What are the common tools in CNC machining center tools?
The tools used in CNC machining centers are equipped with each machining center equipment manufacturer, and there are also some very good CNC machining center tool manufacturers.
Presumably, the manufacturers that do CNC processing often encounter some people who sell tools plus our WeChat to recommend their tools. So who is good?
This depends on the tools used in our machining center equipment. Generally speaking, high-durability tools are selected to ensure the best economic benefits.
On the machining center, the spindle speed is 1 to 2 times higher than that of ordinary machine tools.
The spindle speed of some special-purpose CNC machine tools and machining centers can reach tens of thousands of revolutions.
Therefore, the strength and durability of cutting tools for CNC machine tools are very important.
At present, tools such as coated tools and cubic boron nitride have been widely used in machining centers.
Ceramic and diamond tools are also being used in machining centers.
Generally speaking, the tools for CNC machine tools should have high durability and stiffness, and the tool materials have good brittleness resistance.
Has good chip breaking performance and adjustable and easy to replace.
For example, when selecting a tool for milling on a CNC machine, pay attention to the following points:
When face milling, a hard alloy end mill or end mill should be used.
In general milling, it is better to use the second pass machining. The first pass is best rough-milled with an end mill, and the feed is continuously made along the workpiece surface.
Select the width of each pass and the diameter of the milling cutter so that the cutting marks do not affect the precision of the cutting pass.
Therefore, when the machining allowance is large and uneven, the diameter of the milling cutter should be smaller, otherwise, the diameter should be larger.
When finishing, the diameter of the milling cutter should be larger, and it is best to accommodate the entire width of the working surface.
Type of tool magazine:
The tool magazine is used to store tools, and it is one of the main components in the automatic tool changer.
Depending on the number of tools in the inventory and how they are taken, the magazine can be designed in different types.
Figure 7.1 shows the common types of tool magazines.
(1) Linear tool magazine. As shown in Figure 7.1 (a), the tools are arranged in a straight line in the magazine, the structure is simple, the number of stored tools is limited (generally 8 to 12), and they are rarely used.
(2) Disc magazine. As shown in Figure 7.1 (b)-(g), there are various types of knife storage ranging from 6 to 8 and 50 to 60.
The tool magazine shown in Figure 7.1 (b), where the tools are arranged radially and occupy a large space, is generally placed on the upper end of the machine tool column.
The tool magazine shown in Figure 7.1 (c), the tools are arranged axially and are often placed on the side of the spindle.
The axis of the magazine can be placed vertically or horizontally.
The tool magazine shown in Figure 7.1 (d), the tools are arranged in an umbrella shape, and are mostly placed at the upper end of the column.
In order to further expand the tool storage capacity, some machines use a disk magazine with multi-circle distributed tools (Figure 7.1 (e)).
Multi-layer disc tool magazine (Figure 7.1 (f)) and multi-row disc tool magazine (Figure 7.1 (g)). The multi-row disc magazine has 4 tools per row, which can be replaced in the entire row.
The last three magazine formats are used less often.
(3) Chain tool magazine. Chain tool magazine is the most commonly used form (Figure 7.1 (h), (i)),
Commonly used are single-row chain tool magazines (Figure 7.1 (h)) and chain tool magazines with extended chains (Figure 7.1 (i)).
(4) Other tool magazines. Lattice box type tool magazine, as shown in Figure 7.1 (j), k, has a large tool magazine capacity.
Figure 7.1 (j) is a single-sided type, and Figure 7.1 (k) is a multi-sided type.
There are many types of tools in machining centers:
Classified according to the standard of tool holders, commonly used standards: BT, JT, ISO, DIN, HSK, CAT, CAPTO, etc. Classified by use: milling cutters, drilling and boring, turning tools, etc.
Classification by specifications: BT30, BT40, BT50, ISO60, HSK100, etc. are the common categories, and there are more detailed classifications for different industries and different machine tools.
Machining Center Tools
End mills and end mills with carbide inserts are mainly used for machining bosses, grooves and box surfaces.
In order to make the knife easier to feed in the axial feed, a milling cutter with special sharpening of the end teeth is used. To reduce vibration,
Non-equidistant three-tooth or four-tooth milling cutters as shown in Figure b can be used. In order to increase the strength of the milling cutter, the cone center should be enlarged and the groove depth should be changed.
In order to improve the machining accuracy of the groove width and reduce the types of milling cutters, a milling cutter with a diameter smaller than the groove width can be used for processing.
The middle part of the groove is milled first, and then both sides of the groove are milled with the tool radius compensation function.
The peripheral contours of milling flat parts generally use end mills. The structural parameters of the tool can be referred to as follows:
① The tool radius R should be smaller than the minimum curvature radius ρ of the inner contour of the part, generally R = (O.8 ～ 0.9) ρ.
② The machining height of the part H≤ (1/4 ～ 1/6) R ensures that the knife has sufficient rigidity.
③ When roughing the inner profile, the tool diameter can be estimated as follows:
In the formula, δ1 is the finishing allowance of the groove; δ is the maximum allowable finishing allowance when machining the inner profile;
φ is the minimum included angle of the inner wall of the part; D is the minimum arc diameter of the inner surface of the workpiece.
Machining Center Tool Daquan Drawings
CNC machining centers commonly use ball-end, ring, drum, and tapered knives when processing curved surfaces and variable beveled contours.
Tool point, which is the reference point used to calculate the tool position during programming. Ball nose tools are most commonly used when machining curved surfaces.
However, the closer to the bottom of the ball-nose knife, the worse the cutting conditions are. Therefore, there is a recent trend of using a ring knife (including a flat-blade knife) instead of the ball-nose knife.
Both drum and tapered knives can be used to process chamfered parts, which is a workaround to replace four-coordinate or five-coordinate machine tools in single or small batch production.
The longitudinal section of the cutting edge of the drum knife is ground into an arc R1, and the upper and lower positions of the tool are controlled during processing, and the cutting position of the knife edge is changed accordingly.
Different bevel values from negative to positive can be cut on the workpiece. The smaller the arc radius R1, the wider the range of bevel angles that the tool can accommodate,
However, the worse the surface quality of the workpiece obtained by line cutting. The disadvantages of the drum knife are that it is difficult to sharpen and the cutting conditions are poor.
And not suitable for machining the inner edge surface. In the case of a tapered knife, the sharpening is easy, the cutting conditions are good, and the machining efficiency is high.
The surface quality of the workpiece is also good, but the flexibility of machining the beveled parts is small.
When the range of the bevel angle of the workpiece is large, it is necessary to change the tool in stages, leaving a lot of metal residues, which increases the amount of manual file repair.
Machining centers are usually classified by the relative positions of the spindle and the table, and are divided into horizontal, vertical and universal machining centers.
(1) Horizontal machining center: refers to a machining center where the axis of the spindle is set parallel to the table, and is mainly suitable for processing box parts.
(2) Vertical machining center: refers to a machining center where the axis of the spindle is perpendicular to the table. It is mainly suitable for processing complex parts such as plates, disks, molds and small shells.
(3) Universal machining center (also known as multi-axis linkage machining center): refers to a machining center that can control the coordinated change by processing the angle of the spindle axis and the rotation axis of the table to complete the processing of complex space curved surfaces. Suitable for machining impeller rotors, molds, cutting tools and other workpieces with complex space curved surfaces.