Monthly Archive September 17, 2020

CNC machining refers to the processing with CNC machining tools. CNC index controlled machine tool is programmed by NC machining language, usually G code. NC machining G code language tells CNC machine tool which Cartesian position coordinates, and controls the tool feed speed and spindle speed, as well as tool converter, coolant and other functions. In CNC machining, the determination of processing route should follow the following principles.

1、 The accuracy and surface roughness of the workpiece to be processed shall be guaranteed.

2、 It can shorten the processing route, reduce the idle travel time and improve the processing efficiency.

3、 Simplify the workload of numerical calculation and simplify the processing program.

4、 For some reusable programs, subroutines should be used.

CNC is also called computer gong, cncch or CNC machine tool. In fact, it was introduced into the Pearl River Delta of mainland China. It is actually a CNC milling machine. In Guangzhou, Jiangsu, Zhejiang and Shanghai, a new type of machining technology is called CNC machining center. Its main work is to compile processing programs, that is, to convert the original manual work into computer programming. Of course, manual processing experience is required. So, what are the advantages of CNC processing?

1、 A large number of tooling is reduced, and complex tooling is not needed to process parts with complex shapes. If you want to change the shape and size of parts, you only need to modify the part processing program, which is suitable for the development and modification of new products.

2、 The machining quality is stable, the machining precision is high, and the repetition precision is high, which can meet the processing requirements of aircraft.

3、 In the case of multi variety and small batch production, the production efficiency is higher, the time of production preparation, machine tool adjustment and process inspection can be reduced, and the cutting time is reduced due to the use of the best cutting amount.

4、 It can machine complex surface which is difficult to process by conventional method, and even can process some parts which cannot be observed.

CNC Lathe Feed processing route refers to the path from the start of tool setting point (or the machine’s constant origin) to returning to the point and ending the processing program. It includes the path of cutting and the path of non cutting empty stroke such as tool cut in and tool out.

The feed path of finish machining is basically carried out in sequence along the appearance of the parts. Therefore, the focus of confirming the feed path is to confirm the feed path of rough machining and empty stroke.

In the NC lathe processing, the affirmation of the processing route is usually in accordance with the following principles.

① The accuracy and surface roughness of the workpiece to be processed shall be guaranteed.

② It can shorten the processing route, reduce the time of empty travel and improve the processing efficiency.

③ Although the workload of numerical calculation is simplified and the processing program is simplified.

④ Subroutines should be used for some repeated procedures

In the process of machining, there are many factors that can affect the cold work hardening of CNC parts. There are not only one but also many kinds. When we encounter problems, we need to find out the causes to solve them. So the machining of CNC parts is the same. So what are the main reasons that affect the cold work hardening of CNC parts?

1. Processed data elements: the hardness of processed data is small, and the greater the plasticity, the more serious the cold work hardening level is.
2. Tool shape elements: CNC machining tool front angle, edge fillet and tool back wear have a great impact on the cold work hardening layer. The depth and hardness of the hardened layer increase with the decrease of the rake angle and the increase of the wear loss of the edge and back.

CNC parts processing in Dongguan

1. Cutting parameters of CNC parts: the change of cutting speed and feed rate has great influence on cold work hardening. When the cutting speed increases, the contact time between the tool and the workpiece is short, the plastic deformation level is small, and the hardening layer and hardness are reduced. With the increase of feed rate, the plastic deformation level and the surface cold work hardening level increase.

With the change of the times, our very products need to be processed to get the corresponding effect, and the processing method is also very good, not only to get that effect, CNC processing is one of them, so where are the advantages of CNC processing reflected?

① A large number of tooling is reduced, and complex tooling is not needed to process parts with complex shapes. If you want to change the shape and size of parts, you only need to modify the part processing program, which is suitable for the development and modification of new products.

② CNC machining has the advantages of stable machining quality, high machining precision and high repetition accuracy, which can meet the processing requirements of aircraft.

CNC machining

③ In the case of multi variety and small batch production, the production efficiency is higher, the time of production preparation, machine tool adjustment and process inspection can be reduced, and the cutting time is reduced due to the use of the best cutting amount.

④ It can machine complex surface which is difficult to process by conventional method, and even can process some parts which cannot be observed.

CNC machining has the following advantages:

① The number of tooling is greatly reduced, and complex tooling is not required for parts with complex processing forms. If we want to change the form and size of parts, we only need to modify the part processing program, which is applicable to the development and modification of new products.

② The machining quality is stable, the machining precision is high, and the repeated precision is high, which is suitable for the processing requirements of aircraft.

③ It can reduce the time of production planning, machine tool adjustment and process inspection, and reduce the cutting time due to the use of good cutting amount.

④ It can be used to machine the complex surface which is difficult to machine by conventional way, and even can process some parts which cannot be observed.

The disadvantage of NC machining is the high cost of machine tools, which requires maintenance staff to have a high level.

1. What are the key points of CNC engraving and CNC milling?

Both CNC engraving and CNC milling are based on milling principle. Focus on the use of tool diameter, CNC milling commonly used tool diameter boundary is 6-40 mm, while CNC engraving tool diameter is 0.2-3 mm.

1. Is CNC milling only for rough machining and CNC engraving only for finishing?

Before answering this question, let’s first understand the meaning of the process. The amount of rough machining is large, while the amount of finishing is small. Therefore, some people habitually regard rough machining as “heavy cutting” and fine machining as “light cutting”. In essence, rough machining, semi finishing and finishing are the meaning of technological process, which represent the different processing stages. Therefore, the exact answer to this question is that CNC milling may as well do heavy cutting or light cutting, while CNC engraving can only do light cutting.

1. Can CNC engraving process be used for rough machining of steel raw materials?

To infer whether CNC engraving can process a certain raw material, the key point is to see how large a tool can be used. The cutting tool used in CNC engraving determines its comparative cutting strength. If the mold form allows the use of tools with a diameter of more than 6 mm, it is proposed to use CNC milling first, and then use engraving to eliminate the remaining raw materials.

1. Whether adding a speed increasing head to the spindle of CNC machining center can complete the engraving process?

It can’t be over. This kind of product appeared in the exhibition two years ago, but it was impossible to complete the carving process. The main reason is that the design of CNC machining center studies its own tool boundary, and the overall structure is not suitable for engraving. The main reason for this mistake is that they mistook the high-speed motorized spindle as the only feature of a successful engraving machine.

1. CNC engraving may use a tool with a small diameter. Can it replace EDM?

It cannot be replaced. Although engraving reduces the tool diameter boundary for milling, small molds that used to only be machined by EDM can now be completed by engraving. However, the length / diameter ratio of engraving tools is usually controlled at 5:1. When using small diameter tools, only a very shallow cavity can be machined, while EDM has almost no cutting force. As long as the electrode can be made, the cavity can be machined.

1. What are the key factors affecting the carving process?

Machining is a complex process, and there are many factors affecting it. The key points are as follows: machine tool characteristics, cutting tools, control system, raw material characteristics, processing technology, auxiliary fixture and surrounding environment.

1. What are the requirements for the control system of CNC engraving?

CNC engraving processing is milling processing first, so the control system must have the control strength of milling processing. For small tool machining, feed-forward performance must be provided at the same time, and the path speed can be reduced in advance to reduce the tool breaking frequency of small tool. At the same time, the cutting speed should be increased in the smooth path section, so as to improve the engraving efficiency.

1. What characteristics of raw materials affect processing?

The key factors affecting the engraving performance of raw materials are the type of raw materials, hardness and toughness. The category of raw materials includes metallic raw materials and non-metallic raw materials. In general, the higher the hardness, the worse the processability; the higher the viscosity, the worse the processability. The more impurities, the worse the processability, the greater the hardness of the particles inside the raw materials, the worse the processability. A general rule is: the higher the carbon content, the worse the processability; the higher the alloy content, the worse the processability; the higher the content of non-metallic elements, the better the processability (but usually the nonmetal content in raw materials is strictly controlled).

1. Which raw materials are suitable for carving?

The non-metallic materials suitable for carving include plexiglass, resin, wood, etc., while those unsuitable for carving include natural marble and glass. The metal raw materials suitable for engraving include copper, aluminum, mild steel with hardness less than hrc40, and those unsuitable for carving include quenched steel, etc

With the continuous emergence of various technologies in front of us, and CNC machining is one of them. We all know that it is a relatively common technology in the industry, and it is also a more common technology that we use. What is the precision detection of CNC machining?

CNC machinist CNC lathe for different shape of guide rail, each surface should control which plane straightness error?

In CNC machining, scraping and lapping method is used to trim the straight line of guide rail to pass the lost time. The method of grinding point is often used in the inspection of short guide rail. Because of the simple deformation when the leveling ruler exceeds 2000mm, it is difficult to manufacture and affects the measurement accuracy. When scraping and grinding the short guide rail.

The straightness error of guide rail is usually ensured by the accuracy of the leveling ruler, and the density of lapping points per unit area is also determined. According to the accuracy requirements in the middle of processing and the nature and important level of the guide rail in the middle of the processing, the rules are as follows: no less than 10 ~ 20 points per 25 mm × 25 mm internal lapping points (i.e. the number of points in each scraping Square).

The common shapes of CNC machining intermediate guide rail are rectangular guide rail and V-shaped guide rail. The degree surface of the rectangular guide controls the straightness error of the guide in the pen plane. The error of straightness in the degree plane is controlled by two or four sides of rectangular guide rail. For the V-shaped guide rail, the two inclined surfaces not only control the straightness error in the straight plane, but also control the straightness error in the degree plane.