The relevance of performance information to product quality

Engineering

Management International,

3 (198

175

Elsevier Science Publishers B.V., Amsterdam -

our and B.G. Dale Department

of Ma

UMIST,

P.D. Box 88, Manchester,

M60

IClD, 0.LK.I

ABSTRACT

Information feedback on product formance is a potentially major initiative for design reviews and others improving changes. There are two of potential feedback information -nom analysis of complaints, spares etc. ; and external information the product from the end use reports on the sources of pe back information which exi

per-

INTRODUCTION

Quality is a very wide-ranging attribute of a product; it encompasses every facet of the product from its design through to its packaging and subsequent delivery, and it will remain for the majority of nations a cornerstone of their industrial prosperity. It is not something that can be “added on” to a product by making “adjustments” and massaging after manufacture. Quality is inherent in the product itself, in the production methods used, in the definition of the product’s use and in the design characteristics that satisfy that use. Governments in countries other than Japan are becoming more and inore interested in quality and are offering inducements to organizations to improve quality and awards upon the attainment of quality. In the United Kingdom (U.K.), the government, through a National Quality 0167-5419/85/$03.30

tional chemical company, and the type of feedback information which equipment manufacturers would like to receive and how they would use such information. It is coneluded that if companies wish to see an improvement in the quality of supplied products, they should expend more effort in feeding back to the suppliers information on how their product(s) perform in practice.

Campaign, is currently aiieinpting to make quality a priority in much the same way as a company would attempt to make the quality of its products a matter of concern for everybody employed in the organization. In any manufacturing organization the transmission of internal and external feedback information is an essential element of a quality control system. Internal information is that which is available to the manufacturer from the normal course of his business, whi!e external information is that which come6 from the customer on product performance: this should contain data in sufficient detail to be useful to ths supplier. &ran and Gryna (1980) quote the following sources of internal feedback information: measurement of field complaints: measure of returns for credit; information on spare part orders; customer reactions; and records +-m-s lost. Such information can be of cusL#v-u_

o 1985 Elsevier Science Publishers B.V.

1’76

obtained free without the need to press customers for performance data. External information can however, despite being much harder to obtain, be of far greater value. Jum and Gryna (1980) believe that the supplier needs two items of customer feedback: firstly, all the quality problems encountered by the customer (e.g., number of failures, other instances of trouble, problems not covered by the guarantee) and secondly, the relative importance of quality problems as viewed by the customer. These two items of information are not easy to obtain, but their criticality in assuring proper emphasis in a quality programme dictates that an effort be made to obtain the information. The usefulness of feedback information is primarily in design reviews and in the continuous process of design-usage-redesign spirals. The importance of feedback information . m quality assurance systems is almost universally agreed upon. Most major works on quality mention feedback and its importance, but very few go farther than that. It would appear from the literature that few feedback systems exist which report product performance to the manufacturer and &hat few suppliers receive any feedback information other than warranty complaints. Robertson (1971) makes the point that a weakness of many quality control systems is a lack of feedback information from the user. Juran and Gryna (1980) comment that relatively little has been done to develop sensing systems to obtain the customers views on quality. In a recent study of the U.K. pressure vessel fabrication industry, Dale and Plunkett (1984) concluded that most fabricators they studied do not obtain feedback on product performance unless it is considered unsatisfactory early in its service life. Cited in the literature are examples where performance feedback information from users has been instrumental in improving quality. Gretzinger (1965) describes a successful system operated by the Buick Motor Division on a sampling basis in the early sixties. Another system, this time for grinding wheels, is described by Schiliing and Davies (1964).

Geyde (1968) describes a simple system operated by the Rover company in which car dealers attempted to feedback defect information which was as complete as possible, this was then incorporated into redesigns. A more recent and well publicised example concerns Jaguar Cars and is reported by Elgin and Jones (1982). Jaguar supplemented their quality programme with phone calls to customers which gave the customer a chance to feed back their views on the cars direct to Jaguar. The quality programme has been a huge success at Jaguar, who have now reconquered a once lost American luxury car market.

SOURCES OF PERFORMANCE INFORMATION WITHIN VARIOUS PLANTS OF A MULTINATIONAL CHEMICAL COMPANY Background

The U.K. part of the company’s operation comprises several operating sites. The company operates a centralised materials services function which includes purchasing, sourcing and agreements, purchasing and inventory control, and quality assuranee. It is of interest to this paper that the materials services function, which has as one of its duties ensuring that the company only places orders with suppliers who are capable of manufacturing to the quality required, receives no feedback from the various operating sites on how well equipment actually performs subsequent to purchasing. Information such as relationship of downtime to operating time, reasons for downtime, reports on breakdown, and details of modifications to the plant is stored within computer systems at the various operating sites, but its use is limited to within the site itself. If this information was forthcoming, the central material services could collate and examine feedback information from a variety of operating sites within the U.K., leading to a large reservoir of potential

177

information which could be fed back to both suppliers and the company’s own design department. If the information was sent to head office along with similar information from other sites throughout the world, a central library of equipment history could be established. Performance recording methods

An outline is now given of the methods by which the company, as a large user of equipment, records the details of the performance of that equipment from the time of delivery onto site until the end of its useful life. This process of recording starts upun the delivery of equipment to the site when it is checked and inspected agaiast the order. It continues with the compilation of maintenance history records up until such time as the eauinment is scrapped. (i) Delivery and inspection: From the delivery and inspection procedures two types of feedback information emerge. Firstly, the reasons for any material rejection on inspection are made known to the supplier. Secondly, the frequency with which any supplier has material rejected is recorded and entered into an information system, this information is also fed back to the supplier. A supplier whose material fails persistently is brought to the attention of the quality appraisal department which may then wish to reappraise that supplier as a recognised source of supply. The company has a grading scheme for rating its suppliers: for suppliers in categories 1 and 2 the amount of inspection is considerably less than for suppliers in categories 3, 4 and 5. Frequent meetings are held between technical representatives of the company and category 3, 4 and 5 suppliers. Such discussions could be classified as an informal source of information feedback. (ii) Criticism of material: Another source of feedback information is known as a criticism of material (COM). This is distinct from a notice of rejection in that the latter is made

at the goods inward stage, whereas a COM is

raised at the operations stage. The COM is primarily for new equipment which is still within the warranty period, or for repotiing on any damage that has occurred duing transit. The main use of the COM is rtcognised as a direct source of feedback information to buyers and suppliers from the manufacturing location. The main purposes of a COM are (a) adverse criticism for: 0 material not meeting specification l defective material l material failed in normal operations l material damaged through inadequate specialised packing. and (b) positive criticism for: l a new product which has proved to be most beneticial in operation l a product which has been successfully used in alternative operations l a new method of approach for favourable results (e.g., a new type of packing) of a material which had been previously adversely critic;sed. These functions are intended as action and information points in order that: claims and replacements can be effected investigations can be made although no claim is made checks may be made with other operating companies, and their experience requested material standards can be amended improvements can be effected groupwide quality assurance analysis may be recorded. The most common reasons for raising a COM are when a new piece of equipment has malfunctioned under normal conditions or where packaging is damaged or faulty. They can also be raised where material is below specification or the type of material is unsuitable. The COM is used mainly as a warranty claim on the supplier for faulty equipment, It is a source of feedback information to the supplier which as otilined above can be used for either adverse or positive criticism.

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(iii) Long term performance data (maintenance history systems): The information gathering systems discussed above have been concerned with new or recently purchased materials/equipment; the compilation of long-term performance data is now disThese systems primarily record cussed. of equipment rather than performance materials. They c.Alect data from various sources and provide extensive engineering costing and equipment history information. Historical data is compiled and stored on items of equipment such as motors, compressors, pumps, turbines and gearboxes. MAINTENANCE

EXCESSIVE

ZONE

There are two main types of systems in the U.K. operating sites which collect and make available (for internal use only) the sort of described external feedback information by other writers. Both these systems record information on the number of failures in a degree of detail which is sufficient to be of some use if fed back to the supplier. Neither records the losses to the user resulting from the breakdown (other than the cost of effecting the repair). The actual downtime for each repair is not recorded, although some idea of the time taken to effect the repair can be gained from the labour cost figure. Mean HISTORY

FAILURE

REPORT

-

AD1 P TREATER RECIP

PUMP TANK 1 to A CAUSTIC SODA SOLUT DRIVEN BY MOTOR DRIL’IYC WORKS AC

FOR SELECTION

- HIGH COST EXCESSIVE EXCESSIVE fXCESSIVE EXCESS1 VE

OVER LAST 12 MONTHS FAILURES FAILURES Of SAME COhPOYENT FAILURES DUf TO SAME CA’ISE FAILI!RES OF SAME COMP/CAbSE

MAINTENANCE cos1 OVER LAST 12 MON THS PER AVERAGE FOR ALL METERING PUMPS

MAINTENANCE

DATE

ft&tTPMENT

PLANT

WORKS NO. METERING

REASDII

RUNNING

13 7 8 7

KW RATIYC

f

(PM)

f

PUMP 5.50

KW

Off Off Off Off

2EE.% 333.43

HIS TORY

FAILURE

MGCE

RESUL TINC

fRC@l

CAUSED

BY

DCSCRIPTION LA8

ww YY 37 28 16 15 14 13 06 04 52 49 47 42 41

82 82 82 82 82 82 82 82 81 81 81 81 81

INSPECTION SCHED MAINTENANCE INSPECTION LEAKAGE REDUCED PERFORMANCE LEAKAGE LEAKAGE LEAKAGE LEAKAGE EXL-fSS VIBR/NOISE REDUCED PERFORMANCE LEAKAGE LEAKAGE

NONE NONE NONE PACKING NOT KNOWN PACKING PACKING PACKING PlCKING BOLTS PISTON PACKING PACKING

NONE NONE NONE MECHANICAL NOT KNOWN MECHANICAL MECHANICAL MECHANICAL MECHANICAL CRACKING MECHANICAL MECHANICAL MECHANICAL

WEAR WEAR WEAR WEAR WEAR WEAR WEAR WEAR

CN LINE INSP SCHEDULED LUBRICATION DN LINE INSP A/N GLANDS LKNE REMOVE IO CHS ACJ. GLANDS 4CJ. GLANDS CHECK GLANDS CHECK GLANDS GLAND BOLTS SHEARED APR METERING PUMP GLAND PACKINGS REPACK GLAND V SEALS

0 13 0 2 343 36 16 39 10 26 ED 33 0 TOTAL

27 22 20 10 04 03 03

81 81 81 81 81 81 81

SCHED MAINTENANCE REDUCED PERFORMANCE LEAKAGE INSPECTION LEAKAGE LEAKAGE LEAKAGE

NONE TIMING GEAR PACKING NONE MECHANICAL SEAL PACKING PACKING N.H.

LATEST

20

RECORDS

NONE MECHANICAL MECHANICAL NONE MECHANICAL MECHANICAL MECHANICAL ONLY,

Fig. 1. Example of an excessive failure report.

FURTHER

WEAR WEAR WEAR WEAR WEAR INFO.

SCHEDULED LUBRICATION CHECK ADJUSTER CfK. GLAND CN LINE INSP A/N Rf’K GLANDS REPACK GLNDS PUMP GLANDS LEAKING ON REQUEST

FOR 10 162 9 0 13 44 49

COSTS MATS

D/C

00 0 0 00 00 567 232 0 0 0 0 0 0 !i5 3:

0 0 0 0 0

JOb NO 0 0 0 0 0 0 5: 0 0 D 0

12 MTHS 0 456 00 DO 0 C on

1142 36 :69 66 26 179 33 34

871025 L55443 870918 539248 53075c 539818 538828 537636 535168 533990 532496 530770 531598

1586

0 159

0 0

0 0 I.? D 0 D 0

10 777 9 0 13 44 49

L51965 53644A 53520A 870217 537961 532817 532871

179

time between fG.lure information is not specifically produced but can be simply calculated from the dates of the failures which are given. Erom the various inputs a number of reports relative to feedback are produced: equipment history - month1.y and cumulative; excessive activity/cost; and engineers’/ inspectors’ reports. The first three reports are produced automatically according to given criteria. A good example of how such systems may be used to pick up possible faults in equipment is shown in Fig. 1. This is the maintenance history of a pump. It can be seen that leakage caused by mechanical wear in the packing appears to be a recurrent problem. This problem occurs very frequently, sometimes at one or two week intervals. The report picks out seven failures of the same component (the packing). This seems to warrant some form of feedback to the manufacturer, or at least a closer examination of the packing problem by an engineer. The system also includes summarised engineers’/inspectors’ reports. Periodic inspection reports are made on all items of equipment on the site. Engineers’ reports are also made from time to time on particularly troublesome plant items or any other subject thought to warrant an investigation. These reports with their greater detail may well shed light on a design or other problem which is not picked up from the history equipment reports. This sort of detail is very useful as potential feedback information. Equipment manufacturers viewpoints

Indepth interviews were held with eight of the company’s main equipment manufacturers in an attempt to discover their feelings on the question of performance feedback data. From the outset there was no intention of conducting a statistically designed survey; the primary aim was to discover whether any performance information ever reached the suppliers, or indeed, whether or not this type of information was thought of as

potentially useful. The sizes of companies studied ranged from 130 to 3000 employees with sales turnovers from $5M to S60M which covers the small to medium sized engineering sector. The products were all equipment products such as pumps, motors, compressed air equipment, gearing and turbines. All the companies said they would find performance feedback information from cuetomers useful with regard to the quality of their products. They were unanimous in that they received very little feedback from CUStomers and what they did receive was mainly in the form of warranty complaints; there was little evidence to suggest that any warranty claim analysis was carried out. The general view was that they received slightly more feedback from Naval or Military customers. Most of the companies complained that the information they did receive was generally very unspecific. One company gave the example “pump will not pump liquid” as being typical. There was some variation on the companies’ ideas of how specific and detailed feedback information should be. The consensus view was that the information should be reasonably specific if it was to be any use. One company wanted back-up information from the users’ expert departments. The authors’ view is that this is asking quite a lot in all but serious or highly recurrent cases. Seven of the companies thought information pointing out components that were subject to repeated failures would be highly desirable. All of them would like to see information feedback concerning components subjected to repeated failures, types of failure, and causes of failure. Other types of information such as simple improvements, praiseworthy points, information on service loads and duty cycles, ur;e of the equipment, change of duties, etc. were requested by several respondents. The type of feedback which the equipment manufacturers felt they required is definitely available in the company’s long term performance data collection systems. All the companies indicated that the per-

180

formance feedback information would be used in some way to alter the design of their equipment in order to improve product quality. The information would also be used in design reviews. Most of them would like to see at least a sample of information on their equipment fed back from customers for over two years after installation up to a complete life history of some equipment. Each crImpany was subject to quality audits and six of them thought it would be useful if visiting auditors brought performance information with them. Only one company indicated that some auditors did have this type of information available. The fact that there does appear to be a feedback problem between industries was confirmed when it was established that none of the various suppliers to the eight equipment manufacturers had ever requested feedback information on the performance of their products. If feedback information is only going to be transmitted by request, each manufacturer guilty of this is surely contaminating the water from which they themselves have to drink.

CONCLUDING

REMARKS

Information feedback on product performance is a potentially major source of initiative for quality improving changes, but it would append that in the U.K. very few feedback systems exist by which manufacturers receive performance data on their products after installation. Indeed, in the case study company featured in this paper, prior to presenting the research findings outlined here, there was also an internal feedback problem in that the quality appraisal department did not receive any information from the operating sites on how a manufacturer’s equipment was performing. It

would appear that few suppliers appear to receive any feedback information other than warranty complaints, on which little performance analysis is carried out. If information is to be fed back by users, then the more comprehensive and specific the information, the more useful it will be to the supplier. Most large companies have computerised maintenance history systems, the data from such systems can be used as source of feedback to the equipment manufacturers. Typically, the data required to be collected by the craftsmen for input into such systems includes: reasons for maintenance; causes of failure; and type of work carried out. If the data contained in a maintenance history system is to be used for feedback it is important to include another cateogry of data (i.e., component). Seven out of eight manufacturers questioned suggested that a simple indication of components that were subject to repeated failures would be highly desirable as feedback information. Table 1 shows some suggested maintenance history failure codes for components which have been developed for inclusion in the case study company’s maintenance history system. The company is currently experimenting on how best to manipulate its system to feed performance data back to their main equipment suppliers. The larger companies are moving towards the compilation of a material administration vendor information system, intending it to be a complete package of important information not covered in a quality appraisal (e.g. 9 complete product range and specifications, delivery performance, commercial data). If performance information were to be collected by such a system, this could be a good central point by which information on product performance and vendor rating type data could be fed back to the supplier.

181

TABLE Suggested Running 01

02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

1 component

codes for inclusion

equipment

Crankcase/casing/ bedplate Crankshaft/Shaft Sleeve Main bearings Big end bearings Radial bearing Thrust bearing Conrod assembly Camshaft assembly Valve assembly Cylinder head Cylinder liner Piston Piston rings Bucket/ram assembly Cylinder head gasket Turbine rotor Impeller Propeller Positive displacement screw Diaphragm Diffuserlstator Wear rings Steam nozzle Fuel atomiser/injector Fuel pump Lub oil system Cooling system Seal oil system Starting system Exhaust system Belt drive system Coupling Flywheel Fan Worm gear Wheel gear Rack Pinion Governor assembly Control valve Air distributor Timing gear Pressure relief valve Mechanical seal Packing Labyrinth seal ‘0’ Ring/shaft seal Product filter Guard

in a computerised

maintenance

Static equipment 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 96 97 98 99

Plates/shell Stairs/ladder Nozzles Welds Pipe Flange Internals Skirt Roof drain Roof seal Roof vent Channel box division plate Header/channel box Tube sheet Tubes Baffles Stays Venturi Nipples Tube support Joint Throat Dual fuel gun Gas ring Air register Dampers Ducting Furnace Convection bank Air preheater Slack Soot blowers Shot cleaning equipment Thermocouples Floating head Bolts Sight glass Lagging Overhaul None Not known Others

history

system

REFERENCES Dale, B.G. and Plunkett, J.J., 1984. A study of audits, inspection, and quality costs in the pressure vessel fabrication sector of the process plant industry. Proceedings of the Institution of Mechanical Engineers, 198( 1): 45-54. Elgin, R. and Jones, W.E., 1982. Jaguar climbs out of the pit. Sunday Times, ‘7 November: 61. Gretzinger, J.R., 19’75. Buicks reliability program. Industrial Quality Control, 21( 9): 449-453.

Geyde, R., 1968. A Managers Guide to Quality and Reliability. John Wiley and Son Ltd., New York, 140 pp. Juran, J.M. and Gryna, F.M., 1980. Quality Planning and Analysis from Product Development through Use. McGraw-Hill Book Co., New York, 629 pp. Robertson, A.G., 1971. Quality Control and Reliability. Pitman, Belmont, CA, 189 pp. Schilling, E.G. and Davies, H.J., 1964. Quality assessment - a missing link. Transactions of the American Society for Quality Control, March: 279-286.