CNC Knowledge: How to calculate the cutting speed and power speed of the CNC machining center?

Cutting speed and power speed of the CNC machining center:

1: pin speed = 1000vc / πd

2: Maximum cutting vax of general tools (VC): high speed steel 50 m / min; = 275-325 Steel tool at high speed VC = 18 m / min;

There are two calculation methods for the speed of the pin. The other is that the G96 S80 is a constant linear speed, which is the pin speed determined by the surface of the room.

There are also two types of power speeds. The other is G95 F0.1, which shows that the tool supply scale is 0.1 mm per turn of the spindle. Determination of the selection of tools and cutting volume in CNC machining

The selection of tools and the determination of the use of the cut are important content in the CNC machining process. The development of CAD / CAM skills made it possible to directly use CAO planning data in CNC machining, in particular the connection between microcomputers and CNC machine tools, so that the entire planning process, Process planning and programming is completed on the computer and generally, no output is required.

Nowadays, many CAD / CAM software packages provide active programming functions. Can be actively generated and transmitted to the CNC machine for treatment. Consequently, the selection of tools and the determination of the use of the cut in CNC machining are completed in human-computer interaction, which is a clear contrast to the general treatment of machines. You must fully consider the characteristics of CNC machining. This article deals with the problems of selecting tools and the determination of the use of use which are necessary in the CNC programming, gives several directives and proposals, and discusses the questions to which must be attentive.

1. Types and characteristics of tools commonly used for CNC machining

CNC machining knives have the characteristics that must be adapted to CNC machines which are at high speed, effective and very proactive. The handle of the tool must be connected to the tool and installed on the supply head of the tooltip, it was therefore gradually standardized and serialized. There are many ways to classify CNC tools.

Depending on the structure of the tool, it can be divided into: ① full type; As a composite tool, shock tools, etc. According to information used to make the tool, it can be divided into high -speed steel tools; From the cutting process, it can be divided into: ① turn tools, which are divided into outdoor circle, inner hole, wire, cutting tools, etc. tools; ④ ④ ④ ④ ④ ④ ④ ④ ④ ④ ④ ④ ④ The milling tools await. In order to meet the requirements of CNC machine tools for sustainable, stable, easy-to-adjust and replaceable tools, the machine-tightened indexable tools have been widely used in recent years, reaching 30% to 40% of the whole of CNC tool in quantity in quantity, metal reduction The volume represents 80% to 90% of the total.

Compared to the tools used in general machine tools, CNC tools have many different requirements and the following characteristics are the first:

⑴ Good rigidity (in particular rough treatment tools), great precision, low vibration and thermal deformation;

⑵ Good interchangeability, which facilitates the quickly modification of the tool;

High lifespan, stable and reliable cutting performance;

⑷ The size of the tool is easy to adjust to reduce time when changing the tool;

⑸ The tool must be able to break the fleas firmly or to drive firmly to facilitate the elimination of fleas;

⑹Serialization and standardization to facilitate the programming and processing of tools.

2. Selection of CNC machining tools

The selection of tools is carried out in the state of interaction of human computers of the CNC programming. Tools and tool holders must be properly selected depending on the machine-tool machining capacity, part data performance, processing process, cutting and other factors Related. The general selection criteria of tools are as follows: easy to install and settle, good rigidity, high sustainability and precision. Regarding satisfaction of processing requirements, try to select a shorter tool holder to improve the rigidity of tool processing.

When selecting a tool, the tool scale must be adapted to the room surface scale to be treated. During production, final factories are often used for the treatment of the periphery of flat parts; Virgin surfaces or rough treatment when you use holes, you can choose a corn crushing striker with carbide insert;

When you do free surface machining, as the final cutting speed of the balloon head tool is zero, to ensure the precision of the treatment, the spacing of the cutting lines is generally very dense, so that The ball head is often used to finish the curved surface. Flat -headed tools are better than ball head tools in terms of appearance and cutting quality. In addition, the sustainability and precision of the tool are closely linked to the price of the tool. .

In the machining center, various tools are installed separately on the tool magazine and the tool selection and change of tools are carried out at any time depending on the procedures. Therefore, it is necessary to use standard tool holders so that the standard tools used in borehole, boredom, expansion, milling and other processes can be installed on the spindle or the magazine of Machine-tool tool. Programmers must include the structural scale, adjustment methods and adjustment scale of the tool holder used on the tool machine, in order to determine the radial and axial scale of the tool during programming. Currently, my country’s machining centers use the East-West TSG system, and its tool holder includes two types: the right handle (three standards) and the conical handle (four standards), and a total 16 tool holders with different uses.

In the economic machining of the CNC, since the sharpness, the measurement and replacement of the tools are mainly carried out manually and take a long time auxiliary, it is necessary to organize the order of the tools reasonably. Generally, the following directives must be followed: ① Minimize the number of tools; ② Once a tool is tight, all the treatment parts that can be completed; ④ Moulin first, then Forez; If you want to learn UG programming, you can add the qq editor: 770573829 to receive the UG tutorial.

3. Determination of the quantity of CNC machining and cutting

The principle of rationally reducing selection is that during approximate processing, improvement of yield is generally the main objective, but the economy and the cost of processing must also be taken into account; Ensure the quality of transformation, economy and processing cost. The detailed values ​​must be determined according to the instructions manual of the machine tool, the cutting dosage manual and combined with the experience.

⑴ Cutting depth t. When the tool-tool, the part and the rigidity of the tool are agreed, T is equal to the machining allowance, which is a useful means of improving productivity. In order to ensure the machining precision and the surface roughness of the parts, a certain margin must generally be left to the finish. The finishing allowance of CNC machine tools can be slightly smaller than that of ordinary machine tools.

⑵ Cutting width L. Generally, the is proportional to the diameter of the D tool and inversely proportional to the cutting depth. In the economic treatment of the CNC, the general value scale of EST: L = (0.6 ~ 0.9) d.

⑶ The cutting speed v. Advance V is also a way to improve productivity, but V is more closely linked to the sustainability of tools. As V increases, the sustainability of the tool decreases sharply, so that the choice of V depends first on the sustainability of the tool. In addition, the cutting speed is also closely linked to processing data. min.

⑷ pin speed n (r / min). The pin speed is generally selected depending on the cutting speed V. The calculation formula is:

Where D is the diameter of the tool or part (mm).

The CNC machine tool control panel is generally equipped with a spindle speed adjustment switch (multiplier), which can adjust the pin speed in a whole multiple during the processing process.

⑸ VF power speed

The FV must be selected according to the machining precision and the surface roughness requirements of the parts and the information on the tool and the part. Increasing the FV can also improve the output power. When the roughness requirements of the machining surface are low, the VF can be selected as greater. During the processing process, the FV can also be adjusted manually via the adjustment switch of the configuration panel of the tool-tool, but the maximum power supply speed is subject to the stress of the rigidity of the equipment and performance of the system of the system food.