China Shenzhen Perfect Precision Product Co., Ltd. company news

The unique tool magazine of CNC machining center can realize the function of automatic tool change and spindle orientation. Compared with the general machine tool cost is higher, of course, the processing accuracy and efficiency is also higher. So to choose the right machining center, so as to ensure that the CNC machining center to play the most - the greatest benefit. So for companies to choose the machining center model is also to be quite careful, so what specifically to pay attention to? First, the selection procedure should be reasonable, the premise is to have a comprehensive understanding of the processing center - center, including its performance, characteristics, type, the main parameters applicable range, etc. Only on the basis of a full understanding of the following procedures can be launched.   Second, choose the right type. When choosing the type of CNC machining process, processing objects, scope, price and other factors should be taken into account. For example, single-sided processing of workpieces, such as a variety of plate parts, etc., should choose vertical machining work - center; more than two sides of the workpiece or in the surrounding radially radiating row of holes, surface processing, should choose horizontal machining; complex surface processing, such as the guide wheel, the engine on the whole impeller, etc., you can choose five-axis machining center; for the workpiece of high precision requirements, the use of bedroom machining center - center. When processing larger size workpiece, such as machine bed, column, etc., you can choose gantry type machining center. Of course the above methods are only as a reference, the final decision should be made under the conditions of process requirements and financial balance.

Machining parts on CNC lathe should be divided into processes according to the principle of process concentration, and most or even all surfaces should be finished under one clamping as far as possible. According to different structure shapes, usually choose external circle, end face or internal hole, end face clamping, and strive to unify the design reference, process reference and programming origin. In mass production, the following methods are commonly used to divide the process. 1, according to the part processing surface division process   That is, the completion of the same part of the surface process for a process, for the processing of multiple and complex surface parts, according to its structural characteristics (such as internal shape, shape, surface and plane, etc.) into multiple processes. The surface requiring high positional accuracy will be completed in one clamping, so as not to affect the positional accuracy of the error generated by multiple positioning clamping. As shown in Figure 1, in accordance with the process characteristics of the part, the outer and inner contours of the rough and finish machining in a process to reduce the number of clamping, which is conducive to ensuring coaxiality.   2、Dividing the process by roughing and finishing   That is, the part of the process completed in rough machining is a process, and the part of the process completed in finishing machining is a process. For the parts with large margin and high processing accuracy requirements, roughing and finishing should be separated and divided into two or more processes. Rough turning will be arranged in the lower precision, higher power CNC machine tools to carry out, the finish turning will be arranged in the higher precision CNC machine tools to complete.   This division method is suitable for parts with large deformation after machining, which require separate rough and finish machining, such as parts with blanks of castings, welded parts or forgings.   Dividing the process according to the type of tool used   3、Dividing the process according to the type of tool used   The same tool to complete the part of the process for a process, this method is suitable for the workpiece surface to be machined more, machine tools work continuously for a long time, the preparation of processing procedures and check the difficulty of the situation. 4, according to the number of times the installation process   A part of the process to complete the installation for a process. This method is suitable for workpieces with little processing content, the processing is completed to reach the state of pending inspection.   After serious and careful analysis of the part diagram, the following basic principles should be followed to develop the machining plan - coarse first, then fine, near then far, inside and outside cross, the least number of program segments, and the shortest tool route.   (1) Coarse first and then fine   It means that the machining accuracy is gradually improved according to the sequence of rough turning and half finishing turning. In order to improve production efficiency and ensure the quality of finishing parts, in the cutting process, the roughing process should be arranged first, in a shorter period of time, most of the machining allowance before finishing is removed, while trying to ensure that the finishing allowance is uniform.   (2) Near first and then far   The far and near mentioned here are according to the distance of the machining part relative to the tooling point. In general, especially in rough machining, it is usually arranged that the part near to the tool point will be machined first, and the part far from the tool point will be machined later, in order to shorten the tool movement distance and reduce the empty travel time.   (3) Internal and external crossover   For both the inner surface (inner cavity) and the outer surface of the parts to be machined, the processing sequence should be arranged so that rough machining of the inner and outer surfaces is carried out first, followed by finishing machining of the inner and outer surfaces

The arrangement of the machining sequence should be considered according to the structure of the part and the condition of the blank, as well as the need for positioning and clamping, the heavy - point is that the rigidity of the workpiece is not destroyed. The sequence should generally be carried out according to the following principles. (1) the processing of the previous process can not affect the positioning and clamping of the next process, interspersed with general-purpose machine tool processing process should also be considered.   (2) first inside the shape of the cavity plus process, after the shape of the processing process.   (3) to the same positioning, clamping or the same knife processing process is best - the best connection to reduce the number of repeated positioning, the number of times to change the knife and move the platen times.   (4) For multiple processes in the same installation, the process with less rigid damage to the workpiece should be arranged first.

In the middle of the 20th century, when the Soviet Lazarinkov women studied the phenomenon and causes of corrosion damage to switch contacts by spark discharge, they found that the instantaneous high temperature of electric spark could make the local metal melt and oxidize and be corroded away, thus creating and inventing the electric spark machining method wire-cut discharge machine was also invented in the Soviet Union in 1960. At that time, a projector was used to view the contour before the left and right manual feed to the table for processing, and it was thought that the processing speed was slow, but it could process the fine shapes that were not easily processed by conventional machinery. A typical practical example is the processing of shaped holes by chemical weaving nozzles. The processing fluid used at that time was mineral oil (lamp oil). Because of the high insulation and small distance between poles, the processing speed was lower than that of the current machine, and the practicality was limited. The first machine to be NC-educated and processed in deionized water (close to distilled water) was exhibited at the 1969 Paris Workhorse Exhibition by a Swiss electrical discharge machine manufacturer, which improved the processing speed and established the safety of unmanned operation. However, the production of NC paper tape was very laborious, and it was a great burden to the user if it was not programmed automatically by a large computer. Until the advent of inexpensive Automatic Programed Tools (APT), the popularity was slow. The Japanese manufacturer developed a small computerized automatic programmed wire-cutting EDM machine, which is cheap and accelerated the popularity. The processing shape of WEDM is a quadratic profile. The emergence of the simple APT (APT language is easier than the official model) was an important factor in the development of WEDM machines.

Cutting processing is roughly divided into turning, milling and cutting (drilling, end mill end cutting, etc.), the cutting heat of these cutting processes on the tip of the cutting edge is also different. Turning is a continuous cutting, the cutting force at the tip of the cutting edge does not change significantly, the cutting heat acts continuously on the cutting edge; milling is a kind of intermittent cutting, the cutting force is intermittent on the tip of the cutting edge, cutting vibration will occur, the tip of the cutting edge is affected by the heat, is alternately heated when cutting and non-cutting cooling, the total heat is less than when turning. The cutting heat during milling is a kind of intermittent heating phenomenon, and the tool teeth are cooled during non-cutting, which will contribute to the extension of tool life. Japan Institute of Physical and Chemical Research of turning and milling tool life for comparative testing, milling tools used for ball end mill, turning for general turning tools, both in the same processed materials and cutting conditions (due to different cutting methods, depth of cut, feed, cutting speed, etc. can only be roughly the same) and the same environmental conditions for cutting comparison test, the results show that milling processing to extend tool life is more The results show that milling is more beneficial to prolong the tool life. When cutting with tools such as drills and ball end mills with a central edge (i.e., the part with cutting speed = 0 m/min), the tool life near the central edge is often low, but it is still better than when turning. In cutting difficult to machine materials, the cutting edge is affected by heat, often reducing tool life, cutting method such as milling, the tool life will be relatively long. However, difficult-to-machine materials can not be used from start to finish all milling, there will always be a need for turning or drilling in the middle of the time, therefore, should be for different cutting methods, take the appropriate technical measures to improve processing efficiency.

Parts processing process is a direct change in the appearance of raw materials (shape, size, location, performance), so that it becomes a semi-finished workpiece or finished process, the process we call the process, that is, the parts of the processing process benchmark, precision parts processing process is more complex. Precision parts processing process benchmark can be divided into different processes: casting, forging, stamping, welding, heat treatment, machining, assembly and so on categories. Precision parts processing process generally refers to the entire part of the CNC machining and machine assembly process in general, and other such as cleaning, inspection, equipment maintenance, oil seals, etc. are only auxiliary processes. Turning methods to change the surface properties of raw materials or semi-finished products, this process we call the CNC machining process, precision parts processing industry in the CNC machining process is the most important process. The following is a detailed introduction to the CNC precision parts machining process benchmark   (1) positioning datum, the positioning datum used by the lathe or fixture in the CNC lathe for processing.   (2) measurement benchmark, this benchmark usually refers to the size or position of the standard to be observed during inspection.   (3) assembly benchmark, this benchmark we usually refers to the position of the parts in the assembly process standards.

Parts processing process is a direct change in the appearance of raw materials (shape, size, location, performance), so that it becomes a semi-finished workpiece or finished process, the process we call the process, that is, the parts of the processing process benchmark, precision parts processing process is more complex. Precision parts processing process benchmark can be divided into different processes: casting, forging, stamping, welding, heat treatment, machining, assembly and so on categories. Precision parts processing process generally refers to the entire part of the CNC machining and machine assembly process in general, and other such as cleaning, inspection, equipment maintenance, oil seals, etc. are only auxiliary processes. Turning methods to change the surface properties of raw materials or semi-finished products, this process we call the CNC machining process, precision parts processing industry in the CNC machining process is the most important process. The following is a detailed introduction to the CNC precision parts machining process benchmark   (1) positioning datum, the positioning datum used by the lathe or fixture in the CNC lathe for processing.   (2) measurement benchmark, this benchmark usually refers to the size or position of the standard to be observed during inspection.   (3) assembly benchmark, this benchmark we usually refers to the position of the parts in the assembly process standards.

As we all know, the reason why the processing of precision parts is called precision machining, precisely because of its processing procedures and process requirements are very high, the precision requirements of the product is very high, and the precision of the processing of precision parts contains the accuracy of the location, size accuracy, shape accuracy, etc., Rui Sheng Technology General Manager combined with the company's more than 10 years of production and processing experience for us to summarize the following impact on the precision of precision parts processing Factors. (1) the machine tool spindle rotation runout can produce a certain error on the machining accuracy of the parts.   (2) the accuracy of the machine tool guide inaccuracy can also lead to precision parts processing workpiece shape error.   (3) transmission components can also lead to errors in the processing of the workpiece, which is also the most important factor in the production of the workpiece surface error.   (4) tool, fixture type of different will also have different degrees of impact on the accuracy of the machined workpiece.   (5) In the process of machining and cutting due to changes in the location of the force point will lead to deformation of the system, resulting in differences, which can also make the accuracy of the workpiece to produce different degrees of error. (6) The size of the cutting force is different, which can also lead to the accuracy of the workpiece being affected.   (7) process system by heat deformation caused by the error, machining process, the process system will be in the role of various heat sources to produce a certain amount of thermal deformation.   (8) process system deformation caused by heat often leads to the accuracy of the workpiece is affected.   (9) The deformation of the machine tool by heat will lead to the deformation of the workpiece.   (10) Heat deformation of the tool can have a great impact on the workpiece.   (11) The workpiece itself is deformed by heat, mainly in the cutting process.   The above is the introduction of "factors affecting the precision of precision parts machining".

The precision of the hardware parts almost determines the quality of the product, the more precise the hardware parts the higher the precision requirements will be, then the precision hardware parts processing accuracy why it will become poor? The first factor is the poor processing accuracy of the parts themselves, generally speaking, if the dynamic error between the shaft is not well adjusted at the time of installation, or because the shaft drive chain changes due to wear will affect the accuracy of the parts. Generally speaking, this type of error caused by the accuracy of the chapter can be re-adjusted compensation amount to solve. If the error is too large or even if the alarm is generated, it is necessary to check the servo motor and observe whether its speed is too high.   The second factor is the machine tool in operation overshoot will also affect the machining accuracy, possibly because the acceleration and deceleration time is too short, the appropriate extension of the change time, of course, is also very likely because the link between the screw and the servo motor produced loose. The third factor is because of the two-axis linkage generated by the roundness of the super poor, mechanical is not adjusted to form a circle of axial deformation, the axis of the screw gap compensation is not correct or axis positioning offset, may have an impact on the accuracy of precision parts.

Precision parts processing process is generally the most common processing method is the turning process and milling parts, that is, some of our common precision parts are milling parts or turning parts, can be collectively referred to as cutting parts, and cutting can be divided into "rough cutting" and "fine cutting". So what is the difference between rough cutting and fine cutting? After rough cutting, the workpiece is actually very close to the appearance and size of the workpiece itself, but at this time there is still a small margin on the surface of the workpiece for fine cutting, the surface of the workpiece after fine cutting treatment is more polished, the size will also be more accurate.   Usually, the workpiece can achieve the required appearance and size after one rough cut and one finish cut. However, not all workpieces require only one cut, and some parts of the workpiece may require multiple rough cuts. At the same time, there are some workpieces that do not require too much precision or have a small cutting volume, and they may only need to go through one finishing cut to achieve the requirements of the workpiece. Rough cutting because the workpiece needs to cut a large margin, so it needs to have a greater cutting force than fine cutting, which requires the machine, tool, workpiece can meet the three, and rough cutting is fast to remove the margin, and the effect of the surface properties can not be too rough.   Fine cutting is the surface performance of the workpiece, and dimensional accuracy to meet the requirements of the workpiece, so fine cutting requires the use of tools also need to be very sharp, because the cutting volume is small, so the measurement of precision requirements are very high.