As we already discussed in one of our previous blogs (What is the problem?), the main issue in the problem-solving process is to identify the right problem and to separate between a failure and the actual problem. We should always be concentrating on problem-solving and not wasting the time on fixing the failure. As a quick reminder, a single failure can, and usually does cause several different problems. Some recommendations on how to define a problem statement described in the blog How to define a problem statement?
The concept is that failure can cause a wide variety of problems. In addition, the main attribute of a problem is that the problem can be solved, while the symptom of a failure cannot be fixed.
The problem statement is key to problem-solving. PRIZ Innovation Platform drives the innovator to think and complete this step at the very beginning of the problem-solving process.
Your company produces discs from glass — very clean, transparent, and beautiful disks.
The process contains a number of operations, including formation, thermal treatment, etching, thin-film deposition, polish, and so on. The very last operation is washing with pure chemistry. The washing process is susceptible and may dramatically impact the final product.
The washing process is performed with standard equipment: the disk is held from the backside and rotates. The chemistry dispences through the nozzle to the center of the rotating disc.
What had happened? Background.
At some point, the quality control revealed that several discs were covered with some unusual and unknown defects. As a result, the affected discs were scrapped. Engineers analyzed the details of this excursion and identified that the defects started appearing after the introduction of a new batch of chemistry.
The comparative chemical analyses of the previous and suspected batch showed that all parameters for both batches are within specification limits. The only difference found is that the concentration of one of the components is slightly elevated in the suspected batch. Nevertheless, it is important to highlight that the elevated component remained well within the specification limits.
So, what is the problem? How to define the problem that we are going to solve? How to solve the problem?
The traditional approach to problem-solving
The new batch of chemistry is contaminated. The chemical content of the suspected batch does not match the typical composition of the chemistry.
Direction to solve this problem
Remove the batch from the production line. Dispose or return it to the vendor and ask to prepare another batch with a purity that matches the typical batches.
Change the specification limits to be tighter than the current to avoid similar excursions in the future.
The solution evaluation
Such solutions might be acceptable, but there are disadvantages in this approach
Cost increase – production cost will be definitely elevated
Recurring excursions – similar excursions may occur again with the same or other components
Lack of innovation – this solution is not improving the process or developing the technology
You guessed right! Lack of innovation is the most critical disadvantage of the above approach. Indeed, any excursion or failure is an opportunity to learn the phenomenon and improve the process. The main reason for the disadvantages is that the problem statement has not been defined correctly.
As usual, everything in the platform is contained within a project. In a project, let’s navigate to Problem Statement page.
As per PRIZ Innovation Platform convention, we need to define the problem statement in three steps.
The first step: Describe the current situation.
We need to describe what we see, what is the difference from the regular situation. We actually should describe the failure.
We defined it as: Defects were found on the surface of the disc after the washing with the chemistry
The second step: Describe the disadvantages.
In other words, why is it not good?
We described it as: The discs contaminated with the defects cannot be sold to the customer. The defective discs will be scrapped.
The third step: Describe the problem statement based on two previous steps.
We wrote: “ Defects remain on the disc surface while the washing process.“
Indeed, it is not so important if the chemistry is able to create defects or not. What is really important for us is that the defects remain on the surface of the disc. This is a real problem that we have to solve.
Now we have to analyze the process and understand how it is working and why the defects can get created on the disc surface while the washing process.
Root Cause Analysis
PRIZ Innovation Platform offers a Root Cause Analysis using the Cause and Effect Chain tool. The tool contains two chains. The left chain is a Cause and Effect chain that is built by answering the question “Why?” On the right side, possible explanations or solutions are described if a certain cause is considered as a Root Cause. This is a very effective way to analyze and elaborate on the directions for how to solve the problem.
Our result of analysis is shown below:
Fundamental Root Cause (FRC) is the contaminated batch of the chemistry. We have already discussed possible solutions to this root cause at the beginning of this blog. The chemistry replacement could solve the problem temporarily, but it does not create innovation.
On the right side of the table, you can see how a number of ideas we generated during the analysis.
If we summarize the ideas, we can reveal the model of the creation of the defect as follows.
Chemistry poured on the disc through a nozzle
The disc rotates and rotation forces of the chemistry from the disk
The disc rotation creates a low-pressure area near the disc surface that results in evaporation of the chemistry
If the chemistry removed by centrifugal forces, then the defects will be washed away with the liquid
If the chemistry evaporates, then the defects will remain on the disc surface.
In order to solve this problem, we need to prevent evaporation so the particles are washed away with the solution. There are different ways that we can think about: increase pressure, reduce the temperature of the air, and so on.
Another one could be to increase the amount of chemistry, but this will increase the cost of the whole process. Some parameter improves while another degrades. This is a typical conflict; aka Engineering Contradiction.
40 Inventive Principles
40 Inventive Principles is an excellent instrument for solving such type of problems. It helps to break a contradiction.
Once we built an Engineering Contradiction and completed of the analysis of the parameters, the PRIZ Platform suggests 4 principles that should help us to solve the problem.
#7. Nesting dolls #15. Dynamism #13. The other way around #16. Partial or excessive action
Reminder: The principles are not the solutions, they assist us in the thinking process. We can treat the principles as tips that help us think and focus on a certain direction. “Principles” help us to innovate.
Generate ideas with the help of inventive principles
Principle #7 – Nesting dolls – place one object inside another.
Based on this principle we generated the following idea:
Why do we use only one nozzle? Why not a shower? The shower has several holes – a lot of nozzles. More than that, we can make the holes different in diameter. With this approach, we can ensure equal coverage of the disc with the chemistry.
Idea #1: replace the nozzle with the shower
Principle #15 – Dynamism – change an object from rigid to movable or adaptive
This principle led us to the next idea.
Replace the constant flow of the chemistry with variable one to ensure particles removal from the disc. This will be especially helpful at the end of the process.
Idea #2: variable flow during the cleaning process
Principle #13 – The other way around – Turn the object “upside down”
This is a great tip. Why the disk is kept “face-up” during the washing process? It would be much better to keep the disc “face down” to improve cleaning.
Idea #3: keep the disc “face down” during the washing process
Principle #16 – Partial or accessive action – do slightly more or slightly less
We decided to leave this one to you as an exercise. The explanation of this principle is available in the PRIZ Innovation Platform.
Read the explanation and try to think about how the process can be changed to ensure that variation in the quality of chemicals will not affect contamination levels and cause defects.
Any failure is an opportunity for innovation. Do not miss the chance to innovate and develop your process.
The key to innovation success is the correct definition of the problem.