78: Bringing his wife and children to Harbin Institute of Technology

When Ye Bingwen arrived at the infrastructure department, Director Sun was drinking tea.

"Are you the student who wants to build a factory on campus?"

Director Sun looked Ye Bingwen up and down.

"Yes, Director Sun. My name is Ye Bingwen, from the Mechanical Engineering Department."

Ye Bingwen took out a roll of blueprints from his canvas bag and unfolded it on his desk.

"These are the construction drawings for the new factory. Please take a look."

Director Sun leaned over to look at the blueprints.

He tapped the section on the foundation cross-section of the blueprint with his finger.

"Who gave you this foundation plan? One and a half meters of gravel replacement? Do you know how much more money that will cost?"

"I designed it myself."

Ye Bingwen spoke calmly.

"You yourself?"

Director Sun snorted.

"You, a mechanical engineering student, are here to teach us how to do infrastructure? I've been doing that for twenty years."

"I've built more factories than you've lived in houses. Let me tell you, for a small factory like yours, we'll dig half a meter deep."

"Lay down a layer of gravel, then pour concrete on top—that's enough! Why bother with a 1.5-meter layer? It's a complete waste of money!"

Ye Bingwen did not get angry.

In his previous life, when he was supervising doctoral students at Peking University, he witnessed too many such scenes—the clash between empiricism and scientific methods.

Director Sun is not a bad person; he is just using the experience he has accumulated over the past twenty years to judge the issue.

Ye Bingwen knew that such experience could be fatal when dealing with precision machine tools, which have special requirements for the foundation.

"Director Sun, may I ask you a question?"

Ye Bingwen took a notebook out of his bag and turned to a page.

"What kind of equipment was stored in those factory buildings you built before?"

Director Sun was taken aback, not understanding what the student wanted to do.

"We have all kinds of equipment: drilling machines, milling machines, planers, you name it."

Do you have any high-precision CNC machine tools?

"CNC?"

Director Sun chuckled.

"There are only a handful of those in our country, how could a school-run factory like mine possibly use one?"

"That's the crux of the problem."

Ye Bingwen opened his notebook, which contained the materials he had spent three hours organizing the previous night.

"Director Sun, the new machine tool I ordered is a regular milling machine, but it has very high precision requirements—the outer diameter tolerance must be within one millimeter."

Do you know what this level of precision means?

Director Sun remained silent.

Ye Bingwen squatted down and picked up a piece of chalk from the ground.

He drew a circle on the cement floor, and then drew a rectangle next to the circle.

"This is a machine tool, and this is the foundation."

He talked as he drew.

"When a machine tool is working, it generates vibrations, which are transmitted to the foundation."

"When the foundation is subjected to vibration, it will also vibrate on its own."

"If the vibration frequency of the foundation itself and the operating frequency of the machine tool coincide, resonance will occur."

He drew two wavy lines, one to represent the machine tool and the other to represent the foundation.

"During resonance, the amplitude will be magnified many times over."

He drew a large cross with chalk where the two wavy lines overlapped.

"Machine tools will bounce up and down like they're sitting on a spring. The factories you built before housed ordinary machine tools."

"The precision requirements are not high; resonance simply means a bit more noise."

"But my machine tool is no good. Even the slightest tolerance will cause resonance, rendering the entire product unusable."

Director Sun stared at the map on the ground for a long time.

He wasn't completely unable to understand, but these things were beyond the scope of his experience over the past twenty years.

In all the projects he had worked on, no one had ever mentioned these words to him.

"Is there any basis for what you're saying?"

Director Sun's tone was skeptical.

Ye Bingwen opened his notebook.

"The spindle speed of my new milling machine is 1,800 revolutions per minute. Divide it by 60, and the operating frequency is exactly 30 Hz."

"Did you see that? The frequencies overlap. Resonance is inevitable."

Director Sun remained silent for a full half minute.

He wasn't unconvinced.

But he was even more aware that if Ye Bingwen's plan were followed, the project cost would nearly double.

Who will pay for this? Who will be responsible if anything goes wrong?

The most important thing he learned from his twenty years in infrastructure construction was to avoid making mistakes rather than seeking merit.

"No matter how nicely you put it, you're still a student."

Director Sun picked up the enamel mug and put it down again.

"I can consider the proposed solutions, but I can't shoulder this responsibility alone."

"Here's what we'll do: find someone who can speak up for you, a professor in your department, or a university leader. I'll listen to whoever speaks for me." "You're just a student; I can't listen to you."

Ye Bingwen understood what Director Sun meant.

He wasn't persuaded by reason, but rather intimidated by the responsibility.

We need to find someone influential to endorse it.

"Okay. Director Sun, I'll come again tomorrow."

Ye Bingwen stuffed the blueprints into his canvas bag.

As he walked out of the infrastructure department, he heard Director Sun talking to his colleagues inside.

"These students nowadays, they've only studied for a few days and they already know who they are, and they're trying to teach me how to build a foundation..."

My colleague chuckled.

"After all, they are college students."

"What's wrong with college students? I've been working in infrastructure for twenty years, what haven't I seen?"

Ye Bingwen rode his bicycle toward the teaching building.

The second period this morning was Professor Zhao's "Principles of Machinery" class.

Professor Zhao walked into the classroom with his lecture notes.

He taught at Harbin Institute of Technology for thirty years, and not a single student in the Mechanical Engineering Department was afraid of him.

It wasn't because he was strict, but because he was too serious.

"Last lesson we talked about calculating the degrees of freedom of planar mechanisms. Today we will talk about the instantaneous center of velocity method."

Professor Zhao drew a four-link hinge mechanism on the blackboard.

"Could any student tell me the total number of instantaneous hearts this organization has?"

The classroom was silent for five seconds.

Ye Bingwen raised his hand.

"Ye Bingwen".

"The total number of instantaneous centers is six. When N equals 4, the number of instantaneous centers equals 4 multiplied by 3 divided by 2, which equals six."

Yes. Sit down.

Professor Zhao began explaining how to find the instantaneous center of velocity.

Ye Bingwen was taking notes diligently, but something else was on his mind—how to bring it up with Professor Zhao.

The bell rang, signaling the end of get out of class.

Professor Zhao closed his lecture notes, said "get out of class dismissed," and picked up his enamel mug to leave.

Ye Bingwen packed his things and quickly followed.

"Professor Zhao, could I have a few minutes of your time?"

Professor Zhao turned around and glanced at him.

"What is it?"

"I'd like to ask you for a favor. My school-run factory needs to build a new factory building."

"Director Sun of the Infrastructure Department disagrees with my foundation plan and would like to ask you to put in a good word for me."

Professor Zhao stopped in his tracks.

"What foundation plan? Tell me about it."

Ye Bingwen took out the blueprints from his bag.

He used the simplest language to explain the reasons for replacing the gravel with 1.5 meters of fill, the dangers of resonance, and the calculation of the natural frequency.

Professor Zhao listened.

Then extend your hand.

"Show me your calculations."

Ye Bingwen handed over the notebook.