Chapter 1088 Adaptive CNC Machining
However, the relaxed atmosphere did not last long.
A good designer will indeed consider the difficulties of the production process during the design stage.
But the processing plan planned by Chang Haonan is not much more anthropomorphic than the blade itself he designed...
I saw him click the mouse and flip the PPT to the next page. At the same time he said:
"First, a milling process is used to process a three-layer titanium alloy thin plate with a certain shape, and selective soldering inhibitor is applied on the titanium plate according to the forming requirements of the triangular truss structure..."
"Then a diffusion connection process is used , weld three layers of titanium plates into one, and put the welded blade blank together with the clamp into a vacuum furnace to heat it to the superplastic state of the titanium alloy, and form a swept blade shape under the action of torque..."
"Then inert gas is blown between the titanium plates, so that the blade blank and the clamp are completely fitted, forming a triangular truss hollow structure and aerodynamic shape."
"Finally, CNC machining is used to process the tenon, blade body, front and rear The edges and blade tips are usually processed by grinding or milling to form the tenon tooth surface, the blade body is processed by abrasive belt grinding to improve the surface processing quality, and the front and rear edges are processed by multi-axis milling..."
“……”
At first, no one realized the seriousness of the situation.
But soon, Zhang Zhenhua, who was in charge of process production, began to look wrong.
As a designer, it is naturally impossible for Chang Haonan to prepare the process parameters, otherwise the production engineers like them would have no value in existence.
This production route would not be a big problem if it were applied to small and medium-sized fans such as Turbofan 10 or SeA650 with a blade chord length of about 50-60 cm.
However, the diameter of the AE1500 fan is nearly two meters, which is almost 30% larger than the CFM56-7 of the same level. The bypass ratio reaches an astonishing 9.03, and the blade chord length also exceeds 90 cm. In terms of size alone, It is completely a cross-band product.
With the same processing technology, after the product is doubled, the difficulty will not be doubled.
"Mr. Chang..."
After thinking for a moment, Zhang Zhenhua truthfully reported his judgment:
"If we are just producing samples for testing, then our equipment They have all been upgraded and should be available soon... before the end of the year at the latest, but if you want to put this kind of process into mass production..."
At this point, he waved his hands slightly. I rubbed my hands a little nervously:
"I dare not give a clear timetable."
Then he took a deep breath and continued as if he had made up his mind:
"The inner shape of the hollow triangular truss structure is undergoing superplastic forming. /During the one-time forming process of the diffusion joining process, a small amount of polishing of 0.1~0.15mm is left at the blade body part, while the margin at the tip and root part can reach up to 1.2mm. The structural characteristics of each processed part require The use of diversified CNC machining methods makes it difficult to smoothly transfer adjacent areas of each machining part.”
“In addition, the blade tips, blade roots, and front and rear edges are solid structures and have strong rigidity. In the hollow part of the blade body, coupled with the alternating virtual and real triangular hollow truss structure, the entire blade has alternating strong and weak stiffness characteristics, resulting in a very complex deformation pattern of the fan blade during CNC machining. It is difficult to control the machining deformation by existing means alone. Quantity. ”
“Also, during the forming process, the titanium alloy sheet goes through multiple high-temperature and high-pressure cycles. Since it is impossible to control the cooling parameters and wall bonding rate 100% accurately, the blades are different. The stress level of the parts and the amount of strain caused by the stress are also difficult to control. ”
“If these problems are taken out individually, they are actually not difficult to solve, but when combined together and put into mass production, it is likely that even the blade blanks of the same batch will have poor consistency, requiring several separate processes. , to check the semi-finished products in the production process..."
"..."
Zhang Zhenhua did not continue.
But this is indeed a big and fatal problem.
Industrial production is actually not afraid of simplicity and complexity.
As long as the equipment and money are in place, and you are willing to spend time, the process parameters, no matter how complex, can be gradually determined.
Once it enters the mass production process, it will no longer involve cost investment at the research and development level.
As product output gradually increases, production efficiency and costs can always reach a relatively stable state.
But if the result of a certain processing process cannot be determined, it means that for each individual product, the subsequent process parameters may have to be determined separately.
Although it is much simpler than developing it from scratch, it will definitely limit the output and cost.
If it is building rockets or industrial aircraft, then the annual output is not much anyway, so this semi-industrial and semi-handicraft approach is still acceptable.
But aircraft engine blades are in huge demand after all, and it is impossible to produce them with carving skills.
For a time, almost all the eyes in the entire conference room were focused on Chang Haonan sitting in front.
“Regarding this issue...you should do it according to the sample method first. It doesn’t matter if the output is small, as long as it can ensure normal entry into the testing process.” Obstacles in the production process, he had already conceived the overall design at the very beginning It was already expected.
Otherwise, it would be impossible to allow such a long execution time for the entire project on the premise that the core machine is already available.
"The specific process..."
Zhang Zhenhua said and glanced at the flow chart on the PPT.
“I’ll do what I just said!”
Chang Haonan gave a decisive answer, and then continued:
"I plan to cooperate with the machine tool department to solve the problem of adaptive machining before the mass production of AE1500. This can be regarded as solving some technical difficulties for our brother units in advance..."
In fact, in the original timeline, the final It is not the aviation industry that is troubled by this problem first, but aerospace and shipbuilding.
In the mid-to-late 2010s, China Aerospace had a dark moment when its launch success rate was even lower than that of India next door. It was going through the painful period of transition from handicraft industry to industry.
In the end it took many years to solve it.
Now Chang Haonan has laid a trap for them.
"Machine tool department?"
Zhang Zhenhua was stunned -
Have you never heard that his own group has a unit specifically responsible for equipment manufacturing?
“It is a joint venture established by Torch Group and C.B. Ferrari.”
Chang Haonan explained:
“The problem of poor processing consistency cannot be solved by calculations and predictions before production alone. We can only find solutions in the process of process execution... Comrade Zhenhua also said just now that the most direct solution is to After a step is completed, the processing results are measured, and then the process parameters of the next step are determined based on the measurement results. ”
“If this process is carried out alone, it will definitely interrupt the production process, but if it can be implemented in Machine measurement, that is, in the next step, the measurement and processing operations are completed at the same time with one clamping to avoid the impact of repeated disassembly and clamping on the measurement and processing accuracy, combined with the overall adaptive deformation and local smooth transition of the template knife position The deformed adaptive CNC technology can maintain the continuity of the entire production process..."
"..."
In fact, Zhang Zhenhua originally just casually asked about the equipment.
This is not his area of expertise.
However, the idea given by Chang Haonan was really outrageous.
To put it simply, it does not solve the consistency problem in the production process, but directly ensures the consistency of the final product by using different parameters for different semi-finished products.
It is equivalent to automating the manual work of the old master.
But regardless of whether the adaptive CNC programming technology can truly "teach students in accordance with their aptitude", the previous on-machine measurement is also very difficult to implement.
He asked almost subconsciously:
"But Mr. Chang, due to the limitations of the clamping method and the excessive bending and twisting of the blades during the measurement process, some positioning points on the trailing edge must be manually calibrated... If this part is abandoned, the final accuracy may be different from manual intervention. There will be a certain gap in comparison..."
This is true.
With the development of human industry to this day, the most precise part of the work is actually still done by human hands.
Therefore, in the traditional processing ideas, accuracy and production efficiency are almost an irreconcilable contradiction.
But sometimes, you can actually change your mind——
From overcoming errors to accepting errors.
However, before Chang Haonan could give feedback, Ren Bingda, who had been silent before, first raised his head:
“Actually, when I was inspecting Luo Luo before, I found that their requirements for the outer edge of the fan or turbine blades are not so precise.”
“They usually process the front and rear edges according to the size of the blank, and then process the same batch. The blades are measured and weighed together, and blades with similar shape, mass and center of mass position are selected and installed on the same turbofan engine, instead of 100% ensuring that all blades are processed exactly the same.”
"So, according to Mr. Chang's thinking, the accuracy of on-machine detection...may be acceptable."
(End of this chapter)