Inside the transmission box of the precision grinding machine, gears and shafts intertwined, gleaming coldly under the temporary work light. Liu Li pointed to a gear in the middle, her voice clear: "That's the problem."
She used cleaning agent to polish the gears until they shone brightly. Master Wang held up a powerful flashlight and shone it from the side. Everyone looked at it for a long time before they vaguely noticed something was wrong: the edges of the gears didn't seem to be perfectly round under the light, but rather had a slight "flatness" that was almost invisible to the naked eye.
"My God, the deformation is probably less than five microns!" Zhang, the foreman of the machine repair team, clicked his tongue in amazement. "How could anyone normally tell?"
"It's this micron-level deformation that causes the meshing clearance to change when the gear rotates faster, which is why it vibrates so much," Liu Li added. Fu Jingchen nodded in agreement, "The measurement data also matches; the vibration frequency is exactly the meshing frequency of the gear."
But his joy lasted only a few seconds before Squad Leader Zhang sighed, "Knowing the problem is useless! Our factory simply can't process these imported gears. Applying for new ones would take at least half a year, and military-grade parts can't wait!"
The moment those words were spoken, the atmosphere, which had just warmed up, cooled down again. Liu Li suddenly spoke up, "How about we don't change this gear?"
"Not changing it?" Master Wang frowned, questioning his apprentice's words for the first time.
“Yes, we won’t replace it.” Liu Li looked at Master Wang and said seriously, “This gear is just a little deformed, but it’s not broken or worn, so it can still be used. We don’t need to fix its shape, let’s try to ‘fix’ its mistakes—adjust its angle on the shaft, and then change the meshing clearance with the gear next to it to offset the effects of the deformation. Maybe then it will work.”
"You can do that?" Director Zhao also came over, his eyes full of surprise.
Fu Jingchen quickly took out a draft paper: "Theoretically, it's feasible! I calculated that as long as the angle is adjusted accurately and the gap is controlled well, the error can be reduced to the allowable range, which is much faster than waiting for a new gear!"
Master Wang stared at the gears for a long time, then glanced at Liu Li and Fu Jingchen, before suddenly speaking up: "This is a risky move, but it's not reckless. Machines are like people; a minor problem doesn't necessarily mean replacing all the parts. If we adjust it properly, it might still work." He looked at Director Zhao, "I think we can try it! Liu Li will lead the effort, I'll work with the mechanics team, and Engineer Fu will calculate the data. I'll take responsibility if anything goes wrong!"
With Master Wang's words, Director Zhao immediately made the decision: "That's how it'll be done! Just tell me what you need!"
Over the next few days, Fu Jingchen and Liu Li spent all their time in the technical department calculating data, and the meals that Zhang Shulan brought were all cold; in the workshop, Master Wang led the machine repair team to prepare tools, with dial indicators and gauge blocks neatly arranged, and even the wrenches were polished to a shine.
On the day the adjustment began, Liu Li stood in front of the grinder, took a deep breath, and focused as intently as she would when blindly duplicating keys during a martial arts competition. Following the angle calculated by Fu Jingchen, she gently turned the faulty gear with a special dial—Fu Jingchen measured each turn with a dial indicator.
"3.5 marks to the left," Fu Jingchen reported.
Liu Li's fingers were very steady as she slowly turned the gears; the sound of metal rubbing together was so faint it was almost inaudible.
"Stop! The phase angle is correct, now adjust the gap!" Fu Jingchen shouted.
Master Wang personally tightened the adjusting screw, while Liu Li placed a stethoscope to her ear and her other hand on the equipment to listen for sounds. "Master Wang, slow down, go in half a thread more... Good!" She judged based on the sound, "Now the sound is smooth, not muffled."
Fu Jingchen stared at the watch face: "The gap on the left is two and a half millimeters, within range!"
Several hours passed, Liu Li's forehead was covered in sweat, Fu Jingchen's eyes were red, and Master Wang's arms were sore. Finally, Fu Jingchen breathed a sigh of relief: "Everything is correct! The gap and phase angle are both fine!"
"Try it under no-load!" Director Zhao's voice trembled slightly.
Liu Li pressed the start button, and the grinding machine began to hum—without the previous trembling, only a steady, low hum. The dial indicator needle on the machine bed wobbled very little, even more steadily than when it was working properly!
"It's done! It's really done!" Foreman Zhang was the first to shout, and the workshop immediately erupted in cheers as his coworkers surrounded him and applauded.
Later, Liu Li used this grinding machine to process test pieces, and the inspection room said the precision was just as good as when it left the factory. Now, the whole factory knew that there was a female worker named Liu Li in the machining workshop who was not only skilled but also quick-witted and could even solve problems with foreign equipment.
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