Setup for the Surface Grinder 241

"Setup for the Surface Grinder" provides a comprehensive overview of the steps and considerations involved in setting up a surface grinding machine. Setup includes selecting a grinding wheel, testing and preparing the wheel, selecting the correct workholding and/or fixtures for the operation, mounting the workpiece, and setting cutting variables.

Setup is integral to achieving an accurate, precise grinding operation. If any step in the setup process is not performed properly, the entire operation may be compromised, leading to a part that is out of tolerance and must be scrapped. An understanding of how to correctly and efficiently set up a surface grinding operation is necessary for increasing part quality and production rates while decreasing scrap.

Class Details

Class Name:
Setup for the Surface Grinder 241
Description:
"Setup for the Surface Grinder" provides a comprehensive overview of the steps and considerations involved in setting up a surface grinding machine. Setup includes selecting a grinding wheel, testing and preparing the wheel, selecting the correct workholding and/or fixtures for the operation, mounting the workpiece, and setting cutting variables.

Setup is integral to achieving an accurate, precise grinding operation. If any step in the setup process is not performed properly, the entire operation may be compromised, leading to a part that is out of tolerance and must be scrapped. An understanding of how to correctly and efficiently set up a surface grinding operation is necessary for increasing part quality and production rates while decreasing scrap.
Version:
2.0
Difficulty:
Intermediate
Number of Lessons:
14

Class Outline

  • Surface Grinding
  • Safety for the Surface Grinder
  • Selecting a Grinding Wheel: Shape
  • Selecting a Grinding Wheel: Materials
  • Preparing the Wheel for Grinding
  • Review: Grinding Safety and Wheels
  • The Magnetic Chuck
  • Magnetic Chuck Types
  • Specialized Workholding
  • Specialized Workholding in Action
  • Review: Workholding Review
  • Mounting the Workpiece
  • Setting Grinding Variables
  • Final Review

Objectives

  • Define surface grinder setup.
  • Describe best practices for surface grinder safety.
  • Describe basic wheel shapes.
  • Describe grinding wheel materials.
  • Describe the processes for preparing a grinding wheel.
  • Describe magnetic chucks.
  • Describe permanent magnetic and electromagnetic chucks.
  • Identify supplementary or alternative workholding.
  • Describe how to mount a workpiece on a magnetic chuck.
  • Describe setting grinding variables.

Certifications

Glossary

Vocabulary Term Definition
abrasive A material consisting of hard particles used to wear away or remove workpiece material. Abrasives are bonded in the shape of a wheel for grinding operations.
adapter plate A flat steel and brass fixture used to improve the hold on thinner workpieces. Adapter plates optimize the magnetism that flows through the workpiece.
aluminum A silvery white, light-weight metal. Aluminum is non-magnetic but a good conductor of electrical and thermal energy.
aluminum oxide A compound made from bauxite and other additives that is commonly used as an abrasive material. Aluminum oxide is a conventional abrasive.
American National Standards Institute ANSI. A nonprofit organization that establishes standards and guidelines for several industries. The American National Standards Institute sets specific safety guidelines for the use of grinding wheels to be followed by all manufacturers and machine operators.
ANSI B7.1 "Safety Requirements for the Use, Care and Protection of Abrasive Wheels." Industry safety standards set by the American National Standards Institute. ANSI B7.1 includes guidelines for wheel speeds, wheel mounting, and safety guards.
balancing The process of ensuring that a grinding wheel has equal weight across the wheel. A wheel that is out of balance negatively affects grinding operations.
Blanchard grinders A type of surface grinder that has a vertical spindle and rotary machine table. Blanchard grinders’ spindle and table configuration allows for grinding multiple workpieces uniformly and continuously.
bonding material The adhesive material in grinding wheels that holds the abrasive grains together. Bonding materials can be vitrified, organic, and resinoid.
brittle The condition of a material with the tendency to break when drawn, stretched, or formed. Brittle materials are hard and break away easily.
burrs A sharp projection left by a cutting tool after a cutting operation. Burrs must be removed to ensure precise grinding.
cast iron A metal consisting of iron, over 2.11% carbon, and 1 to 3% silicon. Cast irons will normally contain trace amounts of other elements.
chips Pieces of metal that are removed from a workpiece when a tool cuts or grinds the metal. Small chips are removed by the grinding wheel’s abrasive grains during grinding.
clamps A workholding device that maintains the position of a workpiece by holding it in place. Clamps commonly provide additional locating support to other workholding devices used for surface grinding.
coarse An abrasive tool or set of abrasive grains that have large-sized grains. Coarse grains produce the roughest surface finish.
coils Multiple loops of conducting wire used to create a magnetic field when current is passed through it. This magnetic field is used to energize a device.
conductive Allowing the easy flow of electricity. Most conductive materials are metal.
creep feed grinding A grinding method in which the depth of cut is increased while the feed rate is decreased. Creep feed grinding is used for large amounts of material removal.
cubic boron nitride CBN. A cutting tool material with hardness that is second only to diamond. Cubic boron nitride tools are very effective but also very expensive.
cup wheel A grinding wheel that is shaped like a cup or a bowl. Cup wheels may have straight or flared sides.
demagnetism Elimination of a material’s magnetism. To demagnitize a material, disrupt the regular pattern of magnetic polarity.
depth of cut The amount of penetration a grinding wheel makes, or the distance from the uncut surface to the machined surface. In surface grinding, depth of cut refers to how far a grinding wheel grinds into the workpiece.
diamond The hardest known substance. Diamond is both a naturally occurring and manufactured superabrasive.
direct current Electrical charge that flows in one direction. Direct current powers the electromagnetic chuck.
dressing Removing swarf, dull grains, and bonding material from a grinding wheel by fracturing away the wheel surface. Dressing also sharpens the wheel.
electromagnetic chuck A magnetic workholding device with a direct current power source that contains conductive coils. When turned on, the electromagnetic chuck can hold a variety of workpieces but is inactive when off.
electromagnets A powerful magnet that gains an attractive force only when current passes through it. Electromagnets are very powerful.
ferrous A metal that contains iron. Ferrous materials can be held by magnetism, while nonferrous materials cannot.
fine An abrasive tool or set of abrasive grains that have small-sized grains. Fine grains produce tight tolerances and surface finishes.
fixtures A customized workholding device that is used to position a workpiece. Fixtures may require additional workholding devices to hold the workpiece securely in place.
grain size The size of the abrasive grains that compose a grinding wheel. Grain sizes help to determine the tolerance and surface finish that the wheel can create.
grains A small, hard particle or crystal of abrasive material. Abrasive grains are bonded together to create grinding wheels and other abrasive tools.
grinding variables The measureable rate of movement of a cutting tool or workpiece. Grinding variables include wheel speed, table feed, and depth of cut.
grinding variables The measureable rate of movement of a grinding wheel or workpiece. Grinding variables for surface grinding include wheel speed, table feed, and depth of cut.
laminated V-block A magnetic workholding component with a fixed, unchangeable V-shaped groove down the middle of its body. Laminated V-blocks are designed to hold round, square, or rectangular workpieces.
magna-lock clamps A two-piece magnetic clamping system with flexible fingers designed to hold non-magnetic or very small workpieces during grinding. Magna-lock clamps are also known as magna-vise clamps.
magna-vise clamps A two-piece magnetic clamping system with flexible fingers designed to hold non-magnetic or very small workpieces during grinding. Magna-vise clamps are also known as magna-lock clamps.
magnetic chuck A device that uses magnetism to support, locate, and hold a workpiece. The magnetic chuck is a common workholding device on the surface grinder.
magnetic chuck block A magnetic fixture that holds oddly shaped workpieces on the magnetic chuck. Magnetic chuck blocks optimize magnetism and provide physical support.
magnetic field The area in and around a magnet in which a magnetic force exists. Magnetic fields exhibit the power of attraction and repulsion.
magnetic flux The force that surrounds a magnet and exhibits the powers of attraction and repulsion. Magnetic flux is described as imaginary lines of force that exit the magnet’s north pole and return to its south pole.
magnetic parallels A workholding device used to extend the magnetic field of a magnetic chuck to hold a workpiece. Magnetic parallels can support warped or otherwise oddly shaped workpieces that would otherwise flatten out when magnetically chucked.
magnetic V-block A magnetic workholding component with a V-shaped groove down the middle of its body that can be changed and set to various angles. Magnetic V-blocks are designed for grinding angles and to hold round, square, or rectangular workpieces.
magnetism The power of attraction and repulsion that exists in materials. Magnetism most often occurs between metals.
magnetizes To make a material magnetic or attractive to other metals. Magnetized materials can be held in place by magnetic workholding devices.
magnets A metallic object or substance that possesses a force that attracts or repels other metals. Magnets attract opposite charges and repel like charges.
meters per minute m/min. A measurement of feed that indicates how many meters the cutting tool or workpiece has traveled in one minute. Meters per minute is a metric measurement.
oilstone A fine-grained sharpening device that is typically lubricated with oil. Oilstones are used to remove minor abnormalities from workpieces and workholding devices.
organic bonds An abrasive bonding material derived from a naturally occurring material that contains carbon. Organic bonds tend to soften with heating.
parallel Two lines or axes that are equidistant from one another at all points. Parallel lines do not intersect.
periphery The perimeter, or the outer edge, of an object such as a tool or workpiece. Many types of grinding wheels cut with their periphery.
permanent magnetic chuck A magnetic workholding device that contains a series of magnetic inserts arranged side by side within a grid of conductive material. Permanent magnetic chucks generate a magnetic field to hold a workpiece in place.
personal protective equipment PPE. Safety equipment that workers wear or use to prevent injury in the workplace. Personal protective equipment includes safety glasses.
polarity Having two oppositely charged poles, one positive and one negative. Polarity determines the direction in which current flows.
poles Opposite ends of an axis. Poles also refer to the opposite ends of a magnet.
profile A shape or physical feature of a part created by a specialized grinding wheel edge. Profiles may be unique, non-standard shapes.
recessed wheel An abrasive wheel that resembles a flat disc with a depressed area surrounding the wheel center. Recessed wheels are wider at their periphery than their center.
residual magnetism The attractive force that exists in an object or substance after it has been removed from a magnetic field. Residual magnetism may occur with a workpiece when using permanent magnetic chucks.
resin An organic bonding material used to hold abrasive grains to the backing of abrasive belts and wheels. Resins are similar to the base material of plastics.
resinoid bonds An organic bonding material used in grinding tools that offers rapid stock removal and fine finishes. Resinoid bonds are made from synthetic resins.
rigid The condition of a workpiece, machine, or machine setup characterized as stiff and immovable. Rigid machine components are fixed securely in place.
ring test A manual test used to detect damage in bonded grinding wheels. Ring tests produce a ringing sound when tapping an undamaged wheel with a tool.
rubber An organic bond used to hold abrasive grains together in grinding wheels. Rubber offers smooth grinding action and fine finishing.
safety glasses Protective eyewear worn during surface grinder operation. Safety glasses can prevent potential eye injury caused by material flying off the grinding wheel or work surface at high speed.
setup All the necessary preparation of tooling and fixturing that occurs on a machine before a grinding operation can be executed. Setup includes preparing machines, tools, and materials.
shim A thin or tapered component used to support a workpiece by filling small gaps or abnormal shapes. Shims are often used to make a workpiece level or to increase workpiece stability.
silicon carbide A hard, brittle material used as a conventional abrasive. Silicon carbide grinding wheels are hard and sharp, and the grains break away easily.
slot A narrow channel on the surface of an object. Slots are thin, recessed features cut into the surface of a workpiece by a specially shaped grinding wheel.
steel A ferrous metal consisting of iron and carbon, usually with small amounts of manganese, phosphors, sulphur, and silicon. Steels are the most common metals used in manufacturing.
straight wheel A common type of abrasive tool used in grinding and cutoff operations. Straight wheels generally appear as flat discs.
superabrasive A relatively expensive but effective material possessing superior hardness and abrasion resistance. Superabrasives include cubic boron nitride (CBN) and diamond.
surface feet per minute sfm. A measurement of speed that is a direct function of the workpiece or tool diameter and its rate of rotation. Surface feet per minute measures the number of feet that a location on the grinding wheel travels in one minute.
surface finishes The smoothness of a surface after it has been ground. Surface finish is the complete, desired surface.
surface grinding A common grinding process that uses a rotating grinding wheel to remove precise amounts of material from a flat workpiece surface. Surface grinding can be one part, often the last, of a sequence of machining operations.
swarf The gritty combination of chips, abrasive grains, residual coolant, and worn bonding material produced during grinding processes. Swarf can clog a grinding wheel and cause it to function improperly.
synthetic Manufactured or produced through deliberate processes rather than a natural origin. Synthetic materials are artificial or human-made.
table feed The feed of the workpiece past the grinding wheel, which is based on the worktable’s rate of movement. Table feed is also known as work feed.
taper An angular surface cut into a workpiece. Tapers on flat or rectangular workpieces are gradual changes from a larger height to a smaller height at a constant slope or incline.
tolerances An acceptable deviation from a given dimension or geometry. Tolerances indicate the allowable difference between a physical feature and its intended design.
truing To restore a grinding wheel to its original, intended shape. Truing is also a method of wheel balancing.
vacuum chuck A workholding device that holds a workpiece to its surface through air pressure. Vacuum chucks can be used for non-magnetic workpieces during surface grinding.
vises A workholding device with one fixed jaw and one moveable jaw. Vises are often used to hold simple rectangular or cubic workpieces on a surface grinder.
vitrified bonds A clay or ceramic bond characterized by its strength, rigidity, and resistance to oils, water, and temperature changes. Vitrified bonds have qualities similar to glass.
wheel guard A protective covering that bolts in place over a grinding wheel. Wheel guards protect operators from being struck by broken wheel fragments.
wheel segments A smaller section or portion of a whole wheel. Wheel segments are typically used on surface grinders with rotary tables, such as Blanchard grinders.
wheel speed The rate at which the grinding wheel rotates at the point of contact with the workpiece. Wheel speed depends upon the spindle speed and wheel size.
work feed The feed of the workpiece past the grinding wheel, which is based on the worktable’s rate of movement. Work feed is also known as table feed.
workholding A device used to support, locate, and hold a workpiece. Workholding devices commonly used in surface grinding include the magnetic chuck and various clamps.