UA5691U - Method for working the through holes by reamer-type tool - Google Patents

Abstract

The method for working the through holes by a tool of the type countersink-reamer includes simultaneous rotary motion and tool advance. Chips, which are removed by the teeth of countersink, are directed to the workable surface at the angle of chips withdrawal. In this case, the chips, which are removed by teeth of reamer, are placed in the chip grooves of countersink.

Description

A useful model refers to cutting and can be used when machining through holes.

There is a known method of processing through holes with a countersink reamer (Federal application Me2750705, M kl3 B23077/14, publ. 1979), which has a short front stage, made in the form of a countersink, and a long back stage, which is a reamer, while the teeth of the tool have a large uneven angular step.

This method of processing is characterized by obtaining a low cut of the hole, however, the chip moves through the chip grooves of the reamer, which is removed by both the rough and the clean part of the tool, which have different depths of the chip grooves. The disadvantage of this method is bagging of chips in the chip grooves of the reamer and pits on the treated surface.

The closest, in terms of technical essence, is the method of processing with a reamer (Swiss patent, class B23077/00,

Mo542683, publ. 30.11.73), the cutting teeth of which through one have the opposite direction of the helical groove. The method provides simultaneous rotational movement of the tool and feed movement.

The disadvantage of this method is the following: the chip grooves with the left direction ensure the movement of chips in the direction of feed, while the teeth with the right direction of the chip grooves grab the chips, which leads to an increase in roughness, as well as chip packing and tool breakage.

The general features closest to the analogue and the presented processing method are that the tool simultaneously makes a translational and rotational movement, and the part remains stationary, chip grooves are provided to remove chips from the cutting zone.

The basis of the useful model is the task of improving the method of chip transportation by controlling the direction of chip movement, which allows to ensure the necessary roughness of the machined surface, to exclude chip packing and to avoid premature tool failure.

The problem is solved by the fact that in the method of processing through holes, which includes simultaneous rotary movement and feeding of the tool, according to a useful model, the chips removed by the teeth of the countersink are directed to the surface to be processed at the angle of departure of the chips, the value of which is determined by the dependence

ApKUH » f--agoso - .-.'« 2E oz 'l4 t) s 5 KI) tod Vd 14 (1--sishch9))-1945-8).G de b. tolerance on the machined hole;

E - modulus of elasticity of the processed material (MPA);

Y - the moment of inertia of the tool neck; tod. shear stress for the tangential component of the cutting force on the front surface;

VA permissible amount of axial runout of cutting edges; 9. chipping angle, which determines the position of the displacement plane;

Y - cutting depth;

Y. - flight of the tool. at the same time, the chips removed by the teeth of the reamer are placed in the chip grooves of the countersink, and the volume of the chip grooves of the countersink is determined depending on

Ho Moska, pok "Varoir: І отв" (d) where І отв - the length of the machined hole; bar. feed on the reamer tooth; iv. depth of cutting of the reamer;

Kk filling ratio of chip grooves;

PP - the number of teeth of the sweeper.

The values of the angles of chip departure for different combinations of the geometric parameters of the countersink and reamer with their cutting modes, obtained on the basis of analytical and experimental studies, are presented in Tables 1 and 2.

Table 1 o o Depth of cutting, mm. from | -5 | -86 | -y24 | -135 | -3.08 | 13.9 | -377 55 | 892 | 26 | 03 | -08 | -5 | -9 0.125 45| 15 | 0 | 66 | 88 | 98 | 03 | forehead -5 | 69 | 25 | 5 | -73 | 82 | 87 55 | 114 | 27 | 0 | 4 | 22 | -6 from 0| -5| 08 | -8 | -08 | -21st | 28 | -32 03 ' 5 | 228 | 92 | 46 | 23 | 1 | 0 45| 5 | 134 | 0 | -6 | -68 | - | -89 | 33 | 96 | -4 | -6b2 | -74 | 81

Table 2 0 | 77076 77111717 71111117 shk 55 | shsh 24 | 0 | 7" ( 5 | ..yuD-3yu03 2 шЩшч | 7 | 66 pat zo | la | vy | 777425 | 7777106

The chip, which is removed by the teeth of the countersink, is moved in the direction of the machined hole at the angle of departure of the chip peAps, due to rationally selected cutting modes and geometric parameters of the tool.

The chip, which is removed by the teeth of the reamer, is progressively moved in the direction of the machined hole at an angle le" due to the rationally selected cutting modes and geometric parameters of the tool, and is placed in the chip grooves of the countersink, which will avoid the contact of the chip with the machined surface, and therefore bumps and scratches on treated surface. Also, due to the fact that the chips removed by the teeth of the countersink are not placed in the chip grooves of the tool, and the chips removed by the teeth of the reamer are placed in deeper chip grooves of the countersink, the possibility of chip packing is excluded, and therefore the possibility of premature tool failure.

Example. It is necessary to process a pre-drilled hole with a diameter of 37.75 mm to 40 mm with a countersink, while it is necessary to avoid pits and scratches on the treated surface. The length of the opening of the first cell is 180 mm.

According to the task, we choose a countersink with the following design parameters: Oz3z-39.75mm; 73-45 Or-40,00mm; 20-8. According to formula 1, we determine the maximum allowable angle of departure of the chip, previously the tach o accepted the main angle in the plan F-6o0"; Ap ZA. According to table 1, we determine the cutting modes and geometric parameters for the countersink, provided that , that the angle of departure of the chip should be "2 - depth of cutting - 1mm: 52-0, Zmm/tooth; X--25"7. Next, we determine the modes of cutting with a reamer, which ensure free placement of chips in the grooves of the countersink, according to formula 2: Zdosir 5 0036. According to Table 2, we select the modes of cutting so that the product of the feed to the depth of cut is less than 0.036, given the condition is satisfied by the cutting depth yr-0.1mm; feed 52-0.25mm. According to the given modes, we select the geometric parameters of the reamer. Since with the given cutting modes, the most optimal angle of departure of the chips is ps 7, which ensures the movement of chips from under the teeth of the reamer in the translational direction chip grooves of the countersink, then we accept the following geometric parameters of reaming: the main angle in the plan f-:5", the angle of inclination of the main cutting edge X--20".

A countersink with the selected geometric parameters will ensure the movement of chips in the direction of the machined surface, which in turn will ensure the necessary roughness of the machined surface, avoid bagging of chips and premature breakage of the tool.

Thus, the proposed processing method ensures steady movement of the chip in the feed direction and also allows you to avoid hole breakage, chip packing, nadirs on the processed surface, due to controlling its direction.

Claims (1)

The method of processing through holes with a tool of the countersink-reamer type, which includes simultaneous rotational movement and feeding of the tool, which differs in that the chips, which are "removed by the teeth of the countersink, are directed to the machined surface at an angle of east-Chgrurkya, the deviation of which is determined by the dependence: Che o 2f-agosov )---B54Ж7ЖЖ.l88--Ш-- With tod VA 1-01 gray (Oge: 18(45 - 9). 1; p) where b. tolerance on the machined hole; E - modulus of elasticity of the processed material (MPA); Y - the moment of inertia of the tool neck; t. . - . not sl. - shear stress for the tangential component of the cutting force on the front surface; in - A - the permissible value of the axial runout of the cutting edges; 9. chipping angle, which determines the position of the displacement plane; Y - cutting depth; Y. - tool flight, while the chips removed by the teeth of the reamer are placed in the chip grooves of the countersink, and the volume of the concentric grooves of the countersink is determined depending on the pitch. PC: r, r "open (2) I. where hole is the length of the processed hole; -R. - feed to the reamer tooth; " . P - depth of cutting reamer; Kk filling factor of the chip groove; PP - the number of teeth of the sweeper.