The advantages and disadvantages of CNC machine tool hard rails and line rails

Generally if the machining center is used to make products, then buy wire rails, if it is to process the mold, then buy hard rails, wire rails are more accurate than hard rails, but hard rails are stronger and more durable.

Hard rail features

I. Advantages of hard rails.

1、To withstand greater loads, suitable for large tool volume, large feed roughing machine tools.

2, because of the large contact area of the guide rails, machine operation is more stable, suitable for machine tools with high vibration requirements, such as grinding machines.

Second, the disadvantages of hard rails.

1, uneven material, because it is generally cast molding, so the material is easy to produce sand sandwich, porosity, loose casting defects, if these defects exist in the guide surface, the service life of the guide and the precision of the machine is a very negative impact.

2, processing difficulty, because this type of guide rail is generally connected with the main parts of the machine such as the base, column, table, saddle and so on, so in the processing process, its shape and position tolerance, roughness requirements, aging treatment, quenching process is difficult to control, which leads to the processing quality of the parts can not meet the requirements of the assembly.

3, assembly is difficult, "assembly" means that the word is both to be fitted with, and the process is a combination of technical and physical with the process, not the average worker can complete, the relative number of technologies needed, the overall accuracy of the machine have a good grasp of the assembly workers can be completed, but also need to be equipped with shovel, flat ruler, angle ruler, square ruler, percent table, thousand table and other appropriate tools to complete.

4, service life is not long, this can only be relative, in the same maintenance and use conditions, the universal hard rail service life is less than the service life of the line rail, which has a great relationship with their mode of movement, hard rail is sliding friction running, while the line rail is rolling friction running, from the friction suffered, hard rail friction is much greater than the friction suffered by the line rail, especially in the case of inadequate lubrication, hard rail friction even more.

5, maintenance costs are too high, hard rail maintenance either in the difficulty or maintenance costs are far greater than the maintenance of the rail, if the spade scraping margin in the case of insufficient, may involve all the pieces of the machine tool disassembled from the new quenching process and machining, and even more may want to recast the big parts, while the line gauge as long as the replacement of the corresponding line rail can be, basically will not have a great impact on the use of the relevant big parts.

6, the machine tool running speed is low, hard rail because of its mode of movement and said to withstand excessive friction, so usually can not withstand excessive operating speed, which and the current processing concept is contrary to some. Especially many factory workers do not have the appropriate maintenance knowledge of machine tools, often they only know the use of machine tools, but largely ignore the maintenance of the machine tool, the maintenance of the machine tool track is the most important, once the track is not sufficiently lubricated, it will cause the track burned or wear and tear transition, the precision of these machine tools are fatal to the injury.

Line rail characteristics

I. Advantages of line rails

1, easy and simple assembly, as long as a little training can complete a high-quality assembly. Because of the precision of the machine tool, a lot of ah degree of precision in the transmission mechanism is determined, the transmission mechanism is generally composed of a line rail and screw, that is to say, the accuracy of the line rail and screw itself determines the precision of the machine tool, and the line rail and screw are generally in the form of standard parts, you just have to choose the manufacturer to provide the corresponding precision, generally will not have a big problem.

2, the choice is large, whether from the structural form of the line rail or precision grade, lubrication or load-bearing capacity, processing mode to the operating speed and other parameters are available, you can design the machine according to your specific circumstances, any configuration you need the line rail model.

3、Running speed, many machine tools now run extremely fast, especially the empty speed, this is largely dependent on the merits of the line rail, because the rolling friction mode of operation and high-precision processing, and effectively ensure the precision and smoothness of high-speed operation of the machine tool, greatly enhance the processing efficiency and accuracy of processing.

4, high processing accuracy, because the line rail as a standard commodity, whether it is material or processing methods are into a benign controllable range, so in many finishing areas of machine tools, most of them are using high-precision line rail as the machine tool guideway, which also greatly ensures the machining accuracy of the machine tool, the domestic do better with the Nanjing process, Hanjiang line rail, Taiwan has on the silver line rail, Germany has Rexroth company. Japan has THK line rail, etc., these brands are greatly enriched and meet the market demand for a variety of different requirements of the line rail needs, personal favorite choice of Japanese THK, stable performance, fine workmanship, is high price.

5, long service life, because the way the line rail operation is rolling friction, slider in the steel ball through the rolling on the track to drive the feed component of the move, this rolling friction withstands friction than hard rail is much smaller, so whether it is transfer efficiency or service life, line rail are more ideal than hard rail a lot.

6, maintenance cost is low, whether from the maintenance cost or the convenience of maintenance, line rail has its natural advantages and convenience, because as a standard, line rail replacement form and replace a screw is the same, of course, there are still some precision on the return adjustment, but compared to the hard rail, it is really too convenient.

7, short delivery cycle, line rail delivery cycle in general can be completed within half a month, unless you choose a foreign brand, such as Rexroth and THK, in fact, these two brands are also in the domestic processing plant, as long as you choose a line rail model is not very partial to the kind, basically half a month or so delivery period can still be guaranteed, and Taiwan on the silver line rail can even do a week delivery cycle, but the same hard rail is not so good time control ability, if the action is relatively large, such as to recasting, that cycle may be in more than a few months are indeterminate.

Second, the disadvantages of the line rail

1, bearing capacity is relatively small, this relatively small is only for the hard rail, in fact, now many manufacturers of line rail through the structure of some of the design, has greatly improved its bearing capacity, of course, relative to the bearing capacity of the hard rail, it is still relatively small.

2, smoothness relative to the hard rail has a certain weakness, such as anti-vibration ability, but I still want to emphasize, this weakness is relative to the hard rail, in fact, now many of the smoothness of the line rail is also doing very well, as long as you design the equipment is not too special requirements, are generally able to meet the needs.

3, transportation and assembly process to pay special attention to the protection of the line rail, because as a standard, its unique structural characteristics, so that it is in a more vulnerable to damage the embarrassing situation, such as the shape of the slender leading to the rigidity of the line rail, in the extrusion is easy to bend and deformation, resulting in the loss of precision; and for example, because it is steel, if not to do rust-proof treatment, in transport and assembly process in contact with water or other solvents, easy to produce rust and corrosion and other phenomena, resulting in the loss of precision.

The above is a engaged in the design of machine tools more than 10 years of the designer of the hard rail and line rail of some humble understanding, I hope you can help.