The project team's focus shifted unknowingly to that troublesome high-speed spindle.
This thing is no exaggeration to call the heart of a new type of textile machinery. It requires incredibly high rotational speeds, yet it must be as stable as the surface of water, without the slightest sway. But the reality is, no matter how beautiful the design drawings are, once it comes to processing, assembly, and trial operation, slight vibrations are inevitable. Once the speed increases, the noise is like someone with malaria shivering, causing the entire machine to tremble.
"Another one burned out!" That morning, Liu Li had just entered the office when she heard Xiao Zhao, who was in charge of testing, complaining with a bitter face, "The endurance test we did last night has caused the main spindle bearing to seize up again! This is the third one!"
The atmosphere in the office suddenly became heavy. Zhou Wei stared at the vibration spectrum analysis graph on the computer screen, where the peaks representing abnormal vibrations stood out glaringly; Sun Mei flipped through a thick stack of test reports, which recorded vibration data from different batches of spindles, varying greatly in quality and exhibiting extremely poor stability.
This problem has brought the entire project to a standstill. With the main issue unresolved, all subsequent debugging and optimization efforts are futile. The collaborating factories are constantly calling to urge progress, and the pressure is mounting.
During the group discussion, the air was thick with smoke, and the arguments were much louder than usual.
"If you ask me, it's still the materials that are inadequate! They can't achieve the strength and fatigue life required for such high rotational speeds!" Old Zhang from the materials team slammed his fist on the table.
“Materials are one aspect, but I think the key is dynamic balance! If the rotor’s mass distribution is even slightly uneven, the centrifugal force at high speed will be astonishing, and the vibration will be impossible to control!” Zhou Wei adjusted his glasses, his tone urgent.
"What about machining precision? If the basic precision of bearing fit tolerances and spindle journal roundness cannot be guaranteed, even the best design and materials are useless!" Sun Mei pays more attention to the manufacturing process.
Everyone had their own opinion, each believing they had grasped the crux of the problem, yet none could completely convince the other. Team Leader Chen sat in the main seat, his brow furrowed, oblivious to the fact that the cigarette between his fingers was almost burning down to the filter.
Liu Li didn't rush to join the argument. She held the recently scrapped spindle in her hand; it was heavy. There were obvious signs of overheating and blue discoloration on the bearing, and near the flange, she could feel a very subtle vibration. She remembered the linkage bushing that had caused the vibration and was worn down by several micrometers when she was repairing a gantry planer at the Hongxing Factory.
Sometimes, problems are hidden in these subtle details that are difficult to see with the naked eye.
“Show me the vibration data,” she said, walking over to Zhou Wei and leaning over to look at the screen. “Which frequency range is it mainly concentrated in?”
"It mainly involves the first and second harmonics of the rotational speed, which are typical characteristics of imbalance, but there are also some high-frequency components mixed in, which may be a problem with the bearings or gear meshing," Zhou Wei explained, pointing to the spectrum diagram.
“What about the processing records?” she asked, turning to Sun Mei.
"The pass rate for critical dimensions is not low, but the dispersion is quite large. Look at the roundness of this spindle journal. The best one is 0.8 micrometers, and the worst one is almost 2 micrometers. It is not obvious at low speeds, but once the speed increases, this small error is magnified."
Liu Li listened and watched, her mind racing. Materials, balance, precision… these factors were intertwined like a tangled mess, influencing each other. Focusing solely on one aspect wouldn't solve the problem.
“Team Leader Chen,” she looked up at Chen Siyuan, who had remained silent, “I think we might need to change our approach. This problem isn’t a single-step issue; we need to treat it like a system, like repairing a gantry plane. Could we organize a joint investigation? From raw material inspection to roughing, finishing, heat treatment, dynamic balancing, all the way to final assembly and testing, let’s connect all the data from the entire process and see where the problem lies, or… which accumulated error in one step ultimately led to the loss of control.”
Her suggestion essentially broke down the previous fragmented work style and necessitated deeper collaboration. A moment of silence fell over the meeting room.
Team Leader Chen stubbed out his cigarette and glanced at everyone: "Liu Li's suggestion is worth considering. Treating the symptoms without addressing the root cause won't solve the problem. Let's do as she says and establish a joint analysis team. Zhou Wei, Sun Mei, Lao Zhang, you core members will participate, and Liu Li, you'll lead the coordination and get the data chain straight!"
A new and heavy responsibility, along with this most challenging technical problem, once again fell on Liu Li's shoulders. The high-speed main shaft stood like a towering mountain, blocking the project's path forward, and she had to lead the team to find a way to climb it.
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