Scraping
2020-01-15 13:08:02
When scraping a general plane, a long strip-shaped scraper is used. The material is generally spring steel (forging with a used bearing back to the furnace), and the cutter head can be directly used for fine scraping after heat treatment, or the alloy blade can be welded for rough scraping.
Concept Scraping is the use of a scraper to scrape off trace metals on the surface of a machined workpiece to improve surface shape accuracy and improve the fit between the surfaces. Scraping is an important method for finalizing various profiles (such as machine tool guide faces, joint faces, bushings, mating spheres, etc.) in machine building and repair. The real role of scraping is to improve the matching precision between the interactive mating parts and to improve the oil storage conditions. At the same time of the scraping motion, the grinding between the workpieces has a certain improvement on the hardness of the workpiece surface, and the small pits left on the surface of the workpiece after scraping can be The oil is stored so that the workpiece can be sufficiently lubricated during reciprocation without causing overheating.
Application scraping is generally performed by a fitter's hand-held scraper, with both planar and curved scraping methods. The scraper is generally made of carbon tool steel or bearing steel. The back end is equipped with a wooden handle. The part of the cutter body is hardened to about HRC60. The cutting edge is ground and can be re-grinded after being worn. The surface of the workpiece is first machined and the scraping allowance is 0.05 to 0.4 mm. The flat scraping operation is divided into two types: push and pull. Pushing mainly relies on the pushing force of the arm force and the ankle, and the cutting force is large, which is suitable for large-area rough scraping and semi-fine scraping. The pulling stroke relies only on the arm force to pressurize and pull back, and the cutting force is small, but the scraping length is easy to control, and is suitable for fine scraping and scratching.
When the surface is scraped, the curved blade is controlled by the wrist force, so that the side edge is scraped along the surface of the workpiece.
Before each scraping, in order to identify the position and extent of the workpiece error, it is necessary to apply a thin layer of display agent (also applied to the workpiece) on a precision flat plate, flat ruler, special inspection tool or the matching part of the workpiece. Then, the workpiece is combined with the workpiece. After the grinding, some bumps on the surface of the workpiece will be clearly displayed. This process is called a display point. Commonly used display agents are reddish oil (iron oxide or lead oxide plus mechanical oil) or blue oil (Prussian blue and castor oil or mechanical oil). After the display, the convex portion shown is scraped off. After repeated display and scraping, the number of display points on the surface of the workpiece is gradually increased and evenly distributed, which means that the shape error of the surface is gradually reduced. Therefore, scraping is also commonly referred to as scraping.
The quality of the scraped surface is usually measured by the number of dots uniformly distributed over a 25 x 25 mm area. Generally, the connection surface requires 5 to 8 points; the general guide surface requires 8 to 16 points; the surface of the inspection tool such as the flat plate and the flat ruler and the precision guide surface of the sliding fit are required to have 16 to 25 points; some high-precision measuring tools are required. The surface requirements are 25 to 30 points. On the exposed surface after scraping, a neat fish scale or diagonal pattern is sometimes scraped to improve the appearance. A layer of crescent pattern or chain pattern on the precision sliding surface after fine planing, finishing or grinding can improve the lubrication conditions during work, form micro oil grooves and improve wear resistance.
When scraping a general plane, a long strip-shaped scraper is used. The material is generally spring steel (forging with a used bearing back to the furnace), and the cutter head can be directly used for fine scraping after heat treatment, or the alloy blade can be welded for rough scraping. The scraping surface is generally a triangular scraper. The material is generally high carbon steel. For example, the main shaft copper sleeve of the scraping lathe is illuminated by running lights, scraped with the strength of the elbow, and displayed with red powder. Any machine in this respect can not be replaced. At the same time of scraping, it is necessary to measure the geometrical tolerances in different time periods. At the same time, pay attention to the requirements of the research points. To approach the tolerance standard is to increase the number of scraping points. When the accuracy requirements are met, the number of points must also meet the inspection requirements before successful scraping.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
Concept Scraping is the use of a scraper to scrape off trace metals on the surface of a machined workpiece to improve surface shape accuracy and improve the fit between the surfaces. Scraping is an important method for finalizing various profiles (such as machine tool guide faces, joint faces, bushings, mating spheres, etc.) in machine building and repair. The real role of scraping is to improve the matching precision between the interactive mating parts and to improve the oil storage conditions. At the same time of the scraping motion, the grinding between the workpieces has a certain improvement on the hardness of the workpiece surface, and the small pits left on the surface of the workpiece after scraping can be The oil is stored so that the workpiece can be sufficiently lubricated during reciprocation without causing overheating.
Application scraping is generally performed by a fitter's hand-held scraper, with both planar and curved scraping methods. The scraper is generally made of carbon tool steel or bearing steel. The back end is equipped with a wooden handle. The part of the cutter body is hardened to about HRC60. The cutting edge is ground and can be re-grinded after being worn. The surface of the workpiece is first machined and the scraping allowance is 0.05 to 0.4 mm. The flat scraping operation is divided into two types: push and pull. Pushing mainly relies on the pushing force of the arm force and the ankle, and the cutting force is large, which is suitable for large-area rough scraping and semi-fine scraping. The pulling stroke relies only on the arm force to pressurize and pull back, and the cutting force is small, but the scraping length is easy to control, and is suitable for fine scraping and scratching.
When the surface is scraped, the curved blade is controlled by the wrist force, so that the side edge is scraped along the surface of the workpiece.
Before each scraping, in order to identify the position and extent of the workpiece error, it is necessary to apply a thin layer of display agent (also applied to the workpiece) on a precision flat plate, flat ruler, special inspection tool or the matching part of the workpiece. Then, the workpiece is combined with the workpiece. After the grinding, some bumps on the surface of the workpiece will be clearly displayed. This process is called a display point. Commonly used display agents are reddish oil (iron oxide or lead oxide plus mechanical oil) or blue oil (Prussian blue and castor oil or mechanical oil). After the display, the convex portion shown is scraped off. After repeated display and scraping, the number of display points on the surface of the workpiece is gradually increased and evenly distributed, which means that the shape error of the surface is gradually reduced. Therefore, scraping is also commonly referred to as scraping.
The quality of the scraped surface is usually measured by the number of dots uniformly distributed over a 25 x 25 mm area. Generally, the connection surface requires 5 to 8 points; the general guide surface requires 8 to 16 points; the surface of the inspection tool such as the flat plate and the flat ruler and the precision guide surface of the sliding fit are required to have 16 to 25 points; some high-precision measuring tools are required. The surface requirements are 25 to 30 points. On the exposed surface after scraping, a neat fish scale or diagonal pattern is sometimes scraped to improve the appearance. A layer of crescent pattern or chain pattern on the precision sliding surface after fine planing, finishing or grinding can improve the lubrication conditions during work, form micro oil grooves and improve wear resistance.
When scraping a general plane, a long strip-shaped scraper is used. The material is generally spring steel (forging with a used bearing back to the furnace), and the cutter head can be directly used for fine scraping after heat treatment, or the alloy blade can be welded for rough scraping. The scraping surface is generally a triangular scraper. The material is generally high carbon steel. For example, the main shaft copper sleeve of the scraping lathe is illuminated by running lights, scraped with the strength of the elbow, and displayed with red powder. Any machine in this respect can not be replaced. At the same time of scraping, it is necessary to measure the geometrical tolerances in different time periods. At the same time, pay attention to the requirements of the research points. To approach the tolerance standard is to increase the number of scraping points. When the accuracy requirements are met, the number of points must also meet the inspection requirements before successful scraping.
Http://news.chinawj.com.cn Editor: (Hardware Business Network Information Center) http://news.chinawj.com.cn
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