RU153802U1 - HIGH RESISTANCE COMBINED END MILL - Google Patents

Abstract

An end mill containing a shank and a body with straight and oblique teeth and nape, characterized in that the mill body is made of end and main parts, mechanically interconnected by pins and screws with the formation between the parts of the gap value of h, equal to 1 mm, which plays the role chip separation grooves, the main part of the body containing straight teeth and nape, and the front part of the body containing nape and oblique teeth, the height of which is equal to its height, and straight teeth with a height less than the height of the oblique teeth by h.

Description

The technical field to which the utility model belongs.

The utility model relates to cutting tools for metalworking, in particular to end mills for machining planes, grooves, ledges in the manufacture of machine parts.

The level of technology.

Known end mill with soldered carbide straight straight cutting plates (blades), manufactured according to the technical specifications TU2-085-591-77, containing a shank and a cylindrical cutting part, including the nape, the teeth resting on them with soldered straight linear cutting blades located on a cylindrical surface and end cutting blades, each of which is inclined at an angle to a straight lateral cutting blade, and the top of each tooth is formed at the intersection of the straight side of the cutting blade with an end cutting blade, and the vertices of all the teeth lie in the end plane perpendicular to the axis of the cylindrical surface.

The disadvantage of this cutter is the unused reserve for increasing resistance due to uneven wear of the side and end cutting blades, since the end cutting blades wear out 2 times faster and determine the resistance of the cutter as a whole faster and determine the resistance of the cutter as a whole.

This disadvantage is eliminated in the end mill. Patent for utility model 125502 B23C 5/10 08/19/2012. RF In this utility model, at least two additional teeth of lower height are made with oblique side cutting blades, each of which is inclined at an angle to the axis of the cylindrical surface and located on the cylindrical surface, and end cutting blades, each of which is inclined at an angle to the oblique side cutting the blade, and the top of each additional tooth is formed at the intersection of the oblique side cutting blade with an end cutting blade, and the vertices of all additional teeth lie in the end plane, perpendicular to the axis of the cylindrical surface.

That is, in this utility model, additional teeth are installed in the end plane of the cutter, which perform a certain amount of cutting work in the most worn, end cutting area, making the side and end cutting blades approximately equally stable. That is, the resistance of the cutter as a whole to regrinding is significantly increased.

End mill 125502 B23C 5/10 08/19/2012. The Russian Federation is the prototype of the proposed utility model.

End mill utility model 125502 B23C 5/10 08/19/2012. The Russian Federation has, as a prototype, a significant drawback consisting in the following. A metal cutting tool (unlike machine parts where it limits wear and fatigue life) must have a certain resistance of the cutting teeth blades and when they become blunt, the teeth must be resharpened. Tool life is an essential tool performance parameter. For example, a standard end mill can work for about 1 hour before blunting, after which it is resharpened; the number of regrinding is approximately equal to 15. The regrinding of standard mills is carried out by disk grinding wheels on automatic machines with certain cutting standards. Tool regrinding should not take a lot of machine time, otherwise the economic efficiency of the tool is reduced.

The disadvantage of the end mill of utility model 125502 B23C 5/10 08/19/2012 of the Russian Federation is that the oblique teeth in the end plane of the cutter are at a certain angle to the straight teeth and when grinding the oblique teeth, the disk grinding wheel, which usually has a large diameter and large idle runs stroke, crashes into straight teeth. And this is unacceptable, as it leads to damage to straight teeth. Therefore, the grinding of the helical teeth in the prototype should be carried out by small grinding heads in diameter, and this reduces the productivity of the grinding machine and reduces the economic efficiency of the cutting tool itself. The elimination of this drawback by constructive methods is implemented in the proposed utility model.

An analogue of a utility model is the invention RU 2392095 C1 End mill. The essence of this invention is that in addition to the existing teeth with side cylindrical cutting blades and end cutting blades, the intersection of which are the tops of the teeth located on the side surface of the cutter, two additional end cutting blades are made. These additional end blades are short and therefore not in contact with the side cylindrical surface of the cutter. The purpose of this invention is the possibility of cutting the mill in the axial direction, which is important when milling keyways.

The invention RU 23943670 C1 is also known. An end mill having torsional rigidity. The essence of this invention is to create a profile of the cutter tooth having enlarged chip grooves for ejecting (retracting) the chip in order to facilitate the operation of the cutter and provide increased rigidity.

Also known is the end mill with soldered carbide screw plates GOST 20538-75. The helical teeth of this cutter are located on a cylindrical surface, which includes the cutting part of the cutter.

Also known is the end mill with crowns made of hard alloy GOST 87620-69 with oblique teeth. The oblique teeth of this cutter are located on a cylindrical surface, which includes the cutting part of the cutter.

DISCLOSURE OF A USEFUL MODEL

The proposed utility model “Combined end mill with increased durability” has the goal of eliminating the drawback consisting in the inadequate choice of a reserve for increasing the economic, technological and operational feasibility of end mills having multidirectional additional, special cutting blades (teeth) at the end face of the mill; for example in the end mill Utility model No. 125502 V23C 5/10 08/19/2012. RF

This expediency is achieved by constructive methods, the essence of which consists in the fact that instead of the construction of a solid cutter, two parts of the cutter structurally take place. One part of the cutter is the main one, and the other part of the cutter contains the end part, which necessarily includes additional, special cutting blades (teeth), taking into account the joint work of all the teeth, as well as, for example, those elements to which they are attached.

A metal cutting tool (unlike machine parts where it limits wear and fatigue life) must have a certain resistance of the cutting teeth blades and when they become blunt, the teeth must be resharpened. Tool life is an essential tool performance parameter. For example, a standard end mill can work for about 1 hour before blunting, after which it is resharpened; the number of regrinding is approximately equal to 15. The regrinding of standard mills is carried out by disk grinding wheels on automatic machines with certain cutting standards. Tool regrinding should not take a lot of machine time, otherwise the economic efficiency of the tool is reduced.

The disadvantage of the end mill utility model No. 125502 V23C 5/10 08/19/2012 of the Russian Federation is that the oblique teeth in the end plane of the cutter are at a certain angle to the straight teeth and when grinding the oblique teeth, the disk grinding wheel, which usually has a large diameter and large run-ups idling, crashes into straight teeth. And this is unacceptable, as it leads to damage to straight teeth. Therefore, the grinding of the bevel teeth should be carried out by small grinding heads in diameter, and this reduces the productivity of the grinding machine and reduces the economic efficiency of the cutting tool itself.

The elimination of this drawback by constructive methods is implemented in the proposed utility model.

The proposed utility model solves the problem as follows. An end mill containing a shank and a body with straight and oblique teeth and nape, the body of the cutter is made of end and main parts mechanically interconnected by pins and screws with the formation between the parts of the gap value of h, equal to 1 mm, which acts as a chip separating groove, and the main body part contains straight teeth and nape, and the front part of the body contains nape and oblique teeth, the height of which is equal to its height, and straight teeth with a height less than the height of the oblique teeth by h.

When the teeth are blunted, the end part of the cutter is removed and ground separately from the main (remaining) part of the cutter and then installed again. If the strength of all the teeth is equal (when the number of oblique teeth is equal to the number of straight teeth), the end part of the cutter is removed, then the teeth of the end part of the cutter and the teeth of the main (remaining) part of the cutter are re-sharpened independently, and the combined cutter is assembled again; in this case, after regrinding, the diameter of the cutter D of the end part and the main part of the cutter should be the same.

Between the carbide inserts of the end part of the cutter and the main part of the cutter there should be a gap of h. If there is no gap and the carbide plates are in contact, then due to the inevitable (albeit insignificant) deformation of the mechanical connection (pins and screw) under the influence of mechanical and thermal loads, contacting of the plate sections will be chipped, since the hard alloy has a small margin of safety brittle chipping.

The clearance of h during operation acts as a chip separating groove. Chip separating grooves are often used in metal cutting tools in a wide variety of modifications. For example, in A.S. 1537414 В23С 5/10 21 12 87. USSR. Chip separation grooves are used, the lateral surfaces of which are made according to a third-order curve. But the use of chip separating grooves should be technically and technologically justified, since these grooves after blunting the teeth require editing, and this is additional technological work. In the proposed utility model, the combined end mill has a chip separating groove due to a change in the design of the end part to ensure the operability of the combined mill. The chip separation grooves reduce cutting forces and improve chip control, which is important when machining less hard and viscous steels (steel 20, steel 30). When machining hard steels (for example, steel 20X2H4A), the effect of the chip separation groove in this mill is negligible. But here we should pay attention to the following important circumstance. The use of end mills is concentrated mainly on CNC machines. And on these machines, several parts that have different hardness and viscosity can be processed with one mill; different hardness and toughness can occur when processing various surfaces of one part ..

The chip separating grooves in the proposed utility model are non-standard, as it has a depth of the entire thickness of the carbide plate, and the standard chip separating groove has a depth of about 2 mm to 5 mm.

Custom design, chip separation groove is critical for combination end mill

The width of the non-parting groove is approximately 1 mm, that is, it should guarantee that the carbide plate of the end part of the mill does not come in contact with the carbide plate of the rest of the mill.

In the combined end mill of the proposed utility model, the chip separation groove in the end part of the mill and the mechanical fastening of the end part to the main part of the mill are structurally interconnected. Mechanical fastening consists of pins and screw; this is a detachable mount (in contrast, for example, from a welding, soldered or adhesive joint) and the elements of this mount are deformed. Any elements of mechanical fastenings have deformation: key, wedge, etc. Preference is given to a mechanical connection of pins and screws, as more technologically advanced for connecting two collapsible surfaces; that is, the end part with collapsible connection can be replaced with another with a different number of bevel teeth.

The introduction of a non-standard chip separation groove in combination with mechanical fastening and the introduction of the design of the replaceable end part of the cutter itself are an essential sign of a utility model.

The objectively manifest technical result consists in increasing the operational performance of the cutter as a result of improving the grinding of teeth associated with a change in the design of the cutter, that is, using a combined design of the cutter.

IMPLEMENTATION OF A USEFUL MODEL

An end mill (Fig. 1-6), containing a shank 1 and a body 2 with straight 3 and oblique 4 teeth and nape 5, the body 2 of the cutter is made of end 6 and the main 7 parts, mechanically interconnected by pins 8 and screw 9 formation between the parts of the gap with a value of h equal to 1 mm, acting as a chip separating groove, the main part 7 of the body 2 contains straight 10 teeth and the nape 11, and the end part 6 of the body 2 contains the nape 12 and the oblique teeth 4, the height of which is equal to its height, and straight teeth 13 with a height less than the height of the oblique teeth 4 on led rank h.

In the proposed utility model, the combined end mill has a chip separating groove of width h due to a change in the design of the end part to ensure the operability of the combined mill. The chip separation grooves reduce cutting forces and improve chip control, which is important when machining less hard and viscous steels (steel 20, steel 30). When machining hard steels (for example, steel 20X2H4A), the effect of the chip separation groove in this mill is negligible. But here we should pay attention to the following important circumstance. The use of end mills is concentrated mainly on CNC machines. And on these machines, several parts that have different hardness and viscosity can be processed with one mill; different hardness and toughness can occur when processing various surfaces of one part, and the end part of the cutter is in operation more often.

When milling, the combined end mill operates in the usual end mill mode until the teeth become blunt.

When the teeth are blunted, the end part of the cutter is removed and ground separately from the main (remaining) part of the cutter and then installed again. If the resistance of all the teeth is equal, the end part of the cutter is removed, then the teeth of the end part of the cutter and the teeth of the main (remaining) part of the cutter are shifted separately, independently of each other and the combined cutter is assembled again; in this case, after regrinding, the diameter of the cutter D of the end part and the main part of the cutter should be the same.

The regrinding of teeth in the combined end mill is carried out by high-performance disk circles on ordinary tool-grinding serial machines, which are used for regrinding standard mills. In mill No. 125502 V23C 5/10, regrinding is carried out by special grinding heads according to a special program for CNC machines, which reduces productivity and ultimately affects the profitability of the tool.

The manufacture of a combined end mill does not present any technological difficulties when centering and installing the pin joints and the fixing screw of the contacting surfaces. After regrinding, the diameter D of the end part and the rest (main) part of the mill should be the same; first, the teeth of the main part of the cutter are grinded and the size of the outer outer diameter D is measured after regrinding, and then the teeth of the end part are grinded to the same diameter D.

For experimental work in order to obtain and analyze the parameters of the combined end mill, this mill can be obtained from the prototype. The end part of the cutter is cut off with an abrasive circle at the height of the bevel teeth and then (after reducing the height of the straight teeth with an abrasive tool) it is joined to the main part of the cutter by means of pins and a screw. Docking is carried out on the body of the cutter having a material of steel 30 or steel 40X. It does not even require carbide tools for drills, reamers, swords, but you can get by with a less expensive tool made of high-speed steel P9 or P18.

In the production of the proposed combined end mill in workshop conditions, this mill is a serious competitor to mill No. 125502, and in many cases it is preferable in terms of improving operational parameters.

Claims (1)

An end mill containing a shank and a body with straight and oblique teeth and nape, characterized in that the mill body is made of end and main parts, mechanically interconnected by pins and screws with the formation between the parts of the gap value of h, equal to 1 mm, which plays the role chip separation grooves, the main body part containing straight teeth and nape, and the front part of the body containing nape and oblique teeth, the height of which is equal to its height, and straight teeth with a height less than the height of the oblique teeth by h.

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