In the actual production process, we will find that the same CNC machine tools are operated by different personnel, and the production efficiency varies greatly during the same working hours. The processing capabilities of many CNC machine tools cannot be fully reflected and cannot play their optimal role. .
1. Develop a reasonable processing route to reduce the auxiliary time of CNC milling
In order to improve the production efficiency of CNC machine tools, we must first carefully analyze the parts processed by CNC lathes, and clarify the technical requirements of the parts' materials, structural characteristics, geometric tolerance requirements, roughness, and heat treatment. Then, on this basis, choose a reasonable milling process and a simple processing route.
Formulation of processing technology: Usually a part can have several different processes. The process of the part is different, and its production efficiency, processing cost and processing accuracy often have significant differences. Therefore, we should ensure the quality of the processing of the parts according to Specific production conditions, try to improve production efficiency and reduce production costs, and work out a reasonable processing technology.
Determination of the processing route: A correct and concise processing route is the basis for ensuring processing quality and improving efficiency. When choosing the processing route of the part, the principle of determining the processing route must be followed in order to achieve the goal of improving production efficiency. The main principles for determining the processing route are: it should be able to ensure the requirements of the machining accuracy and surface roughness of the parts, and the efficiency is high; the processing route should be minimized as much as possible, which can reduce the program segments and reduce the tool idle time ; The numerical calculation should be simple and the number of program segments should be small to reduce the programming workload.
2. Choose the right tool
The selection of tools should consider factors such as the processing capacity of the CNC lathe, process content, and workpiece material. The tool selected for the CNC lathe not only requires high hardness, high wear resistance, sufficient strength and toughness, high heat resistance and good manufacturability, but also requires dimensional stability and easy installation and adjustment. Therefore, new high-quality materials should be used to manufacture CNC machining tools, and the tool parameters should be optimized so that the size of the tool is compatible with the surface size and shape of the workpiece. So, how to choose the right cutting tool?
(1) Choose the appropriate tool
In the cutting process of CNC machine tools, the role of metal cutting tools is extremely important. The material used to make the tool must have high hardness, wear resistance and heat resistance, sufficient strength and toughness, good thermal conductivity and manufacturability, and good economy. In the process of selecting tools, on the premise of meeting the requirements of parts processing, try to choose a tool with a larger diameter, which has better strength and toughness; in the same process, the number of tools selected is as small as possible to reduce the number of tool changes; It is possible to choose general-purpose standard tools instead of using special non-standard tools.
(2) Reasonably determine the tool setting point
The tool setting point is the starting point of the movement of the tool relative to the workpiece when machining parts on the CNC machine tool. Also called "program starting point" or "starting point". The selection of tool setting points must comply with the following principles: easy to use digital processing and simplify programming; easy to align on the machine tool, easy to process and easy to check; the processing error caused is small. The position of the tool setting point can be selected on the workpiece or on the outside of the workpiece (such as a fixture or a lathe), but it must have a certain size relationship with the positioning reference of the part. The tool setting point should be selected as far as possible on the design reference or process reference of the part, such as the workpiece positioned with a hole, the center of the hole can be selected as the tool setting point. The position of the tool is aligned with this hole, so that the "in-position point" and the "tool setting point" coincide. In this way, the efficiency of tool setting can be better improved and the processing quality can be guaranteed.
3. Reasonably install and clamp the workpiece to increase the clamping speed
When machining a workpiece on a CNC machine tool, the positioning and installation of the workpiece should ensure that the design basis, process reference and programming calculation basis are unified; try to reduce the number of clamping times, and try to machine all the surfaces to be processed after positioning and clamping once; avoid Use the machine to adjust the processing plan manually to give full play to the effectiveness of the CNC machine tool.
When cutting with CNC machine tools, it is necessary to fully consider the positioning of parts, the design of clamping, and the selection and design of furniture. When designing furniture, we must first ensure that the coordinate direction of the furniture is relatively fixed with the coordinate direction of the lathe. Secondly, it is necessary to coordinate the size relationship between the parts and the lathe coordinate system. At the same time, you should also consider:
(1) When the production batch of parts is not large, modular fixtures, adjustable fixtures and general fixtures should be used as much as possible to shorten production preparation time and save production costs;
(2) Only consider the use of special fixtures in mass production, and strive for a simple structure;
(3) The loading and unloading of parts should be fast, convenient and reliable to shorten the machine downtime;
(4) The parts on the fixture should not hinder the machining of the parts on the surface of the machine;
(5) When selecting tooling, tool exchange should be facilitated to avoid interference and collision;
(6) Multi-position and multi-piece fixtures can also be used in batch production to improve processing efficiency.
4. Reasonably choose the cutting amount to improve the cutting efficiency of the machining allowance
Cutting parameters include: spindle speed, cutting depth, and feed rate. When selecting the cutting parameters of the CNC milling machine, if it is roughing, the productivity is generally improved, but economy and processing cost should also be considered, and a larger cutting depth and feed rate can be selected; if it is semi-finishing and finishing , On the premise of ensuring the processing quality, taking into account the efficiency, economy and processing cost; the cutting tool should be set as high as possible feed speed when doing idle motion. The specific value should be determined according to the lathe manual, cutting parameter manual, and combined with experience.
5. Implement tool pre-adjustment and automatic measurement of wolf, reducing the time occupied by machine adjustment
Many different tools are often used in the process of CNC machine tools. If the tools cannot be adjusted in advance, the operator needs to install each tool on the spindle and slowly determine their exact length and diameter. Then, manually input through the buttons on the CNC control surface. If a tool setting instrument is used, it can accurately measure the diameter and length of the tool, reduce the time occupied by the machine tool, increase the first part pass rate, and greatly improve the production efficiency of the CNC milling machine.
6. Flexible use of various auxiliary functions and macro programs of CNC machine tools
The CNC machine tool has the function of tool radius and length compensation. By changing the method of tool compensation, the tool size error can be compensated. The same processing program can realize layered milling and roughing and finishing or used to improve the processing accuracy. The same processing program can be used to process matching parts.
The biggest feature of using a macro program is that the regular shape or size is expressed in the shortest program, and when the machine tool executes this type of program, it is faster and more responsive than the program generated by the CAD/CAM software. Macro programs can use variables and assign values to variables. Variables can be calculated, and program operations can jump. Modular processing programs can be formed. When applying, you only need to enter part information and processing parameters into the call statement of the corresponding module. Shorten the programming and input time.
The CNC machine tool also has the fixed cycle function, subroutine function, mirror processing function, and rotating lamp function. Using these functions can eliminate the input of long programs. If used properly, you can get a multiplier effect with half the effort.