A New TRIZ Practitioner's Experience for Solving an Industrial Problem using ARIZ 85C: Increasing a Textile Kiss-Coat Operation Speed

By: Frank Grace, Dr. Slocum, and Dr. Clapp

By
Frank C. Grace

TE 589A Theory of Inventive Problem Solving (TRIZ)

Fall 2000

Professors:
Dr. Michael Slocum &
Dr. Timothy Clapp

The following paper summarizes a real industrial problem solving experience that was part of a graduate-level course. The course focused on an in-depth study of the fundamental principles of the Theory of Inventive Problem Solving. Each student selected a real problem to solve using the methods as part of the class. The algorithm, ARIZ - 85C, was used to guide the student systematically through the problem solving process. The following paper describes one student's experience applying TRIZ methods.

The topic for this paper involves a textile coating process known as kiss-coating. This process is currently being used where I work as a textile chemist. A water based adhesive, which is an emulsion, is fed into a trough until the trough is 75% full. Inside the trough an engraved gravure print roll turns. As the roll turns the engraved cells on the surface of the print roll fill with the coating mixture in the trough. A doctor blade cleans off excess coating that is on the printing roll and this excess coating mix is returned to the trough for reuse. Once the print roll is clear of excess coating mix, it then meets a rubber roll that is under downward pressure. The fabric passes in between the two rolls. As the fabric gets nipped between the print roll and the rubber roll, a slight vacuum is created and the coating mix leaves the cells on the print roll and transfer to the surface of the fabric. This particular coating process is used to obtain a surface coating rather than saturating the fabric with coating. The wet-coated fabric then wraps around heated drying cans to drive off the water on the coated fabric and leave behind the adhesive coating.

As in many operations, the line speed dictates the cost of a product. The faster a product is made the higher the production rate (units made per hours or shift) and therefore its cheaper to manufacture the product. The money saved by running at higher production rates turns into company profits or is sometimes passed onto the customer in an effort to remain competitive in the textile industry. The higher product rates also allow for an increase in machine production capacity, which is needed by most growing companies.

It was discovered in this operation in question that as the speed of the machine was increased, the coating weight decreased. This forced the product to be run through a two-pass operation or at a slower speed so that the desired coating weight could be achieved. The slower coating operation caused the production rate to go down and the faster two-pass operation had the same effect on the production rate.

What is needed is a method that allows for an increased production rate (faster coating speed) and at the same time provides a sufficient coating weight. ARIZ-85C will be used to solve this problem.

Some of the initial ideas that were generated to solve this problem are as follows:

• The idea behind this was to use a larger cell to hold more coating mixture in hopes of getting more of the coating mixture on the fabric. The cell size was changed to a larger size but the problem still existed.

• It was thought that if the viscosity of the mixture was decreased, it might move more easily out of the cells and onto the fabric. Problems experienced with this idea is that as the viscosity decreases via diluting with water, the percent solids in the mixture decrease. This means that although it may be possible to pick-up more coating mixture, there will be fewer solids picked up and therefore still a decrease in coating weight.

The coating assembly speed influences the amount of coating being applied to the fabric.

The coating assembly does not apply enough coating to the fabric when its speed is increased.

The common elements in the useful and harmful functions are the coated fabric and the coating assembly.

The faster coating head speed provides a Useful Function by increasing production rates but provides a Harmful Function by not applying enough coating.

Very fast coating speed

Production rate Decrease of coating weight

IC-1: If the coating speed is exponentially increased then (+) very high production rates will be obtained but (-) the coating weight will be extremely low.

If the coating line speed is decreased below normal running conditions (-) production output will be reduced below what is normally expected but (+) the coating weight will not drop below specifications.

Production rate

Very slow Coating speed Extremely low coating weight

IC-2: If the coating assembly is run at a slower than normal speed, then (+) the lower coating weight can be eliminated but (-) the production rate will drastically decrease.

There is a technical system for performing an increased coating speed, including a coating assembly and coated fabric.

It is essential under minimum changes in the system to perform (+) an increased coating speed without (-) producing a fabric with a reduced coating weight.

The coating assembly should be operating to perform an increased coating speed and should also coat the fabric with sufficient coating.

Utilization of the Contradiction Matrix Theory may be employed to attempt to resolve the PFC.

Following Altshuller’s 39 parameters, the following features of the system are in question and hence the technical contradiction:

Utilization of the Matrix Table reveals the following principles used most to solve the contradiction stated: 11, 35, 27, and 28

Principle 11 - Cushion in Advance: Compensate for the relatively low reliability of an object by countermeasures taken in advance.

• Since the coating weight decreases with coating speed. There may be an opportunity to chemically treat the fabric during the finishing process (before the coating process in question) with an additional chemical that may improve the wet-out properties of the fabric. This would allow the fabric to absorb the coating faster, which would let the fabric pick-up more coating during the increased speed.
• There also may be an additional chemical that may be added to coating mix that goes onto the fabric during the coating process that would assist in coating mix transfer to the moving fabric.
• These solutions would “cushion” the fabric or coating mix in advance before the coating process in question.

Change the aggregate state of an object, the concentration of density, the degree of flexibility or the temperature.

• Change of the chemical states of the fabric or coating mix are mentioned in possible solutions generated from principle 11 (stated above).
• The fabric is currently a blend of 50% cotton and 50% polyester. The fabric could be changed to 100% cotton, which has inherent abilities to absorb the coating mix through its wicking properties. The polyester fiber in the current fabric does not have high absorbent properties as cotton. However, it should be noted that this would drastically change the final product and affect both the physical properties of the coated fabric (tensile strength, elongation properties and hand) and the cost of the base fabric (100% cotton fabric is more expensive than a 50/50 blend of cotton/polyester).
• Before the fabric is coated, heat may be applied to pre-heat the fabric, which may help in picking-up the coating mix during the coating process. This may help dry out the fabric and help in absorbing the coating mix.
• The viscosity of the coating mix (2,500 cps) can be lowered to approximately 1,000 cps by heating the coating mix. This would assist in the flow properties on the coating mix and may allow the coating mix to move easily from the coating assembly to the fabric.

Replace an expensive object by a collection of inexpensive ones, compromising other properties (longevity, for instance). This improves the existing system but does not directly address the problem at hand.

• A patent review of similar processes revealed that a relatively expensive object in the coating assembly, the steel doctor blade, should be replaced with a cheap plastic blade. It was discovered that the plastic blade is more reliable and allows for better coating weight control.

Replace a mechanical system by an optical, acoustical or odor system. Replace fields.

• The current nip roll, which lies and applies pressure onto the fabric and print roll is made of solid steel, which has a coating of hard rubber. Because the rubber is relatively hard, there is no give in the rubber when it makes contact with the print roll. This makes the contact area between the rubber roll and print roll small. If a softer rubber roll with more give is used, the contact area will increase when pressure is applied. This would increase the dwell time of the fabric to pick up the coating. This mechanical pressure from the rubber roll could also be replaced with a pneumatic roll where you can increase the hardness of the roll by inflating or deflating the hollow roll.

If the coating speed is increased exponentially then the system will get to a point where there is little or no coating being applied to the fabric.

If the coating speed is decrease to a speed of almost 0 yards per minute (a “crawling” speed) then production rate will be zero.

Given that the coating speed and coating weight participate in the conflict.

IC-1: If the coating speed is exponentially increased then (+) very high production rates will be obtained but (-) the coating weight will be extremely low.

Very fast coating speed

Production rate Decrease of coating weight

It is essential to introduce the X-Resource, which prevents the Harmful Function of decrease in coating weight and maintains (does not prevent) the Useful Function of increased production rate.

Given that the coating speed and coating weight participate in the conflict

IC-2: If the coating assembly is run at a slower than normal speed, then (+) the lower coating weight can be eliminated but (-) the production rate will drastically decrease.

Very slow Coating speed

Production rate Extremely low coating weight

It is essential to introduce the X-Resource, which provides 100% performing the Useful Function of a sufficient coating on fabric and maintains (does not prevent) complete eliminating of the Harmful Function of poor production rate.

• Separate the tool and the product of Harmful Function from the Graphical Scheme of Direct Conflict
• Put them as substances in the appropriate SU-Field Model

IC-1: If the coating speed is exponentially increased then (+) very high production rates will be obtained but (-) the coating weight will be extremely low.

SU-Field Model for Problem on step 4.1:

Fme	Mechanical Field of speed of coating fabric (Fast coating speed)	Source of energy
S1	Fabric to be coated	Recipient of the systems action - Product
S2	Coating assembly	Means by which energy is applied to the fabric - Tool

The function of the system is to apply coating to the fabric at an increased speed via the coating assembly.

The SU-Field model above describes that the coating assembly has an insufficient effect of the fabric to be coated at an increased coating speed.

5.2. Try to solve the problem with SU-Field Model from step 5.1 using SU-Field Transformations:

The typical solution is proposed through use of the SU-Field Transformations:

• Introduce the second field F2. This would be taken from Standard Solution 2-1-2. A second field would be introduced to intensify the effect that the coating has on the fabric. This may possibly be a field that compensates for the increase in coating speed.

5.3. Render the initial SU-Field Model for the Problem on step 4.2, for which purpose:

• Separate the tool and the product of Useful Function from the Graphical Scheme of Reverse Conflict
• Put them as substances in the appropriate SU-Field Model

IC-2: If the coating assembly is run at a slower than normal speed, then (+) the lower coating weight can be eliminated but (-) the production rate will drastically decrease.

SU-Field Model for Problem on step 4.2:

The function of the system is to apply coating to the fabric at a decreased speed via the coating assembly.

The SU-Field model above describes that the slow coating speed has an insufficient effect on the fabric. Coated fabric production rate goes to near zero.

5.4. Try to solve the problem with SU-Field Model from step 5.3 using SU-Field Transformations:

The typical solution is proposed through use of the SU-Field Transformations:

• Standard Solution 1-1-8-2 could be used where if a selective-maximum effect is required (maximum in certain zones, and minimum in other zones), the field should be minimal; then a substance that produces a local effect interacting with a field is introduced in places where a maximum effect is required.

The selective maximum effect that is required for IC-2 is slow coating speed and should be maximum to produce the high production rate but at a minimum when coating the fabric so that a good coating weight can be obtained. The minimal field is the slow coating speed effect.

This promotes an idea that you get an effect at the coating assembly that prints as though the coating process is slow but the added substance still provides a high production rate. This is the same type of idea generated in the SU-Field model for IC-1. A connection can be made where the system move fast but coat the fabric as if it is moving slow.

Physical Contradiction Theory:

At this stage in the algorithm, I can see how this engineering problem can also be stated as a Physical Contradiction.

Physical Contradiction: The process must be both fast and slow at the same time.

Separation Within a Whole Object and Its Parts: I believe that the solution for this Physical Contradiction would be found using the Separation Within a Whole Object and Its Parts principle. The fabric must pass through the production line at a high speed to achieve the high production rate but when the fabric gets coated, it must run through a slower process to achieve a good coating weight. The coating process could be looked at very closely at the slow speed and may somehow be duplicated at the fast speed. It sounds as though the time may play an important factor in solving this problem.

5.5. If the Conflict Enforcement IC-2 on step 4.2 leads to disappearance or inactivity on the Useful Function Tool, render the appropriate SU-Field Model:

When IC-2 Conflict is enforced, it leads to a disappearance or inactivity on the Useful Function Tool:

S1 and S2 stand alone with no interaction

The system is incomplete and no production is made. No field is present to have interaction between the Production Rate and the Fabric.

5.6. Try to solve the problem with SU-Field Model from step 5.5 using SU-Field Transformations:

A field is needed to complete the incomplete system:

It is not known at this time what this proposed field may be.

6. Operational Zone Analysis and Resources Discovering

6.1. Determine the Operational Zone (OZ):

Picture 1. Descriptive Picture of Coating Process

Picture 2. Textile Kiss-Coat Operation. Useful Function Operational Zone (UFOZ = Increased Speed of coating assembly. Harmful Function Operation Zone (HFOZ = Decreased coating weight) determined and labeled in process

The Useful Zone of the process is the properly coated fabric produced at an increased coating assembly speed, which in turn provides an increased production rate.

The Harmful Zone of the process is when not enough coating is transferred to the fabric at an increased coating speed. This happens at the contact point between the rubber nip roll and the gravure print roll.

1. Mechanical downward pressure from rubber roll onto gravure print roll
2. Uncoated fabric between both rolls
3. Coating located inside print cells on gravure roll
4. Vacuum created between print roll and rubber roll

1. Same fields and substances as in UFOZ are present in HFOZ because of Operational Time of Conflict.

1. Fabric is uncoated and moving toward coating assembly.
2. Gravure print roll cells are filling with coating mixture.

• Processes going on in the OZ during OT
• Flows of substance and/or energy passing through OZs during OT
  • Indicate amounts (magnitudes) of parameters of these processes and flows, if possible.

The coating assembly is filled with coating mix and the gravure print roll is turned on. As the gravure roll turns, the cells within the print roll collect the coating mixture that is located within the trough. The doctor blade then wipes excess coating from the surface of the roll leaving the coating that is within the cells. The fabric then passes over then print roll as the rubber roll is brought down via air pressure pistons. As the fabric is pressed between the rubber roll and the print roll with its cells filled with coating mixture a slight vacuum is created by squeezing the fabric. The fabric is then released from the pressure and the vacuum promotes the coating within the print cells of the gravure roll to be transferred onto the surface of the fabric. The fabric then leaves the coating assembly for drying. The system is in a continuous process and repeats itself without interruption.

The Zone of Conflict occurs only when the coating speed is increased. This takes form in that the fabric does not pick-up enough coating from the coating assembly at the increased speed.

MLP is found to be extremely useful in this problem. The model can be depicted below as the MLP being on fabric whose job is to grasp the MLP on the print roll in the form of the coating mix in the print cells filled with MLP looking to leave the print roll and grasp the MLP on the fabric. This would transfer the coating MLP to the fabric MLP.

Initial Model: The fabric people represent sites where the coating people can attach themselves to by letting the fabric people pull the coating people out of there cells.

At a slow coating speed, the fabric people have enough time to grasp the coating people as can be seen in the following model:

The “Was” Model: In the “was” model, the coating speed has been increased and the fabric people cannot grasp all the coating people. Therefore some of the coating people are left inside their cells as displayed in the following picture:

The “Should Be” Model: This model should be the same as when the coating speed is lowered but we are coating at a faster coating speed:

Solution 1: The current scenario is that that fabric is moving too fast for the fabric people to grasp onto the coating people. This implies that there is a time constraint present due to the increase in coating speed. This constraint was not present when the coating speed was reduced because the coating on the fabric was not reduced. The solution to get to the “should be” model at a fast coating speed is to increase the time that the fabric people and coating people have together so that the fabric people will have time to grasp onto the coating people. Since the coating speed cannot be lowered to allow for this, it must me accomplished in another way.

The MLP modeling allows for a closer look at the situation. The contact time that the MLP have with each other can be determined by measuring the contact area between the rubber roll and the print roll (at the nip point). It is this contact area that must be increased to make up for the decrease in time lost when the coating speed was increased. The contact time and area are also known in the field as dwell time. So the dwell time between the two sets of MLP must me increased so that coating transfer can occur.

A softer rubber roll will increase this dwell time between the MLP and should allow for the coating MLP to be grasped by the fabric MLP. The softer rubber will provide for contact area when in contact (under pressure) with the gravure print roll.

Solution 2: The fabric MLP people could be enhanced to become better able to grasp the coating MLP when passing by at a fast speed. Adding a re-wetting agent to the fabric prior to the coating operation may do this. This re-wetting chemical agent would give the fabric additional wet-out properties that may increase the fabric’s MLPs to grasp the coating MLP.

Solution 3: Lowering the coating mix viscosity will help the coating MLP to move more freely from there cells. This may help the fabric MLP to pull the coating MLP from the cells more effectively even though the dwell time that they have would still be decreased. It should be noted however that if the viscosity is reduced, the % solids in the coating mix should not be lowered because it will add to lowering the final coating weight.

The input from the Technical Contradiction Matrix Theory, SU-Field Analysis, Physical Contradiction Theory, and MLP modeling has solved the engineering contradiction presented in the introduction to this paper. I do not feel that completing sections 7 through 11 of ARIZ-85C is necessary. I have had the opportunity to apply what I have learned using ARIZ-85C with real problem. I am glad to say that I have been able to apply Solution 1 from the MLP modeling in a real life situation where I work. It should also be noted that Solution 1 from MLP modeling also ties into the Technical Contradiction Matrix Theory, SU-Field Analysis, and Physical Contradiction Theory. The outputs from these tools have let to the idea of compensating for the increase in coating speed by matching the coating dwell time that was achieved at the slow coating speed.

Although I do not think that this solution is a very innovative solution, it was a real problem that was solved using TRIZ tools. The tools provided a method to see through the physiological inertia that was actually present in my work environment.

As stated before, this problem initially started off as an administrative problem in that the coating line was running at 30 yds./min. and there was little understanding as to why the coating weight was so low. It was known that the coating weight must be increased and the speed was not thought to play a role. I did not have much experience on the production line or this particular coating process. I was able to provide an outside view of what may be happening. This outside view also allowed me to be free of much of the psychological inertia that others had by working on the problem. I also owed a great deal to what this class has taught me.

I proposed that a study of line speed versus coating weight be performed because it was the easiest variable that we had control over. The results can be found below in Figure 3 below.

From the results of this study, it became clear what the real problem was. It was a technical contradiction in that when the line speed was increased, the coating weight decreased. I therefore decided that I would use this as my major project for TE 589A.

I applied Solution 1 from the MLP modeling found in Section 6.6 by replacing the 90 hardness (Shore A) rubber roll with a 60 hardness (Shore A) softer rubber roll. We were looking for a total coating weight of approximately 2.50 oz./yd². Our results before the rubber roll change were around 2.35 oz./yd² at 30 yds./min., which can be seen on Figure 3. The softer rubber roll idea from Solution 1 results can be seen in Figure 4.

A large increase in coating weight was achieved by using the softer rubber roll and MLP Solution 1 provided a means where the coating speed could be increased and the coating increased within specifications. The Engineering Technical Contradiction was resolved.

This problem is probably a level 2 for solution inventiveness, which is why the full completion on ARIZ may have been too much since ARIZ is usually used to solve hard (possibly level 4 or 5) inventive problems. However, as a new practitioner of TRIZ methods, ARIZ systematically guided me through the problem solving process.

Even though my primary academic training is Textile Chemistry, following the systematic approach to apply TRIZ methods enabled me to identify a mechanical solution that solved my problem. Although the solution may have been one identified by a mechanical engineer, I was able to "look" in a new direction for solutions.

TRIZ methods and practices I have learned in this class have changed the way I tackle problems in my everyday work related situations. I will continue to use this method whenever possible.

The following book and articles were found to especially useful in learning and applying the TRIZ methods used in this paper:

1. Altshuller, G.S., Creativity As An Exact Science: The Theory of the Solution of Inventive Problems. The Netherlands: Gordon and Breach Science Publishers Inc., 1998.
2. Salamatov, Yuri, TRIZ: The Right Solution at the Right Time, A Guide To Innovation Problem Solving. Ed. Valeri Souchkov and Michael Solcum, Ph.D. The Netherlands: Insytec B.V. 1999.
3. Terninko, John, Alla Zusman, and Boris Zlotin. STEP-by-STEP TRIZ: Creating Innovative Solution Concepts. Nottingham: Responsible Management Inc. 1996.
4. TRIZ Journal. www.triz-journal.com <http://www.triz-journal.com>
5. ARIZ: The Algorithm for Inventive Problem Solving - An Americanized Learning Framework - By Janice Marconi. TRIZ Journal. www.triz-journal.com <http://www.triz-journal.com>. April 1998.
6. Digging Your Way Out of the Psychological Inertia Hole - By Darrell Mann. TRIZ Journal. www.triz-journal.com <http://www.triz-journal.com>. August 1998.
7. Accelerating Innovative Idea Generation Using TRIZ Methods - TE 589A Class Presentation Notes - By Timothy G. Clapp, PhD, PE, North Carolina State University, College of Textiles. December 1999.
8. TRIZ in Progress, Transactions of the Ideation Research Group, Ideation International, February 1999.

APPENDIX A

Spring 2000 TE589A: Theory of Inventive Problem Solving

Survey Summary

Dr. Michael S. Slocum, Dr. Timothy G. Clapp

1. Has TRIZ changed the way you perceive a problem?
   
   Absolutely.
   
   If yes, how? If no, why?
   
   I work in an environment where people end up doing what we call “fire-fighting”. This is when a problem comes up during production, people scurry to solve the problem. The solution usually ends up being “band-aide” and does not get to the root of the problem. In fact, the real problem is usually not really understood and the problem resurfaces in a short time.
   
   I received my BS in textile chemistry and I worked within this textile-manufacturing environment for 2 years as a manger of product development and a member of the technical support team. Needless to say, without much prior experience this form of problem solving became a part of me. After all, my superiors all treated problem solving this way.
   
   This course taught me to understand and well define what the real problems are and that one does not have to accept an engineering trade-off as a solution.
   
   
2. Has TRIZ increased your ability to solve problems?
   
   Yes.
   
   If yes, how? If no, why?
   
   I now approach work related problems with confidence and the ability to solve them using TRIZ. I now realize that no problem is unsolvable. I can identify when I am being affected by my prior experience or in-experience (psychological inertia) and see through self-imposed barriers (such as “it can’t be done or we’ve tried that already”) to solve problems.
   
3. Rank the TRIZ tools in order of usefulness to you (the lower the score the better):
   
   Does not apply.
   
4. Please quantify and describe any increase in solution quality?
   
   I believe that I have improved my solution quality by 95%.
   
   
5. Please quantify any increase in the Level of Innovativeness associated with your solutions?
   
   1 level:
   2 levels: Not sure of the exact meaning question but the number of the solutions that I am now able to generate using TRIZ has increased. I no longer come up with only one possible solution but now have several possible solutions.
   
   
6. Will you continue to use TRIZ? Why or why not.
   
   I will continue to use TRIZ at work because it is extremely helpful in solving problems and provides an algorithm to problem solving and helps to scientifically direct you toward an inventive solution.
   
   
7. Will you teach TRIZ to co-workers? Why or why not.
   
   I will teach TRIZ to my co-workers because it is so effective. They have already heard my praises for the theory. I was able to solve an actual work related problem in the course’s final major project for TE 589A that the company has been working on by using the trial and error methodology. I explained several of the TRIZ methods I used in my solution such as the Contradiction Matrix and Modeling with Many Little People and generated a lot of interest for the theory.
   
   
8. Will you use TRIZ software?
   
   Through NC State’s distance learning program (Textile Off-campus Textile Education), I did not have the opportunity to see or try any TRIZ software. I have been to the Ideation website and have read reviews on what the software provides. It sounds interesting and will look into the software and I become more experienced with TRIZ tools.
   
   
9. How useful did you find the TRIZ Journal (www.triz-journal.com)?
   
   I found the TRIZ Journal extremely useful and have become a member of the free monthly subscription newsletter. I would suggest all students visit the web site often to read the monthly articles and become a member to learn about when the latest papers are published.
   
   The journal articles also provided insight into some TRIZ tools that I had some questions about and clarified many issues.
   
   
10. What portions of the class helped the most to reinforce learning?
    
    I would definitely say that the homework problems provided the greatest reinforcement because I feel I would not have really had a firm grasp of the subject without applying the TRIZ tools in homework problems. The major project of applying ARIZ to a problem was also very helpful in watching all the TRIZ tools work together and leads to possible solutions.
    
    
11. What portions of the class helped the least to reinforce learning?
    
    At this time, I cannot honestly think of any part of the class that did not reinforce the learning.
    
    
12. Where the guest lectures useful? If yes, how? If no, why?
    
    Does not apply.
    
    
13. What roadblock, if any, do you think would prohibit the wide-spread implementation of TRIZ in industry?
    
    I think the main roadblock would be from people in industry that are close-minded and are not willing to accept that an algorithm can be used to solve problems. I feel that some people would feel threatened that industry experience is not the only quality needed to solve problems. The sooner people are introduced to TRIZ, the more willing they may be to accept and use TRIZ.
    
    I initially think that it would be considered more valuable to students/professionals that have experience in industry dealing with problems. Students that have not had much experience in industry may not realize just how valuable learning TRIZ tools are. This course is a must for all people and I highly recommend it. Even if you do not realize it now because of lack of work experience, learning to apply TRIZ will make you more valuable to employers.