肯堂 – Page 9 – CNC Machining & Turning, Milling, Metal parts

CNC computer gong processing mechanical structure

1、 Analysis from the angle of numerical control

The CNC milling center requires a general speed for the CNC system, and the spindle speed is about 0 ~ 8000rpm
The engraving and milling machine requires a high-speed numerical control system, and the spindle speed is about 3000 ~ 30000 rpm
High speed cutting machine tools require high-speed CNC system and excellent servo motor characteristics. The spindle speed is about 1500 ~ 30000 rpm

2、 Analysis on programming software

In terms of software, standard CAD / CAM software such as MasterCAM Cimatron PE UG can be used in CNC milling centers, high-speed cutting machines and engraving and milling machines. Milling machine usually thinks Cimatron tool path is better. The new software fully studies the uniformity of cutting amount at every moment of the tool, especially the speed and smoothness of the moment when the tool enters and leaves the work, as well as the following error at the inflection point, which makes the results and design graphics more close to each other. In the CAD part, the intuitive three-dimensional solid modeling, such as SolidWorks, has been widely used And then transfer it to CAM software for processing through Igs.

But don’t worry, the development speed of CAD / CAM is much faster than that of CNC machine tools.

Because of the particularity of its cutting tool, engraving process has quite small angle control, so type3 is better.

3、 – requirements for automatic tool change and automatic tool setting of tool magazine

Machining center is a decent term, machining center is to complete a variety of processes in the automatic state of numerical control equipment, mainly for some fixed mass production operations, if we process a box with many holes and teeth, and have to do almost every day, what good way to improve efficiency, do not use the tool library, and will not cause artificial tool change error, there is only one way Automatic tool setting system, one tool is installed upward, one button, automatic tool setting, direct processing, the error is within 0.001 ~ 0.0003 μ m, compared with the automatic time change, the efficiency is not a bit slow. If it is a machining center without automatic tool setting device, the efficiency of the latter is much higher than that of the former. Note that the price of the best brand of automatic tool setting instrument, such as MARPOSS, is only about 10000 yuan, and it is unlikely to be damaged. In this way, if we fully consider the utilization value of capital, we must not use machining center equipment. In addition, there are many problems in the tool magazine of domestic manufacturers.

The processing method of CNC machine tool

There are two main forms of NC lathe processing in production and processing,

They are solid heat treatment and melt heat treatment. There is a certain difference between the two ways to make precision hardware processing parts. What’s more, they use different steel to make different workpieces. CNC lathe is composed of bed, headstock, turret feed system, cooling and lubrication system and CNC system. Different from the ordinary lathe, the feed system of CNC lathe is qualitatively different from that of ordinary lathe,

It does not have the traditional tool box, slide box and change gear frame, but directly uses servo motor or stepper motor to drive slide and tool through ball screw to realize feed movement. The NC system consists of NC unit, input and output module and operation panel. (1) Solid solution strengthening: because the solute atoms enter into the gap or node of the solvent lattice, the lattice will be distorted and the hardness and strength of the solid solution will increase. This phenomenon is called solid solution strengthening. 2. Compound: a new crystal solid structure with metallic properties is formed by the combination of alloy components.

Mechanical mixture: an alloy consisting of two crystal structures. Although it has two kinds of crystals, it is a component with independent mechanical properties.

Ferrite: interstitial solid solution of carbon in a-Fe (body centered cubic iron).
Austenite: interstitial solid solution of carbon in g-fe.
Cementite: stable compound (Fe3C) formed by carbon and iron.
Pearlite: a mechanical mixture of ferrite and cementite (F + Fe3C contains 0.8% carbon)
Ledeburite: a mechanical mixture of cementite and austenite (containing 4.3% carbon) Metal heat treatment is one of the important processes in mechanical manufacturing. Compared with other processes, heat treatment generally does not change the shape and overall chemical composition of the workpiece, but endows or improves the performance of the workpiece by changing the microstructure inside the workpiece or the chemical composition on the surface of the workpiece.

How to add four and five axes to CNC computer gongs

CNC computer gong is a typical set of high-tech machining equipment, its development represents the level of a country’s manufacturing industry, has been highly valued at home and abroad.

Compared with general CNC machine tools, CNC computer gong has the following outstanding features:

All CNC computer gongs are equipped with protective doors. When processing, closing the protective doors can effectively prevent personal injury accidents.
The CNC computer gong generally has multiple feed axes (more than three axes) and even multiple spindles, and the number of linkage axes is also very large, such as three-axis linkage, five axis linkage, seven axis linkage and so on. Therefore, it can actively complete the processing of multiple planes and multiple viewpoints, and finish the high-precision processing of messy parts. The CNC computer gong can finish milling, boring, drilling, expanding, reaming, tapping and other processing with high concentration.
The CNC computer gong is equipped with a tool magazine and an active tool changing device,

Before machining, the required tools are loaded into the tool magazine, and the tools can be replaced actively through program control during machining.

The use of multiple worktables, worktable active exchange CNC computer gong processing, if with active exchange worktable, can end a worktable in the processing together, another worktable finish workpiece clamping, and then greatly shorten the auxiliary time, improve the processing power.
CNC computer gongs can be used for turning and grinding. For example, the circular worktable can drive the workpiece to rotate at high speed, and the cutting tool can only do the main motion without feeding. This makes CNC computer gongs have a wider processing scale
CNC computer gongs with high initiative, high precision and high power have high spindle speed, feed speed and rapid positioning accuracy. Through reasonable selection of cutting parameters, they can fully show the cutting performance of cutting tools and reduce cutting time. All kinds of auxiliary actions are fast and active, which reduces auxiliary action time and downtime. Therefore, CNC computer gongs are very popular The production power is very high.
High investment due to the high degree of intelligence, disordered structure and powerful function of CNC computer gong, the one-time investment and maintenance cost of CNC computer gong is much higher than that of ordinary machine tools.
In the appropriate conditions, the ability to perform the best benefits, that is, in the process of using the performance of the advantages of CNC machine tools, ability to fully reflect the benefits, which is very important for the rational use of CNC computer gongs.

Function introduction of engraving and milling machine

In terms of appearance and volume:

The volume of machining center is the largest, the volume of large 1690 machine is 4m * 3M, and that of small 850 machine is 2.5m * 2.5m; carving and milling machine is the second, and that of large 750 machine is 2.2m * 2m; carving machine is the smallest.

In terms of mechanical structure:

Machining centers generally use cantilever type, carving and milling machines and carving machines generally use gantry type structure, gantry type is divided into pillar type and fixed beam type, at present, carving and milling machines are mostly fixed beam type.

In terms of index data:

Spindle maximum speed (R / min): 8000 machining center; carving and milling machine is the most common 240000, high-speed machine is the lowest 30000; engraving machine is generally the same as carving and milling machine, engraving machine for high gloss processing can reach 80000, but it is not ordinary motorized spindle, but air floating spindle.

Spindle power: machining center is the largest, from thousands of watts to tens of kilowatts; carving and milling machine is the second, generally within ten kilowatts; carving machine is the smallest.

Cutting capacity: machining center is the largest, especially suitable for heavy cutting, roughing; carving and milling machine is the second, suitable for finishing; carving machine is the smallest. Engraving and milling machine

Speed: because the engraving and milling machine and engraving machine are relatively light, their moving speed and feed speed are faster than the machining center, especially the high-speed machine equipped with linear motor, the maximum moving speed can reach 120m / min

Accuracy: the accuracy of the three is almost the same.

From the processing dimension: the area of the worktable can better reflect this. The smallest worktable area (unit mm, the same below) of domestic machining center (computer gong) is 830 * 500 (850 machines); the largest worktable area of engraving and milling machine is 700 * 620 (750 machines), and the smallest is 450 * 450 (400 machines); engraving machine generally does not exceed 450 * 450, the common is 45 * 270 (250 machines).

In terms of application objects: machining center is used to complete the processing equipment of large amount of milling work pieces, large molds and materials with relatively high hardness, which is also suitable for roughening of ordinary molds; engraving and milling machine is used to complete the finishing of small amount of milling work pieces and small molds, which is suitable for copper and graphite processing; low-end engraving machine is inclined to wood, two-color board, acrylic board and other materials with low hardness Plate processing, high-end suitable for wafer, metal shell polishing.

It is generally believed that machining centers and engraving and milling machines can be used for both products and molds, while engraving machines can only be used for products.

Tool setting point and tool changing point of computer gong

When programming large-scale computer gongs, we should first consider the selection of tool point position,

The tool setting point is the starting point of tool movement relative to the workpiece in NC machining. Since the program is also executed from this point, the tool setting point is also called the program starting point or tool starting 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 choice of tool setting point for computer gong processing 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 tool position refers to the intersection of the tool axis and the tool bottom surface for flat end milling cutter; the ball end milling cutter refers to the ball center of the ball head part; the turning tool refers to the tool tip; the drill bit refers to the drill tip; the processing for the wire electrode cutting machine tool refers to the focus of the wire electrode axis and the part surface.

Stress and warpage analysis based on two-sided flow technique

According to the solidification effect of gate and the analysis results of 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 technology, a special double shell element is used to predict the warpage of the product at the time of demoulding.

Function introduction of engraving and milling machine

In terms of appearance and volume:

The volume of machining center is the largest, the volume of large 1690 machine is 4m * 3M, and that of small 850 machine is 2.5m * 2.5m; carving and milling machine is the second, and that of large 750 machine is 2.2m * 2m; carving machine is the smallest.

In terms of mechanical structure:

Machining centers generally use cantilever type, carving and milling machines and carving machines generally use gantry type structure, gantry type is divided into pillar type and fixed beam type, at present, carving and milling machines are mostly fixed beam type.

In terms of index data:

Spindle maximum speed (R / min): 8000 machining center; carving and milling machine is the most common 240000, high-speed machine is the lowest 30000; engraving machine is generally the same as carving and milling machine, engraving machine for high gloss processing can reach 80000, but it is not ordinary motorized spindle, but air floating spindle.

Spindle power: machining center is the largest, from thousands of watts to tens of kilowatts; carving and milling machine is the second, generally within ten kilowatts; carving machine is the smallest.

Cutting capacity: machining center is the largest, especially suitable for heavy cutting, roughing; carving and milling machine is the second, suitable for finishing; carving machine is the smallest. Engraving and milling machine

Speed: because the engraving and milling machine and engraving machine are relatively light, their moving speed and feed speed are faster than the machining center, especially the high-speed machine equipped with linear motor, the maximum moving speed can reach 120m / min

Accuracy: the accuracy of the three is almost the same.

From the processing dimension: the area of the worktable can better reflect this. The smallest worktable area (unit mm, the same below) of domestic machining center (computer gong) is 830 * 500 (850 machines); the largest worktable area of engraving and milling machine is 700 * 620 (750 machines), and the smallest is 450 * 450 (400 machines); engraving machine generally does not exceed 450 * 450, the common is 45 * 270 (250 machines).

In terms of application objects: machining center is used to complete the processing equipment of large amount of milling work pieces, large molds and materials with relatively high hardness, which is also suitable for roughening of ordinary molds; engraving and milling machine is used to complete the finishing of small amount of milling work pieces and small molds, which is suitable for copper and graphite processing; low-end engraving machine is inclined to wood, two-color board, acrylic board and other materials with low hardness Plate processing, high-end suitable for wafer, metal shell polishing.

It is generally believed that machining centers and engraving and milling machines can be used for both products and molds, while engraving machines can only be used for products.

CNC computer gong processing advantages

Computer gong is a kind of artificial intelligence, which is controlled by computer to complete complex processing.

Computer gong processing is also called CNC milling machine processing, CNC milling machine is developed on the basis of general milling machine, the two processing technology is basically the same, the structure is also somewhat similar, CNC milling machine is in the general milling machine integrated digital control system, can be under the control of the program code more accurate milling machine.

1、 Testing standard of computer gong before processing

Divide the center and copy the number. After each division, first copy the work coordinate number, and then recheck whether the distance from the center to both sides is consistent after clearing, so as to ensure that the division and copy are correct.
Tool selection, tool loading, tool setting and z-axis coordinate counting. Select the right tool according to the programming list, clean the tool head and nozzle thoroughly before installing the tool, and use the calibration table to check whether the tool has deflection after installing the tool. Check again after reading the number of correct knives to avoid the serious loss to the company caused by the wrong number of correct knives.
transmit program, start processing: use the single section execution before the knife, transfer the speed and feed speed to the slowest, slow down the knife, watch the machine tool showing the Z axis margin, check whether there is any abnormal, if abnormal, press the pause button immediately, find out the reason to solve the anomaly, confirm that everything is adjusted to the right speed to start processing.
In the process of machining, it is necessary to observe whether the machining is abnormal and whether the tool is worn. If the tool is seriously worn, it is necessary to stop grinding to ensure the normal machining.

Difference of NC milling machine

The biggest difference of CNC milling machine is that the machining center has the ability to exchange machining tools automatically. By installing different tools on the tool magazine, the machining tools on the spindle can be changed through the automatic tool changing device in one clamping, so as to realize a variety of processing functions.

CNC machining center is composed of mechanical equipment and CNC system, which is suitable for processing complex parts. CNC machining center is one of the most widely used CNC machine tools with the highest output in the world. Its comprehensive processing ability is strong, the workpiece can complete more processing content after clamping at one time, and the processing accuracy is high. For the batch workpiece with medium processing difficulty, its efficiency is 5-10 times higher than that of ordinary equipment, especially it can complete the processing that many ordinary equipment can’t complete, and it is more suitable for single piece processing with complex shape and high precision requirements or small and medium batch multi variety production. It concentrates the functions of milling, boring, drilling, tapping and cutting threads on one equipment, so that it has a variety of technological means.

Machining centers are classified into horizontal and vertical machining centers according to the spatial position of the spindle. According to the classification of process uses: boring and milling machining center, composite machining center. According to the special functions, there are single table, double table and multi table machining centers. Machining center of single axle, double axle, three axle and changeable headstock.

Technology standard of high speed computer gong

The machining center is an efficient and high-precision CNC machine tool. The workpiece can be processed in multiple processes in one clamping. At the same time, it is equipped with tool library and automatic tool change function. The rich functions of machining center determine the complexity of programming.

The machining center can realize the linkage control of three or more axes, so as to ensure the machining of complex surface. In addition to linear interpolation and circular interpolation, the machining center also has various functions, such as processing fixed cycle, automatic compensation of tool radius, automatic compensation of tool length, graphic display of machining process, man-machine dialogue, automatic fault diagnosis, off-line programming, etc.

Machining center is developed from CNC milling machine. The biggest difference between CNC milling machine and machining center is that the machining center has the ability to exchange machining tools automatically. By installing different tools on the tool magazine, the machining tools on the spindle can be changed through the automatic tool changing device in one clamping, and a variety of machining functions can be realized.

The broad meaning of benchmark is “basis”. The datum in mechanical manufacturing refers to the points, lines and surfaces used to determine the geometric relationship between the geometric elements on the production object. According to different functions and applications, datum can be divided into design datum and process datum, and process datum can be divided into process datum, positioning datum, measurement datum and assembly datum.

The technology of high-speed CNC machining is the premise to ensure the production of high-quality parts.

On lathe, the shape and size of the blank can be changed by the rotary motion of the workpiece and the linear or curvilinear motion of the cutter, and it can be processed to meet the requirements of the drawing.

Ordinary machine tools are more and more difficult to meet the needs of processing precision parts. At the same time, due to the improvement of production level, the price of CNC machine tools is falling from time to time. CNC precision parts processing mainly includes ultra precision turning, mirror grinding and grinding.

The primary premise of CNC precision parts processing is the accuracy of process datum. Datum on mechanical drawings are represented by capital letters a, B, C, D, etc. with a specific reference symbol with circle. When the reference symbol is aligned with the surface and its extension line or the dimension limit of the surface, the surface is taken as the datum. When the datum mark is aligned with the dimension line, it means that the solid center line of the dimension is taken as the datum. It is a more general statement that the process is accurate.

Assembly benchmark refers to the precision used to determine the position of parts in components or products during assembly. Measurement datum refers to the specification for the size and position of the machined surface to be measured during the inspection of parts. Positioning datum refers to the datum used for positioning the workpiece in the machine tool or fixture during machining.

Machining analysis of CNC high precision parts

Analysis of high precision machining industry

The concept, significance and characteristics of high precision parts manufacturing high precision parts manufacturing takes high precision mechanical parts as processing objects. Based on the systematic and integrated theory and technology, according to the structure and requirements of the workpiece, the organic combination and optimization of feeding, processing, detection and handling are realized, and the production of parts is completed under the precise processing conditions.
Application field of high precision parts and components high precision parts and components are used in all walks of life testing equipment – scientific instruments. In China, they are mainly used in the instrument and instrument industry of scientific instruments.
High precision machining has the advantages of high precision, low energy consumption, flexible production and high efficiency. Reducing the size of the whole manufacturing system and precision parts can not only save energy, but also save manufacturing space and resources, which is in line with the production mode of energy saving and environmental protection. It is one of the development directions of green manufacturing.
Compared with ordinary machinery manufacturing, precision machinery manufacturing has high technology content (design and production), excellent processing equipment, high added value, and small batch sales.
Analysis of foreign development situation high precision machinery manufacturing technology is known as one of the key technologies in the 20th century. It is the key development direction in the 21st century and has been highly valued by all countries in the world. Japan, the European Union, South Korea, the United States and other developed countries have invested a lot of human, material and financial resources to develop their own high-precision mechanical parts research and development and technology.
China’s high-precision machinery manufacturing technology was gradually developed in the late 1980s and early 1990s. It is a rapidly developing industry in China today. High precision machinery manufacturing products are widely used in national defense, medical, aerospace, electronics and other military and civil fields.

The purpose of high-precision mechanical parts processing is to realize the concept of “small machine tool processing small parts”, which is different from the manufacturing method and technology of ordinary mechanical parts. It will become the most effective processing method for high precision parts of non silicon materials (such as metal, ceramics, etc.). It can fundamentally solve the problems existing in the processing methods of precision instrument parts.