Ensure precision of turn-milling combination

Turning and milling is an advanced cutting method that uses the combined motion of milling cutter rotation and workpiece rotation to achieve the cutting of the workpiece, so that the workpiece can meet the requirements of use in shape accuracy, position accuracy and surface integrity.
Turning and milling combined machining is not a simple combination of turning and milling into one machine. Instead, it uses a combination of turning and milling to complete various types of surfaces. It is a kind of condition that is developed under the condition that CNC technology is greatly developed. New cutting theory and cutting technology.
The following briefly introduces the factors that affect the accuracy of the turning and milling machine:

Accuracy of electric spindle system for turning and milling composite machine tools

(1) Rotational accuracy of the electric spindle system
The CNC turning and milling composite machining center is a high-precision machining machine. The spindle group is a key component. The rotation accuracy of the spindle group directly affects the precision of the workpiece. In order to ensure the high precision of the spindle group, in the electric spindle system, the connection between the spindle and the motor rotor, the cooperation of the stator casing and the spindle housing, and the cooperation between the two ends of the spindle and the bearing assembly take technical measures.
(2) Indexing accuracy and quasi-stop accuracy of the electric spindle system
The indexing accuracy and the quasi-stop precision of the electric spindle system of the turning and milling machine tool are an important indicator for evaluating the precision of the machine tool spindle, and are an important factor affecting the machining accuracy of the machine tool. In order to achieve high indexing accuracy and quasi-stop precision of the electric spindle system, the international CNC turning and milling machining center adopts the built-in spindle motor (referred to as the electric spindle). The spindle and the motor rotor are integrated into one, reducing the intermediate transmission link to the spindle. The impact of accuracy.

Thermal balance of the electric spindle system

(1) Thermal balance of the electric spindle system
In the electric spindle system, the motor is a heating element, and the front and rear bearings of the high-speed rotation are also heating elements, which will increase the temperature of the electric spindle and affect the machining accuracy of the electric spindle system. How to eliminate the influence of heat source on the precision of machine tool spindle, and realize the heat balance of electric spindle system is the key problem to be solved in the design and manufacturing process of turning-milling composite machine tool.
(2) Tool holder indexing positioning accuracy and position accuracy
Each station of the Turn-Milling and Machining Center tool holder can be equipped with both turning tools and radial and axial power tools, and the type and number of tools can be configured according to the needs of the workpiece being machined. The positional accuracy of the electric tool holder is an important factor affecting the machining accuracy of the turning and milling machine tool. It should be paid attention to in the design and manufacturing process of the machine tool.
(3) Dynamic performance of turning and milling machine tools
The machining accuracy of the machine tool is not only affected by the previous factors, but also by the dynamic characteristics of the electric spindle-bearing system, and the vibration of the machine tool depends on the dynamic characteristics of the electric spindle-bearing system. Since the electric spindle-bearing system is a complex vibration system, its dynamic characteristics are not only related to the damping and static stiffness of the system, but also to the mode shape determined by the system structure. The overall rigidity of the machine bed has a great influence on the machining accuracy of the turning and milling machine tool. In the design of the machine tool, the finite element analysis of the bed and body of the machine tool is also carried out to optimize the structure of the machine bed, improve the rigidity of the machine bed and improve the machine tool. The dynamic performance of the whole machine avoids the deformation of the machine structure caused by insufficient local stiffness of the machine tool, which has an impact on the machining accuracy of the machine tool.

lathe tool and cutting oil performance

(1) Performance of cutting oil
Cutting oil plays a role in lubrication and cooling in turning and milling. Non-special oils such as rapeseed oil, mechanical oil and reclaimed oil are used because they do not contain cutting additives, resulting in instantaneous cracking of the oil film during machining, tools and workpieces. Direct contact produces wear under stress and reduces workpiece accuracy.
(2) Material of lathe tool
The material and performance of the lathe tool directly affect the process precision. Under the high temperature of cutting, the tool with poor thermal conductivity will deform, and the contact area between the tool and the workpiece will increase. The actual machining accuracy and design accuracy will be inconsistent.

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