standard or -specification. The documented
procedure established at this stage should ensure that any inspection or tests conducted
at an earlier stage have been performed and the data obtained acted upon.
- Sampling Procedures Sampling procedures used should be such that any information
gained from the sample equally relates to the bulk from which they were taken.
- Control of Non-Conforming Material There must be an effective system established
to deal with non-conforming material to ensure it is clearly identified, segregated
and disposed of. Adequate records must be maintained for subsequent review.
Any repair
or rework activities to correct non-conforming material must be clearly identified
and documented. - Alternative Inspection Procedures and Equipment Where you wish to use alternative
inspection procedures and equipment valid evidence must be available to ensure they
provide equivalent assurance of quality.
- Indication of Inspection Status You must establish and maintain a procedure to clearly
identify products at each stage of manufacture e.g. products not inspected; products
inspected and passed; and products inspected and rejected.
- Protection and Preservation of Product Quality during- -Handling, Storage and Delivery
Procedures and instruction must be established to: -
- Clearly identify materials and products form receipt to despatch.
- Control and protect all materials and products during handling, manufacture, storage
and delivery.
- Ensure finished products are stored and delivered commensurate to the quality standards
demanded by the customer.
All personnel involved with the management of quality must be experienced to receive
adequate training to ensure they are competent to perform their required task.
Training must be an ongoing commitment with appropriate records being maintained.
QUALITY CONTROL IN THE DESIGN AND DEVELOPMENT DEPT
If disorganisation in sampling is to be avoided guideline procedure must be established
beforehand.
Modifications to the development sample must be noted for inclusion in the final
specification.
A handle sample (sealed if necessary) must be established as well as a working sample.
A proper flow diagram must be established with appropriate time factors, and all
personnel concerned informed of the duty and timing of their part.
In the following pages, a diagram of typical steps is shown together with details
of the duties of Q.C. personnel in this scheme.
In addition, Q.C. can be involved in development at an earlier stage by sampling
new yarns. In combination with wearer trials and laboratory tests, assessments of
seasonal and other goods can be made, e.g. tests made to ascertain whether fabric
is too heavy for spring, is suitable for trousers, drapes correctly for dresses or
curtains, or suitable for use in bright sunlight.
- If routine checks are carried out on yarn choose a delivery of average tex (count,
denier).
- If incoming yarn is not checked then check the tex (count, denier) of the delivery
intended for samples and only use if it is within acceptable limits.
- Carry out other appropriate tests on yarn e.g. crimp nylon-Crimp Rigidity test. Knit
a small sample and check that dye is fast to light, washing and perspiration etc.
- Record details of yarn type, supplier, tex (denier, count) etc. and pass information
to knitting room.
- Record all details required to produce the fabric or garment blanks including chain
set out, stitch length and any instrument measurements.