How to properly match tools for CNC machining

How to properly match tools for CNC machining

Before making a tooling plan for a product, most manufacturers will give us the product drawing of the workpiece to be processed, but how to make a tooling plan after we get the drawing is very technical work, especially for newcomers, this technology can be It was not learned in school, so the following points will explain the prototypes of the knives one by one, so that newcomers can avoid detours, get started as soon as possible, and improve our own sense of mission.

First, how to determine the types of machining and selection criteria?

(1) Commonly used processes in machining are: turning, milling, drilling, grinding and planing. In actual processing, most of them are turning, milling, drilling, etc. But how do you know which milling machines to use? Which ones are machined with lathes? The parts we see are roughly divided into two categories: one is the box type; the other is the shaft type. The machining of the box body is relatively complex, requiring a large number of tools, which can be completed by the machining center. The machining of the disc shaft parts is relatively simple and can be completed by lathe machining, but there are usually products that combine the box body and the shaft. Generally, turning is preferred, because the cost of lathes is relatively low, and the processing cost is relatively low.

(2) Matrix with knife From my experience, there are several methods available:

I. See clearly the processing requirements of the drawing, know the processing technology, and then select the tool from the surface to the point. Special attention should be paid to:

① Pay attention to grooving and profiling when machining the outer circle, and avoid the contact between the back of the blade and the workpiece. The most important problems in turning machining are the contacted surfaces and chip removal. It is enough to avoid the machined surface and tool nose to complete the cutting route during processing.

② Consider the accuracy of profiling and machining in milling, as well as some special requirements in machining.

II. When there are a variety of tools to choose from, it can be considered from two aspects.

① Considering the existing inventory, reducing the inventory is the first choice.

② Starting from the cost of the tool, the low cost will give priority to the customer's acceptance. It is not excluded that customers give priority to quality, and choose to put quality first.

III. When matching knives, you must know which ones consume a lot of money and which ones are durable and can be ordered at one time?

① For customers, the main consideration is the price, and the low price is preferred for those who are durable and one-time ordering.

② As long as the customer considers the processing quality, they can choose a better one, such as the imported arbor.

③ Consumables such as milling cutters and blades are our homepage. We must choose our advantageous brands, preferably only us, so that others cannot replace them. It's hard to replace, but he can replace someone else's brand.

Second, some common sense about lathe knives

Some models of turning tools are interchangeable, such as: outer turning tools and inner hole turning tools, so that the KOTLOY blade can be installed with the KYOCERA knife body, and vice versa. Its subdivisions are base metal, cutting groove and coating. For grooving knives, cutting knives, and thread knives, each manufacturer is generally different.

(1) Cylindrical turning tool:

The composition of the cylindrical tool holder number consists of: the pressing method of the tool holder (P, S, C, D, M, S), the height of the tool holder (12, 16, 20, 25, 32, 40, etc.) and the width ( 12, 16, 20, 25, 32, 40, etc.), the entering angle of the tool bar (A, B, C, D, E, F, G, H, J, etc.), the clearance angle of the tool bar and the blade contact and The associated angles (A, B, C, D, E, F, G, N, P, O) and the overall length of the shank (F, H, K, M, N, P, Q, S). (The height and width are determined by the machine tool. The first group of numbers represents the center height of the tool on the lathe, which must be satisfied first. The second group of numbers is the width of the tool, which can be appropriately widened or narrowed), and the drawing of the workpiece determines the lathe The entering angle and blade of the knife. The blade is in conventional (C diamond 80°D diamond 55°V diamond 35°S regular quadrilateral W equilateral unequal triangle, T equilateral triangle)

(2) Inner hole turning tool:

When choosing an inner hole cutter, you should know the diameter and depth of the customer's drawing, and at the same time, you should understand the existing tool pockets of the factory. According to the tool design, it is known that the general steel structure car can only extend three times the diameter of the tool body (the code is No special code is indicated); general anti-vibration turning tools can extend 5 times the diameter of the tool body (the code is E), while the full-carbide inner hole turning tool can extend 7 times its tool body (the other The code is represented by W); when machining deep holes and requiring a better surface finish, be sure to choose a tool body with oil holes (the code name is generally with H). It is worth noting that some tools require a right-handed knife and a left-handed one. Blade, left hand knife with right hand blade.

(3) Grooving knife:

It is necessary to know the width and depth of the drawing and the cutting direction. The cutting direction includes: external groove knife, internal hole groove knife, end face groove knife, etc. When machining the end face groove, it is also necessary to know the diameter of its machining, because the end face groove cutter has the limitation of the minimum diameter and the maximum diameter. When the diameter of the workpiece is small, it can be used as a cutting knife, but pay attention to its processing requirements.

(4) Cutting knife

Under the premise of cutting conditions, try to select a cutting knife with a small blade width to meet the requirements of reducing processing costs.

(5) Thread turning tool

There are many kinds of threads. Generally, the drawings encountered now are metric, inch and other threads. They are divided into

Third, some common sense about tools used in machining centers

(1) Milling cutter

《1》Integral end mill

End mills are mainly divided into high-speed steel milling cutters, all-carbide milling cutters, and welding end milling cutters. Considering the wear resistance of the tool and the machinability of high-hardness materials, various coating series are added. Common There are TIN, TICN and ALTICN. It is divided into double-edged knives and multi-edged knives, etc. When selecting an end mill, the following aspects should be paid attention to: First, generally speaking, if the number of edges is small and the chip groove is large, the discharge of chips can be relatively smooth, but at the same time, The cross-sectional area of the tool is small, the rigidity of the tool body is low, and the tool body is prone to bending during cutting. On the contrary, if the number of flutes increases and the cross-sectional area of the tool increases, the rigidity of the tool body will increase, but the chip pocket will become smaller, and the chip holding force will decrease, which will easily lead to chip clogging and reduce the surface finish of the workpiece. The shorter the cutting edge, the greater the rigidity of the cutter body and the better the cutting performance. The rigidity of the end mill is inversely proportional to the third power of the edge length (overhang length). Therefore, if the blade length (overhang length) is doubled, the rigidity of the cutter body will be reduced to 1/8 of the original. It is important that end mills are radially used tools, and if the edge length of the end mill greatly exceeds the necessary cutting length, it will negatively affect the end mill and its performance.

《2》Insert milling cutter

①Spindle type milling cutter

Compared with the blade of the cutter head, the clamping method is different. The milling cutter of the mandrel mainly has a side-fixed clamping, and the others are similar to those of the cutter head.

②Cutter type

The cutter head type milling cutter mainly considers the angle of the contact surface between the cutter and the workpiece, generally (45°75°90°)

(2) Drill bits

①Straight shank drill

Drills are the most demanding tools, but in reality, many people don`t think about it so much. Now the drills used in factories mainly include high-speed steel drills and carbide drills. Generally speaking, the diameter is larger than D25 and it is rarely hard. Alloy body.

②Taper shank drill

The taper shank bit is mainly a high-speed steel shank, and the diameter of the tool is relatively large, because the connection method of the taper shank is relatively tight. To know the taper number of the tool (1#, 2#, 3#, 4#, 5#)

(3) Wire tapping

①Spiral tap

The screw tap is a tool specially used for processing the thread of the hole. The main difficulty of the hole and the through hole is that the former is more difficult to remove chips, while the latter does not need to consider the problem of chip removal. The screw tap is very helpful for chip removal.

②Straight groove tap

Generally, straight groove taps are manual tapping and machined through-hole threads. (4) Chamfering knife:

Know the largest angle and the smallest angle, and also know how many degrees the angle is (5) Reamer

①Straight shank reamer

The reamer is a finishing tool, and its requirements are relatively high. It is necessary to know the accuracy and processing depth required by its drawings.

③ Shank reamer

The required method is the same as that of the straight shank, but the connection method is the taper shank, and its number is 1#, 2#, 3#, 4#, 5#

Fourth, non-standard categories

Gun drills:

To know the connection method and diameter of its shank, and at the same time to know the material it is processed. It is best to have drawings of the workpiece and gun drill.

other kind:

Such as drill hinges, composite drill bits, etc. should be made according to the drawings