Application of the hottest Cimatron in high speed

2022-08-15
  • Detail

Cimatron's application in cavity mold high-speed machining

Abstract: high speed machining technology is a high-tech developing rapidly in today's machinery manufacturing industry. It is widely used in mold manufacturing, which can greatly improve the efficiency and quality of mold processing. Starting from the characteristics of high-speed machining, this paper discusses the general programming process of Cimatron Software, analyzes the high-speed machining function and cutting strategy of the software, and summarizes the common methods of cavity mold NC machining

Keywords: Cimatron; Cavity mold; The appearance of the high-speed plus 1 experimental machine should not have irregular protrusions, depressions, roughness and other damages. As the key tooling for the production of new products, the design and production of the mold has increasingly become a decisive factor in the development cycle of new products. With the development of NC machining equipment and high-performance machining tool technology, the application of high-speed machining technology to mold manufacturing can greatly improve the mold processing speed, reduce the processing procedures, shorten or even eliminate the fitter repair work, thus greatly shortening the mold production cycle. High speed machining has special machining process requirements that are different from traditional machining, and the NC instructions of NC machining include all technological processes, so the NC automatic programming system applied to high speed machining - cam system must be able to meet the corresponding special requirements: (a) cam system should have a very high calculation and programming speed; (b) The whole process automatic anti overcut processing ability and automatic knife handle interference inspection; (c) Provide rich machining strategies that meet the requirements of high-speed machining; (d) Feed rate optimization processing function

Cimatron is a set of excellent cad/cam software for surface mold manufacturing industry. It not only provides complete modeling design, drawing, analysis and processing programming functions, but also provides an ideal solution for the whole manufacturing process of cavity mold, especially its application of original knowledge-based processing, automatic NC and Intelligent NC Based on blank residue knowledge [1], It has become one of the most ideal cavity mold high-speed programming software. In combination with the application of Cimatron in practical machining, the programming process and the method and strategy of high-speed machining of cavity mold are introduced below

1 Cimatron processing programming process

1.1 modeling

fatigue testing machine features high load, high frequency and low consumption.

it can directly shape products through Cimatron, and it can also be converted into Cimatron model format through IGES standard format with other CAD software. The specific operation process is: select application IGES read in the datainteface module of Cimatron, select IGS file in the input column, and press execute to complete the conversion of part model format

1.2 establish a machining coordinate system

enter the Cimatron environment, open the part model, select the NC machining menu, and the system prompts to select a machining coordinate system. If it does not exist, it is necessary to establish a machining coordinate system. Cimatron provides four methods to establish the machining coordinate system, usually using three-point positioning. The establishment of machining coordinate system must be based on the principle of reasonable part clamping method and convenient measurement. Generally, the center point of the upper surface of the part is taken as the origin of the machining coordinate system

1.3 tool setting

in Cimatron, the tool definition is very flexible. If a machining process is selected, the system will automatically judge whether there are qualified tools in the tool library. If there are, the system will use the last used tools by default; If there is no system, the tool definition menu will be automatically displayed, requiring the definition of tool parameters

1.4 work steps

in the process of work steps, it is required to determine which features can be completed in one clamping, arrange the processing sequence and the tools used, and finally determine what processing method to use to complete these work steps respectively. When a machining method is selected, it is necessary to define the machining object, machining range and machining parameters (such as rotating speed, feed rate, cutting amount of each layer, machining allowance, feed mode and safety plane)

after the definition of various parameters in each work step, the software completes the calculation of the tool path, and the machining simulation can be carried out. When the trajectory is not ideal, the parameters can be modified and calculated again. In some cases, good results can also be achieved by directly programming the trajectory

1.5 post processing

after the tool path of all work steps is generated, it is converted to machining G code through a special post-processing program

2 Cimatron high speed machining module analysis and tool walking strategy

the high speed machining center has preview function. When the tool needs to make a sharp turn, the machining center will pre decelerate in advance, and then increase the movement speed after completing the turn. This function of the machine tool is mainly set to avoid excessive inertia impact, resulting in inertia overcut or machine tool spindle damage. When using Cimatron's cam system for NC programming, we should try our best to ensure that the tool path is smooth and stable. In addition, in high-speed machining, the motion speed of the tool is very high, and the tool used is usually very small. Therefore, it is required to maintain a fixed tool load in the machining process to avoid tool overload damaging the machine tool spindle. Cimatron provides a variety of machining methods and tool shifting methods

(a) spiral machining of contour. Spiral machining is to do spiral cutting downward along the closed contour. There is no advance or retreat tool in the middle, and the cutting process is continuous and constant. Right click create-mill-usr from the operation mode management table and click helicprf in the NC folder DLL, defining parameters can generate spiral tool path (Fig. 1)

(b) cycloid contour machining [2]. When selecting profile processing, it is recommended to select trochoid high-speed tool walking in the process parameter interface. The advantage of this method is that it can ensure that the machine tool can remove the blank material with the most challenging process parameters, so as to improve the cutting efficiency of the machine tool. It is suitable for machining narrow grooves and cavities of high hard materials (above HRC50) (as shown in Figure 2)

(c) curved surface cavity machining with unique tool shifting strategy. The process mode selects the curved cavity srfpkt, and an HSM bet will be provided in its process parameter interface Pass on/off switch, when on is selected and rough or rough + finish and parallelcut are selected, three tool shifting strategies of loops inwards/loopsouthwards/golf club will pop up on the interface (as shown in Figure 3); Select spirit cut, and the interface will pop up all corner:round/loop (as shown in Figure 4). This kind of tool path can realize the smooth transition of the edge angle of the tool path and ensure the constant speed feed of the tool in the process of tool moving, so as to effectively slow down the vibration of the machine tool and avoid the occurrence of tool interference

(d) knowledge based contour (wcut) processing. In the process parameter sequence interface of wcut, in the state of rough and rough + finish, select the combined buttons of withstock and min. width to judge the blank quantity and carry out intelligent secondary rough machining

in finish state, select the yes function in HSM between layerconnect yes/no, and NURBS smooth connection is adopted between processing layers (as shown in Figure 5). Its advantage is that the flat area and steep area of the surface to be machined are automatically recognized, so that the finish machining allowance is more uniform and the surface quality is higher

3 programming strategy for high-speed machining of Cimatron cavity mold

in the three-axis NC milling of cavity mold parts, from regular shape blanks to parts processing before finishing, the milling process is generally divided into rough machining, semi finishing machining, finishing machining and root cleaning machining [3]

rough machining can adopt machining methods such as slotting, but contour milling (wcut) has efficient cutting tool walking around and intelligent feed setting, and has a unique interlayer processing function, so it is the most commonly used rough machining (3) fully automatic fixture: from sample size measurement to clamping method

cimatron has the function of knowledge based on blank residue, and can generate tool path according to the condition of blank. Using wcut/rough as the semi finishing process and selecting the withstock option in the machining parameters can completely eliminate the empty tool phenomenon, and the cutting load of the tool is more reasonable and the path is smoother. Srfpkt and wcut/finish are most commonly used in finish machining. For flat surfaces with a slope close to the horizontal, srfpkt process is better for machining along the surface, while for steep surfaces with a slope close to the vertical, wcut/finish process is generally better for machining

4 conclusion

with the continuous popularization of high-speed milling technology, more and more enterprises have begun to apply this technology in production practice. Programming is not only a key work, but also a creative work. Fully excavate and use the high-speed machining programming technology of Cimatron Software, so that mold products can enter the market with high quality, high efficiency, high life, low construction period and low cost, and strive for greater space

References:

[1] Wang Dabin Cimatron three axis milling NC machining details [M] Beijing: Peking University Press, 2003

[2] Sun Quanping Application and research of Cimatron Software [J] Machine manufacturing and automation, 2003 (2): 48 - 50

[3] Zhang Yongjian Research on common strategies and applications of cimatronit cavity mold NC machining [ J ] EDM and die, 2004 (1): 53 - 56 (end)

Copyright © 2011 JIN SHI