Machine tool manufacturers are most concerned about the accuracy, rigidity and service life of the machine tool, and they pay very little attention to the guide rail system. However, the guide rails have laid a reliable foundation for the realization of machine functions. Various types of machine tool working parts use control axes to move on designated guide rails. The machine tool designer selects various different types of guide rail systems according to the type and purpose of the machine tool. The following three types are widely used: plane The guide rail, linear rolling guide and the combination of recirculating roller and flat guide rail constitute a rolling element guide rail.
1. The function of the guide rail
Although the form of the rail system is diverse, the nature of the work is the same. The working parts of the machine tool move on the specified rail system, just like a train traveling in a specified direction along a railroad track. It mainly reflects the following three basic functions:
1. Guiding the movement of the carrier;
2. Provide a smooth moving surface for the carrier;
3. The force generated by the cutting of the machine tool is transmitted to the foundation or the bed to reduce the impact of the generated impact on the passive machining parts. Most of the motion along the guide rail system is linear motion, and a few are arc motion. Many technologies of linear guides can be directly applied to curved guides.
Second, the classification of guide rails
Machine tool manufacturers are doing their best to ensure the accuracy of guide rail installation. Before the guide rail is processed, the guide rail and the working parts have been aging treatment to eliminate internal stress. In order to ensure the accuracy of the guide rail and prolong its service life, scraping is a common process method.
1. Linear guide
The new guide rail system enables the machine tool to obtain rapid feed speed. In the case of the same spindle speed, rapid feed is a characteristic of linear guides. Linear guides, like flat guides, have two basic elements; one as a guide is a fixed element, and the other is a moving element. In order to ensure the accuracy of the machine tool, a small amount of scraping of the bed or column is essential. In general, the installation is relatively simple.
There is no intermediate medium between the moving element and the fixed element of the linear guide rail, but a rolling steel ball. Because the rolling steel ball is suitable for high-speed motion, has a small friction coefficient and high sensitivity, it can meet the working requirements of moving parts, such as the tool holder and carriage of the machine tool.
If the working time is too long, the steel ball begins to wear, and the preload on the steel ball begins to weaken, resulting in a decrease in the movement accuracy of the working parts of the machine tool. If you want to maintain the initial accuracy, you must replace the rail bracket, or even replace the rail. Titanium Machinery is the company's main products with rotary center, screw, machine tool spindle, shaft processing, high-precision tool holder, tool holder, elastic chuck, non-standard parts processing, and machine tool extension! If the rail system has a preload effect. The accuracy of the system has been lost, and the only way is to replace the rolling elements.
2. Linear roller guide
The linear roller guide system is a combination of a flat guide rail and a linear roller guide rail. Rollers are installed on parallel guide rails, and rollers are used instead of steel balls to carry the moving parts of the machine tool. The advantage is that the contact area is large, the bearing load is large, and the sensitivity is high. Viewed from the bottom of the bed, the bracket and rollers are placed on the top and side surfaces of the flat guide rail. In order to obtain high precision, a wedge is set between the working parts of the machine tool and the inner surface of the bracket to make the preload act on the side of the bracket. The working principle of the wedge plate is similar to that of the inclined iron, and the weight of the working part acts on the top surface of the bracket. Since the preload acting on the guide rail system is adjustable, the loss of the wedge plate is compensated for. This feature is widely used in medium or large machine tools because it is sensitive to CNC commands, bears large loads, and is linear. The roller guide system can withstand high-speed operation than traditional flat guides and improve the performance of the machine tool.