RU2204474C2 - Combination method for supplying cutting fluid to grinding zone - Google Patents

Abstract

FIELD: technological processes in machine engineering and machine tool manufacture, namely processes for combination supply of cutting fluid through pores of grinding wheel with axially shifted cutting layer and at using pressure liquid oscillating jet. SUBSTANCE: method comprises steps of supplying two different type cutting fluids through two axial ducts of mandrel formed due to division of its axial cavity by lengthwise partition and through radial openings communicated with said ducts; using wheel consisting of abrasive discs mounted on rotating mandrel and spacing washers placed between discs with axially shifted cutting layer. EFFECT: enhanced efficiency of cutting fluid action due to combination supply of it through pores of grinding wheel at simultaneously using pressure liquid oscillating jet by means of buildup lengthwise-intermittent grinding wheels with axially shifted cutting layer. 4 cl, 3 dwg, 1 ex

Description

 The invention relates to mechanical engineering and machine tool engineering, and in particular to methods for the combined supply of a lubricant-cooling technological mixture (SOTS) through the pores of a grinding wheel with an axially-displaced cutting layer and a pressure fluid oscillating jet.

 A known method of supplying a cutting fluid (coolant) to the grinding zone, according to which the coolant through the axial cavity of a mandrel rotating at a speed ω, is fed into radial channels connected to the cavity and from there into the grinding zone, in addition, a plate auger with radius r with a helical surface formed by a curve described by the above equation [1].

 The disadvantage of this method is the impossibility of ensuring the effectiveness of the coolant in the combined method of supplying the coolant to the grinding zone and the inability to use it when working precast longitudinally discontinuous grinding wheels with an axially offset cutting layer.

 A combined coolant supply method is known, implemented in the construction of a prefabricated abrasive wheel, which is equipped with plates installed between the covers at the base of the abrasive elements and two conical covers installed with axial movement in the cover for supplying coolant, while the surfaces of the conical covers form a second channel for supplying another Coolant [2].

 The disadvantages of the above method are: a complex coolant supply system, the impossibility of ensuring the effectiveness of the coolant for traditional wheels, the narrow specialization of use is only for prefabricated abrasive elements of the wheels and the inability to use it when working prefabricated longitudinally discontinuous grinding wheels with an axially offset cutting layer.

 Known is a combined method (10) for supplying SOTS, carried out by a freely falling stream - “cooling by irrigation” (method 1) and feeding SOTS through the pores of the grinding wheel (method 4) [4]. The first method is used only when grinding parts on universal machines in a single production from materials that have good machinability by grinding (hardened carbon steels).

 However, this method has an insignificant lubricating effect of SOTS and an insignificant washing effect of SOTS with respect to the circle.

 Method 4 for supplying SOTS through the pores of a circle is used only for circles made of ceramic bonds, and the method has an insignificant cooling effect of SOTS and an insignificant washing action of SOTS with respect to the part and the machine.

 The objective of the invention is to ensure the effectiveness of the action of SOTS with a combined method of supplying SOTS to the grinding zone through the pores and a pressure oscillating jet with prefabricated longitudinally discontinuous circles with an axially offset cutting layer.

 The problem is solved by using the proposed method for the combined supply of a lubricant-cooling technological mixture (COTS) into the grinding zone with a combined longitudinally intermittent wheel consisting of abrasive disks mounted on a rotating mandrel and spacer washers between them and made with an axially-displaced cutting layer, and the supply of two dissimilar SOTS through two axial channels of the mandrel formed by the separation of its axial cavity by a longitudinal partition, and radial holes associated with mentioned channels.

 In this case, the supply of one of SOTS, which is used as SOTS with good lubricating properties, is carried out through one of the axial channels connected to the abrasive disks by means of circumferential grooves made on the outer surface of the mandrel at the places of installation of the abrasive disks, the pores of the abrasive disks.

 In addition, as a COTS, which has good lubricating properties, oil is used, the supply of which is carried out by oscillating jets through another axial channel connected to the cavities between the abrasive disks by means of circumferential grooves made on the inner surface of the spacer washers and radial holes of the spacer washers.

 In FIG. 1 shows a prefabricated longitudinally discontinuous circle with an axially offset cutting layer consisting of abrasive disks and spacer washers mounted on a mandrel for implementing the method; figure 2 is a section aa in figure 1; figure 3 is a section bB in figure 1.

 The method of combined supply of a lubricant-cooling technological mixture (COTS) to the grinding zone is implemented using a precast longitudinally intermittent wheel with an axially offset cutting layer.

 It consists of abrasive discs 1 and spacer washers 2 between them, mounted on the mandrel 3 at an angle α to a plane perpendicular to the axis of rotation of the tool. The angle of inclination of the discs 1 is set and adjusted by oblique washers 4, installed in pairs from the external ends of the assembly circle. The disks 1 are mounted on the mandrel with nuts 5.

 The Central cavity of the mandrel 3 is additionally divided by a longitudinal partition 6 with the formation of two axial channels 7 and 8 for supplying two dissimilar SOTS. The sealing of channels 7 and 8 is provided by seals 9 and a screw plug 10.

 SOTS with good lubricating properties (oil) is fed into one axial channel, for example 7, connected by radial holes 11 and circumferential grooves 12, made on the outer surface of the mandrel 3 in the places of installation of the abrasive disks 1, with abrasive disks and from there through the pores into the grinding zone .

 SOTS, with good cooling properties, is fed into the second axial channel 8, connected by radial holes 13 and circumferential grooves 14, made on the inner surface of the hole of the spacer washers 2 and from there through the radial holes of the 15 spacer washers with oscillating jets in the cavity between the abrasive disks 1 into the zone cutting.

 The method is as follows.

 The assembled assembled abrasive wheel is balanced in a known manner and corrected.

 In the process of grinding COTS with good lubricating properties, for example, oil enters through one axial channel 7, passes through radial holes 11 and enters circumferential grooves 12 made on the outer surface of mandrel 3 at the places of installation of abrasive disks 1. Here, the oil is subjected to centrifugal force ejected through the pores of the abrasive discs 1 directly into the cutting zone, providing an effective lubricating effect in the cutting zone.

 An emulsion with good cooling properties (but worse lubricating properties compared to oil) enters the second axial channel 8, passes through the radial holes 13 and enters the circumferential grooves 14 made on the inner surface of the hole of the spacer washers 2. Once in the grooves 14 of the fast-rotating washers 2, the emulsion under the action of centrifugal force is ejected through the radial holes 15 of the spacer washers 2 by oscillating jets in the cavity between the abrasive disks 1 into the cutting zone.

 The implementation of the proposed combined method of supplying SOTS using the developed design of a precast longitudinally discontinuous circle with an axially offset cutting layer, consisting of abrasive disks and spacer washers between them mounted on the mandrel, can significantly increase the efficiency of the applied SOTS.

 The oil entering through the pores of the abrasive disks 1 directly into the cutting zone creates lubricating films on the abrasive grains, significantly reduces the coefficient of friction of the grain and the binder on the material of the workpiece, which leads to a decrease in the friction forces of cutting and temperature in the processing zone.

 It is known that not only the oscillation of the cutting zone due to the inclination of the abrasive discs at an angle α [3], but also the interruption of the cutting zone in the longitudinal direction, make it possible to tighten cutting conditions, increase vibration resistance and reduce grinding heat stress.

 Therefore, following the oscillating movement of the cutting zone discontinuous in the longitudinal direction by abrasive disks, powerful emulsions emitting in the longitudinal direction are directed onto the surface to be treated, having a good cooling effect and having a high speed of movement relative to the workpiece.

 The high relative speed of the oscillating motion in combination with the high cooling effect of the emulsion eliminates burns and other surface defects at high grinding conditions.

 Thus, the proposed combined method of supplying COTS to the grinding zone and a prefabricated longitudinally discontinuous circle with an axially offset cutting layer for its implementation make it possible to ensure its oscillation and the effectiveness of the action of COTS.

Example. We spent processing holes holes on the internal grinding machine mod. 3K228V. The workpiece material is steel 45 GOST 1050-74, HB 260, machining diameter 130 mm, length 60 mm, cutting tools - abrasive disks PP 100x13x20 24A 10 VM1 10 K5 / P40-15 (where: P40-15 - grain size of pore formers from perlite) GOST 2424-83. Processing modes: workpiece speed - 40.8 m / min (100 rpm), tool rotation speed - 31.4 m / s, tool rotation speed - 6000 rpm, minute longitudinal feed S _pr = 5390 mm / min, cross feed of a circle - 0,012 mm / dv.hod.

The number of single abrasive disks in a combined grinding wheel was 3 pcs., The oscillation amplitude of the wheel was set to A _A = 6.5 mm, the angle of inclination of the disks to a plane perpendicular to the axis of rotation was α = 3 ^o 42 ', the axial clearance Z between the abrasive disks was Z = 6.5 mm was installed using two spacer washers.

 Lubricant-cooling technological mixture, passed through the pores of abrasive disks, - industrial oil; served between abrasive disks - an emulsion. Processing was carried out in 20 passes.

Abrasive treatment using a combined method of supplying COTS to the grinding zone with a combined longitudinally intermittent wheel with an axially displaced cutting layer made it possible to increase the feed by a factor of 2.5 by a double stroke, in which a high-quality processed surface of the required roughness is obtained (R _a = 0.63 μm ) free from defects, burns and microcracks.

The time spent on processing - T _o = 0.42 min compared with T _o = 1.17 min - when grinding with a normal circle, allows us to conclude that the invention improves productivity by 2.5-3 times and provides oscillating and effective action of SOTS with the combined method of supplying SOTS.

 The proposed method is suitable for grinding parts on universal, specialized and special machines in a single, serial and mass production from materials having good machinability and difficult to grind.

 This method has a highly effective lubricating effect of COTS and a good cleaning effect of COTS in relation to the circle.

 Moreover, the method has a highly effective cooling effect of SOTS and a good washing effect of SOTS in relation to the part and the machine.

Sources of information
1. A. p. USSR 1673418, MKI V 24 V 55/02. The method of supplying cutting fluid to the grinding zone. Yu.S. Danilov, N.D. Gavrilov, A.A. Simdyankin. Application 4737513/08, application. 09/15/89, publ. 08/30/91. Bull. 32.

 2. A. p. USSR 1034885, MKI V 24 V 55/02. Prefabricated abrasive wheel. V.G. Gusev. Application 3391121 / 25-08, application. 02/05/82, publ. 08/15/83. Bull. thirty.

 3. A. p. USSR 1611714, MKI V 24 V 45/00. Device for attaching the grinding wheel. Yu. M. Ermakov, Yu. S. Stepanov and B.I. Afanasyev. Application 4429371 / 31-08, application. 05.24.88, publ. 12/07/90. Bull. 45.

 4. Kashchuk V.A., Vereshchagin A.B. Handbook grinder. - M.: Mechanical Engineering, 1988 .-- S. 245-252.

Claims (4)

 1. The method of combined supply of a lubricant-cooling technological mixture (COTS) to the grinding zone with a combined longitudinally intermittent wheel, consisting of abrasive disks mounted on a rotating mandrel and spacer washers between them, and made with an axially offset cutting layer, including the supply of two dissimilar COTS through two axial channels of the mandrel, formed by the separation of its axial cavity by a longitudinal partition, and radial holes associated with the said channels.  2. The method according to p. 1, characterized in that the supply of one of the SOTS, which use SOTS with good lubricating properties, is carried out through one of the axial channels associated with the abrasive discs by means of circumferential grooves made on the outer surface of the mandrel at the installation site abrasive disks, and pores of abrasive disks.  3. The method according to p. 2, characterized in that as the COTS, which has good lubricating properties, use oil.  4. The method according to any one of paragraphs. 1-3, characterized in that the supply of COTS, which is used as COTS with good cooling properties, is carried out by oscillating jets through another axial channel connected to the cavities between the abrasive discs by means of circumferential grooves made on the inner surface of the spacer washers and radial holes of the spacer washers.

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