Technical characteristics of horizontal boring and milling machines and floor milling and boring machines

In recent years, the development of horizontal boring and milling machines and floor milling and boring machines at home and abroad has been very rapid. Its characteristics are the continuous updating of product structure, the continuous application of new technologies, the compounding of process performance, the continuous improvement of speed and efficiency, and the emphasis on fine manufacturing.

The development of the horizontal boring and milling machine has received much attention due to its injection acceleration concept. Transmission elements such as electric spindles, linear motors, linear guides, etc., which are used as technical support for high-speed operation, have been widely used, pushing the operating speed of the machine tools to new heights. The innovative design of the spindle replaceable horizontal boring and milling machining center solves the disadvantages of both the spindle and the mast movement and telescopic structure. It has the advantages of composite processing and one machine, and is also a large horizontal boring and milling machine. Technological innovation.

The development of floor-type milling and boring machines leads the trend of modern machining with its new design concept. The high-speed machining concept of flawless shaft rams and the interchange of various types of milling heads make it possible to replace the traditional milling process. the trend of. The various milling head attachments represented by the two-axis swivel heads are the main means for realizing high-speed and high-efficiency composite machining. The process performance is wider, the power is greater, and the rigidity is stronger, which is a major breakthrough in the development of the floor milling and boring machines.

Structural features

Horizontal boring and milling machines

The main key components of the horizontal boring and milling machine are the spindle box, installed on the side of the column, and a few manufacturers adopt the double-column thermal symmetry structure to place the spindle box in the middle of the column. The most important feature of this type of structure is rigidity, balance, and good heat dissipation performance. This provides a reliable guarantee for the high-speed operation of the spindle box. However, the double column structure is not easy to maintain and is the reason why there are not many manufacturers that are used today. The movement of the spindle head is driven by the motor-driven ball screw. It is the core drive of the spindle drive. It uses hydrostatic bearing support and is driven by a servo motor to drive the ball screw. As the spindle speed is higher and higher, the spindle heats up quickly. Now, many manufacturers will use oil mist cooling instead of oil cooling to more effectively control the temperature rise of the spindle and ensure its accuracy is effectively guaranteed.

Spindle system mainly has two types of structure, one is the traditional mast retractable structure, with deep hole and high power cutting characteristics; the other is a modern high-speed motor spindle structure, with high speed, high speed, high efficiency The advantages of high precision.

There are more and more high-speed electric spindles in horizontal boring and milling machines. In addition to the substantial increase in spindle speed and accuracy, the internal structure of the spindle box is also simplified, and the manufacturing cycle is shortened. Especially, high-speed cutting is possible, and the highest spindle speed can be achieved. Large 10000r/min or more. The disadvantage is that the power is limited, the manufacturing cost is high, and in particular deep hole machining is not possible. The mast telescopic structure has a limited speed, although the accuracy is not as good as the spindle structure, but the deep hole can be processed, and the power is large, can be processed at full load, high efficiency, is unmatched by the electric spindle. Therefore, the two structures coexist, and the process performance varies, but it gives users more choices.

Now, another type of replaceable spindle system has been developed, which has the function of one machine and two functions. The user can select and use according to different machining objects, that is, the electric spindle and the mast can be used interchangeably. This structure takes into account both structural deficiencies and greatly reduces costs. It is a big innovation in the current horizontal boring and milling machine. The advantages of electric spindles are high-speed cutting and rapid feed, which greatly improves the accuracy and efficiency of the machine.

Horizontal boring and milling machines are operating at higher and higher speeds, with a rapid speed of 25 to 30 m/min and a maximum speed of 6000 r/min. The horizontal machining center has a higher speed, rapid movement of up to 50m/min, acceleration of 5m/s2, position accuracy of 0.008 to 0.01mm, and repeatability of positioning accuracy of 0.004 to 0.005mm.

Floor type milling and boring mills

As the floor-type milling and boring machine mainly processes large-sized parts, the milling process has a wide range, especially high-power and powerful cutting is a large processing advantage of the floor-type milling and boring machine. This is also the traditional process concept of the floor-type milling and boring machine. The technical development of the contemporary floor milling and boring machine is changing the traditional concept and processing method. The concept of high speed machining is replacing the traditional concept of heavy cutting, and it brings about changes in the processing technology with high speed, high precision, and high efficiency, which also promotes The structural change and technical level of floor-type milling and boring machines have been improved.

Today, the most important feature of the development of floor-type milling and boring machines is the development of high-speed milling. Both are ram-type (non-twist) structures and equipped with milling head attachments of various technological properties. The advantage of this structure is that the ram has a large cross-section, good rigidity, long stroke, fast moving speed, easy installation of various function accessories, mainly high-speed boring, milling head, two-axis double-angle milling head, etc. The performance and processing range are maximized, which greatly improves the processing speed and efficiency.

Traditional milling is done by boring bar. Modern milling processing is completed by various functional accessories through rams. It has replaced the traditional processing trend. Its advantages are not only the milling speed, high efficiency, but also mainly can be carried out. The processing of polyhedrons and curved surfaces cannot be accomplished by traditional processing methods. Therefore, nowadays, many manufacturers are racing to develop and produce high-speed ram-type machining centers because of their economical and technological advantages, and they can greatly improve the technological level and process range of the machine tools. At the same time, it also improves the processing accuracy and processing efficiency. Of course, various types of high-precision milling head attachments are required for technical support and their requirements are also high.

The high-speed milling brings structural changes to the floor-type milling and boring machine. The centering structure of the spindle box is more common and its rigidity is high, which is suitable for high-speed operation. The ram drive structure uses a linear guide rail driven by a linear motor. This structure is required for high-speed cutting. Foreign manufacturers have adopted floor-type milling and boring machines. Similar products are rare in China, and linearity is only adopted in small and medium-sized machine tools. guide. High-speed processing also imposes higher requirements on the environment and safety, which in turn has created the concept of pleasant production. Each manufacturer attaches great importance to the safety and operability of the machine under high-speed operation conditions, and will operate the console and column. A fully enclosed structure is safe and beautiful.

Process characteristics

The traditional horizontal boring and milling machine is mainly suitable for the processing of various mechanical parts, especially the mechanical transmission box body and various curved body parts. Due to the improvement of various equipment technologies, the mechanical structure requirements are more and more simplified, fewer transmission components are needed, especially the parts used as the transmission box body will be less and less, the mechanical transmission takes more direct drive, and the transmission parts Accuracy requirements are very high, which puts higher requirements on the technological performance of horizontal boring and milling machines. As a result, the machining target of the conventional stern shaft structure is decreasing, and it will be replaced by a shaftless electric spindle, that is, a high-speed machining center to complete the processing of various parts. Horizontal boring and milling machines develop to high-speed machining centers. On the one hand, the process adaptability is stronger, and on the other hand, the performance level and processing accuracy are also improved. While improving the processing technology range, various function accessories are needed for process protection. Boring and milling, drilling and tapping, and fitting of a digitally controlled oscillating milling head attachment, can also be used to machine various curved body parts. Equipped with a switching table to form a flexible processing unit, the parts can be processed in batches.

The floor-type milling and boring machine mainly processes large-size and super-large parts of various types of surfaces. Its process features are equipped with a large floor-standing platform (the size of the table is not limited), and can process ultra-long and extra-wide parts. At the same time, it can also be equipped with a rotary table, that can be used for rotary indexing, radial radial motion can also be achieved through the indexing of the parts of the multi-order processing, greatly improving the scope of the process. Nowadays, the floor-type milling and boring machine produced by Pama, Italy, is specially equipped with an inclined adjustable table, which further broadens the processing range. High-power and high-efficiency cutting is a major processing advantage of floor-type milling and boring machines. The high-speed, high-precision technical requirements increasingly affect the technical development of floor-type milling and boring machines, and are important means for improving the level of floor-type milling and boring machines. Therefore, the floor-type milling and boring machine is changing a single high-power, high-efficiency cutting, and more into the high-speed, high-precision technology. Now, the ram-type structure has become the main structural type of high-speed milling and boring processing. The ram has large cross-section, high rigidity, and high-speed running stability, which facilitates the installation of various milling head attachments to achieve high-speed machining.

development trend

The development of heavy machine tools will present two major trends. On the one hand, it is technically the development direction of machining centers or large-scale flexible machining units and large-scale combined-type composite processing machines. Among them, horizontal boring and milling machines will gradually be replaced by high-speed machining centers and flexible machining units; floor-type milling and boring machines for the development of large-scale Combined modular machining center is mainly composed of two or more main machines combined into a composite processing machine to meet the single-piece and small-batch production of large-scale processing parts. The process is complicated, the auxiliary time and the processing cycle are long. It is very difficult for the machine tool to complete all the machining operations, but it can be realized by two combined machining centers. Such as: two CNC gantry boring and milling machine to form a composite machining center, and share the bed and rails, respectively, with a rectangular table and a rotary table (indexing), can be boring, milling processing; a floor type milling boring machine and A single-column vertical lathe makes up a large-scale compound machining center, sharing bed rails, with a landing platform and a turntable, can complete the car, boring, milling, drilling and other processing, rotary table can be indexed. There are also many combinations of two large-scale floor milling and boring machines sharing bed rails. This saves floor space, reduces costs, and increases processing efficiency. Another trend is to pursue refinement of manufacturing, increase the technological content of equipment manufacturing, and reflect the safety, environmental protection and humane characteristics of the machine tool.

To sum up, the technology of contemporary horizontal boring and milling machines and floor-type milling and boring machines is developing very fast. It is mainly reflected in the updating of design concepts and the improvement of machine tool operating speed and manufacturing process level. On the other hand, the machine tool structure changes greatly. The application of new technologies is endless. The structure of the horizontal boring and milling machine develops towards the direction of the high-speed motor spindle. The floor-type milling and boring machine develops in the direction of the ram-type (non-twisted-axis) structure, and the functional accessories show the development trend of high-speed, multi-axis linkage and diversified structure types. This will be A new trend of technological development in the coming period.