Types of Chip MCQ Quiz in తెలుగు - Objective Question with Answer for Types of Chip - ముఫ్త్ [PDF] డౌన్‌లోడ్ కరెన్

Continuous Chip (With BUE)

• Ductile materials
• Low-to-medium cutting speeds
• Large feed
• Small rake angle
• Cutting fluid, Absent or inadequate
• Tool-chip friction causes portions of a chip to adhere to rake face
• Built up Edge (BUE) forms, then breaks off, cyclically

Discontinuous Chip

• Brittle work materials
• Low cutting speeds
• Large feed and depth of cut
• Small rake angle
• High tool-chip friction

Continuous Chip (Without BUE)

• Ductile work materials
• High cutting speeds
• Small feeds and depths
• Sharp cutting edge
• Large rake angle
• Low tool-chip friction

Explanation:

Built-up edge (B.U.E):

• In machining ductile material with long chip tool contact length, a lot of stress and temperature develops in the secondary deformation zone at the chip tool interface. Under such high stress and temperature in between two clean surfaces of metals, strong bonding may locally take place due to adhesion similar to welding.
• Such bonding will be encouraged and accelerated if the chip tool material has mutual affinity or solubility.
• The weld material starts forming as an embryo at the most favorable location and thus gradually grows, with the growth of the B.U.E, the forces also gradually increased due to the wedging action of the tooltip along with the B.U.E formed on it. Whenever the force exceeds and bonding force of the B.U.E, the B.U.E is broken or sheared off and taken away the flowing chip, then again starts forming and growing.
• Low cutting speed also contributes to the formation of B.U.E.

Elimination of BUE:

• High cutting speed.
• High rake angle.
• Low feed.
• Low depth of cut.

Effects of built-up edge:

Harmful effect:

• Poor surface finish.
• It changes the rake angle in an unfavorable fashion at the tooltip thus increasing the cutting forces.
• Induce vibration.

Good effect:

• BUE protects the cutting edge or tool i.e. Increase the tool life.