SU1514590A1 - Method of dressing abrasive wheel - Google Patents

Description

The invention relates to the abrasive machining of parts and can be used on various grinding operations. The purpose of the invention relates to the abrasive machining of parts and can be used in the implementation of various grinding operations.

The purpose of the invention is to improve the quality of editing abrasive wheels while simultaneously improving the durability of the governing instrument with a conical working part by discretely turning it around its own axis with an increase in torque 1.8-3.1 times per step, determined depending on the ratio of the size of the working abrasive grains parts of the governing instrument and its geometrical parameters, according to which op2

The tendency is to improve the quality of edits while increasing the durability of the governing instrument. The ruling tool with a truncated conical working part is installed with the possibility of discrete rotation from contact with the grinding wheel. The installation angle γ is chosen from the mathematical expression provided in the description of the invention. The ruling tool is fixed by means of a gear mounted on its holder that interacts with an elastic element. The magnitude of the angular step of the discrete rotation of the governing instrument is determined by the formula. Rotation of the governing instrument is carried out with increasing torque acting on it 1.8-3.1 times. This improves the quality of editing and tool life. 1 il.

The angle of installation of the axis of the tool ’· ment with respect to the generator of the abrasive disc is determined.

The drawing shows a schematic of the proposed method.

To edit the abrasive wheel 1, the ruling tool 2 is set at an angle γ to the surface of the circle and moved along its generator. The installation angle γ is chosen from the condition

γ = 90 ° - ags Sy (K, - | - +

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where Ρ _ζ , P _y - the tangent and the normal components of the effort

edits;

Oy, 0 _g - respectively, the outer diameter of the working part of the governing instrument and its tip;

K ₍ -coefficient characterizing the magnitude of the forces of u when editing;

K _? - coefficient characterizing the geometric parameters of the governing instrument. 15

In order for the governing instrument to rotate to a strictly defined value as the diamond grains wear out, it is fixed with the help of a gear wheel 3 mounted on its holder, which interacts with an elastic element 4, and the angular pitch of the gear wheel * is determined according to formula 25

<Y = 21G / E,

where E is the integer part of the expression

K 8, / ά ₃ ; thirty

8 ₃ - grain diameter;

K - coefficient characterizing the edit mode, K = 3.5–6.5.

The coefficient K ,, characterizing ^ 5 the magnitude of the forces when editing, must be in the range of 0.35-0.6. With a decrease in the coefficient K _p below 0.35 and an increase above 0.6, there is a decrease in the tool life and the surface quality of the workpiece. The coefficient K characterizing the geometrical parameters of the governing instrument, has optimal values in the range of 0.15-0.30. With values less than 0.15 and more than 0.30, there is a decrease in tool life, as well as the surface quality of the workpiece during subsequent grinding. The turning of the governing instrument around its own axis is carried out discretely as the abrasive grains are blunt on its working part. The moment of rotation is determined by the increase in the torque generated by the tangential component Ρ _{ζ of} the dressing force, by a factor of 1.8–3.1 relative to the initial one.

Primer p. Tests carried out on a circular grinding machine mod. ZB151 when grinding the sleeves of steel 45 (IKS 38-42) with a diameter of 85 mm and a length of 100 mm. Characteristics of the abrasive grinding wheel - PP 600x63x307 24A25SM2K6. A lubricating cooling fluid (coolant) is a 5% solution of emulsol ET-2 in water. The correcting instrument is a special construction with a diameter of 25 mm and a conical working part, on the surface of which diamond grains 2.5 mm in diameter, made of polycrystalline specs, are evenly distributed in the device for editing at an angle of 90 ° - arcs (K ₄ * * P _g / P _a + K ₂ с1 ₂ /,). For these processing conditions K = 0.5; K, = 0.3; P ₂ =

= 5.9 Η; P ^, = 20 N (taken from monograms); 8, = 25 mm - outer

diameter of the working part of the tool;

γ = 69.9 °, which ensures stable straightening and rotation (turning from contact with a circle) with the adopted straightening mode; V _kr = 35 m / s; 5 _L p =

= 0.6 m / min; 8 _Lop = 0,025 mm / course.

A gear wheel with an angular pitch “T = 0.101, defined at K = 6.2, is installed on the holder of the governing instrument.

The ruling tool with a gear wheel mounted on its holder. 4 is kept from turning in the process of editing by an elastic element (plate) of steel 65G. The specified plate with a thickness of 0.1 mm is tipped in such a way that as the grain wears as the cutting forces increase 1.8–2 times, it folds down and allows the gear wheel to rotate on one tooth, while a new grain enters the work. In the above straightening conditions, tool turning occurs when grain wear reaches 0.4 mm. The specified amount of wear is optimal for this type of processing from the point of view of tool life, as well as the surface roughness of the parts after grinding with a filled wheel. Timely cranking of the tool and the entry into work of a new grain make it possible to maintain tool durability and surface quality of parts at a high level.

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In the given example with K, =

= 0.40; K ₂ = 0,18 durability of the governing instrument, expressed by the relative expense, is

3.6 mg / kg, and the surface roughness is = 1.25 μm. When K =

= 0.28; K _? = 0.10 The durability of the governing instrument, expressed by the relative expense, is 4.5 mg / kg, and the surface roughness is K _and = 1.60 μm. With an increase in the coefficient K, to 0.70 and K _g to 0.35 (outside the optimal range), the tool life decreases to a relative flow rate of 5.1 mg / kg, and the surface roughness is =

= 1.8 microns. Thus, when the values of the coefficients outside the optimal ranges (K, = 0.35 0.60 and K ₄ = 0.15-0.30), a decrease in the durability of the governing instrument and a deterioration in the roughness of the machined surface of the parts is observed.

Claims (1)

Claim The method of editing the abrasive wheel, according to which the governing instrument with abrasive grains and with a truncated conical working surface is installed with the possibility of rotation around its own axis, orient its axis at an angle, 35 equal to half the angle of the cone, to the circle generators and move along the circle generators, which is the fact that, in order to improve the quality of edits at 40, simultaneously increasing the durability of the governing instrument, the turn of the governing instrument is carried out discretely with increasing, the tangential component the moment 1.8-3.1 times, while the angle of orientation of the axis of the governing instrument to the circle generator is determined by the formula 10 Y ^{= 90} ° “ ^{arcs (Κ} ι" I " ⁺ at ⁺ ' 15 where P _£ is the tangent component of the editing power; Ru is a normal component of the editing power; ά · - outer diameter of the working 20 parts of the governing instrument; 8 2 - diameter of the tip of the truncated cone of the governing instrument; 25 - the coefficient characterizing the magnitude of the power of editing and equal to 0,35-0,60; - the coefficient characterizing the geometric parameters of the 30 ruling instrument and equal to 0.15-0.30, and the pitch is determined by the dependence where E is the integer part of the expression ka78 ₃ ; where K is a coefficient characterizing the editing mode and is equal to 3.56.5; 8 ₃ - the diameter of the grains of the governing instrument. 1514590