Yearly Archive September 17, 2020

“CNC parts processing” sequence

In our CNC machining parts, there are often several surfaces that need to be processed. Machining on the surface not only has certain accuracy requirements, but also is very important for the position requirements. In addition, the sequence of processing can not be disordered.

1. In order to ensure the important surface finish of CNC parts, it is necessary to finish the surface of important parts.
2. After finishing datum machining, roughing, semi finishing and finishing should be carried out on the main surfaces with high precision requirements. The surface with high precision needs to be finished.
3. The surface as a precision reference should be machined at the beginning of the CNC part processing process, because it is used to locate other surfaces in subsequent processes. That is, “benchmark first, then others”.
4. It is necessary to use coarse datum to locate the precise datum plane of CNC parts. In single piece production, small batch production and even batch production, for castings and forgings with complex shape or large size, as well as blanks with large size error, the marking process should be arranged before the machining process, so as to provide alignment reference for precision reference processing.
5. For the process prone to waste products, finishing and finishing can be appropriately placed in front, and some minor surface processing can be placed behind.

CNC machining, CNC machining refers to the processing with CNC machining tools. So what is the composition and characteristics of machine tools for processing?

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. Compared with manual machining, CNC machining has great advantages, such as the parts produced by CNC machining are very accurate and repeatable; CNC machining can produce parts with complex shapes that cannot be completed by manual processing. CNC machining technology has been widely promoted, most of the machining workshops have the ability of NC machining. The most common NC machining methods in typical machining workshops are CNC milling, CNC lathe and CNC EDM wire cutting (WEDM). The tool for NC milling is called CNC milling machine or CNC machining center. CNC turning lathe is called CNC lathe center. NC machining G code can be manually programmed, but usually the machining workshop uses CAM software to automatically read CAD file and generate G code program to control NC machine tool.

All kinds of machine tools are usually composed of the following basic parts: supporting parts, which are used to install and support other parts and workpieces to bear their weight and cutting force, such as bed and column; speed changing mechanism, which is used to change the speed of main motion; feed mechanism, which is used to change feed rate; headstock for installing machine tool spindle; tool holder, tool magazine; control and control system; lubrication system; cooling System. The accessory devices of machine tool include loading and unloading device, manipulator, industrial robot and other machine tool accessories, as well as chuck, suction cup spring chuck, vise, rotary table and dividing head and other machine tool accessories.

CNC machine tools have the following characteristics:

1、 High machining precision and stable machining quality;

2、 The complex shape of the parts can be processed by linkage;

3、 When the machining parts are changed, only the NC program needs to be changed, which can save the production preparation time;

4、 The machine tool itself has high precision and rigidity. It can choose favorable processing amount and high productivity (generally 3 ~ 5 times of ordinary machine tool);

5、 High degree of automation of machine tools can reduce labor intensity;

6、 Mass production, product quality is easy to control;

7、 The requirements for the quality of operators are low, and the technical requirements for maintenance personnel are high.

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.