2020 – Page 56 – CNC Machining & Turning, Milling, Metal parts

Requirements of CNC parts processing

Part material, single piece production. The parts have been machined to size.

Selected equipment: Machining Center

2、 Preparatory work

Finish related preparation work before machining, including process analysis and process route design, tool and fixture selection, programming, etc.

3、 Operation steps and contents

1. Start the machine and manually return each coordinate axis to the origin of the machine tool

2. Tool preparation

According to the processing requirements, select a Φ 20 end mill, a Φ 5 center drill and a Φ 8 twist drill, and then use the spring chuck shank to clamp the Φ 20 end mill. The tool number is set to T01. Use the chuck handle to clamp the Φ 5 center drill and Φ 8 twist drill, and set the tool number to T02 and T03.

3. Put the toolholder with the tool clamped into the tool magazine manually

1) Enter “T01 M06” to execute

2) Manually install the tool T01 onto the spindle

3) Put T02, T03 and T04 into the tool magazine according to the above steps

4. Clean the worktable, install the fixture and workpiece, clean and install the flat jaw vise on the clean workbench, align and level the vise through the dial indicator, and then install the workpiece on the vise.

5. Tool setting, determine and input workpiece coordinate system parameters

1) Use the edge finder to set the cutter, determine the zero offset value of X and Y direction, and set the zero deviation value of X and Y direction

Input to the workpiece coordinate system g54, the zero bias value of Z direction in g54 is 0;

2) the Z axis setter is placed on the upper surface of the workpiece, and the 1 cutter is installed on the upper surface of the workpiece. The spindle is determined by using the tool to determine the zero value of the workpiece coordinate system Z, and the Z to zero offset value is input into the corresponding length compensation code of the machine tool. The “+” and “-” numbers are determined by G43 and G44 in the program. If the length compensation instruction in the program is G43, then the input “-” Z to zero deviation value to the machine tool. Corresponding length compensation code;

3) In the same procedure, input the zero offset value of No.2 and No.3 tools into the corresponding length compensation code of the machine tool.

6. Input processing program

The processing program generated by computer is transferred to the memory of CNC system through data line.

7. Debug processing program

The method of moving the workpiece coordinate system along + Z direction, that is, tool lifting operation, is adopted for debugging.

1) Debug the main program and check whether the 3 tools complete the tool change action according to the process design;

2) Debug three subroutines corresponding to the three tools to check whether the tool action and machining path are correct.

8. Automatic processing

After confirming that the program is correct, restore the Z value of the workpiece coordinate system to the original value, set the fast moving rate switch and cutting feed rate switch to low gear, press the NC start key to run the program and start machining. Pay attention to observe the tool path and the remaining moving distance during machining.

9. Take down the workpiece, carry out the inspection, select the vernier caliper for size detection, and conduct quality analysis after detection.

10. Cleaning the processing site

11. Shut down

Development trend of CNC parts processing

The product quality of CNC parts products, whose products improve the product quality of users, can get customers. For the improvement of processing technology, all walks of life have not stopped. Taking the hard oxidation industry as an example, the early products are all using electroplating oxidation because of its low cost and easy control, which has been recognized by the market. However, with the development of surface treatment technology, this product has been developed In order to seize the market, the product manufacturers use aluminum shell, which makes the material feel better and more beautiful, and can be made into high-quality parts. In the surface treatment method, the advanced hard oxidation treatment is used. The surface has texture and good aesthetics. The important thing is that the hard oxidation strengthens the surface quality of the product, increases the corrosion resistance, and makes the product quality more stable and service life Long life, has been recognized by the market.

In today’s manufacturing industry, there are many products customers need to carry out hard oxidation surface treatment when designing. How to ensure the quality of hard oxidation products in batch production. If the surface treatment of CNC precision parts does not reach the required oxidation thickness, it will not meet the customer’s order requirements. Therefore, it is necessary for the hard oxidation factory to have sufficient technical equipment and experienced technicians, so that the customer products can have higher added value and the whole industry can be developed.

CNC parts processing is an important part of the manufacturing industry. Many machinery and parts with ≡ technology need CNC parts with high precision and hardness. In the processing and production, the surface treatment effect of parts will directly affect the quality of products. Therefore, enterprises should attach great importance to the selection of hard oxidation processing plants.

Process analysis

The NC machining process of the parts to be processed involves a wide range of issues. In this paper, combined with the possibility and convenience of programming, some main contents to be analyzed and reviewed are proposed.

1. Dimension marking should conform to the characteristics of NC machining

In NC programming, all the sizes and positions of points, lines and surfaces are based on the programming origin. Therefore, the coordinate size is directly given on the part drawing, or the dimension is quoted with the same datum as far as possible.

2. The conditions of geometric elements should be complete and accurate

In the process of programming, the programmer must fully master the geometric parameters of the part contour and the relationship between the geometric elements. Because it is necessary to define all geometric elements of the part contour in automatic programming, and to calculate the coordinates of each node in manual programming, no matter which point is unclear or uncertain, programming cannot be carried out. However, due to the part designer’s carelessness or neglect in the design process, the parameters are often incomplete or unclear, such as whether the arc and the straight line, the arc and the arc are tangent or intersecting or separated. Therefore, in the review and analysis of drawings, we must be careful, and timely contact the designer if problems are found.

3. The positioning datum is reliable

In NC machining, the working procedure is often concentrated, so it is very important to locate with the same datum. Therefore, it is often necessary to set some auxiliary datum or add some process boss on the blank.

4. Uniform geometry type or size

The shape and inner cavity of the parts are of uniform geometry type or size, which can reduce the number of tool change, and may also apply control program or special program to shorten the program length. The shape of the parts should be symmetrical as far as possible, so that it is convenient to use the mirror processing function of CNC machine tool to program, so as to save programming time.

How to set the reference point and coordinate of NC lathe in NC machining?

You can see if your bed reference point parameters are set correctly.

Generally, CNC cutting system automatically processes the parts to be processed according to the pre programmed processing program (commonly used drawing software aotocad). According to the instruction code and program format specified by the NC cutting system, a machining program sheet is compiled for the machining process route, process parameters, tool movement path, displacement, cutting parameters (spindle rotation, feed rate, back feed, etc.) and auxiliary functions (tool change, spindle forward rotation, reverse rotation, cutting fluid on and off, etc.), and then record the contents of this program list in the NC cutting system Control medium (such as perforated paper tape, magnetic tape, magnetic disk, magnetic bubble memory), and then input into the numerical control device of the numerical control machine tool, so as to direct the machine tool to process parts.

The whole process from analysis of part drawing to making control medium is called NC programming. The difference between CNC cutting equipment and ordinary hand and semi-automatic cutting equipment in processing parts is that CNC cutting equipment automatically processes parts according to the program, while ordinary hand and semi-automatic cutting equipment needs to be operated by people. We can achieve the purpose of processing different parts as long as we change the program that controls the action of the machine tool. Therefore, CNC cutting equipment is particularly suitable for processing small batch and complex shape parts with high precision requirements!

Because the CNC cutting equipment must process parts according to the program, the programmer will input the program into the CNC system to direct the work of the machine tool. The program input is through the control medium. In this way, the NC system is used to control and complete the processing of parts. The drawing staff can modify the graphics in time, and the accuracy of the parts is greatly improved compared with that of the semi-automatic cutting equipment!

What are the contents of process analysis of part drawing in NC machining?

In the process of NC process analysis, first of all, the process analysis of the part drawing should be carried out to analyze whether the structural process of each part of the part conforms to the characteristics of NC machining

1. The dimension marking of part drawing should conform to the convenience of programming

In the NC machining drawing, it is better to use the same datum to quote the dimension or give the coordinate size directly. This marking method is not only convenient for programming, but also convenient for coordinating the setting and calculation of design datum, process datum, testing datum and programming zero point.

2. The geometric element conditions of the contour structure of parts should be sufficient

In programming, all geometric elements that constitute the contour of the part should be defined. When analyzing the part drawing, it is necessary to analyze whether the conditions of various geometric elements are sufficient. If not, it is impossible to program or model the parts to be processed.

3. Can machining accuracy and dimensional tolerance required by parts be guaranteed

Although the machining accuracy of CNC machine tools is very high, for some special cases, such as the processing of thin-walled parts, due to the poor rigidity of thin-walled parts, the cutting force generated during machining and the elastic yielding of thin-walled parts are easy to produce vibration of the cutting surface, which makes the dimensional tolerance of thin-walled thickness difficult to guarantee, and its surface roughness also increases When its thickness is less than 3 mm, we should pay attention to this problem in technology.

4. Are the geometric types and dimensions of the internal and external contour of the part unified

In NC programming, if the geometric types of the inner contour and outer contour of the part are the same or similar, consider whether it can be programmed in the same program to reduce the tool specification and tool change times as far as possible, so as to reduce the auxiliary time and improve the machining efficiency. It should be noted that the diameter of the tool is often limited by the radius r of the inner contour arc.

5. Can larger diameter tools be used in the process structure design of parts

Using larger diameter milling cutter to process can reduce the number of tool passes and improve the tool rigid system. Not only the machining efficiency is improved, but also the processing quality of the surface and bottom surface of the workpiece is also improved.

6. The fillet radius of the groove bottom or the fillet radius r at the intersection of the base plate and the edge plate should not be too large

Because the large diameter of the cutter contacting with the milling plane D = d-2r, where D is the diameter of the milling cutter. When D is constant, the larger the fillet radius R (as shown in Fig. (1), the worse the ability of milling cutter end edge to mill plane, the lower the efficiency and the worse the manufacturability.. When R reaches a certain degree, it must be processed with ball end milling cutter, which should be avoided. When D is larger and R is smaller, the area of milling surface is larger, the ability of machining plane is stronger, and the milling technology is better. Sometimes, when the bottom surface area of milling is large and the bottom arc R is also large, two milling cutters with different R can be used to cut twice.

7. Principle of ensuring the unification of standards

If the parts are re installed on the other side after milling one side, due to the non-uniform datum, it is often difficult to connect the cutter due to the re installation of the parts, and the contour position and size on the positive and negative sides are not coordinated after machining. Therefore, it is necessary to make full use of the appropriate hole of the part itself or the reference edge of the part contour or specially set the process hole (such as adding process boss on the blank or setting the reference hole on the allowance to be removed in the subsequent process) as the positioning reference, so as to ensure the accuracy of the relative position after two clamping processes.

8. Consider the deformation of parts

When the parts are deformed in the process of NC milling, not only the machining quality of the parts is affected, but also the phenomenon of skipping cutter sometimes occurs. At this time, we should consider the milling process, separate the rough and finish machining as far as possible, or use the symmetrical method to remove the allowance. Of course, heat treatment can also be used to solve the problem.

Analysis of automobile parts processing flow

1、 Drawing design, drawing is the initial part of a part, is designed according to the requirements of customers, so that customers can trust you more.

2、 Material selection, when we are processing, we will select the material suitable for it for processing, so what material is suitable for it? In fact, the material can be said to be the core product of the whole part, so it must be carefully selected.

3、 Programming, CNC lathe is a new type of equipment that can realize automatic production. At present, this equipment can realize full-automatic production and save a lot of unnecessary expenses. It can be said that it is a pure cost-saving mechanical equipment.

4、 No matter what parts are processed, the steps must be carried out according to the conventional process. It is not allowed to change the processing steps at will. Any mistakes in this step will affect the bending of the whole part.

Parts processing

The above processes can be said to be the process of NC machining of automobile parts, which must be carried out according to the overall process. Therefore, the process is the core of parts processing and the capital that can be expanded infinitely in the industry.

报错笔记

Summary of automobile parts processing technology

A car is composed of many parts, each part plays a different role, and it needs to be processed through different processing technology, and then it can be installed on the car for use. What are the processing technologies of automobile parts?

1、 Forging of automobile parts

Forging is widely used in automobile manufacturing. Forging methods are divided into free forging and model forging. Free forging is a method of forming metal blank on anvil under impact or pressure. The blank of automobile gear and shaft is processed by free forging.

2、 Casting processing of automobile parts

Casting is a production method in which molten metal is poured into the mold cavity and cooled and solidified to obtain products. In the process of automobile parts processing and manufacturing, there are many parts made of cast iron, which account for about 10% of the whole vehicle weight, such as air cylinder block, transmission box, steering gear housing, rear axle housing, brake drum, various supports, etc.

Sand mold is usually used to make iron castings. The raw material of sand mold is mainly sand, mixed with binder and water. The sand mold material must have a certain adhesive strength, so that it can be molded into the required shape and can resist the erosion of hot metal without collapse. In order to form a cavity in the sand mold in accordance with the shape of the casting, it is necessary to make a model of wood, called wood mold. The volume of hot molten iron will be reduced after cooling. Therefore, the size of wood mold should be increased according to the shrinkage rate based on the original size of the casting, and the surface to be machined should be thickened accordingly.

3、 Welding processing of automobile parts

Welding is a processing method that two pieces of metal are locally heated or simultaneously heated and pressurized. We often see workers holding a mask in one hand and welding tongs and welding rods connected with wires in the other hand. The welding method is called manual arc welding, which uses the high temperature generated by arc discharge to melt the welding rod and weldment and make them join.

Manual arc welding is not widely used in automobile manufacturing. Spot welding is widely used in automobile body manufacturing. Spot welding is suitable for welding thin steel plates. During operation, two electrodes apply pressure to two steel plates to make them stick and merge. At the same time, the bonding point (circle with a diameter of 5-6 μ m) is heated and melted by electric current, so as to firmly join. When two body parts are welded, a point is welded at the edge every 50-100 ° to form a discontinuous multi-point connection. It usually takes thousands of solder joints to weld the whole car body. The strength requirement of solder joint is very high, each solder joint can bear 5kn tensile force, even tear the steel plate, but the solder joint can not be separated.

4、 Cold stamping of automobile parts

Cold stamping or sheet metal stamping is a processing method to make the sheet metal be cut off or formed under pressure in the die. Daily necessities, such as aluminum pot, lunch box and washbasin, are made by cold stamping. For example, to make a lunch box, the first step is to cut out a rectangular blank with four rounded corners (referred to as “blanking” in the industry), and then the blank is pressed into the female die with a punch to form (referred to as “drawing” in the industry). In the drawing process, the flat sheet metal becomes a box shape, and its four sides are vertically bent upward, and the materials at the four corners accumulate and wrinkles can be seen.

5、 Automobile parts cutting

Automobile parts cutting is a kind of machining method which uses cutting tool to cut the metal blank layer by layer, so that the workpiece can get the required shape, size and surface roughness. Metal cutting includes fitter and mechanical machining. Fitter is a kind of machining method that workers use manual tools to cut. It is flexible and convenient to operate, and it is widely used in assembly and repair. Mechanical processing is completed by means of machine tools, including turning, planing, milling, drilling and grinding.

6、 Heat treatment of automobile parts

Heat treatment is a method to change the structure of solid steel by reheating, holding or cooling, so as to meet the use requirements or process requirements of parts. Different microstructure changes can be produced by heating temperature, holding time and cooling rate. The hardness of the steel parts can be improved by immersing the heated steel parts in water for rapid cooling.

Matters needing attention in CNC machining of aluminum alloy

With the advent of the industrial 2.0 era, China’s manufacturing industry is generally growing, and the requirements for the processing and manufacturing industry are higher. Taking the aluminum parts processing and manufacturing industry as an example, the CNC machining accuracy of aluminum alloy is more stringent. However, this is also the trend of the times. It is obvious that aluminum parts are widely used in high-precision instruments. The following Ju Sheng Yuan hardware products small for everyone to chat about the aluminum alloy CNC processing need to pay attention to.

1. The speed of white steel knife should not be too fast.

2. When the workpiece is too high, please thicken it with a knife of different grade length.

3. After roughening with a rough knife, remove the excess with the knife, and grind the knife after ensuring the excess.

4. The plane is processed with flat bottom edge instead of ball edge to reduce processing time.

5. The four corners of the calibration plane must be flat.

6. The inclination is an integer, which is processed with an inclined cutter, such as tube position.

7. Before each work, want to clear the remaining amount of the previous work after processing, to avoid empty tool and redundant processing.

8. Try to take a simple path. For example, shape, trenching, avoiding single side, lapping, etc.

9. When taking wcut, if you can go to finish, please don’t take rough.

10. In the case of shape light knife, the light should be coarsened first and then exposed. When the workpiece is too high, it should be illuminated first and then.

11. The tolerance should be set reasonably to balance the machining accuracy and computer calculation time. The tolerance is set to 1 / 5 of the remaining value when it is turned on, and 0.01 for a light knife.

12. Add more projects to reduce the time of empty knife. Think more and reduce the chances of mistakes. Increase the auxiliary surface of the auxiliary line slightly to improve the processing condition.

The above is jushengyuan hardware products Xiaobian summed up aluminum alloy CNC processing precautions, I believe that CNC processing enthusiasts will operate CNC processing process will encounter. If you encounter any problems in CNC processing of aluminum alloy, please leave a message below.

CNC machining principle and advantages of aluminum alloy

CNC machining of aluminum alloy, also known as computer gong processing or CNC machine tool processing, mainly aluminum parts, aluminum shell and other aspects of processing. In recent years, due to the high-precision processing of aluminum alloy and aluminum alloy, the high-precision processing technology of aluminum alloy and aluminum alloy has been greatly improved.

1、 CNC machining principle of aluminum alloy:

The CNC machining principle of aluminum alloy is to install digital program flow command to control the bearing automatic start stop, change direction and speed change of CNC machine tool. The NC blade can be selected, and the cutting amount and walking track can be changed according to the NC blade to complete all kinds of auxiliary actions needed in the life-long machining.

2、 Advantages of CNC machining of aluminum alloy:

① CNC machining of aluminum alloy can reduce the total number of tooling in large quantities, and produce complex parts and components, only need to change the process flow.

② CNC machining of aluminum alloy is relatively stable, which will not cause deviation in manual processing, resulting in different aluminum alloy and even defective products.

③ CNC machining of aluminum alloy can produce complex aluminum parts, and even can produce processing parts. It can also produce a variety of varieties, high production efficiency, save labor costs, and realize multiple and large-scale production at the same time.

The above is the principle and advantages of aluminum alloy CNC processing, is jushengyuan hardware products small series, accumulated several years of aluminum alloy CNC processing experience. For aluminum alloy CNC processing and do not understand, can come to consult, there will be unexpected harvest.

Characteristics of CNC machining process for aluminum alloy

The requirement of CNC machining technology for aluminum alloy is that the control system can use control code or other symbol instruction rules to process the program logically, decode the program by computer, and then make the machine move and process parts. After cutting tools, the blank is processed into semi-finished parts, etc. Numerical control cutting is not only a reasonable processing method, but also a common process of aluminum alloy precision machining. Vertical milling cutter, spiral interpolation and contour cutting interpolation with multi-directional cutting function are selected, and a small number of holes are processed with fewer cutters.

CNC machining of aluminum alloy

Ball end milling cutter with spiral interpolation method can be used for continuous processing of conical hole; ball end milling cutter and spiral interpolation bit can be used for boring and chamfering; vertical milling cutter with equal height cutting interpolation can be used for semi precision machining and precision parts processing; end milling cutter with spiral interpolation method for thread processing can process various threaded holes. Assuming that high precision holes of any size are machined by high efficiency aluminum alloy precision parts, the interpolation functions of East and West can be used. Especially when high-speed milling is selected, the load of each tool is relatively light. Therefore, with the same coating cemented carbide end milling cutter, all kinds of processed materials can be processed with high speed and high precision.

Milling cutter

In the CNC machining process of aluminum alloy shell, it is necessary to master the processing skills of processing technology paint. Select a reasonable cutting amount, and select the cutting speed according to the needs of processing materials, hardness, cutting conditions, material types, cutting depth, etc.

These conditions are necessary to reduce machine wear. In general, when using rough turning, it is better to select high-strength cutting tools to better meet the requirements of rough turning. The reasonable selection of fixture parts should fully meet the needs of the machine, so as to reduce unnecessary positioning error, so as to select special fixture to accommodate the items. Acknowledge a reasonable process. Shorten the machining stroke as far as possible and reduce the wear of the machine.

CNC machining shell of aluminum alloy

Peach and plum do not say, their groin. In the actual processing and production process, these advanced CNC machining experience greatly improves the CNC machining and quality of aluminum alloy shell.