China's wire cutting machine tools and user selection guide
At present, the main production bases for domestic wire cutting are in Suzhou, Hangzhou, Shanghai, Taizhou and Ningbo. Due to different business concepts and product positioning, the performance and price of the products are very different. The following is a status quo written by a wire-cutting manufacturer. Although there is a certain bias, it has certain reference value.
1. China's wire cutting machine tool industry status:
China's wire-cutting machine tools originated in the early 1970s. Before the implementation of the market economy, the development of wire-cutting machine tools was relatively slow, mainly because China's electronics industry was relatively backward at the time. The production lines of wire-cutting machine tools were state-owned enterprises, although the technology Strong ability, but due to the disconnection from the market, coupled with the constraints of the planned economy, the wire-cutting machine not only has a high failure rate, but also has limited performance (only 50mm thick, efficiency is 20~30mm2/min) but in any case Wire-cutting machine is a unique machine tool in China. Although it has lower precision than foreign wire-cutting machine tools, its manufacturing and use cost is absolutely superior. It is very suitable for developing countries. Due to the demand of this potential market, after the implementation of the market economy in China, many wire-cutting machine tool manufacturers have emerged in the country. As a result, disordered competition has emerged in the wire-cutting market, and disorderly competition has evolved into price competition. In order to reduce costs, Some enterprises with poor technical strength reduce production standards, and the management of relevant state technical supervision agencies does not Force, the quality of the wire-cutting machine tools of different manufacturers on the market is very different, the same is that the wire-cutting machine can use 10 years of precision without attenuation, and some can only be used for two years, the price of wire-cutting machine of the same specification can be different by 10 Ten thousand yuan, this does cause great difficulties for the user's selection (especially for foreign users). If it is not so good, why can these unqualified wire-cutting machines appear on the market? This is mainly the popularity of wire-cutting applications in China's manufacturing industry. The application of wire-cutting machine tools is not limited to the manufacture of molds. A considerable part of the roughing of mechanical parts is also used in wire-cutting machines, so low-grade wire-cutting machines There are also certain markets. Another reason is that the accuracy standard of GB7926-87 wire-cutting machine clearly stipulates: Before reaching this standard, it must first reach JB2670-82 "General Rules for Precision Inspection of Metal Cutting Machine Tools", while some non-capable production plants drill the national standard. Ignore the JB2670-80 national standard, reduce the processing precision in the production process, use inferior materials, so there is a complete loss of precision after 1-2 years as mentioned above.
From the perspective of social environment, China has not implemented a market economy for a long time. Some small wire-cutting machine tool manufacturers are still in the stage of accumulation of original capital. These manufacturers often do not have the whole machine manufacturing capability, but can only be assembled production and production. The quality control of the whole process is hard to talk about, and R&D and innovation are even more impossible. Such manufacturers are very much in the eastern part of China, and the laws that are currently compatible with China’s market economy are still immature and Driven by local government protection, these non-productive enterprises will continue to survive. From the current situation, the state's attitude towards this is naturally eliminated through market competition.
2. What aspects should be paid attention to when purchasing a wire cutting machine:
Wire-cutting machine tools are finishing equipment. As mentioned above, the relevant national departments have formulated a series of technical standards for its manufacturing and precision testing. However, due to the high market demand, some manufacturers ignore the quality in order to increase production, especially in eastern China. Some small private enterprises that do not have the conditions for the production of machine tools are also producing wire-cutting machine tools, which are shoddy, which brings inconvenience to the selection of users, especially foreign users, and the slightest inadvertent user’s own interests are infringed, so Selection is especially important when determining the manufacturer and brand.
First of all, the function and size of the machine tool should be determined according to the product and production needs. When selecting the model, the user can easily neglect the requirements for future development, because the machine tool is not a consumable item, although the one-time investment is large but the service life is very long. Just considering the development factors of the company itself, there will be repetitive investments in the near future. The users of this situation have encountered a lot of people. Therefore, there must be a sense of advancement in the selection and development vision. In the selection, the machine tool of your choice should be reserved in terms of function and technical level. The second is how to determine the manufacturer, the focus is on the comparison of quality, reputation and product prices, in terms of quality and credibility from the following aspects:
(1) Production scale: The scale is too small to be eliminated in the fierce market competition, and there is no strength in product research and development and innovation.
(2) Production mode: The quality of each production process can be effectively controlled by the whole machine manufacturer, and the assembled production has no control over the internal quality of the machine tool and the whole process of production, because the main machine tool of this production mode The institutions are all manufactured by CNC systems and are completed by other manufacturers. At present, developed countries use this kind of socialized production for complex products. The premise of such production methods is perfect market system and sound commercial laws. There is still a gap in China in this respect, so users are reminded that they should pay sufficient attention to the production methods of the manufacturing plants.
The third aspect is price, which is also the most sensitive to users and manufacturers, but one thing is consistent, that is, product performance is the basis of price, product price is the embodiment of performance and quality, which is the performance price we often say. Than, so it is meaningless to talk about performance, but the price is high, but users are not acceptable, but the price is too low is not a good thing, because low prices mean that manufacturers must reduce costs (doing business can not lose money), but quality and cost There is a critical point. Below this point is purely quenched inferior products. This is the case with some wire cutting machine tool manufacturers in eastern China. Therefore, users should consider the price while not forgetting that the wire cutting machine is a long-term precision machining. equipment.
The fourth aspect is that the ears are imaginary and seeing is believing. Due to the fierce competition in the market, manufacturers will inevitably show some words and deeds that intentionally hurt the other party. Although this mood can be understood, it disturbs the user's selection. Environment, so the bad words and deeds of these manufacturers are irresponsible to the users themselves, but as long as the users do what they see, the interference will not break, so the user must look at the real thing when purchasing the wire cutting machine. Look at the sample, especially the high-thickness demo, so that users can know what they are.
3. How to correctly understand the relationship between quality and service when purchasing wire cutting machine tools:
The ultimate goal of product quality and after-sales service is to guarantee the user's normal use of the product. Zero failure rate is also the eternal pursuit of the enterprise. Excellent quality is the basis of after-sales service, and after-sales service is the continuation of product quality. We believe that high-quality products must be from a strong and regular enterprise, and because of the guarantee of their own reputation, such enterprises also attach great importance to after-sales service. In addition, the product quality is low, the failure rate is low, and the cost of after-sales service will also be Reduce, although the two are indispensable, but the user should first pay attention to the quality of the product, the after-sales service is done well, the quality can only be a way to make up, and a mature and reliable wire cutting machine The design and development process has already considered the reduction of the failure rate and how to make the maintenance service more convenient. The quality of after-sales service first reflects the value and ethics of the enterprise, followed by the management ability of the enterprise and the service personnel themselves. Morality, only those companies that have the strength and development, depending on the brand, such as life, can have these three
4. How to judge the precision retention of the machine tool during the selection:
In the mold processing, the line cutting process is generally the final process, so the machining accuracy is very high. If the machine tool's mechanical precision is not good, it will directly affect the processing quality of the product and the mold, eventually leading to loss of users and loss of the market. When it comes to type, how to judge the mechanical precision and structure, the advantages and disadvantages are very important.
Generally speaking, the accuracy of the new machine tool is easy to judge. Because there is a national standard GB7926-87 and the related general standard for machine tool accuracy, the new machine tool can know whether it is qualified or not when it is tested. However, the most important thing is to judge the accuracy of the machine tool, because the accuracy of the machine tool accuracy will only be reflected when the machine tool is used for a certain period of time, and the national standard cannot strictly control it. It can only be the user's own in-depth and meticulous understanding of the machine tool and structure during the selection. Do not listen to the rumors, or listen to some unfounded rumors, so as not to confuse your judgment. Below we will elaborate on the transmission structure, guide rail structure and driving method of the machine table.
4-1, lead screw and its mounting structure
The precision of the lead screw is important, but if the mounting structure of the lead screw is unreasonable, no matter how good the lead screw is.
First look at the form of the screw to see if it is a ball screw, or a triangular thread screw or a trapezoidal thread screw. On the online cutting machine, the ball screw is superior to the triangular threaded screw and the trapezoidal threaded screw, and the diameter of the screw is required to be as large as possible to increase the rigidity.
Secondly, the mounting structure of the screw and the ball screw are precision transmission parts. Therefore, in order to give full play to its precision, the assembly structure of the screw is also required. It must be fixed at both ends and supported by bearings. The lead screw is also pre-stretched to reduce the deflection of the lead screw, thereby improving the movement accuracy of the machine table.
4-2, gear transmission structure
(1) Firstly, the number of gears in the gearbox should be known in detail. The more gears that participate in the transmission, the greater the transmission resistance, the easy to wear the tooth surface, and the gear gap is easy to be generated, resulting in a larger system error of the machine table and more gears. If the assembly is not good, it is easy to produce accidental errors. Therefore, the fewer the transmission gears, the better. The minimum error of a pair of gear transmissions is very important. Therefore, it is very important to understand the gear transmission structure of the table movement during the selection.
(2) Carefully observe the working environment and lubrication performance of the worktable transmission gear box. Due to the unreasonable design of the early machine tools of some manufacturers, the cutting fluid can easily enter the gear box, so that the gears work in the soaking of the cutting fluid for a long time. This design is very unreasonable, and the lighter increases the wear of the gears. The heavy one causes the stepping motor to burn out in the water, so the user must observe the position of the table gear box when selecting the type to ensure that the cutting fluid must not be immersed. This is crucial for the accuracy of the machine tool.
4-3. Rigidity and overall structure of the guide rail
(1) The guide rail is the key to ensure the accuracy of the worktable. Users should pay great attention to the selection. First, observe the cross-section of the guide rail. Under the same conditions, the thicker the shape, the better the rigidity, and the more difficult it is to deform during processing. Secondly, the material and heat treatment process of the guide rail are known to the manufacturer. In general, in order to ensure its strength and small deformation, high carbon alloy steel, integral quenching or over-audio quenching process is better.
(2) Direct observation of the rail structure, the current common rail structure on the market has the following:
1 inlaid steel ball type rolling guide;
2 inlaid steel roller type rolling guide;
3 linear rolling guides;
4 elastic bearing cast iron guide. The difference between the first type and the second type is on the roller of the guide rail, one is a ball and the other is a roller. The ball is in point contact with the rail surface, and the roller and the rail surface are in line contact, so its wear resistance and load carrying capacity are much better than the ball type, and the elastic bearing cast iron guide rail is a simple guide rail and is eliminated. At present, the second and third structures are used in the machine tools imported by Japan's Sodick, Japan's Mitsubishi, Swiss Charmill, and Swiss Archie. Therefore, by comparison, users should consider the following when selecting the model. Two and three structures.
4-4, driving method
CNC wire-cutting machine tools are generally driven by stepper motors. In stepper motors, there are reactive and hybrid types to achieve different step angles. The most common type of reactive stepping motor on the market is the reaction. The stepping motor has different driving modes such as three-phase three-shot, three-phase six-shot, five-phase ten-shot, five-phase double ten-shot. Such a motor has a large step angle and only three-phase windings. With the continuous improvement of market demand and the improvement of the overall level of the machine tool industry by the relevant departments of the Ministry of Machinery Industry, the five-phase ten-shot will gradually replace the three-phase six-shot. This is because the five-phase ten-shot not only subdivides the step angle of the three-phase six-shot, but also increases the motor winding to five phases, so the transmission is smooth and powerful.
In summary, in order to ensure long-term reliability of the machine tool during the selection, the user should choose such a structure:
(1) Select a precision ball screw with a diameter as large as possible, and have a fixed bearing support structure at both ends;
(2) The transmission gear of the workbench should be less, preferably a pair of gears, and the positional structure of the gearbox ensures that the cutting fluid must not be immersed;
(3) Try to use roller-type steel-inlaid rolling guides or linear guides with large cross-sectional area or large width-to-thickness ratio;
(4) Select the five-phase ten-step stepping motor drive mode. If there are conditions, it is more ideal to use hybrid subdivision drive or AC servo drive.
5. What problems should be paid attention to when purchasing large-scale wire-cutting machine tools:
Large-scale wire-cutting machine tools, due to the large processing capacity of the processing range (such as deep DKM800 type, X, Y stroke is 800 × 1000, the capacity is more than 2000Kg), foreign machine tools can not be compared when processing large molds Compared, so the benefits it can create are considerable, but if there is a problem with the machine tool, especially the memory quality of the machine itself, the damage caused by it is also heavy, so the selection of large-scale wire-cutting machine tools Be very careful.
Due to the characteristics of large stroke and large load, the structure and rigidity of the machine tool should be considered when selecting the type, so that it can ensure the accuracy of the large workpiece processing, and the structure is similar to the small and medium-sized wire cutting machine. The difference:
1 The workbench must adopt a full support structure to increase the rigidity of the machine tool to ensure heavy load without deformation. 2 Imported linear guides ensure good sensitivity and motion accuracy under heavy load.
3 Compared with small machine tools, the diameter of the ball screw must be increased.
4 If the user has a certain strength, the working table of the machine tool is preferably driven by an AC servo motor, which is characterized by accurate accuracy, fast moving speed, high reliability and convenient operation.
6. How to judge the quality and grade of a wire cutting machine when you see it at the exhibition:
We often encounter such a situation: different manufacturers exhibit the same products at the exhibition. If the manufacturers’ introductions seem to be excellent products, plus the exhibitors’ careful arrangement of the booth booths, if not experienced. Experts, we will definitely think that the machine tools displayed are all fine products. This is also the purpose of exhibitors. In the end, those machine tools are genuine products? As long as we carefully look at, compare, and ask three steps, we can distinguish them:
1 Look: The first is to look at the appearance. It depends on the nuances that are not easy to be noticed by people. The quality level of the appearance is the key to these small parts. This is not because we are picky, but because these small links can reflect the craftsmanship of the manufacturers. The management level of the production process and the quality of the employees of the manufacturing plant.
The second is to look at the structure, according to the knowledge described in this Guide, observe whether the structure of the machine tool is reasonable, and observe some simple operations to increase the perceptual knowledge.
2 ratio: After careful observation, you can compare different manufacturers. If you are not afraid of not knowing the goods, you will be afraid of the goods, so it is easy to find the gap. When you compare, you must target the product, not to be beautiful. The booths and booths are tempted, and the luxury booths are not necessarily boutique.
3Q: After looking at, comparing, and discovering the problem, you can directly ask the exhibitor questions. The question has two purposes. One is to understand the reasons for the difference between the gaps. The second is to examine the technical level of the exhibitors, because the exhibitors themselves represent the exhibitors. The image of the manufacturer is also the quality of the exhibitors. Through the exchanges with the exhibitors, there is a side understanding of the exhibitors, and this understanding sometimes gets unexpected gains.
Concerned about surprises
Label: Selection Guide Cutting Fluid Motion Accuracy Guide Linear Guide
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