Liu Lang continued to take the class

"We also need to improve the accuracy of the parts with the bearing, first of all, to improve the machining accuracy of the box support hole and the spindle journal, or to improve the machining accuracy of the surface matched with the bearing, and also to measure and adjust the radial runout range of the corresponding parts, so that the error compensation or offset. ”

"There is also the need for proper preloading of rolling bearings, which eliminates clearance, increases bearing stiffness, and equalizes rolling element errors. ”

"There is also the adjustment of the process system, such as the adjustment of the trial cutting method, that is, through the test cutting - measuring the size - adjusting the amount of the tool - cutting - cutting - and then trying to cut, and so on until the required size is reached. This method has low production efficiency and is mainly used for single-piece and small-batch production. ”

There is also the reduction of tool wear, i.e. the tool must be resharpened before the tool size wears to a stage of rapid wear.

Or reduce the transmission chain transmission error, such as the number of transmission parts is small, the transmission chain is short, the transmission accuracy is high, or the use of speed reduction transmission, is an important principle to ensure the transmission accuracy, and the closer to the end of the transmission pair, the smaller the transmission ratio should be, and the accuracy of the end piece should be higher than other transmission parts.

There are also ways to reduce the force deformation of the process system, reduce the residual stress, reduce the thermal deformation of the process system, and so on.

Let's take a look at the reasons for the machining accuracy error, mainly the machining principle error, which refers to the error caused by the use of an approximate blade profile or an approximate transmission relationship for machining. Machining principle errors mostly occur in threads, gears, and complex surface machining.

For example, the gear hob used for processing involute gear, in order to make the hob manufacturing convenient, the Archimedes basic worm or the normal straight profile basic worm is used instead of the involute basic worm, so that the gear involute tooth shape produces an error. Another example is when turning the modulus worm, because the pitch of the worm is equal to the circumference of the worm gear (i.e., mπ), where m is the modulus, and π is an irrational number, but the number of teeth of the replacement gear of the lathe is limited, and the π can only be calculated as an approximate fractional value (π=3.1415) when selecting the replacement gear, which will cause the inaccuracy of the tool to the forming motion (spiral motion) of the workpiece, resulting in the pitch error.

There is also machine tool error, which refers to the manufacturing error, installation error and wear of the machine tool. It mainly includes the guidance error of the guide rail of the machine tool, the rotation error of the spindle of the machine tool, and the transmission error of the transmission chain of the machine tool.

There are also the influence of guide rail guidance accuracy on cutting processing, machine tool spindle rotation error, process system force deformation, tool manufacturing error and wear, processing site environmental impact, thermal deformation of process system, residual stress inside the workpiece, etc. ”

Liu Lang's class can be described as full of voice, starting at half past eight in the morning, talking about eating at eleven o'clock, resting for a while after eating, and then continuing to speak, until more than four o'clock in the afternoon, this is still Liu Lang, if others want to explain the problem clearly, it will take a few days, but even he is tired enough, just drinking a few catties of water.

If just lecturing is nothing, the key is to practice, there are various tools next to the machine tool, Liu Lang is like a surgeon operating on the machine tool.

After the course was finished, this CNC machine tool was basically dismantled by Liu Lang in addition to the control system, and the parts were neatly placed in front of everyone, and everyone panicked when they saw it.

A machine tool costs more than 3 million! Just dismantle it? What if it can't be restored?

Machine tool accessories mainly include tools, tool fixtures, operating parts, indexing heads, workbenches, chucks, joints, chip removal devices, hoses, drag chains, protective covers, etc., these accessories can also be split separately, and finally there are more than 500 parts, which have many precision devices, such as a diameter of only 0.05 mm, a length of two centimeters of drills, thinner than a hair.

Liu Lang dismantled more than 100 parts this time, mainly in the operating parts and the workbench, which are also the two most critical components that affect the accuracy, only such an explanation can make people remember it firmly.

Of course, it is impossible to restore it, and all the structures of this machine tool are remembered by Liu Lang in the form of stereoscopic projections.

In fact, with Liu Lang's current memory, not to mention this kind of low-end CNC machine tool with only a few hundred parts, even a high-end machine tool with one or two thousand parts can be recorded, but he has not dismantled these machine tools in the United States.

And he also felt that it was almost useless to teach by dismantling the machine tools, and the most important thing for the employees of NORINCO Group was to improve the craftsmanship.

In the past, the staff level of NORINCO Group could only be regarded as a medium level, of course, this medium level is measured by the level of developed countries, and it may be worse than the average, which should be lower than the middle.

The so-called lower middle does not mean that in terms of personal ability, in terms of personal ability, Liu Lang believes that his workers are not inferior to the industrial workers of any country, and even slightly stronger.

This refers to the comprehensive manufacturing capacity, but also to consider the machine, to make a strong and durable parts including a good equipment and a good operator, this is the comprehensive manufacturing capacity of the withdrawal.

To put it bluntly, the closer the man and the machine, the stronger the manufacturing capacity.

Western countries have advanced equipment, and the craftsmanship of workers comes mostly from inheritance, which is the precipitation of nearly 100 years of industrialization, while China is much worse, the equipment is backward, and the quality of the workers is also uneven, and most of the levels are not high, after all, the country's industrialization accumulation time is too short and lacks heritage.

According to this standard, NORINCO's manufacturing capacity is in the middle of the world, and this evaluation is still very objective.

However, NORINCO is the top level in China, which is a recognized fact in the domestic industry, so that now, every time an industry competition is held, NORINCO will send two or three workers to meaning, otherwise others will not have a chance to participate in the competition.

In China, Liu Lang's workers are already invincible, but the purpose of NORINCO Group is not to "nest in the nest", the company's goal is the whole world, which requires workers to improve their ability again, from the lower middle level to at least the upper middle level, only in this way can it be regarded as entering the house, in order to stand on the same running line with developed countries.

In Liu Lang's view, even if my industrial base is not as good as yours, we can make up for some gaps through high-quality industrial workers, and improve equipment through industrial workers, which is Liu Lang's thinking.

In more than three years, the workers have learned too many skills in Liu Lang, which is taught by Liu Lang, that is, the ancient master taught the apprentice, many people feel that their ability is almost the same, to this day they have seen a higher level of ability, the ancients said that they want to be poor, go to the next level, and now they are going to climb to a higher level, and at the same time Liu Lang's real ability will also be taken out.