FUSE Application Experiment 22888Dissemination / Demonstrator document

Advanced Electronic Thermostat for Home Appliances

AE number: 22888New Technology: MicroprocessorContact TTN: COTECPublicity status: Update

Abstract description

COPRECI, S.Coop. is a 825-employee Spanish company, and one of the biggest within theMCC group (Grupo Corporativo Mondragón). The main products manufactured by COPRECIare electro-mechanical components used in the home appliance sector, like timers, drainpumps, pressure switches, gas and electric thermostats, gas valves and taps and high voltagetransformers for microwave ovens.

This exclusively electro-mechanical technology has limited the adaptability of the product line tothe new trends in home appliances, putting the company in a position of competitivedisadvantage. The objective of the Application Experiment was to improve the performance,reliability, and control of a high-end range of thermostats for convection ovens through theintroduction of electronic technology (microprocessor).

The new thermostat will improve the product performance by allowing tighter control of the oventemperature by means of a predictive algorithm based on fuzzy logic. One of the mostchallenging tasks of the project was meeting the difficult reliability standards required fordevices with an electronic circuit working in a high temperature environment. There were othertechnologies as potential candidates to implement this project but the best trade off betweenperformance and the capability to customise them was offered by the microcontroller.

The electronic module was developed at a cost of 66 KECU over a development period of 16months The company expects to recover the total of this and the industrialisation investments(1700 ECU) in around 18 months. At the present level of the market demand and based on themarket penetration Copreci expects a Return of Investment of 82% over a 5 year investmentand 3 year product life cycle.

There are lessons learnt and experiences acquired in the technical, economical, strategic andchoice of subcontractors areas.

Our main conclusion is that there are strong economic benefits from the introduction of new(innovative) electronic technologies in products. Given good partners (subcontractors) andsupport, cultural and technology barriers can be overcome. The risks of the Introduction ofelectronic technology to non-electronic products are by considering improvement of highervalue added products as a first step.

First User Company Profile

Company name: COPRECI, S. Coop.Company size: 825Industrial sector(s): ME

Company size, personnel involved, and expertise & experience prior to theApplication Experiment

Company size is 825 employees and 100 MECU. There was no previous electronic engineeringstaff in the company.

The company has mechanical design expertise using CAE, CAD, CAM tooling together withmass production expertise, automatic assembly, testing and packaging. The company has alsoexpertise in lean production systems and in quality control systems like “EFQM”.

The company did not have electronic design products' expertise, and did not have anyexperience in electronics manufacturing technology. The use of the electronic technology wasseen as a means to get commercial advantages and break into the emerging high-end range ofelectronic thermostats market. The development of this electronic product will also enable thetransfer of this technology to other products in the company’s product catalogue. It is foreseenthat growth in sales and employment will follow.

Three electromechanical engineers were involved in this Application Experiment, with a juniorElectronic Engineer, hired specifically for this project.

Company business description

COPRECI designs, manufactures and markets:1. Gas regulators for cookers, ovens and hob units.2. Washer and dishwasher components

• Timers• Electrically driven drainage pumps• Pressure switches• Electrical thermostats

3. Transformer for microwave ovens 4. Gas thermostats for domestic gas cookers, ovens, and grills 5. Adjustable electric thermostat Company markets

The industrial market place, which the company serves, can be identified in terms of customersprofile, technologies used and geographical regions. The typical profile of the customer is that of an original equipment manufacturer with productionfacilities and expertise in specific application markets, as oven and grill burners, cookers,washers and dishwashers, and appliances in general. All those mentioned applications aredemanding thermostats. The total European demand, classified by the technology used tomanufacture the thermostat, is summed up in the following chart. The electromechanical thermostat segment of the market is a declining segment, while thebimetallic type still grows at a low rate. The most appealing segment of the market is howeverthe electronic type, which has been growing at a cumulative growth rate of nearly 15%according to the information gathered by the marketing research services of the FU andprovided in the following chart. This situation is extremely promising when assessing the salesopportunities of projects like this one, although for the time being the market share of theelectronic technology is only 8 % of the total available market

European Thermostats Market (n. of units in 1995 and forecast for 2002)

ITEM 1995 2002 Electromechanical 34.500.000 31.000.000 Bimetallic 13.100.000 15.600.000 Electronics 3.800.000 10.000.000

The major demanding thermostat application and also the most challenging, in terms oftechnical specifications, has to do with the oven and grill burners. It represents 32 % of the totalthermostat market. Dishwashers and washing machines follow with 28 % and water-heaterswith 25%. The remaining 15% is spread over a set of miscellaneous small appliances In terms of geographical split, the thermostat manufacturers are primarily focused to serve theGerman and Italian customers who are the largest white goods manufacturers The competition is fierce in this market especially on the non-electronic types of thermostats In line with the above Copreci has defined its policy as retaining the market share in the nonelectronic types while increasing progressively production of the new electronic type The figure below shows Copreci's market share of components for the appliance market,including thermostats, from 1992 to 1996. The electronic thermostat product is a clear opportunity for Copreci in the high performancesegment of the market because the white goods manufacturers are more often looking forpartners in the business to design a customised appliance rather than to having a simple lowprice supplier. The electronic thermostat is an ideal component to achieve this aim

Fig.1 Customers share of Copreci

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The EU countries are the prime markets for Copreci products. Leading the ranking are Spain,Germany and France, with a market share of 82% of Copreci production. The Mexico subsidiaryis currently breaking into the North American market with the intention of gaining market shareof the American OEM's. The introduction process, started in 1993 is yielding positive results inboth the Spanish and Mexican plants because of the achievement of ISO 9001 certification. Company competitive position at the start of the Application Experiment

Figure 2 indicates the present market shares by geographical areas of Copreci products in1996. Copreci revenues during 1996 amounted to 100 MECU (16.500 Mptas).

Thermostats hold a 10% of the whole range of appliance components. This means a thermostatturnover of 1650 MPtas. (10 M ECU) or 2’4 M units of thermostats at an average price of 4’1ECU. Copreci holds a share of 5% of the whole European thermostat market, as can be seenon the following chart.

Fig.2 Market share by geographical area

THERMOSTATS EUROPE COPRECI’S SALES Electromechanical 34,500,000 units 1,400,000 Bimetallic 13,100,000 units 1,000,000 Electronics 3,800,000 units -

Thermostat European Market 1996 (figures in UNITS)

The total European market of thermostats, which is near to 200 M ECU, is led by companies likeJaeger, Imit, Ego and Emerson from both a revenue and technology point of view. However thismarket is extremely fragmented since no one company holds more than 20 % of the Europeanmarket. Some of them are very strong in their respective domestic markets. The purpose of this FUSE project is to provide Copreci with the capability to have an offer of theelectronic items, competing with well consolidated companies in the electronic thermostatEuropean arena while taking over the important share held in the domestic and captive Spanishmarket. Below are indicated the whole set of Copreci competitors which spans both large and SMEcompanies. All of them are however very active in technological innovation. In fact all thesecompanies are attempting to set up their electronic technology to capture the largest part of thisemerging segment of the thermostat market. Prices are in the range of 12-15 ECU per unit, allof them have microcontroller technology while some of them also have the fuzzy logic ascontrol. • EGO

Europe82%

Others5%

USA8%

SouthAmerica

5%Europe

Others

USA

South America

• JAEGER• IMIT• CAEM• ATEA• METALFLEX• TECASA• PRODIGY• ROBERT SHAW (USA)• EMERSON (USA)

The remaining portfolio of products of the above said companies, besides the overlapping andcompeting area of thermostats, is quite different, Some of them, like Copreci, Ego, Imit andCaem are primarily oriented to the white appliances market. These companies manufacturedrainage pumps, pressure sensors, gas burners, electrical heaters, etc. Emerson makescomponents for TV sets and cable TV, Jaeger and Prodigy for the automotive market and finallyRobert Shaw is involved in the design and production of transducers for the data acquisition andhousehold market.

Application Experiment Information

Product / System name: Electronic ThermostatIndustrial Sector of Product: ME

Description of the product to be improved and its industrial sectors

Industry sectors: Manufacturers of home appliances

The existing electromechanical products manufactured by the company could be grouped in twomajor families, electromechanical and bimetallic thermostats, with adjustable electric control ascan be seen in figure 3.

The working principle of both thermostats is the same, but the second one has somerefinements improves the precision of temperature setting. There is a heating sensor which isfull of a liquid. This expands through a capillary tube when heated, pushing a diaphragm, whichin turn triggers a snap-action switch. Electric power is activated by this switch. There is often acalibration or adjusting mechanism, using a screw spindle, to offset the fabrication tolerances inthe diaphragm. This is one of the key elements to manufacture a precise and high qualitythermostat.

Fig. 3 Electromechanical and bimetallic thermostats

The technical features of the electromechanical thermostats are the following.• Body: drop-forged brass.• Body bushing: injected aluminium.• Core: injected aluminium or die-cut steel with anti-rust characteristic.• Spindle: bar-cut brass.• Minimum flow via by-pass to be determined• 7.200 valid for all gases and 22.300 for natural gas & GLP• Maximum gas pressure 50 mbar• Maximum ambient temperature 120º C (150º C optional)• Maximum bulb temperature 320º C• Field of regulation 150º - 300º C.• Manufactured to E.N. standards.• Thermostat size as per demand.• Thermostat regulation to be determined

• Optional pilot outlet on 7.200

Safety thermostat with fixed temperature regulation and manual reset:

REGULATION AMBIENT TEMPERATURE TRIP-SWITCH 0 - 320 120º C (on request)

• Contact boss: Ceramic or plastic• Capillary tube: Stainless steel? 1 mm. Cu 1,5 - 1,4 mm• Bulb:

- Straight Stainless steel 3,5 mm. - Cu 3,5 8.- Rolled cap, generally 1,4 mm.- Button type in different shapes and sizes.

• Terminal- 6,3 x 0,8 DIN front and side outlets- Earth (on request)

Two main parameters determine the price and exert a direct influence on the thermostatmanufacturer's reputation .The first one is the precision with which the reference temperatureset is reached. The second one is the MTBF or number of times that the above saidtemperature operation can be successfully repeated without failure.

Copreci believes that has built a reputation of medium price with high quality by supplying themarket with the current non-electronic thermostats. The MTBF of the non electronic currentproduct is around 16 failure/million operating hours. The new electronic thermostat has anestimation of MTBF, according to the reliability tests, of 6’53 failure/million operating hours.

Description of the technical product improvements

The prime motivation of this project was to achieve more precise temperature control and higherreliability in the harsh environment of a high-end convection oven, through the incorporation of asimple microcontroller electronic solution. Although the new product will of course be moreexpensive than the classical electromechanical thermostat, the company foresees a demandopportunity in the market for controllers for the high range of domestic ovens. Some successfulcontacts with potential customers (domestic oven manufacturers) have already been explored..

The logical design of this thermostat has struggled to overturn the current state of the art in themarket. For this reason the control algorithm for this system can accommodate either simplestrategies such as ON/OFF strategy, or quite complex such as fuzzy control. An accuratedesign has been used to analyse the effect of different transient conditions and perturbations onthe system reliability. The steps of the design have been:

Modelling the control system.

A transfer function description of each block has been used. The model of the oven has beenobtained by using identification techniques. The models for the sensor and switch have beenobtained from direct analysis and data sheet information.

Design of the control algorithm.

The objective of the system modelling is the definition of the system dynamic behaviour inclosed loop. According to this model, the design of the control algorithm will be done using fuzzylogic methods. Next figure shows the block diagram of the system.

Figure 4A Block diagram of the domestic oven in closed-loop.

An explanation of the notations in Fig. 4 is given:Tref: temperature reference (target value for the temperature in the centre of the oven)Tc: temperature in the centre of the oven (the temperature of the load)e: error, which is the difference Tref-TcC: the control transfer function; this box is implemented by the microcontroller (according

to the error input e, it computes the state of the actuator A, given by the digital value z)A: the actuator transfer function, defined by the relay systemP: electric power applied to the ovenGp: the oven transfer functionTs: temperature on the sensor (the temperature actually measured)H: the sensor transfer functionTm: measured value of the temperature (using a temperature sensor)Gt: transfer function defining the relationship of the centre temperature Tc to the measured

temperature Tm

The implementation of this step implies the control law selection and the definition of its model.The MATHLAB software package has been used, because it includes a fuzzy-logic toolbox.

Analysis of the closed-loop system.

The objective has been the dynamic system operation simulation, using a transfer functionmodel. MATLAB has been used again and results in both time domain and frequency domainhave been obtained.Objective of the fuzzy algorithm.The idea of the fuzzy algorithm is given in the figure 4B

Fig. 4B: Graphic description of the objective of the fuzzy algorithm

Tref

CONTROL C

ACTUATOR A

OVEN Gp

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The figure 4B shows a diagram with the evolution of the oven temperature (bold line). Someimportant marks have been drawn. A solid line shows the value of the reference temperature,the target of the control system. Two sets of double lines define the limits of the oventemperature, according to the reference temperature and the tolerance. Finally, thediscontinuous lines show the variables ON _temperature and OFF_ temperature. Thesevariables define the times at which the relay should be turned on (when T<ON_temperature)and off (when T>OFF_temperature). The graph shows the overshoot of the oven temperaturewith the fuzzy device, since the oven temperature continues to raise after turning-off the relaybecause of the thermal inertia (the same is true for the other transition of course).

The fuzzy algorithm has adapted the levels of the variables ON_temperature andOFF_temperature according to the operating conditions. The goal is to satisfy the limits definedby the Tref and the tolerance, but limiting to the minimum the number of commutations of therelay. This is important in order to satisfy the flicker and EMC standards. The new Fuzzy devicehas minimised the overshooting while is able to narrow or improving four fold the tolerance (±2ºC instead ±8ºC of the bimetallic thermostat). Moreover, this operation is satisfied for all theoperating modes of the oven. The figure 5 shows the block diagram of the fuzzy control system.

Fig. 5. General block diagram of the fuzzy control system.

The functional diagram for the prototype is given in figure 6. For convenience, the figure 6shows the power section (the relay driver and the power supply), as well as the analoguesection of the circuit (the reset circuit). The figure 7 shows the microcontroller circuit.

Figure 6. Functional diagram of the prototype circuit: power and analoguesection.

FuzzificationFuzzification

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Figure 7. Microcontroller circuit section.

Figure 8: PCB prototype

Combining the logic design and the electronic implementation is quite feasible to reach thefollowing functional performances and improvements:

S0

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PrecisionMaximum difference between upper and lower temperature comprised between 4 and 12º C.Maximum error 10º C, for a given setting maximum error induced for the ambient temperature5º.

Control temperature range50 - 260º C (for the basic temperature sensor) but extended to up to 700º C.

Operation temperature of the electronics0º C - 105º C.

Durability (useful life)Up to 60.000 cycles at 120º C or 5.000 cycles at 150º C.

ReliabilityFailure rate after one year of use less than 0,05%, failure rate after 70.000 cycles less than0,3%.

CostA very strong condition of this device is the cost, due to the very competitive market of theseapplications. For this reason many of the choices of the technology are based on costconsiderations.

Programmable characteristicThe electronic thermostat gives the opportunity of offering features not available with theelectromechanical one. Among these features, one of the most important, now offered just bysome high-end thermostats, is that related to preventing thermal overshoot, by predicting theevolution of the temperature inside the oven. This is accomplished using the well-establishedtechnique above explained called proportional-derivative coefficients.

Display of the temperature and timeThe display of main temperature and timing characteristics is included as well.

Safety built-in features to avoid over-temperaturesBesides the programmable characteristics, an over-temperature control avoiding long termoverheating of the appliances is to be included (T<350º C).

Extension to include some more functionsSelf-cleaning is an additional function which is necessary to play some role on the high-endmarket. Self-cleaning is implemented through a high temperature cycle with door locking bothfunctions to be included in the general operation of the thermostat (temperature of the cycle600º C).

The time to market.This is very short, since products are already being released into the market due to the strongdemand of such type of thermostat from the white goods manufacturers.

The analysis of the design cost versus volumeThe high flexibility in production of the electronic technology set up in this project which means ahigh volume for the device reduces the impact of volume on the end product cost to virtuallyzero.

Choices and rationale for selected technologies, tools and methodologies

ProductElectro-mechanical technology can no longer meet the demands of the complex functionalityrequired to satisfy the needs of an energy and feature conscious consumer in today's whitegoods marketplace. Expectations of reliability, maintenance and capability, particularly in thehigher added value (price) products, is far beyond the potential of non electronic devices.

Greater accuracy of thermal control is an absolute requirement, while the flexibility to customiseto the evermore demanding needs and variety of solutions is mandatory.

The primary requirements of the new product to be designed were therefore:

• Competitive cost in higher added value market.• Improved accuracy for energy saving and heating control. (10 C°)• Improved reliability (1 in 10000 after 1 year of use)• Short customisation time.• Increased functionality to meet customer demands.• Implement complex algorithms.

An analogue design was the first considered. However discrete analogue design are verycritical when the feedback is non-linear. In addition they are extremely costly in both effort andtime, to customise. Since quick time to market and functional flexibility are key requirementsthe possibility of an analogue solution was eliminated. Amongst the digital possibilities areASIC, FPGA or one of the many varieties of microcontroller or microprocessor.

An ASIC, while attractive from a cost and reliability point of view, is inflexible and would notprovide the required simple customisation needed.

FPGA is more flexible than the ASIC but the cost even in the volumes considered for thecomplexity of device required is too high.

So it seemed some sort of low cost microprogrammable device would be the best option.

Fuzzy or conventional logic.

The thermal model for these products is very complex and small variations in the total productmass can have a serious impact on the control of temperature and response times. The use ofconventional microprocessor logic would require a deep and complete understanding of thermalflow through the various parts of every oven. This heat conductivity model would then have tobe converted to algorithms, programmed and executed.The approach is very difficult except in the case of very simple non linear systems. It was feltthat for the complexity of the thermal model and variety of applications that an approach using a'Proportional Derivative' scheme (Fuzzy Logic) would be more suitable to the customisationrequirements.

Fuzzy logic is especially well suited for non-linear complex systems on which the formulationrequired is insufficiently known.

Once established that the choice of the electronic technology is the most suitable to fulfil therequired functionality, a brief rationale of the choices made (within this technology) for thedifferent elements and methods follows. This project proposes the development of an electronicthermostat composed by:• Sensing element and conditioning circuit.• Control circuit of the thermostat.• Control circuit of the switch device.

• Switch device.• Display and setting circuit.

A survey on the available sensing multipurpose devices leads to the conclusion that theselection is to be made among one of the following: resistive temperature detectors (RTDs),thermistors (both with negative temperature coefficient NTCs and with positive temperaturecoefficients PTCs), or thermocouples.

For this application a good choice is a RTD because is cheaper, does not need a compensationcircuit as a thermocouple does, and it has a wider range of temperature than the thermistorsdoes. Moreover the sensing device can be changed to cover different temperature ranges whileusing essentially the same electronics. This means that a low cost RTD can be used fortemperature lower than 260º C while the RTD of Platinum should be used for the temperaturerange up to 750º C. In the switch side a number of options are available, always under theconstraint that the choice should be made among mass-produced devices, low cost an goodreliability. The simplest one is a relay, still a largely used device, which is rugged and marketedfor a wide range of current and voltages. It is also easily controllable, both to the ON state andto the OFF state. Current electronic thermostats for home appliances use relays, indicating thatfor these applications a relay may be reasonable choice, because of the intrinsic galvanicisolation between control and power circuits and reliability as well. Static switches have howeverclear advantages over electromechanical switches, because they have not mobile parts. A goodchoice for a reliable isolated static switch can be a photo-triac

Design, Fabrication and Test Methodologies

As can be seen from the specifications, the thermal constraint applied to the electronics alongwith reliability of the thermostat are the most challenging criteria to achieve. For this reason, thedesign, fabrication and test methodologies leads straight to those criteria, being the permanentorientation of the project

Design MethodologyThe key point of this system is how the operation of the electronic equipment is assured undersuch thermal constraints. Both CAD design and simulation tools are intensively used in order tocope with the design objectives. Conventional electronics design methodology will then be used,with additional thermal and reliability analysis. An experimental verification by means of abreadboard made up “ ad hoc “ will be also carried out, after the simulation phase.

Fabrication MethodologyCost and reliability considerations advise to employ the surface-mounted-technology (SMT) onPCB substrate. Cost considerations certainly exclude, at this stage ASIC solutions. One of theadvantages sought in the usage of an electronic thermostat is a reduction of the assembly cost.This advantage it is possible by using easy-to-mount, standard and economic connectors to linkmodules of the thermostat such as display and panel-touch devices. Following the ISO 9001quality certification, the regular assembly PCB technologies are specified to implement thedesign. Copreci looks into:

• Automatic devices insertion• Axial• Radial• Surface mounted devices (SMD)• Wave soldering• Test-in-circuit• Functional test.• Burn-in

Test MethodologyThe test methodology has played an important role in the achievement of the goal of thisproject. The long-term performance of the thermostat is not only dependent of the featuresconceived for this device, but also of its steady behaviour along the time and accordance withthe suited test flow chart.

The test methodology has been developed assigning priorities in close relation with the mostfrequent failure reasons detected in the past. In this sense the electrical requirements (ratedcurrent/voltage, safety under humid conditions electromagnetic interference), the functionalrequirements (accuracy), the environment (spindle stress, operation temperature, case ofemergency, corrosion and chemical effect and vibrations), the transport and storage conditions(temperature changes), the endurance, reliability and authority approval are the most significant.

Expertise and experience in microelectronics of the company and the staffallocated to the project

The staff allocated to this project was three electromechanical engineers and a junior electronicengineer, hired for starting the electronic group within the company.

Workplan and rationale

The planned project duration was ten months. There was no delay in the project start date fromthat originally proposed. The testing task of the project required a longer time than plannedprimarily due to the very strict homologation procedures and the reliability testing. Thus theproject over ran the planned duration by six months. The person hours expended by the FU onthe project were 25% more than that planned. There are slips throughout the project primarilydue to the testing tasks as explained later (key phase 5 testing)

The work-plan is shown in a Gantt chart form to indicate the project schedule over the 16 monthduration. This was prepared from the work-plan as part of the project management to assist withthe identification of critical path and overlapped activities.

FIRST USER ACTION - BUDGET CONTROL FORMWORK PLAN: TASKS AND DELIVERABLES

C28 Advanced Electronic Thermostat for Home Appliances

22888 Copreci Year 97 Year 98

EFFORTS (Hours/man) EFFORTS (Kecu) C. DIR. COSTS (Kecu) Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr MayJun

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1 Specifications Th. 80 80 Theoretical 2,00 4,50 6,50

Act. 93 94 Actual 2,13 4,51 6,65 ?1.1 Detail Specifications

1.2Selection of Components

2 Desing Th. 160 400 Theoretical 4,00 22,50 26,50

Act. 189 457 Actual 4,34 22,03 1,31 0,01 27,69 ?2.1 Mechanical and Thermal

2.2 Electronics and Control Desing

3 Manufacturing Th. 320 80 Theoretical 8,00 4,50 12,50

Act. 350 80 Actual 8,05 4,50 12,55 ?

3.1 Breadboard Assembly3.2 Manufacturing Specification

3.3 Pre-series Manufacturing

4 Testing Th. 280 200 Theoretical 7,00 11,25 18,25

Act. 455 205 Actual 7,44 11,53 18,97 ?4.1 Desing of Functional and

Manufacturing4.2 Breadboard Test

4.3 Functional and Reliability Testsof Pre-series

4.4 Final ReportTOTAL Th. 840 760 Theoretical 21,00 42,75 63,75

Act. 1.087 835 Actual 21,96 42,57 1,31 0,01 65,86

Monthly Reports ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

Signing Contract Date: 31st March 97 Exchange rate: 165 Ptas/ Ecu Costs paid in advance: 15.94 Kecus Last Update: 30th June 98

Status of Technical Project: Finished

The key phases of the AE were as follows:

1. TrainingIn this AE the best way to achieve the transfer of knowledge and expertise from thesubcontractor to the company was getting the training on the job, on all the different tasks of theproject. In this sense, besides two courses taught by the subcontractor about ElectronicsDesign and Functional and Reliability tests, the FU has held a very strong collaboration duringthe project job with the subcontractor, specially on the testing task.

2. Specifications definitionThe product specifications have been developed by the company together with thesubcontractor, who provided the guide-lines to follow and identifying the critical issues. Theseveral tasks implemented have been, in sequential order, the detailed specifications, selectionof components, preliminary analysis of cost, reliability and thermal behaviour and identificationof critical elements.

3. DesignThe expertise of the UPC was critical at this point. The different tasks developed under thedesign have been:

Control designThe control algorithm of the system should accommodate either simple strategies such as on/offor quite complex such as fuzzy control. An accurate design was needed in order to analyse theeffect of different transient conditions and perturbations on the system reliability.

Electronics designA simulation analysis was proposed in order to verify in detail the operation of the system.Simulation tools were used.

Detailed thermal design.Thermal simulation was very important in this project. The key point was to ensure the correctsystem operation in the whole temperature range of the electronics (0º C - 105º C).Worst case product designMontecarlo simulation was used for the analysis of the worst-case operating condition.A computation of the MTBF (mean time between failures) was calculated.

4. ManufacturingThe PCB layout was developed mainly by the subcontractor. The prototype PCBs wereproduced and the components assembled during this phase, as well as the developed softwarewas integrated with the constructed prototype.

5. TestingThe specifications of the final test approach were developed with the intense participation ofsome engineers from the company. On the other hand, the formal testing and trials of theintegrated prototypes have been done by the company’s engineers assisted by thesubcontractor. Endurance test has been finished once that the relay has passed more than108.000 set of cycles, equivalent to 10 years life 5 hours per week, without problems The set ofcycles to which has been subjected the prototype during the 108.000 times (3.5 months ofcalendar) is shown in the following picture.

Subcontractor 1

Name: Department of Electronics Engineering at the Universidad Politécnica de CataluñaSize: 14

Business

(D.E.E.-U.P.C.) has a long record in activities of designing and project development over:• Power electronics and control• Reliability and software simulation• Microsystem

Relevant Expertise & ExperienceThe DEE-UPC has more than 12 years in developing successful projects forthe industry. Around 100 projects have been done on this period

Services providedElectronic design and assembly

Personnel1 engineer

Rationale for choice of subcontractor

The company has selected the UPC as a suitable subcontractor to support the development ofthis advanced electronic thermostat for home appliances following not only the theoretical“subcontractor selection criteria“ but also the best practice criteria which have supported thesuccessful growth of the company during last ten years. Those criteria could be summed up inthe following points.

• Experience in power electronics and control design• Experience in simulation tools and Fuzzy devices• Reliability and testing knowledge• Capability to merge UPC and Copreci technical people• Confidentiality degree on the IPR agreement

Control de Temperatura. Horno + Turbo. 200ºC. Estimación en el centro.

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These five points could be considered as the cornerstone of the relationship built between theUPC and Copreci. That is the basic profile of the risk analysis implemented. Additionally thereis a long experience of succeeding collaborating the UPC with other companies of the IndustrialComponent Group of MCC (where Copreci is grouped in the Mondragon CooperativeCorporation) Copreci took in consideration another potential candidates to cope with the profile of idealsubcontractor in this project .The key point, we insist. in addition to the knowledge and technicalcapabilities are the abilities to merge with the company people, generating a truly effectiveworking group. Another key point in the process selection to the subcontractor is the IPR policy or the possibilityto establish a legal protection to the technology developed, which in fact is very near to themarket The IPC offered the most consistent agreement to Copreci in this respect Barriers, Strategies and Knowledge transfer

Barriers perceived by the company in the first use of the AE technology

There were two main barriers that prevented the company from adopting a new technology toimprove its products and to get a competitive position in the market place: Technology barriers The knowledge of the company has always been focused on electro-mechanical technology,automatic assembly, and mass-production and lean-production. The company was not able todesign advanced electronic thermostat, that implied a new technology in which the companyhad a lack of expertise in the design methodology and a lack of knowledge in reliability. planningand emulation Psychological barriers The technical staff has a very good experience in mechanical technology and in automaticsystems for mass production, but there was a genuine fear of any electronic technology. Strategy / steps taken to overcome barriers and arrive at an improvedproduct The process of overcoming the barriers facing COPRECI in adopting the new technology wasstarted from the initial contacts with the TTN The information supplied by the TTN on the possibilities of electronics technology made us thinkabout the real opportunities. The modelling of the potential economic benefits together with theplanning and information on support available reduced our fears and perceptions of the risks. The idea of reducing the risks further by targeting a high added value product convinced us thateven although we were an electromechanical company we could do it. Cotec suggested various support Centres as potential subcontractors as candidates. Coprecigot in touch with all of them and following the regular best practice criteria for the selection ofsubcontractors and services suppliers, pick out to the UPC. A working group between the UPCand Copreci with the advice of the TTN was set up Starting with the technical specifications of existing product the merged working groupendeavours to establish the new functional specifications. Then, with the support of the UPCCopreci made the definition of the main items. The working group proposed the development of an electronic thermostat composed by:

• Sensing elements and conditioning circuits• Control circuit of the thermostat• Control circuit of the switch device• Switch device• Display and setting circuit• Control providing many built-in features based in a microcontroller and fuzzy-logic

At that initial time, and based on the technical features agreed by the working group, the TTNstaff analysed both the available information in terms of the FUSE program and the businessopportunities derived of the high-end thermostat market demand based on the Fuzzy logicplanned to use. This combined support -TTN and UPC -was definitive to overcome the barriers

Knowledge and experience acquired

The company’s technical and management expertise was not in the mechanical and electromechanicalcomponents businesses, prior to the start of the AE.

The company did not have any managerial or technical expertise in microcontroller-basedapplications and development projects, and started getting familiar with the electronicenvironment during the preparation of the FUSE proposal, discussing with the subcontractor thespecifications and the different electronic solutions and receiving the TTN basic training onelectronics economic issues. The proposal to study the reliability was also very didactic. As aresult of the work conducted during the AE, the company has acquired skills and gainedknowledge in the following areas:

• Technical management of electronic based products• Technology choices• Electronics products specifications• Electronic products design• Control algorithm design• Simulation tools• Thermal design and simulation• Reliability issues

Besides all those above said technical knowledge acquired, the FU has accrued an importantexperience in the areas of marketing, competitive and economic analysis and subcontractorchoices.

In terms of marketing the resume of the knowledge gained is that microcontroller basedthermostat business is not primarily price dependent of production volume but of the addedvalue generated through the customisation. This statement is strongly influencing thecompetitive and economic analysis which are progressively shifted from the pure volumestrategy to a combined volume -customisation strategy.

Subcontractor choice is another knowledge gained in the sense of scoring better the ability tocreate efficient working groups with the FU, once the technical requirements are met. Theefficiency and fluency with the working group is an important feature always but specially whenthe customisation reveals as a key feature to succeed.

Lessons learned

Amongst the important lessons learned during this AE are the following ones:

Barriers removal

Perhaps the most important lesson was to realise that it is more difficult to break down thepsychological barriers than the technical ones. During the progress of the AE one of the mostimportant company’s customer request a quotation for electronic thermostats, and the companyhad the choice of positively answering to that request thanks to the development of the FuseAE.

Dealing with SubcontractorCOPRECI normally conducts its design and manufacturing work in-house. In this AE thesubcontractor has been an university department. They have worked very hard and thecollaboration has been very efficient, but we can not forget that the academic world is verydifferent to the industrial one, and sometimes in the relationship arise very different points ofview. We have learnt to enhance with this diversity

The message Copreci wants to transmit to the potential replicant is that, in despite thenumerous support Centres with microcontroller and Fuzzy background available to becamesubcontractors, the one selected should be able to create an intermingled working group with anentire understanding of the FU market requirements. That in practice means the application willbe well modelled and the production flexibility, sought for the new product, fully achieved

ReliabilityThe company learned the way to deal reliability theory, simulation, demonstration design,MTBF, etc. The experience of the subcontractor and the training of the company’s engineerswas a very important lesson in this AE.

Tasks ,schedules and efforts In this respect there is not any unexpected lesson to learn since not special troubles rose duringthe project implementation except in the testing task .The testing efforts were entirelyunderestimated as can be seen on the Gantt chart, where the time required was more than thedouble of the one initially specified. Best practice We repeat what we have said in the subcontractor point: The company has selected the UPC asa suitable subcontractor to support the development of this advanced electronic thermostat forhome appliances following not only the theoretical “ subcontractor selection criteria “ but alsothe best practice criteria which have supported the successful growth of the company during lastten years. The message Copreci wants to transmit to the potential replicant is that, despite thenumerous support Centres with microcontroller and Fuzzy background available to becomesubcontractors, the one selected should be able to create an intermingled working group with anentire understanding of the FU market requirements. That in practice means the application willbe well modelled and the production flexibility, sought for the new product, fully achieved. Perceived riskThe most important perceived risk had to do with the psychological barriers combined withsome failure in initial new product specifications. Fortunately this risk would never get effectivebecause the barriers were progressively removed in the way above explained. We learned thatrisks can be managed with use of information from knowledgeable sources and good planning.

Resulting product, its industrialisation and internal replication

The company is now in the process of strategic planning for the next five years.

The new electronic technology know how is a key consideration in this process of planning forthe future. The likely step to be now considered is to have some electronic design capacity in-house. Referring to the industrialisation, the company initially was considering assembly ofPCBs by the subcontractor. However during the project implementation (mid-1997) 10.000samples of the electronic thermostat were demanded by an important customer. The samplesperformed well mass production has started in house during 1998.

The company has now an electronic manufacturing capacity as a result of this successful AEand an unforeseen improvement on market demand.

The following chart shows the commercialisation schedule

Copreci actual sales and forecast (n. of units)

Thermostattype

1995 1996 1998 1999 2000

Electromechanical 1.700.000 1.900.000 2.000.000 2.100.000 2.200.000 Bimetallic 1.000.000 1.200.000 1.300.000 1.350.000 1.400.000 Electronics - - 500.000 750.000 1.000.000

The cost of commercialisation is virtually equivalent to the one required by the thermostatsexisting types., thus no special provision has been made in the industrialisation costs' planning.Therefore summing up our experience to release into the market the new electronic thermostatfrom the prototype to the manufacturing the chart bellow shows tasks, costs and time-scalesrequired.

Project costs from prototype to manufacturing for the electronic thermostat

Tasks Cost(KECU )

Time-scale(months )

Acquisition and set up of a components pickupmachinery

600 2

Acquisition and set up of a wave soldering machinery 300 2Acquisition and set up of a parametric test equipment 300 3Acquisition and set up of a Oven burn-in equipment 200 2Acquisition and set up of Endurance test equipment 100 1Acquisition and installation of miscellaneous tables andassembly equipment

200 1

Total 170011

Economic impact and improvement in competitive position

The current situation of the international market is characterised by the growing demand ofinnovations, referred both to new specific functions and improvements in the features of theexisting products. The automotive sector is an example of the former statement characterisedby a strong dynamism in the incorporation of new functions such as air bag, ABS, friendlyinterface in the dash board, active suspensions, etc. All these systems are based, to someextent, on the current generation of solid state sensors and microcontrollers.

Copreci now believes it has a very competitive product in this emerging high added valuemarket. The product can be sold at a higher price than the mechanical because it is providingmajor additional benefits in features, functions and performance while pricing and costing arefavourable compared with the industry.

The sector of the domestic appliances is, in certain way, similar to the automotive sector in itsbehaviour, although there have been a stronger slowing down of the speed of incorporatinginnovations, we are considering a changing scenario in which the white-goods appliancesbelonged to the high range of them, will be acting as a catalyse in this process of incorporationof new functions related with energy saving, comfort or user safety.

We will be competitive only if the value added implied by these new functions do suppose anaffordable increase in the final cost of the product. The microelectronics, and its potentialcapacity of a combined massive fabrications of electronic systems with custom features, couldproduce sophisticated components and originate new functions or applications with higher initialprice than the product to replace, but a decreasing production costs trend for the future

In this sense, the electronic thermostat, which is the aim of this experience, pretends to improvethe technical specifications of the electromechanical thermostat and, in that way, penetratinginto the high segment of the market. Market forecasts lead us to think that the evolution of themarket in number of units will follow the tendency showed in the next chart:

European Thermostats Market (n. of units in 1995 and forecast for 2002)

Thermostat type 1995 2002 Electromechanical 34.500.000 31.000.000 Bimetallic 13.100.000 15.600.000 Electronics 3.800.000 10.000.000

The European white goods manufacturers are increasingly demanding electronic thermostats ascan be seen in the market chart .In other words; the market growth is primarily based on theelectronic type. The prime reason is because this electronic type, despite its much higher price,adds proportionately much more value.

The electronic thermostat segment is essentially a new market segment which is being built witha small overlapping in the declining of the non-electronic market types although the primecontribution comes from the thermostat market growth

There would not be Copreci expected sales for the electronic thermostat if there were no FUSEproject. The expected sales therefore are based on the success of the Fuse project and areonly concerned with the products labelled "electronic" on the above chart, starting 1998

Copreci actual sales and forecast (n. of units)

Thermostattype

1995 1996 1998 1999 2000

Electronics - - 500.000 750.000 1.000.000

We estimate an investment of 1.700 KECU including the 66 KECU of technology in this project,as budget devoted to starting production and releasing the product into the market. Thisinvestment encompasses the 1.200 KECU of new machinery for the automatic components pickup and insertion, wave soldering and automatic electrical test components. In addition, a burn-in oven together wit a functional and parametric instrumentation to accomplish endurance tests,during and after the burn-in process and some assembly facilities, were acquired with the 500KECU remaining.

Provided that the price of the electromechanical thermostat is 4’1 ECU on average and of theelectronic ones is 14 ECU, Copreci approach is to obtain a 15% of benefits(the 85 % of theselling price is then the Total production cost including all the manufacturing, the marketing andcommercial, financial and overheads), that means to be able to get a pay-back of 18 monthswith the sales revenues forecast above indicated.

From the year 2000 to 2002 COPRECI believes it can increase market share from 5% to 10% inthe European Market place. Assuming an investment life of five years for this electronicthermostat the sales projection arrives at a total turn over for the period of approximately 60MECU .The derived profit with the company target of 15% would amount to 9M ECU over thewhole period..

The Return on the investment is thus 9 MEcu - 1.766 MEcu = 7.234 Mecu

And an annualised Rate of Return over the 5 year investment life of 82%.

Target audience for dissemination throughout Europe

COPRECI is selling product in Europe. Export’s sales are 70% of total sales. The maincustomers are large companies like Bosch-Siemens, Electrolux, Brandt E., Merloni, Whirpool...

Dissemination of the development of the AE will be of special interest to the small and mediumcompany audience interested in becoming suppliers of those large companies. Another set ofcompanies target of audience could be those ones, either large or SMEs, which haveelectromechanical components or products which could have a higher added value by theincorporation of programmable electronic devices. Finally there are many appliance users,vendors and distribution networks that are willing to support the sector innovations.

The knowledge to be disseminated includes data on:• Migration of the product from a classic electromechanical function to an electronic one• Design process• Reliability study• Training• New possibilities of fuzzy technology in some electronics devices• Marketing forecast

Target audience industries: ME