China's current status of linear cutting machine and how to select users

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 product's performance and price are very different. The following is a status quo written by a wire cutting manufacturer. Although it is somewhat biased, it also has certain reference value.

1. Status of China's wire cutting machine industry:

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, and the production lines of wire-cutting machine tools were all state-owned enterprises. Strong ability, but because of the disconnection from the market, combined with the constraints of the planned economy, the WEDM machine not only has a high failure rate but also has limited performance (only 50mm thickness can be cut and the efficiency is 20-30mm2/min) but in any case Wire-cutting machine tools are unique to China's machine tools. Compared with wire-cutting machine tools from abroad, wire-cutting machine tools are less precise, but their manufacturing and operating costs are absolutely superior. They are very suitable for those developing countries. Due to the demand of this potential market, after the implementation of the market economy in China, a large number of wire-cutting machine tool manufacturers have emerged across the country. As a result, disorderly competition has emerged in the wire-cut market, and disorderly competition has evolved into price competition. In order to reduce costs, Some companies with poor technical skills have lowered their production standards, plus the management of relevant state technical supervision agencies Effectively, the quality of the WEDM machines of different manufacturers on the market is greatly different. Some of the same WEDM machines can use 10 years of precision without attenuation, and some can only use 2 years. The price of WEDM with the same specification can differ by 10 Ten thousand yuan, which does cause great difficulties for the user's selection (especially foreign users), will not be fooled a little, then why these unqualified wire-cutting machine tool can appear in the market? This is mainly due to the popularity of wire cutting applications in China's manufacturing industry. Nowadays, the application of wire-cutting machine tools is not limited to mold making. A considerable number of mechanical parts are also used for wire-cutting machine tools, so low-grade wire-cutting machine tools There is also a certain market. Another reason is that the GB7926-87 wire-cutting machine tool precision standard clearly stipulates that before reaching this standard, it must first meet the JB2670-82 "General Rules for the Inspection of Metal-cutting Machine Tool Accuracy", and some incompetent manufacturers have to drill down the national standard. They Regardless of the JB2670-80 national standard, in the production process, the use of inferior materials was reduced in the accuracy of processing, and thus the precision was completely lost after 1-2 years as described above.

Judging from the social environment, China's implementation of the market economy is not a long time. Some small-scale wire-cutting machine tool manufacturing plants are still in the accumulation stage of the original capital. These manufacturers often do not have the entire machine manufacturing capacity, but only assembled production and production. The whole process of quality control is totally unsound, and R&D and innovation are even more impossible. The number of such manufacturers in the eastern part of China is very large, coupled with the immature laws and regulations that China and the market economy are currently supporting, as well as the benefits Driven by the protection of local governments, these unproductive enterprises will continue to survive. From the current status quo, the country’s attitude towards this is naturally eliminated through market competition.

2, in the purchase of wire cutting machine should pay attention to which aspects of the problem:

Wire-cutting machine tools are precision machining equipment. As mentioned above, the relevant national departments have formulated a series of technical standards for its production and precision testing. However, due to the large market demand, some manufacturers have been ignoring quality in order to increase output, especially in eastern China. Some private small-scale enterprises that do not have the production conditions of machine tools are also producing wire-cutting machine tools, and they are indispensable for the selection of large numbers of users, especially foreign users. The inadvertent user’s own interests are infringed upon. Selection is particularly important when determining the manufacturer and brand.

First of all, according to their own products and production needs to determine the function and size of the machine tool, and in the selection of the user is easy to ignore the requirements for future development, because the machine is not a consumable, although a one-time investment is large but the service life is very long, if Only considering the immediate consideration of the company’s own development factors will inevitably lead to repetitive investments in the near future. We encounter a lot of users in this situation. Therefore, we must have a sense of advancement in the selection process and we must have a vision of development. When selecting a model, it is necessary to make a reserve of the machine of your choice, both in function and in technical level.

The second is how to determine the manufacturer. The emphasis is on the comparison of quality, reputation and product prices. The quality reputation is compared from the following aspects:

(1) Production scale: The scale is too small to be easily eliminated in the fierce market competition, and there is no strength in product research and development and innovation.

(2) Production mode: The entire machine manufacturer can effectively control the quality of each production process, and the assembly-type production has no control over the intrinsic quality of the machine tool and the whole production process because the main machine tool of this production mode is The institutions are all CNC system manufacturers, which are completed by other manufacturers. At present, developed countries use more of this socialized method of production for complex products. The prerequisite for such production methods is a sound market system and sound business laws. There is still a gap in China in this respect, so users should be reminded that they should pay enough attention to the production methods of the manufacturer.

The third aspect is price, which is also the most sensitive for users and manufacturers, but one thing is the same, that is, product performance is the basis of price, and product price is the embodiment of performance and quality, which is the performance price we often say. Therefore, it is meaningless to say that the price is out of the performance. However, if the price is high, the user cannot accept it. However, the price is too low is not a good thing, because the low price means that the manufacturer must reduce the cost (doing business can not lose money), but the quality and cost There is a critical point, below which is a purely quenched product, such as the products of some wire-cutting machine tool manufacturers in eastern China, so users cannot forget that wire-cutting machines are long-time precision machining. equipment.

The fourth aspect is that the hearing is imaginary and the eyesight is true. Due to fierce competition in the market, manufacturers will inevitably reveal some words and deeds that intentionally injure each other. Although this feeling is understandable, it disrupts the selection of users. Environment, so the bad words and deeds of these manufacturers themselves are irresponsible to the user, but as long as the user is able to see the truth, these interference will not break, so the user must look at the physical, Look at the prototypes, especially the high-thickness demos, so that users can know what they think.

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 ensure the normal use of the product, zero failure rate is also an enterprise eternal pursuit of the goal, excellent quality is the basis of after-sales service, and after-sales service is a continuation of product quality , We believe that high-quality products must come from strong and regular enterprises, and the company's reputation for guaranteeing such services is also very important to after-sales service. In addition, the product quality is good and the failure rate is low. The cost of after-sales service will also be Although both are indispensable for reduction, the user should first pay attention to the quality of the product itself, no matter how good the after-sales service is, and can only be a way to make up for the quality, and a mature and reliable wire cutting machine tool. In the process of design and development, the reduction of the failure rate has been considered, and how to make the maintenance service more convenient. The quality of after-sales services first reflects the company’s values ​​and ethical standards, followed by the management capabilities of the company and its own staff. Morality, only those companies that have strength and development, depending on the brand, such as life, can have these three Aspects.

4. How to determine the accuracy of machine tool retention in the selection process:

In the mold processing line cutting process is generally the final process, so the processing accuracy is very demanding, if the machine tool's mechanical accuracy is not good, will directly affect the quality of products and mold processing, and ultimately lead to loss of users, loss of market, so online cutting machine tool selection When it comes to type, how to judge the mechanical accuracy and structure and the merits are very important.

In general, the accuracy of the new machine is easy to judge, because there is a national standard GB7926-87 and related general standards for machine tool accuracy, where the new machine can know whether it is qualified or not when commissioning and acceptance. However, the most important factor is the judgment of the accuracy of the maintenance of the machine tool, because the accuracy of the maintenance of the machine tool will only be reflected in the use of the machine after a certain period of time, but the national standard can not be strictly controlled, so It is only when the user selects a type to do a thorough understanding of the machine tool and structure. Do not listen to hearsay and listen to some unfounded rumors, so as not to disturb your judgment.

Here we elaborate on the drive structure, guide rail structure, and drive mode of the machine tool table.

4-1. The accuracy of the screw and its mounting structure The accuracy of the screw is important, but if the screw is not properly mounted, the screw will not help.

First, look at the form of the screw, and see if it is a ball screw, a triangular thread screw, or a trapezoidal thread screw. On the wire cutting machine, the ball screw is superior to the triangular screw thread and the trapezoidal thread screw, and the screw diameter is required to be as large as possible to increase the rigidity.

Followed by the installation structure of the screw, ball screw is a precision transmission components, so to fully play its precision, then the assembly structure of the screw is also higher, must be fixed at both ends, bearing support, for large stroke machine tools It is also necessary to pre-stretch the screw to reduce the deflection of the screw, thereby improving the accuracy of the machine table.

4-2. Gear Transmission Structure (1) Firstly, it is necessary to know in detail the number of gears in the gear box. The more gears that participate in the transmission, the greater the transmission resistance, the easy wear of tooth surfaces, and the easy transmission of gear gaps, resulting in systematic errors of the machine table. The bigger the gear is, the more gears are, if the assembly is not good, it is easy to produce accidental errors. Therefore, the smaller the transmission gear, the better, and the smallest transmission error is used for a pair of gears. Therefore, it is very important to understand the gear transmission structure of the table movement during the selection.

(2) Observe the working environment and lubrication performance of the gear box of the worktable. Some manufacturers' early machine tools were designed to be irrational, so that the cutting fluid can easily enter the gear box, so that the gears work in the immersion of the cutting fluid for a long time. This design is very unreasonable, and the lighter ones increase the wear of the gears. The heavy ones cause the stepper motor to be flooded, so the user must observe the position of the gearbox of the worktable during the selection to ensure that the cutting fluid must not be immersed. This is critical to 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 table, and the user should pay great attention when selecting the model. First, observe the size of the cross section of the guide rail. Under the same conditions, the thicker the shape is, the better the rigidity is, and the more difficult it is to deform during processing, and secondly, the material of the guide rail and the heat treatment process are known to the manufacturer. In general, in order to ensure its strength and small deformation, it is better to use a high-carbon alloy steel, an overall quenching or an audio quenching process.

(2) Observe the structure of the guide rail directly. The common guide rail structure on the market is as follows:

1 inlaid steel ball type rolling guide;

2 inlaid steel roller type rolling guide;

3 linear rolling guide;

4 elastic bearing cast iron rails.

The difference between the first and the second is on the roller body of the guide rail, one is the ball and the other is the roller. The ball and the rail surface are in point contact, and the roller and the rail surface are in line contact, so its wear resistance and bearing capacity are much better than the ball type, and the elastic bearing cast iron rail is a kind of simple rail that is eliminated. At present, the second and third structures are used in the machines imported by Japan's Sodick Company, Mitsubishi Corporation of Japan, Charmilles of Switzerland, and Archie AG of Switzerland. Therefore, by contrast, the user should consider as many as possible when selecting a model. Two and third structures.

4-4. Drive Modes CNC wire-cutting machine tools are generally driven by stepper motors. In stepper motors, there are also reactive and hybrid types to achieve different step angles. The most common reaction on the market is reaction. Stepping motors, reactive stepper motors have three-phase three-shot, three-phase six-shot, five-phase ten-shot, five-phase double 10-shot and other different driving methods. This type of 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 requirements of the machine tool industry by the relevant departments of the Ministry of Machinery Industry, five phases and ten beats will gradually replace three-phase six-shots. This is because the five-phase ten-shot not only further subdivides the step angle of the three-phase six-beat, but also increases the motor winding resistance to five phases, so the transmission is smooth and powerful.

In summary, the user should choose this type of structure in order to ensure long-term reliability of the machine tool during the selection process:

(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 number of transmission gears on the table is small. A pair of gears is preferable, and the position structure of the gear box ensures that the cutting fluid must not be immersed.

(3) Try to use roller-type inlaid steel rolling guides or linear guides with large cross-sectional area or large aspect ratio;

(4) Select the five-phase ten-step stepper motor drive, if the conditions available to use hybrid subdivision drive or AC servo drive is even more ideal.

5, in the purchase of large-scale wire cutting machine should pay attention to what issues:

Large-sized wire-cutting machine tools, because of the large processing range and high load-carrying capacity (such as the deepening of the company's DKM800 type, X and Y strokes of 800 × 1000, the amount of capacity of 2000Kg or more), in the processing of large-scale mold, the foreign machine tools can not match Than, so it can create considerable benefits, but if there is a problem with the machine tool, especially the memory quality of the machine tool itself, the loss caused by it is also very heavy, so the selection of large-scale wire cutting machine tools Must be especially careful.

Due to the characteristics of large travel and large load bearing, it is important to consider the structure and rigidity of the machine tool when selecting a type, so that it can ensure the accuracy of large-scale workpieces to ensure the accuracy, and in the structure and the small and medium-sized wire cutting machine has the following obvious The difference:

1 Worktables must adopt a full support structure to increase the rigidity of the machine to ensure heavy loads without deformation.

2 Imported linear guide rails ensure good sensitivity and motion accuracy under heavy loads.

3 Compared with small machine tools, the diameter of the ball screw must be increased.

4 If the user has a certain strength, the worktable of the machine tool is preferably driven by an AC servo motor, which is characterized by accurate accuracy, fast movement speed, high reliability, and convenient operation.

6. When you see a WEDM machine at an exhibition, how should you fully determine its quality and grade:

We will often encounter such situations: in the exhibition, different manufacturers exhibit the same products, if listening to the manufacturers' presentation seems to be excellent products, coupled with the elaborate arrangement of exhibitors on booth booths, if not experienced The expert will definitely think that the machine tools displayed by the exhibitors are all excellent products. This is exactly the purpose of the exhibitors. Which machine tools are genuine products? As long as we carefully look through, compare, and ask three steps, we can distinguish them:

1 Look: The first is to look at the appearance. It depends on those parts that are not easily noticed by the people. The quality of the appearance depends on these small parts. This is not our fault, 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 "guide" as described in the previous knowledge, observe whether the structure of the machine tool is designed properly, while doing observation can also do some simple operations to increase perceptual knowledge.

2 ratio: After careful observation, it is possible to compare different manufacturers. If you are not afraid of not knowing the goods, you will be afraid to compare the goods. It is easy to find the gap. When comparing, you must target the product and not be beautiful. Booths, booths, temptation, luxury booths are not necessarily all fine.

3Q: After seeing, comparing and finding problems, you can directly ask the exhibitors questions. The questions have two purposes. One is to understand the reasons for the differences and the other is to examine the technical level of the exhibitors, because the exhibitors themselves are representatives. The image of the manufacturer is also reflected in the quality of the exhibitors. Through the exchanges with the exhibitors, they can have a side understanding of the exhibitors. This kind of understanding can sometimes yield unexpected results.