Exterior surface roughness
- source:MAJA CNC Machining
Com pursues 2 rough degree of average height outline is the biggest high Ry, it is namely inside sampling length, the distance between outline peak top line and outline cereal bottom line. Span parameter shares two: S of between-mean distance of outline Chan Feng, it is namely inside sampling length, the average of span of outline odd peak. And span of outline odd peak, the apogee that is odd peak of two-phase adjacent outline is in the umbriferous length Si on central line. Outline is microcosmic and rough spent between-mean distance Sm. The Smi of length of a paragraph of central line that contains an outline peak and cereal of photograph adjacent outline, call outline microcosmic and rough span. Integrated parameter has only, it is Tp of rate of outline bearing length. It is Np of outline bearing length and sampling length L than. In original national level, the surface is bright and clean spend cent to be 14 class, its code name is 1, 2... 14. The number after is larger, the surface is bright and clean degree taller, namely numerical value of exterior surface roughness is less. In workshop production, the spare parts surface that often comes out according to exterior roughness sample and treatment undertakes comparative, with the feeling of naked eye or finger, will judge the grade of surface roughness of spare parts surface. In addition, still a lot of is measure bright and clean metrical instrument. Exterior surface roughness uses a circumstance to have very big effect to the spare parts. Say commonly, numerical value of exterior surface roughness is little, can rise cooperate quality, decrease wear away, prolong spare parts service life, but the treatment cost of the spare parts can raise. Accordingly, should correct, choose numerical value of exterior surface roughness reasonably. When designing a part, exterior surface roughness counts the option of the value, decide in the action in the machine according to the spare parts. Total principle is: Below the premise that makes sure contented technology asks, choose numerical value of greater exterior surface roughness. When specific choice, OK and referenced undermentioned principle: (1) the surface roughness numerical value that working surface compares blame job face is little. (2) attrition surface is compared do not chafe surface roughness numerical value of the surface is little. The attrition rate of attrition surface heals tall, the unit pressure that gets heals big, should heal tall; Scroll grinds the surface grinds than sliding numerical value of exterior requirement surface roughness is little. (3) to clearance fit, cooperate clearance to heal small, surface roughness numerical value should heal small; Cooperate to be filled with too, be those who assure join intensity is firm and reliable, load heals big, numerical value of requirement surface roughness heals small. General situation clearance fit adds up to surface roughness numerical value to want than be filled with Yun too small. (4) the surface roughness that cooperates the surface should ask to comparative with its dimension precision. When cooperating property photograph to be the same as, spare parts dimension heals small, answer surface roughness numerical value heals small; Same accuracy class, small size wants surface roughness numerical value than large size small, the axis wants surface roughness numerical value than aperture small (especially the precision of IT8 ～ IT5) . (5) the face that gets periodic load and may produce stress to center inside round horn, sunken check is in surface roughness numerical value to answer lesser. Outline is the biggest high Ry is rough the finish mark of L of length of sampling of Ra of average and arithmetical deviation that spends outline of average height Rz 0.