How to Correctly Choose Cutting Tools for CNC Machine Tools

The selection of NC cutting tools and the determination of cutting parameters is an important part of NC machining process,
It not only affects the processing efficiency of CNC machine tools, but also directly affects the processing quality. Today's editor.
To tell you about how to correctly choose CNC machine tools, we hope to help.
At present, many CAD/CAM software packages provide automatic programming functions.
Generally, the programming interface prompts related issues of process planning, such as tool selection, machining path
Planning, cutting usage setting, etc., the programmer can automatically set the relevant parameters.
Generate NC program and transfer to CNC machine tools to complete processing. Therefore, the tool selection in NC machining
The determination of the selection and cutting amount is done in the state of human-computer interaction, which is formed with the processing of ordinary machine tools.
The sharp contrast also requires the programmer to master the tool selection and cutting usage determination.
Basic principles, in the programming fully consider the characteristics of CNC machining, can correctly select the cutting tools and
Cutting usage.
The selection of CNC tools and the determination of the amount of cutting is an important part of the CNC machining process.
It not only affects the processing efficiency of CNC machine tools, but also directly affects the processing quality.
The development of CAD/CAM technology makes direct use of CAD design data in CNC machining.
In particular, the connection between the DNC system microcomputer and the CNC machine tool makes the design, process
The whole process of planning and programming is completed on the computer, and there is generally no need to output special work.
Art documents.
At present, many CAD/CAM software packages provide automatic programming functions.
Generally, the programming interface prompts related issues of process planning, such as tool selection, machining path
Planning, cutting usage setting, etc., the programmer can automatically set the relevant parameters.
Generate NC program and transfer to CNC machine tools to complete processing.
Therefore, tool selection and cutting usage determination in CNC machining are in the state of human-computer interaction.
This is in sharp contrast to ordinary machine tool processing, and also requires programmers
The basic principles of tool selection and cutting usage determination must be mastered, and the NC plus must be fully considered in programming.
The characteristics of the work, the correct choice of cutting tools and cutting parameters.
Types and characteristics of commonly used cutting tools for CNC machining
CNC machining tools must adapt to the characteristics of high speed, high efficiency and high degree of automation of CNC machine tools.
Point, generally should include universal tool, universal connection handle and a small amount of special handle. Shank to be connected
The tool is also mounted on the power head of the machine tool, so it has been gradually standardized and serialized. Points of CNC cutting tools
Class has multiple methods. According to the tool structure, it can be divided into: ① integral type; ② mosaic type, welding
Or machine clamp type connection, machine clamp type can be divided into non-indexable and indexable two kinds; ③ special type, such
Compound cutting tools, shock-absorbing cutting tools, etc. According to the material used in the manufacture of cutting tools can be divided into: ① high speed
Steel tools; ② carbide tools; ③ diamond tools; ④ other materials tools, such as cubic boron nitride
Cutting tools, ceramic cutting tools, etc. From the cutting process can be divided into: ① turning tool, divided into outer circle, inner
Holes, threads, cutting tools, etc.; ② drilling tools, including drills, reamers, taps, etc.; ③
Boring tools; ④ milling tools, etc. In order to adapt to the CNC machine tool for durable, stable, easy
In recent years, the machine clamp type indexable tool has been widely used in the number
30% to 40% of the entire NC tool, metal removal accounted for 80% to 90% of the total.
Compared with the tools used on ordinary machine tools, there are many different requirements.
To have the following characteristics: ① good rigidity (especially rough machining tool), high precision, anti vibration and thermal deformation
Small; ②Good interchangeability, easy to change the tool quickly; ③High life, stable and reliable cutting performance; ④Tool
The size of the tool is easy to adjust to reduce the adjustment time of tool change; ⑤ The tool should be able to reliably break chips or roll
Chip, in order to facilitate the removal of chips; ⑥ serialization, standardization, in order to facilitate programming and tool management.
The choice of NC machining tool
The selection of the cutting tool is carried out in the human-computer interaction state of the numerical control programming. shall be in accordance with the machine
The processing capacity, the performance of the workpiece material, the processing process, the amount of cutting, and other related factors.
Correct selection of tool and handle. The general principle of tool selection is: easy installation and adjustment, good rigidity,
High durability and precision. Under the premise of meeting the processing requirements, try to choose a shorter handle
Improve the rigidity of tool machining.
When selecting a tool, the size of the tool should be adapted to the surface size of the workpiece to be processed.
In production, the peripheral contour of plane parts is often machined by end mills; when milling planes, it should be selected.
Carbide blade milling cutter; When machining boss and groove, choose high-speed steel end mill; Machining blank surface
Or when roughing holes, you can select corn milling cutters with carbide inserts; for some three-dimensional profile and
Variable bevel contour shape processing, often using ball end milling cutter, ring milling cutter, conical milling cutter and disc
Milling cutters.
When machining a free-form surface (mold), the end cutting speed of the ball head tool is
Zero, therefore, in order to ensure the machining accuracy, the cutting row spacing is generally used at the top close spacing, so the ball head is commonly used.
In the surface of the finishing. The flat head tool is superior to the ball in surface processing quality and cutting efficiency.
Head knife, therefore, as long as the premise of ensuring not cutting, whether it is the surface of the rough machining or fine
Processing, should give priority to the choice of flat knife. In addition, the durability and precision of the tool are related to the price of the tool.
The system is extremely large, it must be noted that in most cases, the choice of a good tool although increased
tool cost, but the resulting improvement in processing quality and processing efficiency can make the entire
The processing cost is greatly reduced.
On the machining center, various tools are installed on the tool magazine and selected at any time according to the procedures.
Knife and knife change action. Therefore, it is necessary to use standard tool shanks in order to make drilling, boring, expanding, milling and other work.
The standard tool used in the sequence is quickly and accurately installed on the machine tool spindle or tool magazine. Programmers should.
Solving the structural dimensions of the tool holder used on the machine, the adjustment method and the adjustment range, so that when programming.
Determine the radial and axial dimensions of the tool. At present, China's machining center using TSG tool system
System, its shank has straight shank (3 specifications) and taper shank (4 specifications) 2 kinds, including a total of 16 different
The hilt of the way.
In the processing of economical CNC machine tools, due to the sharpening, measurement and replacement of tools
It is mostly manual and takes up a long time to assist. Therefore, it is necessary to arrange the row of tools reasonably.
Column order. Generally, the following principles should be followed: ① minimize the number of tools; ② a tool clamping
After that, it should complete all the processing steps it can carry out;
Use, even for tools of the same size; ④ Milling before drilling; ⑤ Surface finishing first, and then
Two-dimensional contour finishing; ⑥ Where possible, the self-control of CNC machine tools should be used as much as possible.
Tool change function to improve production efficiency, etc.
The determination of the amount of cutting in the process of machining.
The principle of reasonable selection of cutting amount is: rough machining, generally to improve productivity.
The main, but also should consider the economy and processing costs;
Under the premise of the quality of work, taking into account the cutting efficiency, economy and processing costs. Specific values should be based on
Machine tool manual, cutting usage manual, and combined with experience. Specific to consider the following reasons
element:
① Cutting depth t. where the rigidity of the machine, workpiece and tool allows, t is equal
Machining allowance, which is an effective measure to improve productivity. In order to ensure the machining accuracy of parts
And surface roughness, generally should leave a certain margin for finishing. The finishing surplus of CNC machine tools
The amount can be slightly less than ordinary machine tools.
② Cutting width L. General L is proportional to the tool diameter d, and the depth of cutting into the opposite
Than. In the processing process of economical numerical control machine tools, the value range of general l is: L =(0.6 ~
0.9)d。
③ Cutting speed v. Increasing v is also a measure to increase productivity, but v is related to the tool.
The relationship between durability is relatively close. As v increases, the tool durability decreases sharply, so v's
The choice depends mainly on the tool durability. In addition, the cutting speed and processing materials also have a big
For example, when milling alloy steel 30CrNi2MoVA with an end mill, v can be used at 8 m/min left.
Right; When milling aluminum alloy with the same end mill, v can be selected above 200 m/min.
④ Spindle speed n(r/min). The rotation speed is generally selected according to the cutting speed v. Calculation of public
The formula is: v = ∏ nd/1000. The control panel of CNC machine tools is generally equipped with spindle speed adjustment (times
Rate) switch, which can adjust the spindle speed by an integral multiple during processing.
⑤ Feed speed vF. VF shall be based on the machining accuracy and surface roughness requirements of the parts.
And tool and workpiece materials to choose. The increase in vF can also improve production efficiency. Machined surface
When the roughness requirement is low, vF can be selected to be larger. In the process of machining, vF can also be
The trim switch on the control panel is manually adjusted, but the maximum feed speed is subject to the requirements of the equipment.
and feed system performance, etc.
With the wide application of CNC machine tools in production practice, the formation of quantitative production lines, the number
programming has become one of the key problems in NC machining. In the preparation process of numerical control program
In the human-computer interaction state, to instantly select the tool and determine the cutting amount. Therefore, programming people
The staff must be familiar with the method of tool selection and the principle of determining the amount of cutting, so as to ensure the addition of parts.
The quality of work and processing efficiency, give full play to the advantages of CNC machine tools, improve the economic efficiency of enterprises and
production level