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What Is Grinding? 110

Abrasives Training

Class Information

Tooling U classes are offered at the beginner, intermediate, and advanced levels. The typical class consists of 12 to 25 lessons and typically requires at least two hours of instruction time.

Class Name:	What Is Grinding? 110
Description:	This class describes the grinding action, explains how chips are formed, and covers wheel maintenance and safety.
Prerequisites:	none
Difficulty:	Beginner
Number of Lessons:	15

Class Outline
Objectives What Is Grinding? Chip Formation Cutting Action Grinding Wheels Grain Fracture and Wheel Wear Swarf Negative Results of Grinding Dressing Truing Grinding Fluids Wheel Choice Wheel Specifications Wheel Maintenance and Safety Summary

Class Objectives

Describe the grinding process.
Describe how grinding produces a chip.
Describe the various actions that take place during grinding.
Identify the chip-producing surfaces of grinding wheels.
Explain the fracture process.
Explain how swarf is produced.
Describe variables that negatively affect grinding.
Define dressing.
Define truing.
Explain how fluids improve grinding.
Describe variables that impact grinding wheel selection.
Identify common wheel specifications.
Describe safety practices for grinding wheels.

Class Vocabulary
additive		A substance added in small amounts to another substance or material to change or improve its performance.
American National Standards Institute		A private, non-profit organization that administers and coordinates voluntary standards and systems.
bonding material		The material that holds abrasive grains together in a grinding tool. Bonding materials may consist of rubber, metal, or other material.
chatter mark		An irregular mark left on a workpiece that has been ground with a wheel that is out of true.
chip		An unwanted piece of metal that is removed from a workpiece. Chips are formed when a tool cuts or grinds metal.
coolant		A substance, usually liquid, used to reduce or maintain the temperature of a part being ground.
crush dressing		The use of rolls or special forms to dress the face of a grinding wheel to a specific shape or contour.
cutting		In grinding, the main action that occurs when sharp grains dig into the workpiece and remove chips.
cutting fluid		A liquid used during grinding to clean, cool, and lubricate the grinding site.
dressing		The removal of swarf, dull grains, and bonding material from a grinding wheel. Essentially, dressing sharpens the wheel.
dressing tool		A device used to remove loading and sharpen a grinding wheel. It might consist of an abrasive stick, a single-point diamond, or other tool.
fracture		The breaking apart of grains in an abrasive wheel during grinding. It is part of the wheel's self-sharpening process.
friability		The ability of abrasive grains to fracture and self-sharpen under stress.
glazing		The unwanted formation of a smooth surface on a grinding wheel. Glazing occurs when the heat from grinding reacts with a loaded wheel.
grain		A small, hard particle or crystal of abrasive material.
grinding		The use of an abrasive to wear away at the surface of a workpiece and change its shape.
grinding wheel		A wheel made of a bonded abrasive used to grind the surfaces of parts.
horizontal grinding		A grinding machine with a spindle that is parallel to the work surface.
loading		A build up of swarf in a grinding wheel that clogs the spaces between grains.
lubricant		A substance, often a liquid, used to reduce or prevent friction, resistance, heat, and wear during grinding.
machining		The process of removing metal to form or finish a part, either with traditional methods like turning, drilling, cutting, and grinding, or with less traditional methods that use electricity or ultrasound.
offhand grinding		Generally, grinding in which the workpiece is held in the operator's hand and placed against the grinding wheel. It is used for material removal without regard to surface finish.
out of true		The loss of a grinding wheel's original shape resulting in a wheel that is no longer symmetrical.
peripheral wheel		A grinding wheel in which the outer rim is in contact with the workpiece.
plowing		An action that occurs during grinding when dull grains push into the workpiece without cutting it. Plowing leaves grooves in the work surface.
ring test		A manual test used to determine the presence of damage in bonded grinding wheels. Operators suspend a wheel loosely and tap it with a tool. Wheels that emit a ringing sound are likely undamaged.
roll		A hard wheel used in crush dressing to improve or shape the surface of a grinding wheel.
rubbing		A sliding action that occurs during grinding when dull grains glide over the surface of a workpiece without cutting it.
side wheel		A grinding wheel in which the front portion, or face, is in contact with the workpiece.
swarf		The gritty combination of chips, abrasive grains, and worn bonding material that is produced during grinding.
tool grinding		A specialized type of grinding performed to sharpen cutting tools. Tool grinding is often very precise.
truing		The dressing of a wheel in order to return the wheel to its original shape.
void		An empty space between abrasive grains on a grinding wheel where chips collect.
workpiece		A part that is being worked on. It may be subject to grinding, cutting, welding, forming, or other operations.