The Optimizing Strategy of Systematic Process Innovation ......Innovation in process system can create great value. The rapid development of technology and commercial environment The

Appl. Math. Inf. Sci.9, No. 3, 1593-1604 (2015) 1593

Applied Mathematics & Information SciencesAn International Journal

http://dx.doi.org/10.12785/amis/090356

The Optimizing Strategy of Systematic ProcessInnovation based on QFD TRIZ and AHPChen Wang, Wu Zhao∗, Jie Wang, Xiaolong Li, Kai Zhang, Xin Guo and Jie Zeng

School of Manufacturing Science and Engineering Sichuan University, ChengDu 610065 China

Received: 4 Mar. 2014, Revised: 20 Jun. 2014, Accepted: 12 Jul. 2014Published online: 1 May 2015

Abstract: Process design is often associated with the compromises of conflicting process parameters, which means a rising cost andaloss of quality. Innovation in process system can create great value. The rapid development of technology and commercial environmentsuggests that innovative process design needs the support of a systematic innovation strategy. The strategy combininginventive toolsis proposed to support process innovation. Firstly, analyze the process system according to constraints, and employ Quality FunctionDeployment (QFD) to obtain process requirements. In this way, the conflicts of process system can be found accurately, then analyzethese conflicts comprehensively, and creatively solve these process problems with the help of the Russian Theory of Inventive ProblemSolving (TRIZ), and acquire more feasible solutions or inspiration through the proposed approach. After that, use Analytic HierarchyProcess (AHP) to select the best feasible alternative undermultiple evaluating standards. In this approach, both the efficiency andmaneuverability of applying Inventive tools to solve process problems are improved. Finally, the performance of the proposed strategyis illustrated and validated by the example of grinding process system.

Keywords: Process Innovation, TRIZ, AHP, QFD

1 Introduction

According to the research of U.S. National ProductivitySurvey Committee, process technology contributed 57%to the productivity in the last century. Process also playsan important role between design and production. On theother hand, process design has objectives and constraints,and even a simple process requires a trade-off amongmany factors. The great value created by process and therapidly changing modern marketplace drives companiesto seek competitiveness in process development in termsof innovation, high quality, and speed to market.However, previous research on process innovation designwas not enough compared with the research on productinnovation. Therefore, it is crucial to pay attention to theresearch on process innovation.

Most previous work on process innovation in themanufacturing industry was based on an economicperspective. Stobaugh (1998) argued that increasedcompetition in the industry has propelled innovationthroughout history. Albach (1996) in the EuropeanCommunity Innovation Survey I (CIS I) concluded thatcost and financial factors were the primary concerns forinnovations in the 1990s. While these studies focused on

economic issue, a number of publications have addressedinnovation in the manufacturing industry from anenvironmental perspective. These studies suggest thatprocess efficiency improvement and the use of newtechnology are among the most promising fields ofresearch concerning innovation in process innovation(Dijkema, 2004; Korevaar, 2007; Patel, 2009). Combiningthe economic and technological perspectives, one wouldthen ask: what factors encourage and hinder processinnovation? Or more broadly, is there any scientificmethod to encourage process innovation? So far, a studythat can answer these questions is still needed. Exploringthe answers to this question will provide the industrialcommunity with some insights into how processinnovation in the manufacturing industry can bestimulated.

There are some answers that have been generated tothe research question on process innovation inmanufacturing industry.

First, as far as process efficiency is concerned, R&Dand innovation have not been a top most objective formanufacturing firms. Second, the creative theory which iswidely applied in product innovation hasn’t been

∗ Corresponding author e-mail:[email protected]

c© 2015 NSPNatural Sciences Publishing Cor.

http://dx.doi.org/10.12785/amis/090356

1594 C. Wang et. al.: The Optimizing Strategy of Systematic Process...

Conflicts 1

⋯

Conflicts 3

Conflicts 2

Separations

Principles

Acquire process constraints

Acquire process

requirements based on QFD

Preliminary

Analyses

Standard

Approaches

ARIZ

Contradiction

Matrix

Su-Field

AnalysisEvaluate

solutions with

AHP

Agents Method

Product External userInternal user

technologyManufacture

EconomicProduct

Solution 1

...

Solution 4

Solution 3

Solution 2

TRIZ

Process system

innovation

Innovative

solution

Not satisfied

satisfied

Fig. 1: The strategy of process innovation.

researched in the field of manufacturing process. Third,manufacturing efficiency improvement is a desirable andpossible reward, especially in the case of improvingexisting processes. While improving existing processes isrelated to operational performance, developing newprocesses is a strategic innovation, or of strategicimportance. For developing new processes, specificsynthetic pathways are considered in the first place for itsimportance to firms’ long-term development [1].

Process innovation usually means the change oftechnology, which involves new design, processtechnology, equipment and management model. Atpresent, some researchers have applied innovativemethods to process design. Scholars of SichuanUniversity proposed a strategy of process innovationdesign: Combining process elements, process engineersuse the TRIZ method to guide process innovation, andsolve the conflicts of the process system.

Since the process design in the early design stageplays a critical role which determines the manufacture ofproduct, it is extremely important to build a systematicapproach of process design. For a process engineer, whenhe/she tries to solve a process innovative problem, he/sheusually faces a systematic incompatibility or technicalconflicts. As the process engineer changes certainparameters of the system in his/her thorny designproblem, it might affect other parameters badly, becausenumerous factors which interact with each other have animpact on process conflicts. Traditionally, the processengineer always compromises with this kind ofcontradictory situations and restricts him on performinginnovative design tasks. The practice of using trade-offparameters as a tool for systematic innovation in theprocess design has only recently emerged from TRIZ.Numerous researchers have applied the concept ofprocess design trade-offs to help acknowledge andmanage process conflicting performance parameters, andfind the creative solution of process system.

TRIZ is a theory which can effectively solvetechnological conflicts with creative ideas. There are lotsof conflicts in the process system, so it is appropriate toapply TRIZ into process innovation design. Processengineers need to establish conflict models, whenapplying TRIZ. Consequently, analyzing processrequirements and constraints, which are the source of theprocess conflicts, is inevitable [2]. However, if one wantsto solve a process problem, especially in a complexprocess system, it is necessary to learn about all demands,not only users’ demands but also the demand ofengineers, designers, workers and managers. And QFD(Quality Function Deployment) can be an effective tool toanalyze the requirements. In addition, AHP can be used toselect the most inventive process solutions.

According to the above, this paper proposed anoptimizing strategy of process innovation. QFD, AHP andTRIZ are applied as an integrated methodology forgenerating and selecting of an appropriate process systemsolution. Firstly, the QFD is applied to turn the processrequirements into technical characteristics. Meanwhile,lots of process conflicts can be found, considering theconstraints of process system. In this case, TRIZ isapplied, for example, engineers can use the contradictionmatrix which is one of effective tools of TRIZ to break upthe complex design problem into incentive principles, andseveral alternative innovative solutions are achieved.After that, with the purpose of finding the best solution,the AHP is conducted by decomposing the structure ofdecision process into a hierarchical sequence whichdetermines the relative importance of each alternativeprocess innovations through pairwise comparisons. Thecommon design parameters for selecting a suitableprocess system include productivity, safety andenvironment, quality, flexibility, and cost. If engineers arenot satisfied with the achieved solution, it is needed tosolve the process problem again with TRIZ or other


Appl. Math. Inf. Sci.9, No. 3, 1593-1604 (2015) /www.naturalspublishing.com/Journals.asp 1595

innovative theory. The integrated approach is shown asFig. 1.

2 Methods Explanation

2.1 Evaluate the process system based onrequirements and constraints

Process requirements and constraints existsimultaneously [3], which usually generate lots of processconflicts, for example the contradiction between precisionand speed, and the contradiction between heat dissipationand system complexity, etc.

It is necessary to evaluate the requirements andconstraints of process system [4], if engineers want tofind out the process conflicts with nothing missed. Thefirst thing, engineer need to do is to find out the exactparameters of process requirement rather than a generaldescription. And, QFD (Quality function deployment) canbe an effective tool to do that. Secondly, constrains ofprocess system have to be considered comprehensively,which come from cost, technology and resource. etc. Theproposed approach incorporates the parameters of processrequirement and constraints.

2.1.1 Obtain Process Requirements with QFD

Generally, process requirements mainly stem from threeimportant sources which are shown as below:

1) Process requirements based on the information ofproducts. The engineering drawing contains lots ofprocess requirements, so comprehensively analysing theinformation of drawings is very important [6]. Incooperative atmosphere, process engineers engage in thewhole cycle of product development, and can capture theprocess information comprehensively. Besides, engineerscan acquire some details about process requirements fromprocess design documents, because they convey lots ofinformation which includes header information (e.g.name, number, materials, etc.), structure, size, tolerance,surface roughness, heat treatment and other engineeringrequirements. Process design documents serve to definethe design and they ensure that the design components fittogether. They are useful in communicating ideas andplans to other engineers involved in the design, to externalregulatory agencies, to equipment vendors and toconstruction contractors.

2) Process requirements based on the external users.The ultimate goal of process innovation is to meet therequirements of external users [7]. External users areseriously concerned about quality, function, price,environmental protection, energy saving, service andman-machine engineering, etc.

3) Process requirements based on the internal users.Process engineers also need to consider the process

demands of internal users, such as workers andproduction department [8], etc. Workers want comfortableworking environment and a reduction of working fatigue.On the other hand, production department requires shorttime, low cost, less consumption and easy management,etc. They can also obtain more information about processrequirements with the assistance of QFD (QualityFunction Deployment).

However, the above information is not enough forprocess engineers. All participants including users,engineers and managers, etc. propose their ideas aboutrequirements for planning and designing the processsystem. In order to acquire the comprehensive processrequirements, process engineers should considercarefully, such as: market, technology and the source ofprocess requirements: product, external users and internalusers. With the help of QFD, the general description canbe transformed into specific parameters of processrequirement [9].

QFD (Quality Function Deployment) can turn theprocess demands into process design specifications,process characteristics of components, and processcontrol requirements, by establishing the relation matricesabout them (Fig.2), and prioritize each processcharacteristic while simultaneously setting developmenttargets for process system. Beginning with the initialmatrix, commonly termed the house of quality, depictedin Figure 2, the QFD methodology focuses on the mostimportant process attributes. These are composed all ofprocess participators’ wants and musts.

HOW

Technical

Correlations

How Engineering

Charateristics(EC’s)

Realtions

WHAT

Process

Attributes

(AC’s) Pr ior ity

Planning

Matrix

To help

prioritise

Process

requirements

Technical Matrix

Fig. 2: The House of Quality.

Once you have prioritized the attributes and qualities,QFD deploys them to the appropriate organizationalfunction for action, as shown in Figure 3. In this way, thedeployment of process participators’ needs into processcharacteristics can be smoothly accomplished.

2.1.2 Acquiring Process Constraints

Process constraints have a negative effect on productivityand process system. Process constraints mainly involveeconomic constraints, manufacturing constraints,


www.naturalspublishing.com/Journals.asp


Process

requirements

Pro

cess

partici p

a tor’s

nee d

Engineering

design

Pr o

cess

re qu

ire men

ts

Process

Characteristics

Eng

ineer in

g

desi g

n

Process

requirementsEngineering

designProcess

Characteristics

Requirements

Matrix

1 Design

Matrix

2Process

Characteristics

Matrix

3

Process Control

Pro

ce ss

Ch

ara

cte rist ic s

Process Control

Process

Characteristics

Matrix

4

Fig. 3: Waterfall relationship of QFD matrices.

production pattern constraints, technical constraints andso on [10]. For each system, process constraints playdifferent roles.

1) Economic constraints. Low cost creates moreprofits. It is worth noting that economic constraintsinclude not only short-term profits, but also developmentof strategic value.

2) Manufacturing constraints. Manufacturingenvironment imposes restrictions on component’sattributes, such as structure, size, precision, etc.Constraints involve four categories: (A) Raw materialconstraint. Raw material has a great effect onmanufacturing cost and productivity of components. (B)Resource constraint. The equipment used to manufactureproducts includes machine tools, cutting tools andfixtures, etc. (C) Machine constraint. This kind ofconstraints includes cutting, cooling, scraps discharge andadjacent Machining method, etc. (D) Testing restriction.When processing components with complex geometry orhigh precision, process engineers should consider theconstraints of measuring and testing method.

3) Constraints of the production mode. The mode ofproduction of each product is different from one another.There are also several feasible processing methods forchoice, according to production batch, part feature andprocess requirements.

4) Constraints of technology. Technical engineers area crucial asset for an enterprise. The technological levellargely depends on process engineers.

Once, engineers find out the characteristics of processrequirement and the specific constraints of processsystem, it is much easier to analyze the process systemcomprehensively for engineers, and then they can findconflicts in process system with nothing missed.

2.2 Solve the CoreProcess Conflict with TRIZ

Since the engineers find these problems exciting in theprocess system. It is reasonable that an approach should

be developed address them. According to the search ofother scholars in this field, it is appropriate to applyinnovative tools to solve process problems. Recentlyresearcher in Sichuan University has already appliedTRIZ into process innovation. And it turned out to be aneffective tool for process engineers to find creativesolutions.

2.2.1 Introduction to TRIZ

TRIZ is a human-oriented knowledge-based systematicmethodology of inventive problem solving which wasestablished by Altshuller. It can solve technical problemsand offers innovative solutions by employing aknowledge base built from the analyses of approximately2.5 million patents, primarily on mechanical design. Thecore of TRIZ consists of 40 contradiction principles, andthe matrix; other tools are auxiliary to assisting designengineers in constructing the problem model andanalyzing it. Below, however, is a brief overview of themost popular TRIZ heuristics and instruments [11].

1) Preliminary Analyses can avoid trade-off solutionsof problems containing contradictions and can help clarifyimportant information about the technique and constraintsof forthcoming solutions.

2) The contradiction matrix consists of technicalcontradictions between the characteristics to be improvedand the characteristics that can be adversely affected. Italso has a few inventive principles in each cell that mayhelp resolve the contradictions. The contradiction meansthat a worsening engineering parameter and an improvingparameter exist simultaneously.

3) Separations principles help resolve the generalphysical contradictions between the oppositecharacteristics of a single subsystem. Substance-Field(Su-Field) Analysis is a modeling approach based on asymbolic language that can record transformations oftechnical systems and technological processes.



4) The standard approaches to technical problems(Standards, for short) are based on the observation thatmany inventive technical problems from various fields ofengineering are solved by the same generic approaches.The Standards contain typical classes of inventiveproblems and typical recommendations on their solutions,which usually can be presented in terms of Su-FieldAnalysis.

5) Algorithm for inventive problem solving (ARIZ inits Russian acronym) is a set of sequential logicalprocedures for eliminating the contradictions causing theproblem. ARIZ is considered as one of the most powerfuland elegant instruments of TRIZ. It includes the processof problem reformulation and reinterpretation until theprecise definition is achieved, and the logical anddisciplined process of solving the problem with iterativeuse of most of the TRIZ instruments. It is very “solutionneutral”; it removes preconceived solutions from theproblem statement [12].

6) Agents Method is a graphical-logical procedure forimplementing forward, backward, or bidirectional stepsbetween the initial and desirable situations when they can,respectively, be presented as the correct statement of aproblem and the Ideal Final Result.

These instruments represent a system for handlingdifferent steps during problem solving. It is important toremember that these heuristics and instruments are “forthinking” and not tools to be used “instead of thinking”.Usually, when engineers solve a conflict with TRIZ, theyneed to turn the specific process conflict into a generalconflict model, and then obtain the general solution ofthis conflict model and turn it into a specific solutioncombined with practical conditions, and evaluate thiscreative concept in the end [13].

Altshuller’s early work on patents resulted inclassifying inventive solutions into five levels, rangingfrom trivial improvement to scientific breakthroughs.Although there is potential to structure the creativeprocess around trade-off contradictions, only the technicalcontradiction solution system and physical contradictionsolution system are introduced here.

2.2.2 Contradiction Solution System of TRIZ

With the matrix, engineers can identify the most possibleprocess innovative solutions in the 40 common principles.

There are 39 engineering parameters including theweight of object, the dimension of object, the force ofobject, and so forth. The matrix is a 39-39 matrix, whichcontains the several most likely principles for solvingdesign problems involving the 1482 most commoncontradiction types. The basic process of using TRIZ is asthe following statement: For using TRIZ in the innovativedesign problem solving, firstly the process engineer needsto find out the corresponding contradictions for his/herproblem at hand. Next, the process engineer matches themeaning of each contradiction with two appropriate

parameters from 39 engineering parameters defined in thematrix. The process engineer can find the inventiveprinciples for solving the engineering innovative designproblem from the matrix when he confirms theparameters of contradiction for a process system [14].

Basically, the contradiction matrix can help processdesign engineers to realize the conflict of the processsystem, and obtain the feasible inventive principlesthrough the patent database.

2.2.3 Physical Contradiction Solution System of TRIZ

After long-term study, scholars discovered a further levelof abstraction from the technical contradictions as well asprocess contradictions. These scholars found that, inmany cases, the technical contradiction could bepresented as two extremes of one feature, which he calleda physical contradiction. More formally, a physicalcontradiction requires mutually exclusive states as theyrelate to a function, performance or a component. Forexample, typical physical contradictions includes:“movable vs. stationary”; “fast vs. slow”; “big vs. small”;“hot vs. cold”, etc. The relationship between the technicaland physical contradictions can be described like thattechnical contradiction between parameter A and B hasfurther abstracted to present the contradiction in terms ofcommon variable parameter C, which represents thephysical contradiction. Altshuller found that by definingthe contradiction around one parameter with mutuallyexclusive states the correlation operators used to detect asolution could be more generic and there are fourseparation principles (Table.1) used to help resolve thistype of contradiction. The separation principles can besummarized as follows:

Table 1: Separation principles1 separation of opposite requirements in space2 separation upon condition3 separation within a whole and its parts4 separation of opposite requirements in time

Taking the ship for example, the technicalcontradictions are ‘speed and carrying capacity’, and lookfor another common parameter displaying mutuallyexclusive states. Such a parameter in this example mightbe the cross sectional area of the body of a ship. A smallcross sectional area is required for speed, but for carryingcapacity, a larger cross sectional area is required [15]. Thefour innovation principles would then be considered, andin this case, disintegrate the body of ship, then ‘catamaranwith two parallel hulls that are held in place by a singledeck’ could be considered as the possible option forbigger carrying capacity and higher speed.




2.3 Find the Best Solution with AHP

There are usually several process innovation solutions, itis necessary for engineers to evaluate these solutions andfind the most creative one among them. The most creativeone can solve the key conflict which has greater negativeeffects on the process system than other conflicts, andconsiderably improve the efficiency of process system. Inorder to promote the process system greatly, engineersneed to find the best process innovation solutions in thesealternatives with the help of AHP (The analytic hierarchyprocess).

2.3.1 Introduction to AHP

The analytic hierarchy process (AHP) is a structuredtechnique for organizing and analyzing complexdecisions. Rather than prescribing a “correct” decision,the AHP helps process engineers to find one that bestsuits their goal and their understanding of the processproblem. It provides a comprehensive and rationalframework for structuring a decision problem, forrepresenting and quantifying its elements, for relatingthose elements to overall goals, and for evaluatingalternative process solutions.

Users of the AHP first decompose their decisionproblem into a hierarchy of more easily comprehendedsub-problems, each of which can be analyzedindependently. The elements of the hierarchy can berelated to any aspect of the decision problem tangible orintangible, carefully measured or roughly estimated, wellor poorly understood.

Once the hierarchy is built, the process engineerssystematically evaluate its various elements by comparingthem with each other, and with respect to their impact onan element above them in the hierarchy. The AHPconverts these evaluations to numerical values that can beprocessed and compared over the entire range of theprocess problem [16]. A numerical weight or priority isderived for each process element of the hierarchy,allowing diverse and incommensurable elements to becompared to one another in a rational and consistent way.This capability distinguishes the AHP from other decisionmaking techniques.

In one of important step, numerical priorities arecalculated for each of the decision alternatives. Thesenumbers represent the alternatives’ relative ability toachieve the decision goal, so they allow a straightforwardconsideration of the various courses of action.

The procedure for using the AHP to select the bestprocess solution can be summarized as follows. Modelthe process problem as a hierarchy containing thedecision goal, the alternatives for reaching it, and thecriteria for evaluating the alternatives. Establish prioritiesamong the elements of the hierarchy by making a seriesof judgments based on pairwise comparisons of theelements. For example, when calculating the weight of

each element in the hierarchy, engineers might think lowcost take precedence over short time, short time overenvironmental protection and so on. Synthesize thesejudgments to yield a set of overall priorities for thehierarchy. Check the consistency of the judgments. Cometo a final decision based on the results of this process.

2.3.2 Construct the Hierarchy and Assign Weight by AHP

Analytical Hierarchy Process (AHP) can be used toanalyzing the process system qualitatively andquantitatively. Using the AHP method involvesmathematical synthesis of judgments about the problemon hand, which could help engineers to find the bestprocess solutions among many alternativessystematically [17].

When engineers use AHP to select the best solution,they need to build the hierarchy (Figure. 4). The topmostlevel in the hierarchical structure for the evaluationproblem is the goal of achieving the best process systemdesign. The second levels are a set of carefully chosencriteria and sub-criteria, respectively. The last levelcomprises available alternatives. Usually, the evaluationcriterion of process innovation mainly include: T (time),Q (quality), C (cost), R (resource consumption) and E(environmental impact), etc.

The procedure for using the AHP method can besummarized as follows:

Step 1. Decomposing.Engineers need to model the problem as a hierarchical

structure which contains decision goal, alternatives forreaching it, and the criteria for evaluating thesealternatives. For example, the goal is to find the bestprocess innovation in alternative process solutions. Thecriteria for evaluating process conflict contains time, cost,quality, resource consumption and environment.

Step 2. Weighing.The essence of the AHP is human judgments, which

can be used in performing the evaluations, rather than theunderlying information. Therefore, it’s important toaccurately calculate the weight of each criteria. In orderto calculate the weight among the elements of thehierarchy [18], Engineers need to make a series ofjudgments based on the comparative matrix, andsynthesize these judgments to a set of overall prioritiesfor the hierarchy. Then check the consistency of thejudgments.

So engineers need to establish the judgment matrix andcompare the criteria with the others, which belong to thesame criterion of the higher lever.

The establishedn∗n matrix is shown as follows, and nstands for the number of criteria.

R=

r11 · · · r11...

. . ....

r11 · · · r11

(1)



Time Cost Quality Resource Environment

Solution A Solution B ⋯ Solution N

Innovative Porces SolutionGoal

Evaluation Criterion

Alternative Solutions

A1 A2 A3 A4 A5 N5N4

V1 V2 V3 V4 V5

Fig. 4: The Hierarchical Structure of Process Solutions.

After that engineers check the consistency of theestablishedn ∗ n matrix, and work out the coincidencecriterion. Theλmax is the maximum eigenvalue of thematrix, andn is the order of the matrix.

Ci =λmax−n

n−1(2)

Then consider the random index (RI ), and figure outthe consistency ratio, and the judgment matrix is up to themustard, ifCR < 0.1.

CR =Ci

Ri(3)

Next, rank the criteria into single level. Take theaccuracy and the complexity of operation intoconsideration, select the feature vector method. Theweight vector can be calculated by the following formula.

(A−ni) ·W= 0 (4)

The above formula,N is one of the eigenvalues of thematrix, W represents the eigenvectors of matrixAcorresponding to the eigenvaluesn, which is the weightvector.

After the weight of the criteria which is relative to thehigher level is obtained, multiply each layer weighttogether from bottom to top, and the result is the totalweight [19].

Then if we setVm represent the weight of criterion togoal: short time (V1), low cost (V2), good quality (V3), lowconsumption (V4), environmental friendliness (V5). Thenwe would haveAm,Bm. . .Nm represent the scores ofprocess solution to criterion (Table 2).

Table 2: Weight1 2 3 4 5 ∑

Vm V1 V2 V3 V4 V5 1Am A1 A2 A3 A4 A5· · · · · · · · · · · · · · · · · · · · ·

Nm N1 N2 N3 N4 N5

Note: The sum of the weight is 1. For example:∑Vm=1.

Step 3. Evaluating.Calculate the index:SA,SB, . . . ,SN.

SA = ∑Am ·Vm (5)

SB = ∑Bm ·Vm (6)

· · ·

SC = ∑Cm ·Vm (7)

Step 4. Selecting.Then we can draw a conclusion on the problem based

on the conflict index. Comparing the indexSA,SB . . .SN,the most inventive process solution is the one with thelargest index.

3 Discussion: Grinding System ApplyProcess Innovation Strategy

Since process design is a highly empirical activity, inorder to solve the process conflict effectively, It is neededto establish a strategy of process innovation design,namely, acquire the constraints and requirements of theprocess system, then analyze the process conflictscombining with these requirements and constraints, thensolve these conflicts with TRIZ, finally apply AHPevaluating these solutions to select the most creativeprocess solution. The case of grinding blade illustrateshow to apply this process innovation strategy solvingconflicts in process system [20].

The blade surface of cutting tool has an importantinfluence on its durability and performance. In ManyCases, for example, after long time works, worker needsto grind the blade of milling-tool which may get dull.Because of the complexity of blade, and considering thecost of grinding system (Figure 5), dry grinding is widelyused in traditional grinding process, instead of pouringcooling fluid, which will limit the vision of the workerand increase the cost of grinder. However, the quality ofblade is instable, when machining the blade of tools intraditional dry grinding way, because dry grinding willgenerate lots of heat which causes surface hardening anddeforms the blade of tool. This paper tries to solve theprocess conflicts in this grinding system with the processinnovation strategy which was discussed above.

3.1 Evaluate the Grinding Machine SystemBased on Requirements and Constraints

Firstly, engineers need to find the requirements of theprocess system with the help of QFD. The establishedhouse of Quality is shown as figure 6. From the house ofquality and other information about the grinding system,engineers can easily find the process requirements as




follows. Take away the heat generated by the frictioneffectively. Reduce the difficulty of operation andretaining precision.

After that, it is needed for engineers to analyze theconstraints of this grinding system. The constraints of thisgrinding system mainly come from economic constraints,manufacturing constraints, production constraints andconstraints of technology.

Grinding Wheel

Diluted with Graphite

Milling-Tool

Fig. 5: Process Innovation in Grinding System.

○ ●

● ○ ○

○ ●

●Closely Related ○ Related

○ ● ○ ●

● ○ ○

Fig. 6: The House of Quality of grinding sysytem.

1) Economic constraints. It is absolutely essential forthis system to keep cost down. High cost of the machineor use cost will force company to change the failed cuttingtool. Low cost means the simplicity of the grinding systemand the grinding consumables.

2) Manufacturing constraints. The high temperatureof grinding environment imposes restrictions on grindingmaterial’s attribute, such as heat resistance, structure,size, precision, etc. Since the grinding is an empiricalprocess. The visual field of worker can’t be affected bythe cooling medium.

3) Constraints of the mode of production. This cuttergrinding system belongs to small scale production,therefore, production mode has to be flexible.

4) Constraints of technology. The grinding system hasto be not too complicated to operate for workers.

Then it’s much easier for engineers to evaluate thegrinding system, and draw a conclusion that there are twoconflicts in this process system.

3.2 Solve Process Conflicts with TRIZ

Engineers want to use TRIZ to solve the conflicts in theprocess system, there are some principles they need torefer.

Firstly, express the process conflict in a standardizedway. In the finish machining process, what needed to beimproved is the high temperature caused by the absence ofcooling medium. However, pouring cooling medium willincrease the complexity of the process system (Table.3).

Table 3: Conflicts in Process SystemHigh Temperature Vs Loss of PrecisionTaking away the heat Cooling system willGenerated by the friction Vs Increase the cost and theeffectively difficulty of operation

Secondly, combining the 39 parameters ofcontradiction table, process engineers can obtain a newdescription about this process problem (Table 4).

Table 4: The New Description of ProblemImproved parameter: 31 Object-generated harmful factorsDeteriorated parameter: 36 Device complexity

Thirdly, engineers can obtain the correspondinginnovation principles (01, 19, 31) with the contradictionmatrix (Table.5) which tells you the 40 principles havebeen used most frequently to solve a problem thatinvolves a particular contradiction.

Then comparing the 40 inventive principles which arethe innovation tools of TRIZ, engineers will be inspired bythese three innovation principles (Table 6).

Finally, Engineers can draw a conclusion about thefinal specific solutions considering the innovationprinciples we obtained above. In this specific case, thereare two possible creative process solutions.

Solution one, add lubricant into the grinding wheel inadvance. Because the grinding wheel is porous, engineerscan use oil to dilute solid lubricant such as graphite andmolybdenum dioxide, and then infiltrate into grindingwheel [21]. In practice Cutting oil which evaporateseasily acts as thinner, and graphite powder acts aslubricant, and then they seep into the grinding wheel.Lubricant can reduce the heat generated by the friction of



Table 5: Contradiction Matrix of Grinding System

WorseningFeature

WorseningFeature

Wei

ghto

fm

ovin

gob

ject

Wei

ghto

fst

atiio

nary

···

Dev

ice

com

plex

ity

···

1 2 · · · 36 · · ·

Weight ofmoving object

1 * – · · ·

26 3036 34

· · ·

Weight ofstatiionary

2 – * · · ·

1 1026 39

· · ·

· · · · · · · · · · · · · · · · · · · · ·

Object-affectedharmful

3119 2215 39

35 221 39

– 1 19 31 · · ·

· · · · · · · · · · · · · · · · · · · · ·

Table 6: Principles and MeaningsInventive Principles Meanings01 Segmentation Divide an object into independent

parts.19 Periodic action Instead of continuous action, use

periodic or pulsating actions31 Porous materials Make an object porous or add porous

elements (inserts, coatings, etc.)

grinding. At the same time the evaporating cutting oiltakes away the heat which was generated in grindingprocess. This solution creatively solves the problem ofheat dissipation without increasing the complexity ofgrinding system.

Solution two, add the gas-liquid mixture coolingsystem to the grinding system. It’s an effective method fora process system which generates lots of heat to add acooling system. In some body’s view, it seems thatcooling liquid is the best medium, which possesses theadvantage of low cost and efficiency [22]. However,cooling liquid has a negative effect on the operation of theworker by limiting his visual field. If we change from theliquid to gas-liquid mixture as the cooling medium, wecan neutralize the negative effect on worker’s visual field.On the other hand, the mixture of gas-liquid just mildlyreduces the efficiency of cooling.

3.3 Compare Two Process Innovations withAHP

Engineers model this evaluation as a hierarchical structure.The decision goal is to select the most inventive processsolution, the alternatives for reaching it, and the evaluatingcriteria including quality, cost, efficiency and environment.

Engineers judge the comparative matrix pairs ofcriteria, and synthesize these judgments to yield a set ofoverall priorities for the hierarchy. Then check theconsistency of the judgments. For example, whencalculating the weight of each element in the hierarchy,

engineers decide the quality take precedence over cost,cost over efficiency, efficiency over environmentalprotection. Then engineers setVm to represent the weightof criterion to the goal: quality (V1), low cost (V2),efficiency (V3), environmental friendliness (V4).

As referred by the preceding part of the paper, weselect machining quality, machining requirements andmachining influence as the first level criterion, and selectthe other 8 criteria such as material of the blade, shape ofthe blade and so on as the second level criterion. Afterdiscussing by the process designers, we got the followingjudgment matrix:

The judgment matrix of first level:

A=

1 2 5 81/2 1 3 51/5 1/3 1 21/8 1/5 1/2 1

(8)

Using the square root method, we can acquire theweight:

WA = (0.8578,0.4744,0.1732,0.0959)

Then check the consistency, the check results areshown in Tab7.

Table 7Index Aλmax 4.0104CI 0.00346RI 0.89CR 0.00389

It can be seen from the table, the index ofCR values isless than 0.1, so the criteria are consistent, and the matrixis acceptable. Then we get the weight of each criterionrelative to the total target. The results are shown in Tab.8.

Table 8: Weight of each indexindex weightQuality 0.4286Low Cost 0.2857Efficiency 0.1714Environmental Friendly 0.1143

Then we would haveAm,Bm, which respectivelyrepresent the scores of process solution corresponding tothe criterion. (Table 9)

Calculate the satisfaction index:SA,SB . . .SN.

SA =∑Am ·Vm

= 0.4286∗68+0.2857∗80+0.1714∗76+0.1143∗75

= 73.6285 (9)

SB =∑Bm ·Vm




Table 9: Weight1 2 3 4

Quality Cost Efficiency EnvironmentVm 0.4286 0.2857 0.1714 0.1143Am 68 80 76 75Bm 72 70 85 90

= 0.4286∗72+0.2857∗70+0.1714∗85+0.1143∗90

= 75.695 (10)

Then engineers can draw a conclusion on theevaluation based on the above index. By comparing the“satisfaction index” SA, SB, engineers find the mostinventive process solution is “add the gas-liquid mixturecooling system to the grinding process system”.

4 Conclusions

Process innovation has a significant impact onmanufacturing industry. Currently, process innovationdesign in most industries is still based on the experienceof designers and engineers. The essence of this designprocess is for engineers to acquire and analyze processrequirements, and to gain innovative design solution. Inorder to assist them in solving process problemseffectively, an optimizing strategy is established. Toguarantee applying TRIZ solve process problem, it isessential to co-operate with other existing or newlydeveloped methods. Process problem can be effectivelysolved by a strategy which combining QFD, TRIZ andAHP in a scientific way. It has been shown how thesemethods are used in the strategy of process innovation. Inthis paper, a strategy of process innovation integratedAHP/QFD/TRIZ is proposed, which is composed ofprocess requirements analysis, system assessment andconflicts resolving. The process innovation of grindingsystem is presented to illustrate the effectiveness of theproposed method.

The strategy can be summarized as below: Analyzethe process according to constraints and requirementswhich obtain by QFD, then process engineers analyze theconflicts of the process system comprehensively, andsolve the process problem with the help of TRIZ. Finally,evaluate these solutions and find the best solution with theassistance of AHP. In this way, the maneuverability ofusing Inventive tools to solve process problems isimproved. Future studies will focus on how to applyTRIZ solving the process conflicts more efficiently.

We also propose a point for future researchers andengineers to consider on process innovation based onabove research. While continuing to emphasize theimprovement in existing processes, manufacturingindustry should consider how to develop the nextgeneration processing method. Therefore, policymakersshould develop policy incentives to facilitate the do theseresearches, while firms should consider adding externalcosts to develop a new process.

Acknowledgements

This work was supported in part by NSFC (NationalNatural Science Foundation of China) under Grant No.51175357&No. 51105260&No. 51175355 and theNational 863 High Technology R&D Program (NO.2013AA040606-1).

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Chen Wang studyingfor a doctor’s degreein Mechanical Manufactureand Automation at SichuanUniversity of China. Hisresearch interests are in theareas of innovative design andknowledge base including themathematical methods andmodels for complex systems.

He has published research articles in several internationaljournals.

WU Zhao receivedthe PhD degree in MechanicalManufacture and Automationat Sichuan Universityof China. He was oneof the Innovation methodand the design key laboratoryof sichuan province. Hisresearch interests are in theareas of innovative design and

knowledge base including the mathematical methods andmodels for complex systems. He has published researcharticles in reputed international journals. He is referee andeditor of several reputed international journals.

Jie Wang, Born inFebruary 1964, doctoralsupervisor, institute ofmanufacturing vice presidentand director of engineeringtraining center. The mainresearch direction: computeraided design and manufacture(CAD/CAM); Computerintegrated manufacturing

system (CIMS).

Xiaolong Ii is studyingfor a masters degreein Mechanical Manufactureand Automation at SichuanUniversity of China.His research interests are inthe areas of innovative designand knowledge base. He haspublished research articles inseveral international journals.

Kai Zhang is studyingfor a doctors degree inMechanical Manufactureand Automation at SichuanUniversity of China.His research interests are inthe areas of innovative designand education science. He haspublished research articles inseveral international journals.

Xin Guo is studyingfor a doctors degree inMechanical Manufactureand Automation at SichuanUniversity of China.His research interests are inthe areas of innovative designand education science. He haspublished research articles inseveral international journals.




Jie Zeng is studyingfor a masters degreein Mechanical Manufactureand Automation at SichuanUniversity of China. Hisresearch interests are in theareas of innovative design andnondestructive testing. He haspublished research articles inseveral international journals.


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