Innovation by SIT

A story based on a true case

Itai, head of the final quality control process, made sure that the testing system was properly adjusted. He checked the temperature guage of the huge cooling cell in which the unit had been tested overnight, and nodded to himself satisfactorily - everything was ready for the final testing procedure, the last stage before shipping the product to the customer.

It took only a few seconds for Itai to realize that something was wrong. The rotating sound of the pistons didn’t sound quite right. Instead of a rythmic ticking, he could hear a screeching sound every now and then. Even before he had the chance to decide what to do about it, the system came to a screeching halt and the words “FAIL” flickered in bold red letters across the test screen.

An hour later a similar malfunction occurred in another system… Pandora’s box had been opened!

********

Around the discussion table, along with the other factory managers, sat the chief engineer - a rare phenomenon due to the fact that it was a discussion about yet another failure of the system, getting “stuck” at low temperatures.

However, this time there was a real threat to the supply schedule, as it was dangerously close to the shipment date. Failure of the system during the final testing stages was not characteristic of the producton flow. For this reason, the time allocated to the final testing was fairly close to the shipment date, leaving room for only minor, unexpected hiccups.

The system’s engineer described the findings and the resulting implications clearly and concisely:

“Under low temperature conditions, the pistons inside the cylinders jammed, causing a failure in the operation of the system. Intensive investigation has shown that the reason for the system getting jammed is that an incorrect material (too soft) was used to produce about 3% of the 120 cylinders”

“The implications are that about 4 units could malfunction at any time”.

“How long will it take to check all 120 units to find out which cylinder is faulty?” asked the factory manager.

The answer was not encouraging.

“In the engineering world, the most common way to distinguish between a soft cylinder (abnormal) and a hard cylinder (normal) is to use a special machine to check the materials”.

“The tip of a diamond is embedded into the material, and the hardness is determinded by how far the diamond tip is inserted. In order to use this machine, the entire system needs to be dismantled: remove the cylinders, check the hardness, make a selection, put it back together, and then repeat the cold temperature testing procedure on all the sytems.

“Testing each section of the system will take at least two weeks if we work around the clock, and the supply time delay will be more than a week”.

The silence in the conference room was tangible and tense. Everyone was aware of the obvious dilemma: a delay in supply time would include fines and damage to the company’s good name. On the other hand, they could not take the risk of sending a system that may fail at a point when it was most needed.

As a factory that doesn’t compromise on quality, it was obvious that the second option wasn’t really an option, and so it seemed as though the decision had already been made.

The silence was broken by Ron’s voice, the engineer who had been working on locating the failure mechanism in the last two days almost around the clock:

“Maybe we can think about a creative solution to find the faulty system… I mean, some kind of systematic inventive thinking process,” he clarified.

Knowing that they didn’t have much option, the factory manager approved a two day delay for the benefit of this experiment - to find an inventive solution that would save them the time and effort involved in testing the hardness of the materials.

***
Ron cleared the table and erased the calculations from the board.

Gadi, the head of the mechanical laboratory, and Yoav, the metalurgical engineer who was called in to help take care of the malfunction, were both invited in to discuss the problem.

“The facts are clear”, Ron began, “there’s a shipment of 120 tested units in storage. Among them, approximately 3% of the cylinders are made out of material that is too soft. We need to find a way of identifying these soft cylinders as quickly as possible. How can we do this?”

Spontaneously, a Brainstorming session started up where numerous ideas were thrown into the air:

“Maybe there’s a difference in the magnetic or electrical properties between the hard and soft materials”.

“Maybe the luster of the hard and soft materials is different”.

“What would happen if we activated all the units again at a low temperature and see which one gets stuck?”

“Maybe we should replace all the cylinders with the proper cylinders without checking”.

“Maybe the low temperature test was too severe and cannot really be related to real life situations, and therefore we should not expect problems during functioning”.

“Maybe we should test just a sample of the systems”.

“What would happen if we dismantle and check only one covering out of three and decide according to that if the unit is useable”.

“Is there a non-destructive test to check the hardness of a material (ultrasound, laser?)”

Very soon they realized that it wasn’t possible to use any of these ideas in finding a solution.

“I think it’s time for a coffee break”, said Gadi heading for the kitchen.

When he returned he saw that Ron has just finished drawing a piston and a sleeve (covering) on the board.

“I suggest that we try to be more systematic in our thinking,” said Ron. “Let’s try using the SIT technique”.

“If there’s a creative solution, it needs to fulfill two conditions - the  Closed World condition and the Qualititave Change condition.”

Yoav, who wasn’t familiar with the inventive thinking method, looked puzzled. Ron continued to explain.

“In your opinion, what do you think is the ideal solution?” asked Ron.

“Well,” Yoav replied, “of course the ideal solution would be one in which, without investing time or effort, we’d be able to find the faulty systems”.

“Using the Closed World terminology,” Ron continued, “we’re not supposed to add any new type of objects, tools, or any other means to the system to fulfill the function of testing the hardness of the material”.

“So what you’re saying is that maybe the pistons themselves can check their own hardness?!” shouted Gadi in disbelief.

“That’s definitely a possible direction”, replied Ron. “According to the Closed World conditions, everything that exists in the system or its close environment is a possible candidate to do the test for us”.

There was a moment of silence, before Ron asked, “So what about the cylinders checking themselves?”

Silence once again permeated the air as everyone thought about what this meant.

“Wait a minute”, shouted Gadi, “if I’m holding two cylinders in my hand, a hard one and a soft one, I can check one by scratching it with the other. Hard material will always scratch soft material!”

“And how would we be able to test the exact hardness this way?” asked Yoav, who was a metalurgical engineer familiar with and used to controlled quantity tests.

And then he continued in almost the same breath, getting more excited with every word, “But I’m not interested in testing the absolute hardness of the material, only the relative hardness between a good cylinder and a faulty one!”

The only thing that stopped the excitement and noise that followed was angry knocking on the wall from the office next door telling them to quieten down.

The testing method that they came up with seemed to be an excellent solution, but before activating it on the real system they had to prove that it worked under controlled testing conditions.

It didn’t take very long for them to come up with an idea for a controlled experiment:

“If we take a normal sleeve or covering (that has been checked and its hardness approved according to conventional means) and we sharpen it into the shape of a dental pick, we can use it to test the relative hardness of the others. A soft covering will be easily scratched by it, and a covering of the same hardness won’t scratch. This scratch test is easy to do without dismantling the whole system, because the top part of the cylinder is exposed”.

The idea was quickly translated into action. The three team members stood impatiently around the machine  that was making the improvised pick from the hard cylinder.

In the late afternoon hours of that same day, Ron went to the production manager with the chief engineer to inform him about the dramatic progress. Everything was ready for the controlled experiment that would determine the fate of the idea.

***

On the table in the assembly lab was a pile of 42 cylinders marked with serial numbers. Apparently, the cylinders were completely identical. In fact, there were 39 cylinders made of hard material, and 3 of soft material. One of the assembly technicians (who of course didn’t know which were hard and which were soft) volunteered to be the guinea pig as he held the improvised pick in his hand.

After 15 minutes of working in tense silence surrounded by a large group of technicians and managers, the technician separated the original pile into two piles. The project manager compared the cylinder serial numbers in the pile that was suspected of being faulty to the note in his pocket.

“You did it”, he replied without being able to hide the satisfaction in his voice.

That same night, 4 more picks were manufactured and at the same time packages were being opened, and the protective covers removed from the cylinders. Each unit was placed on the “operating table” as the technician scratched each of the three cylinders.

The whole process took less that 10 minutes per unit. After 24 hours the selection process ended. 5 faulty units were found, fixed, and replaced.

Ron looked at the long line of crates waiting for the delivery truck, and he smiled. The SIT method had proved itself yet again!

Dov Tibi is a Senior SIT facilitator and trainer and an Opto-Mechanical System engineer and Reliability engineer in the R&D Department of RAFAEL, Israel. Dov has extensive experience leading creative problem-solving workshops.

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