In the 1970s, the use of diamond binders and cubic boron nitride whetstones with metal binders was used to process hardened steel or cast iron, and the wear was only 1/150 to 1/250 of ordinary oilstone, and the pressure of the stone on the workpiece was also It can be increased by 2 to 3 times, so that the efficiency and surface quality of honing are further improved.
Introduction Finishing of finished surfaces with oilstone (also known as honing bars) mounted on a honing head. Also known as honing. It mainly processes various cylindrical holes with a diameter of 5 to 500 mm or more, and the ratio of the hole depth to the hole diameter can be 10 or more. Under certain conditions, planes, outer surfaces, spherical surfaces, tooth surfaces, etc. can also be processed. The outer circumference of the honing head is set with 2 to 10 oil stones with a length of about 1/3 to 3/4 of the hole length, which rotates and moves back and forth during the boring, and is evenly raised by the spring or hydraulic control in the honing head. Therefore, the contact area with the surface of the hole is large, and the processing efficiency is high. The dimensional accuracy of the honed hole is IT7~4, and the surface roughness can reach Ra0.32~0.04 microns. The amount of honing allowance depends on the hole diameter and the workpiece material. Generally, the cast iron piece is 0.02 to 0.15 mm, and the steel piece is 0.01 to 0.05 mm. The speed of the honing head is generally 100 to 200 rpm, and the speed of the reciprocating motion is generally 15 to 20 m/min. In order to wash away the chips and abrasive grains, improve the surface roughness and lower the temperature of the cutting zone, it is often necessary to use a large amount of cutting fluid, such as kerosene or a small amount of spindle oil, and sometimes an extreme pressure emulsion.
Method 1 During honing, the workpiece is mounted on a boring machine table or in a fixture. A honing head with a number of oil stone strips is inserted into the machined hole, which is rotated by the machine tool spindle and reciprocated axially. The oil stone strip is in contact with the wall of the hole at a certain pressure to cut off a very thin layer of metal. The honing head is generally in floating connection with the main shaft.
2 The honing head has several types of mechanical pressure, air pressure or hydraulic pressure regulation. The honing head shown in the figure is mechanically pressurized, and the hydraulic pressure regulating type is often used in actual production.
Process characteristic 1 can effectively improve the dimensional accuracy, shape accuracy and reduce the Ra value, but can not mention. 2 Machinable cast iron parts, hardened and unhardened steel parts and bronze parts, etc., but it is not suitable to process the toughness of non-ferrous metal parts. . Positional accuracy of high holes and other surfaces. 3 The processing aperture range is φ5～ φ500, and the aspect ratio can reach 10. 4 Honing is widely used in large batch production of cylinder bores, cylinders, valve bores and various barrels. Can also be used in single-piece small batch production.
Use Finishing of the finished surface with oil stone (also known as honing stick) embedded in the honing head (see cutting). The honing is mainly used for processing various cylindrical holes with a hole diameter of 5 to 500 mm or more, such as a cylinder barrel, a valve hole, a connecting rod hole and a box hole, etc., and the ratio of the hole depth to the aperture is up to 10 or even larger. Under certain conditions, honing can also process outer circles, planes, spheres and tooth surfaces. The surface roughness of cylindrical honing is generally up to Ra0.32~0.08μm, and it can reach Ra0.04μm or less in fine boring, and can improve geometric precision in a small amount, and the processing precision can reach IT7~4. The surface quality of the plane honing is slightly worse.
Honing machines are generally honing machines. The machine tool spindle and the honing head are generally floating joints; however, in order to improve the ability to correct the geometry of the workpiece, rigid joints can also be used. When boring, the outer circumference of the honing head is usually set with 2 to 10 oil stones, which are driven by the machine tool spindle to rotate in the hole and simultaneously reciprocate linearly. This is the main motion; at the same time, the oil stone is evenly controlled by the spring or hydraulic pressure in the honing head. Externally rising, radial feed is made to the wall of the hole being machined. Figure 1 is a schematic diagram of internal circle honing. The ratio of the number of reciprocating times per minute of the honing head to the number of revolutions should be non-integer, so that the processing marks formed by the abrasive on the surface of the workpiece become intersecting nettings without being repeated. Figure 2 shows the trajectory of a single piece of whetstone honed in a hole. The oil stone reciprocates up and down once, and the workpiece rotates more than one turn. The coarse-grained whetstone has an abrasive grain size of 120 to 180, and the fine boring stone has a fine-grained whetstone of W28 or less. The oil stone has a width of 3 to 20 mm and a length of about 1/3 to 3/4 of the length of the hole. When the oil stone reciprocates in the hole, the length of the two ends beyond the hole should not be larger than 1/3 of the full length of the oil stone, otherwise it is easy to produce the mouth; but if the overtravel is less than 1/4 of the length of the oil stone, the hole will be drum shaped. . The external and flat honing principles and operational requirements are the same as for internal honing.
The honing allowance is generally not more than 0.2 mm. The circumferential speed of honing is about 15 to 30 m/min for steel processing, and can be increased to 50 m/min for cast iron or non-ferrous metal; the reciprocating speed of honing should not exceed 15 to 20 m/min. The pressure of the oil stone on the hole wall is generally 0.3-0.5 MPa, the rough å¯è¾¾ can reach about 1 MPa, and the fine ç© can be less than 0.1 MPa. Since the whetstone is in surface contact with the workpiece during honing, the vertical pressure of each abrasive particle on the surface of the workpiece is only 1/50~1/100 when grinding, and the honing speed is low, so the temperature of the cutting zone can be kept at 50-150. In the range of °C, it is beneficial to reduce the residual stress of the machined surface and improve the surface quality. In order to wash the chips and avoid blocking the oil stone, while reducing the temperature of the cutting zone and reducing the surface roughness, the cutting fluid used in the honing must have a certain working pressure and be filtered. Most of the cutting fluids use kerosene, or kerosene plus spindle oil, and extreme pressure emulsions.
Technical Improvements In the 1970s, diamond binders and cubic boron nitride whetstones, which used metal binders, were used to process hardened steel or cast iron, and the wear was only 1/150 to 1/250 of ordinary whetstone, while the whetstone was on the workpiece. The pressure can also be increased by 2 to 3 times, so that the efficiency and surface quality of the honing are further improved.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
According to its solubility, it can be divided into two types: water-soluble and water-insoluble.
Synthetic pigments have bright color, strong coloring power, stable performance, are not easy to fade, and are used in a small amount.
Relatively speaking, they are inexpensive and have been widely used.
Edible Flavor
High Temperature Resistance Edible Flavor, Edible Flavor, High Quality Edible Flavor, Healthy Edible Flavor
Jinan huijinchuan trading Co. LTD , https://www.hjcchemical.com