JD carbide endmill
JD carbide endmill
ntroduction
The price of tungsten steel milling cutter is much more expensive than that of a general milling cutter, and the price is proportional to its cutter length and diameter.
material
Characteristics
Carbide tools (especially indexable carbide tools) are the leading products of CNC machining tools. Some countries have more than 90% of turning tools, and more than 55% of milling cutters are made of hard alloy, and this The trend is still increasing. Since the 1980s, the tool industry has continued to expand the production of various integral and indexable carbide tools or inserts. The variety has been extended to a variety of cutting tools, where the indexable carbide tool is simple. Turning tools and face milling cutters have expanded to include a variety of precision, complex and forming tools. Cemented carbide is also a common material for general-purpose tools such as drills and face milling cutters. At the same time, the use of hard alloys for knives, end mills, medium and large modulus gear tools and broaches for hardened surfaces is also increasing. The annual output value of cemented carbide tools and inserts has accounted for more than 30% of the total output value of cutting tools. [1]
classification
According to the grain size, cemented carbide can be divided into ordinary hard alloy, fine grain hard alloy and ultra-fine grain hard alloy. According to the main chemical composition, cemented carbide can be divided into tungsten carbide-based hard alloy and titanium carbide-based hard alloy. Tungsten carbide-based hard alloys include tungsten-cobalt (YG), tungsten-cobalt-titanium (YT), and rare-carbonized (YW) types, each of which has advantages and disadvantages. The main components are tungsten carbide (WC) and titanium carbide (WC). A common metal bonding phase such as Tic) or niobium carbide (NbC) is Co. Titanium carbide-based cemented carbide is a hard alloy with Tic as its main component, and the commonly used metal bonding phases are Mo and Ni.
length
Divided into standard and extended. Generally, the lengthening knife of the same diameter is more expensive than the standard length.
Carbide milling cutters are mainly divided into: solid carbide milling cutters. Carbide straight shank milling cutters. Carbide saw blade milling cutters. Carbide spiral drill milling cutters. Rectifier milling cutters for cemented carbide machines.
Deformation bending
The reasons for deformation and bending of tungsten steel products can be analyzed from the following aspects:
1. Carbon gradient.
2. Cobalt gradient.
3. Temperature gradient.
4. Pressed product density gradient.
5, improper loading.
6, shrinkage coefficient.
kind
Classified according to the shape of the knife:
1. Can be divided into standard knives, the general diameter is (1---20mm). Tungsten steel 4 blade, 2 blade milling cutter, tungsten steel ball cutter, tungsten steel round nose milling cutter.
2. Non-standard knives, the diameter is uncertain, the shape is weird, a wide variety, such as tungsten steel small diameter flat knife, deep groove knife and so on.
According to the processed particle classification of the knife:
Ultra-fine tungsten steel milling cutters, very fine-grain tungsten steel milling cutters, and ultra-fine ultra-fine tungsten carbide milling cutters; the hardness of milling cutters produced by different particles is different.
abrasion
Wear form
The basic rule of milling cutter wear is similar to that of turning tools. The cutting thickness of the high-speed tungsten steel milling cutter is small, especially in the case of up-cut milling, the cutter teeth are pressed against the surface of the workpiece and the sliding is serious, so the wear of the milling cutter mainly occurs on the back. When milling steel parts with tungsten steel face milling cutters, because of the high cutting speed, the cutting speed of the chips along the front is large, so the rear wears at the same time, and there is also a small milling cutter wear in front.
The tungsten steel face milling cutter performs high-speed interrupted cutting, so that the teeth are subjected to repeated mechanical shocks and thermal shocks, causing cracks and causing fatigue damage of the teeth. The higher the milling speed, the earlier and more severe the wear of the milling cutter. Most tungsten steel face milling cutters lose their cutting ability due to fatigue damage. If the geometrical angle of the milling cutter is unreasonable or improperly used, and the tooth strength is poor, the cutter teeth will wear without a crack after receiving a large impact force.
Preventive measures
(l) Reasonable selection of milling inserts: Blade materials with high toughness, low resistance to thermal cracking, and good heat resistance and wear resistance should be used. For example, when milling steel, YS30, YS25 and other grades can be used; when milling cast iron, YD15 and other grades can be used to prevent the cutter from being worn.
(2) Reasonable use of milling: Under certain processing conditions, there is a safe working area that does not cause damage. Selecting Vc and ƒz in the safe working area ensures that the milling cutter works properly and prevents the milling cutter from wearing out.
(3) Reasonable selection of the relative position between the workpiece and the milling cutter: Reasonably selecting the mounting position of the face milling cutter plays an important role in reducing the wear of the face milling cutter.
Application editing
When the tungsten steel milling cutter is in the milling process, the workpiece can be fed along or relative to the tool rotation direction, which affects the starting and finishing characteristics of the cutting.
When a tungsten steel milling cutter is used for down milling (also called co-directional milling), the feed direction of the workpiece is the same as the direction of rotation of the tungsten steel milling cutter in the cutting area. The chip thickness is gradually reduced from the beginning until the end of the slit is zero when performing peripheral milling; in the case of up-cut milling (also called reverse milling), the feed direction of the workpiece and the milling cutter of the cutting area are rotated. The direction is just the opposite. The chip thickness begins to zero and then gradually increases as the cutting process progresses.
Tungsten steel milling cutters During the up-cut milling, the tungsten steel milling cutters start cutting from zero chip thickness, which creates a high cutting force that pushes the tungsten steel milling cutter and the workpiece away from each other. When the tungsten steel milling cutter blade is forcibly pushed into the slit, it usually comes into contact with the hardened surface caused by the cutting blade, and friction and polishing effect under the action of friction and high temperature. Cutting forces also make it easier to lift the workpiece from the table.
Tungsten steel milling cutters When cutting down, the tungsten steel milling cutters start cutting from the maximum chip thickness. This can avoid polishing by reducing heat and weakening the process of hardening. The application of maximum chip thickness is very advantageous, and the cutting force makes it easier to push the workpiece into the tungsten steel milling cutter for the tungsten steel milling insert to cut.
When milling a tungsten steel cutter, the chips are sometimes bonded or welded to the cutting edge and will collect around the beginning of the next cutting. When performing up-cut milling, the chip breaking is more likely to be trapped or wedged between the blade and the workpiece, which can cause the blade to rupture. In the case of down-cut milling, the same chip breaking is split into two, so that the cutting edge is not damaged. [1]
Regardless of the requirements of machine tools, fixtures and workpieces, down-cut milling is the preferred method.
Since the cutting force is easy to push the blade forward while keeping the workpiece down, the down-cutting has certain special requirements for the machining process. This requires the machine to handle table feed requirements by eliminating backlash. If the tool is pushed into the workpiece, the feed will increase irregularly, resulting in excessive chip thickness and chipping. Up-cut milling should be selected for such applications. In addition, if the machining allowance changes greatly, it is more advantageous to select the up-cut milling. In order to properly clamp the workpiece, a suitable fixture must be required, as well as the correct tool size for the job. But for the vibration trend, the direction of the cutting force is more important.
