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How to improve the efficiency of CNC machining

(1) The size and structure of all kinds of parts are very different, and the universality of machine tools and other process equipment is not high.

(2) Many companies are usually faced with the production task of multi variety, small batch and short production cycle, so the process system is required to have a higher response speed.

(3) The structure of product parts is complex and the processing is difficult.

(4) Thin wall, easy to produce processing deformation. There are a lot of thin-walled and deep cavity structures, which are typical weak rigid structures.

(5) It is difficult to select cutting tools and cutting parameters. Because the development of tool industry can’t catch up with the development and application of new materials, and lack of the support of machining database.

So how to improve the efficiency of CNC machining? Generally speaking, the methods to improve the machining efficiency of CNC machine tools are as follows:

1、 Change the understanding of numerical control technology.

Numerical control technology is a comprehensive technology, in addition to the numerical control machine tool, there must be corresponding supporting technology and personnel support, especially in the numerical control processing process, people play a decisive role, the technical ability of management personnel, engineering and technical personnel, engineering maintenance personnel and operators will affect the production efficiency of numerical control machine tool.

2、 Develop effective tool management measures.

For example, the tool is pre adjusted to reduce the installation and adjustment time of the tool on the machine tool, and the tool is managed through the management system to reduce the errors caused by manual management.

3、 Fixture management.

Because the selection of fixture is directly related to the installation time and measurement time of workpiece, the management of fixture should be realized.

Computer gong processing workpiece collision number

After the workpiece is placed on the pad iron, it is necessary to pull the table for the workpiece datum according to the drawing requirements. For the workpiece that has been ground on six sides, it is necessary to check whether its verticality is qualified.

The nut must be tightened after the work-piece is pulled to prevent the work-piece from shifting during the processing due to the loose clamping; pull the work-piece again to ensure that the error does not exceed the tolerance after the clamping.

Number of workpieces touched

For the clamped workpiece, the contact head can be used to set the processing reference zero position. The contact head can be used in photoelectric type and mechanical type. There are two kinds of methods: middle collision number and unilateral collision number

Photoelectric static, mechanical speed 450 ~ 600rpm. Manually move the x-axis of the worktable according to the collision number to make the collision number head touch one side of the workpiece. When the collision number head just touches the workpiece and the red light is on, set the relative coordinate value of this point to zero. Then manually move the x-axis of the worktable to make the collision number head touch the other side of the workpiece. When the collision number head just touches the workpiece, record the relative coordinate at this time.

According to the relative value minus the diameter of the collision head (i.e. the length of the workpiece), check whether the length of the workpiece meets the requirements of the drawing.

Computer gong processing tool setting point

When the machining accuracy is not high, some surfaces on the workpiece or fixture can be directly used as the tool face; when the machining accuracy is high, the tool setting point should be selected on the design basis or process basis of the part as far as possible, for example, for the part with hole positioning, it is more appropriate to take the axis of the hole as the tool setting point. The tool setting point must have a certain coordinate relationship with the positioning datum of the workpiece. In this way, the relationship between the machine tool coordinate system and the workpiece coordinate system can be determined. The selection of tool setting point should be convenient for coordinate value calculation and tool setting. During tool setting, the tool setting point should coincide with the tool position. The so-called cutter site refers to the intersection of the tool axis and the bottom surface of the tool for the flat end end milling cutter; for ball end milling cutter, it refers to the ball center of the ball head part; for turning tool, it refers to the tool tip; for the drill bit, it refers to the drill point; for the linear electrode cutting machine, it refers to the focus of the axis of the wire electrode and the part surface.

Stress and warpage analysis based on two-sided flow technique

According to the analysis results of gate solidification effect and packing pressure and temperature distribution, the stress and warpage analysis module calculates the stress changes with time in the wall thickness and plane direction of the product, and the shrinkage of the product along the wall thickness direction at the time of demoulding. Based on the double-sided flow technique, a special double-layer shell element is used to predict the warpage of the product at the time of demoulding.

Troubleshooting of CNC machining center

The spindle is the power auxiliary device of CNC machining center. The spindle drives the workpiece to rotate to process the workpiece of the rotating body. Spindle is an important guarantee for high-speed and high-precision machining of CNC machining center, so the maintenance methods and skills of spindle fault are the basic knowledge that operators and maintenance personnel of CNC machining center must master. In the operation of CNC machining center, the spindle will inevitably have some faults. What is the specific reason?

Different types of CNC machining centers adopt different types of spindles. According to the different transmission systems, the spindle system can be divided into the main transmission spindle with variable speed gear, the main transmission spindle with belt transmission, the dual motor drive spindle and the motor spindle integrated spindle. No matter what type of spindle application, the common faults in use are as follows:

Overload.

Fault causes: excessive cutting amount, frequent forward and reverse rotation, spindle motor fault, spindle drive device fault.

The spindle does not rotate

Fault causes: spindle drive failure, CNC device can not output speed signal, spindle motor failure, spindle drive failure, drive belt fracture.

The spindle speed deviates from the command value

Fault causes: motor overload, CNC system output spindle speed command output problem, speed measuring device failure or speed feedback signal disconnection.

The standard of CNC programming program

It takes 1-2 months to be very familiar with. The automatic programming software is a bit complicated and needs to be learned. But it is not difficult for CAD.

In practice, one is:

Readable, well organized, and understood by everyone in the operator.
The program instructions should be as few as possible for the purpose of simple, practical and reliable. From the point of view of programming, I think that the instruction G00 G01 and other auxiliary instructions are convenient for programming.
Easy to adjust. Parts machining accuracy need to be fine tuned is the best without changing the plan. Tool wear, for example, adjustment, just change the tool offset table length, radius.
Easy to operate. Programming will be based on the characteristics of machine operation, conducive to observation, inspection, measurement, safety, and so on. The same parts, for example, the same processing content, in the vertical machining center and horizontal machining center processing, are certainly not the same.

In machining, the simplest method is the best. As long as there is practical experience of the peer, will certainly agree with this sentence!

Skillfully operate CNC machine tools

This requires 1 – 2 years of research, operation delicate feeling, beginners, especially college students, know how to do, can not listen. Learn in this process: operation mode of installation system, clamp, datum alignment, knife, setting zero point offset, setting tool radius, length compensation, compensation, handling of tool and loading and unloading, grinding tools, measurement, skilled use of vernier caliper, micrometer, dial indicator, dial indicator, rod diameter indicator, etc.

CNC machining process of complex parts

It is difficult to guarantee the size of the curve groove at the lower end of the front side of the part, and the two 90 ° notches are not closed, so it is necessary to close the auxiliary line before programming.

There are two ellipses in different directions on the inner contour edge of the back, inner and outer hexagonal petals composed of arcs in the center, and two arc curve islands at the top and bottom. These elements need to be rounded in processing, so it is more convenient to choose a reasonable shape.

Analysis of parts processing technology

Using CAXA to manufacture engineering parts, there is no need to draw a complete part for reprocessing. Firstly, the downtime is long and the processing time is wasted. Secondly, when selecting local processing, the elements between parts will interfere, which is not convenient to draw the program track.

The software supports rough and finish machining only by drawing the contour line of the part when machining the plane contour elements. Surface machining can be programmed by solid or surface. In order to realize local machining, curved surface must be used, and some finishing commands can only be selected by curved surface.

The rough machining command can not only realize rough machining, but also be used as finish machining command.

The finishing command can use the track translation to form multiple levels and connect the tracks into a whole rough machining command; the rough machining command can change a layer of processing track into a finishing command by setting the layer height.

The plane contour elements of CAXA Manufacturing engineer can use the plane area rough machining and contour finish machining to complete the rough and finish machining of parts, and can also use the contour finish machining to do the rough machining. Surface roughing can use contour roughing, parameter line finishing and three-dimensional offset surface finishing commands for roughing and finishing.

Due to the high dimensional accuracy in the drawing, it is decided to adopt rough machining, semi finishing and finishing to achieve dimensional accuracy. Semi finishing and finishing adopt the same cutting tools and cutting parameters, which can correct various geometric errors of the cutting tools and elastic deformation of the parts. It is easy to ensure the size, and finish machining is also required for the important bottom surface.

The part is processed by FANUC CNC machining center, all tool paths are generated according to FANUC post format, and transmitted by CAXA’s own communication function according to FANUC settings, and large surface programs are processed online; the later processing programming ends with tool path.

Methods of improving CNC machining