What is the difference between end mills and keyway mills?
What are the differences?
The purpose is differentThe vertical milling cutter is used to process plane or cylindrical surface, its outer diameter is relatively loose, while keyway milling cutter is used to process keyway, its outer diameter directly affects the matching quality of keyway and keyway, so the tolerance is more strict.
The number of cutter teeth is differentEnd mills generally have more than three teeth, keyway mills generally have two teeth.
The difference of blade beltIn order to improve the working efficiency of end milling cutter, there are many edge strips. The larger the diameter is, the more the edge strips are; Keyway milling cutter generally has two edge belts, mainly for axial feed like drill bit.
The feed is differentThe end milling cutter can’t feed in the axial direction, it can feed in the axial direction only when it moves in the radial direction; Keyway milling cutter can be axial straight into the feed, equivalent to a drill, can drill a flat bottom hole.
How to distinguish different end mills?
End mills with different number and length of edgesThe number of cutting edges is selected according to the cutting mode of end mill.For example, when cutting a groove with the same cutting width and tool diameter, a larger chip holding groove is needed, and a 2-edge end mill is generally selected. In the case of side cutting with smaller cutting width, the tool rigidity should be given priority and the multi-edge end mill should be selected.Selection of blade lengthAccording to the depth of groove shape and other processing shapes, the best edge length of end mill is selected. If we pay attention to the number of regrinding and choose the end milling cutter with too long blade, it will produce chatter, which will lead to the failure to give full play to the characteristics of the end milling cutter, resulting in the difficulty to achieve high-precision finishing surface and other adverse effects.
End mills with different helix anglesThe larger the helix angle of the end mill, the longer the contact length between the workpiece and the cutting edge. In this way, the load on the cutting edge per unit length can be reduced, so the tool life can be prolonged. But at the same time, the cutting resistance will become larger, so it must be considered to use the tool holder with high clamping rigidity.
Types and uses of milling cutters
Cylindrical milling cutter
Used for machining plane on horizontal milling machine. The cutter teeth are distributed on the circumference of the milling cutter and can be divided into straight teeth and spiral teeth according to the tooth shape. According to the number of teeth, it can be divided into coarse teeth and fine teeth. The helical gear coarse tooth milling cutter has less teeth, high tooth strength and large chip space, which is suitable for rough machining, while the fine tooth milling cutter is suitable for finish machining.
Face milling cutter
It is used in vertical milling machine, end face milling machine or gantry milling machine to process plane. There are cutter teeth on the end face and circumference, as well as coarse teeth and fine teeth. There are three types of structure: integral type, inlaid type and indexable type.
It is used for machining groove and step surface. The cutter teeth are on the circumference and end face, and can’t feed along the axial direction when working. When the end milling cutter has an end tooth passing through the center, it can feed axially.
Three face milling cutter
It is used for machining all kinds of groove and step surface. There are cutter teeth on both sides and circumference.
Angle milling cutter
It is used for milling grooves with a certain angle. There are two kinds of single angle and double angle cutters.
Saw blade milling cutter
It is used to process deep groove and cut off workpiece. There are many cutter teeth on the circumference. In order to reduce the friction during milling, there are 15 ‘- 1 on both sides of the cutter teeth ° The secondary deflection angle of the system. In addition, there are keyway milling cutter, dovetail groove milling cutter, T-shaped groove milling cutter and various forming milling cutters.
The cutter body and cutter teeth are integrated.
Integral welding tooth type
The teeth are made of cemented carbide or other wear-resistant tool materials and brazed on the cutter body.
The cutter teeth are fixed on the cutter body by mechanical clamping. The exchangeable cutter teeth can be the cutter head of integral cutter material or the cutter head of welding cutter material. The milling cutter with the cutter head mounted on the cutter body for grinding is called internal grinding type; If the cutter head is grinded separately on the fixture, it is called external grinding.
This structure has been widely used in face milling cutter, end milling cutter and three face edge milling cutter.
For the hard cutting materials with low heat conductivity and great influence on the heating of the blade tip, the use of large spiral angle end milling cutter is helpful to prolong the tool life. In addition, the characteristics of the finishing surface change due to the helix angle. For example, when smooth finishing is required, large helical angle end mills can be used sometimes.
However, when using the large helix angle end milling cutter, the cutting resistance will increase, and the force of the right spiral angle tool will also increase. Therefore, corresponding measures must be taken, such as holding the handle with high rigidity.
Although the rigidity of the tool can be ensured, sometimes small spiral angle end mills are used when the rigidity of the workpiece such as sheet metal processing is low.