Metal Cutting 6 Flashcards
What is abrasive machining?
A material removal process that involves the use of abrasive cutting tools. Regardless of the form of the abrasive tool and machining operation, all
abrasive operations can be considered as material removal processes with geometrically undefined cutting edges.
What are bonded abrasive tools?
Abrasive grains are closely packed into different shapes, the most common is the abrasive wheel. Grains are held together by bonding material.
What are coated abrasive tools?
Abrasive grains are glued onto a flexible cloth, paper or resin backing. Coated abrasives are available in sheets, rolls, endless belts.
What are free abrasives?
abrasive grains are not bonded or glued. Instead, they are introduced either in oil-based fluids or in water or air or contained in a semi-soft binder.
What is grinding?
A material removal process in which abrasive particles arc contained in a bonded grinding wheel that operates at very high surface speeds.
What are grinding wheels?
Grinding wheels consist of abrasive particles and bonding material. There is free space between the grains. Material removal rate is low. Coolant is usually used.
What are some specs for grinding wheels?
Grain size - defines surface finish and MMR.
Bonding materials - Defines how rigid the wheel is
What is rubber bonding?
Plastic and rubber. gives flexibility, perfect for manual grinding.
What is centreless grinding?
Centreless grinding is a process for continuously grinding cylindrical surfaces in which the workpiece is supported not by centres or chucks. The workpiece is ground between two wheels.
What is dressing?
Sharpening of the grinding wheel. the process of conditioning worn grains on the surface of grinding wheels in order
to produce sharp new grains. This is to avoid glazing.
What is glazing?
when chips fill the gap between grains
and produce a shiny surface
What is honing?
a finishing process performed by a honing tool, which
contains a set of bonded abrasive sticks. The sticks are equally spaced about the periphery of the honing tool. They are held against the work surface with controlled light pressure, usually exercised by small springs.
What is lapping?
Lapping is a finishing operation that instead of a bonded abrasive tool, oil-based fluid suspension is used for material removal. The fluid, called a lapping compound, contains very small free abrasive grains
What is superfinishing?
a finishing operation similar to honing, but it involves the use of a single abrasive stick. The reciprocating motion of the stick is performed at higher frequency and small amplitudes. Also, the grit size and pressures
applied on the abrasive stick are smaller.
What is polishing?
a finishing operation to improve the surface finish by means of a polishing wheel made of fabrics or leather and rotating at high speed. The abrasive grains are glued to the outside surface of the polishing wheel.
