Chapter 545: Lin Zhengcheng: Dad, You Taught Me Another Lesson!

"Dad, could you come over and take another look?"

After being tangled up for more than ten minutes, Lin Zhengcheng still decided to seek help from Lin Shengli.

Lin Shengli had just finished sweeping the courtyard for Zheng Juan when he heard the shout and walked into the study:

"What's wrong? Ran into a problem?"

"Look, after reducing the tolerance as you requested, the tool material can't keep up." Lin Zhengcheng pointed at the parameter sheet, his tone urgent, "The current tool can't withstand such high machining precision, and changing the material would waste time. What should we do about this?"

Lin Shengli leaned over, picked up the documents and examined them carefully, then took a pen and drew a simple stress analysis diagram on the paper, saying slowly:

"You're only focusing on a single match of parameters and material; have you considered finding a breakthrough in the machining process? For example, changing the cutting speed, adjusting the cooling method—perhaps we can meet the reduced tolerance without changing the tool."

"Machining process?" Lin Zhengcheng's eyes lit up, as if a lightbulb had gone off. "Why didn't I think of that! I was only considering the match of parameters and material, ignoring the adjustable space of the process."

He immediately sat back at the desk, pulled out the machining process manual, and began simulating adjustments to cutting speed and cooling scheme against the parameters.

After trial calculations of several data sets, a smile finally appeared on his face:

"Got it! Reduce the cutting speed by 15% and adopt an oil‑gas cooling method; the tool's stress can be reduced by 20%, which perfectly fits the reduced tolerance!"

He excitedly picked up the phone, dialed Engineer Li's number, his tone unable to hide his excitement:

"Engineer Li, this is Lin Zhengcheng! I discovered a problem while adjusting the parameters just now, but I've already found a solution. I'll send you the adjusted parameters and the new process plan, and we can focus on this in the afternoon meeting…"

After hanging up, Lin Zhengcheng let out a long sigh; a thin layer of sweat had already seeped down his back, but it was filled with a sense of achievement.

He turned his head toward Lin Shengli, who was standing nearby, and said seriously:

"Thank you, Dad, you taught me another lesson."

Lin Shengli smiled and patted his shoulder:

"That's how research works; encountering problems isn't scary, the key is to learn to think from a different angle. Next time you face this, first ponder on your own, and if you truly can't figure it out, then ask. That's how you truly grow."

Meanwhile, Lin Qinhua and Chen Mo were also making new progress in the institute's laboratory.

After calibrating the equipment, Chen Mo took the freshly prepared test specimen and walked over to Lin Qinhua:

"Qinhua, the test specimen is ready, and the material factory replied—they'll ship the composite material samples tomorrow."

"Great!" Lin Qinhua hung up, took the specimen and examined it carefully, "Then tomorrow we'll first conduct preliminary strength tests on the samples, aiming to quickly determine the selection direction."

As the sunset faded, the red lanterns of the Lin Family Courtyard lit up again.

Lin Shengli returned to the courtyard and saw Zheng Juan and Lou Xiao'e tidying up, Qin Jingru preparing dinner in the kitchen, and Hanna flipping through the equipment inspection notes left by Lin Zhengcheng, her face showing focused concentration.

"All done?" Lin Shengli walked over, took the broom from Zheng Juan's hand, and helped sweep the courtyard.

"Well, the kids are busy with work, we can't help much, so we just clean the house so they'll feel comfortable when they return," Zheng Juan said with a smile. "Hanna just mentioned that regarding Zhengcheng's equipment integration and optimization, she can provide some technical data from Hans's side for reference."

Hanna looked up and said with a smile, "Yes, Lin. My uncle previously worked on similar equipment optimization and has some experience to share. I've already organized the relevant materials and will hand them to Zhengcheng tomorrow."

Lin Shengli nodded, feeling warm inside.

Early the next morning, as dawn broke, Lin Qinhua and Chen Mo, carrying the material factory's sample list, rushed into the institute's laboratory.

The carbon‑fiber composite samples in the sealed bags were neatly arranged: six batches, three pieces each, with labels indicating different resin ratios and molding processes. Chen Mo first moved the samples to the universal testing machine, put on gloves, and inspected them one by one.

"All dimensions are correct, the surface has no bubbles or cracks; the material factory's work this time is quite meticulous."

Lin Qinhua had already set the low‑temperature chamber to -60 °C—this is the extreme low temperature for high‑altitude bomber cruising, 10 °C lower than the temperature used in the previous coating test.

"Let's follow the plan first," she said without looking up while setting the testing machine parameters, "First conduct room‑temperature tensile testing, then the low‑temperature pre‑treatment test, and finally assess fatigue resistance."

Chen Mo responded with a nod and secured the first batch of samples in the fixture.

The moment the start button was pressed, the testing machine emitted a low hum, and the force reading rose slowly.

"380 MPa… 390 MPa…" Lin Qinhua stared at the screen, her pen tip racing across the notebook, "Now at 400 MPa, almost at the target value!"

As soon as the words finished, a light "click" sounded and the specimen snapped, the screen's value dropping to zero instantly.

The two exchanged a glance and both furrowed their brows.

Chen Mo picked up the broken specimen, examined the fracture under the light, and said, "That's not right; the fracture is too brittle, as if the resin didn't fully cure."

Lin Qinhua pulled out the material factory's process sheet and pointed to a line, "Look, their holding time is 35 minutes, which is 5 minutes less than we require. Cutting corners?"

"It probably wasn't intentional," Chen Mo mused, "Maybe their production line demands high efficiency, so they shortened the holding time. How about we reprocess a batch ourselves?"

Lin Qinhua nodded, turned, and fetched an oven from the cabinet, "Put the remaining samples into the oven, hold at 120 °C for 40 minutes to re‑cure. We have plenty of time today, so we'll do it ourselves to ensure accurate data."

The oven's temperature rose gradually, and a faint resin odor filled the laboratory.

Neither of them idled; Chen Mo went to prepare the fatigue‑testing fixtures, while Lin Qinhua adjusted the bomber coating formula based on previous coating data.

"The bomber's fuselage area is much larger than that of the J‑20, so the coating adhesion requirement is higher," Lin Qinhua wrote the formula on paper, "We can add a bit of nano‑aluminum oxide into the silicon‑carbide fibers to strengthen the bond between the coating and the composite fuselage."

Chen Mo leaned over for a look, his eyes bright, "Great idea! If we control the dispersion of nano‑aluminum oxide well, it not only boosts adhesion but also improves high‑temperature resistance."

The two exchanged remarks back and forth, and before they knew it it was noon. The oven gave a "ding" sound, indicating the samples had finished curing.

Chen Mo put on heat‑resistant gloves, carefully removed the samples, and after cooling immediately fixed them onto the testing machine.

This time, the force reading rose steadily, climbing to 420 MPa before slowly descending; the sample did not break, only showing slight deformation.