CNC Machinist Skill Certification Exam Question Bank

Author: Chief Editor: Cui Shirong
Publisher:
Publish Date: 2001-05-01
Features: Accompanying materials for use. It includes three levels: beginner, intermediate, and advanced. Each level consists of three parts: knowledge requirement questions and answers (including true/false questions, multiple-choice questions, calculation questions, and short-answer questions), skill requirement questions, and knowledge requirement examination paper samples. The content progresses from low to high, with a large number of questions, diverse question types, sample examination papers, and scoring standards. It is suitable for learners' review and can also be used by vocational skill assessment departments at all levels for question setting.
Excerpt:
Anger and laziness are not the way to success.
(78) When using a V-block to clamp shaft parts of different diameters, the center position of the workpiece remains unchanged.
(79) The jaw of a shaft vise automatically positions shaft parts.
(80) When using a face mill to score marks on a shaft workpiece for alignment, the marks are elliptical.
(81) The alignment method for a keyway end mill involves positioning the cutting edge of the mill so that its rotational path falls in the middle of a rectangular small flat mark.
(82) When using a dial indicator for alignment, the probe should contact the workpiece's generatrix before adjustment.
(83) Most keyway milling on general-purpose milling machines is performed using the step-milling method.
(84) When a keyway end mill becomes dull, its end face teeth are usually reground.
(85) The center hole of a semi-round keyway end mill can be supported during milling to increase rigidity.
(86) When measuring slot width with an inside micrometer, one jaw serves as a fulcrum, and the other jaw is rotated slightly to find the minimum reading.
(87) The reason for symmetry errors when milling closed keyways with a smaller diameter end mill, in addition to alignment accuracy, is usually due to cutter runout during milling.
(88) Saw blade mills and slotting mills have no side cutting edges. To ensure width accuracy, the width of the mill remains the same from the periphery to the center.
(89) To prevent the saw blade from loosening, a flat key is usually installed between the shank and the saw blade.
(90) When clamping workpieces for cutting, the cut should be as close to the clamping point as possible.
(91) Increasing the contact angle between the saw blade and the workpiece reduces the vertical force, thereby minimizing or preventing tool breakage.
(92) On a horizontal universal milling machine, incorrect worktable zero setting can cause the milling cutter to twist and break when cutting wide workpieces.
(93) When milling V-grooves, the V-part is usually milled first, followed by the narrow middle groove.
(94) One reason for the breakage of T-slot end mills is difficult chip evacuation during milling.
(95) The bottom groove of a T-slot can be milled using a semi-round keyway end mill instead of a T-slot end mill.
(96) When milling ( slots), a 1:50 slope should be chosen for the ( slot end mill).
(97) The main shaft of a dividing head is hollow, with Morse tapers at both ends.
(98) The function of the dividing head worm disengagement handle is only to disengage the worm from the worm gear.
(99) The side shaft of a universal dividing head is connected to the dividing plate via crossed helical gears.
(100) The dividing handle of a universal dividing head directly drives the worm gear to rotate the main shaft.
(101) The F11125 dividing head is equipped with only one dividing plate (hole plate), with the maximum number of holes being 40.
(102) The function of the dividing plate (hole plate) is to solve non-integer division problems.
(103) The function of the dividing head is to facilitate repeated use of the same number of hole circles for division.
(104) When clamping workpieces on a dividing head, the dog and indexing plate are connected to the main shaft via Morse taper.
(105) The tailstock of a dividing head has a handwheel, and the rear tailstock can be adjusted in height, left/right, and front/back directions.
(106) Simple division is based on the worm tooth count (constant) of the dividing head and the number of divisions of the workpiece to calculate the operation.
(107) The results of simple division formulas are always mixed numbers.