车削丝杠螺纹时,必须考虑螺纹升角对车削的影响,车刀进刀方向的后角应取()。
A. 2°~3°
B. 3°~5°
C. (3°~5°)+ψ
D. (3°~5°)-ψ
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According to the passage, what is the best for both parents and children
A. They should adjust themselves to sharing the family expenses.
B. Children should leave their parents when they are grown up.
C. Adult children should visit their parents from time to time.
D. Parents should support their children when they are in trouble.
车淬硬钢时,在冲击条件下,车刀刃倾角可取( )。
A. -10°~-20°
B. 0°
C. 10°~20°
D. -10°~0°
根据《建设工程质量管理条例》的规定,勘察、设计单位必须按照工程建设强制性标准进行勘察、设计,( )应当在设计文件上签字,对设计文件负责。
A. 单位负责人
B. 勘察、设计人
C. 注册执业人员
D. 项目负责人
精车大模数ZA蜗杆时,必须使车刀左右刀刃组成的平面处于水平状态并与工件中心等高,以减少( )误差。
A. 齿
B. 导程
C. 齿形
D. 齿厚