Setup for Centerless Grinders 320

Abrasives Training

Class Information

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Class Name:	Setup for Centerless Grinders 320
Description:	This class explains how to set up the main components of a centerless grinder, as well as how to accurately position the workpiece on the work rest blade for various centerless grinding operations.
Prerequisites:	none
Difficulty:	Advanced
Number of Lessons:	19
Language:	English, Spanish

Below are all the competencies and job programs that contain the class Setup for Centerless Grinders 320. Job programs are our traditional class lists organized according to common job functions. Competencies are our latest job-specific curricula that help tie online learning to practical, hands-on tasks.

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Competencies
Centerless Grinder Operator

Class Outline

Objectives
Setting Up a Centerless Grinder
Preventing Lobing
Workpiece Rounding Effect
Selection of Work Rest Blade
Setting the Work Rest Blade: Height Above Center
Setting the Work Rest Blade: Height Above Lower Slide
Throughfeed Grinding and Work Rest Blade Height
Regulating Wheel Angle of Inclination
Setting the Angle of Inclination
Regulating Wheel and Workpiece Feed Rate
Maintaining Consistent Part Diameter: Work Guides
Setting Work Guides on Regulating Wheel Side
Setting Work Guides on Grinding Wheel Side
Truing the Grinding Wheel
Setup for the Regulating Wheel Truing Angle
Setup for Offsetting the Diamond Dresser
Truing the Regulating Wheel
Summary

Class Objectives

Describe centerless grinding.
Describe lobing.
Describe workpiece rounding.
Describe work rest blade selection.
Calculate work rest blade height above center.
Calculate workpiece positioning above the lower slide.
Describe work rest blade height during throughfeed grinding.
Describe the regulating wheel angle of inclination.
List the steps for adjusting the regulating wheel angle of inclination.
Describe the relationship between the regulating wheel and workpiece feed rate.
Describe how work guides affect workpiece diameter.
Explain how to set work guides on the regulating wheel side of the machine.
Explain how to set work guides on the grinding wheel side of the machine.
List the steps for truing a grinding wheel.
Describe the truing angle for the regulating wheel.
Describe offsetting the diamond dresser for the regulating wheel truing unit.
Describe devices used to true the regulating wheel.

Class Vocabulary
angle of inclination		The angle formed as the regulating wheel swivels to allow the part to pass. The regulating wheel angle of inclination provides axial thrust that feeds the workpiece past the grinding wheel during operation.
axial		Along or parallel to the axis of the workpiece. During throughfeed grinding the part must move in an axial direction.
bearing surface		The circular underside of the bolt head that makes contact with the part. During centerless grinding, the bearing surface of the work guide on the entrance side of the regulating wheel must be set behind the regulating wheel face by a specific amount.
center		A hardened, pointed, cylindrical component used to hold one end of a workpiece during center-type cylindrical grinding. The tip of a center is inserted into a matching hole on the end of a workpiece.
centerless grinding		A common grinding operation during which a cylindrical part is supported on a work rest blade and guided between a grinding wheel and a regulating wheel. Centerless grinding is a type of cylindrical grinding.
chatter marks		Surface imperfections on the workpiece caused by vibrations of the grinding wheel. Positioning the work rest blade too high above the centerline of the grinding and regulating wheels often results in chatter marks.
chattering		Also called whipping, the occasional unwanted vibration between components. Chattering is often caused by kinks or bends in a part.
chuck		A device that holds a workpiece in place as it rotates. The chuck commonly has three or four jaws that can be adjusted to fit various sizes.
cylindrical grinding		A common grinding process during which a cylindrical part is held on each end and rotated as a grinding wheel is guided along its length. Centerless grinding is a type of cylindrical grinding.
diameter		The distance from one edge of a circle to the opposite edge that passes through the center. Accurate setup of a centerless grinder ensures consistent workpiece diameter.
end stop		Device that halts or prevents workpiece motion once the workpiece is ground to a specified location and depth. During throughfeed grinding, the regulating wheel angle holds the workpiece firmly against the end stop.
face		In grinding, the part of the wheel that contacts the workpiece. The truing angle ensures that the workpiece makes a straight line of contact with the regulating wheel face.
feed rate		The rate at which the grinding wheel and the workpiece move in relation to one another. The regulating wheel angle of inclination provides the axial thrust that determines workpiece feed rate.
feeler gauge		A device sometimes used to determine if there is proper clearance between components on a machine. A feeler gauge is often used to ensure sufficient clearance between the regulating wheel and work guide for the workpiece to pass through.
finish		The degree of "smoothness" of a workpiece surface. Accurate setup of a centerless grinder ensures appropriate workpiece finish.
finish grinding		An abrasive process that improves the surface of the part. Finish grinding emphasizes tight tolerances and smooth surface finish.
form grinding		Type of centerless grinding that uses a specialized edge, or profile, that is added to the face of a wheel. The "form" or profile is then imparted into the workpiece during grinding.
grade		The strength of the bond in an abrasive wheel. Using a wheel with a softer grade during centerless grinding helps to prevent chatter marks.
grinding wheel		A wheel made of a bonded abrasive used to remove material from a workpiece surface. A grinding wheel rotates and shears away microscopic chips of material and can produce very fine surface finishes.
hydraulic feeding mechanism		Device that typically controls the rate at which the truing tool travels across the grinding wheel.
infeed grinding		Similar to plunge grinding, a method of centerless grinding in which the workpiece is held stationary while the grinding wheel is fed into the workpiece at a specified location and depth.
lobing		Deviation from workpiece roundness. Lobing is prevented by proper setup of the centerless grinder.
lower slide		The device attached to the swivel plate that moves the regulating wheel toward or away from the workrest blade. The correct positioning of the workpiece above the top of the lower slide assists in part roundness.
periphery		The outer edge of a workpiece. During centerless grinding, any high spot on the periphery of the workpiece causes workpiece lobing.
pick-up		Also called scoring, a centerless grinding problem that occurs when excessive pressure from the work rest blade causes tiny chips to fuse to the blade. Pick-up often occurs when the blade is too hard for the grinding operation.
profile truing attachment		A system used to true a form grinding wheel for centerless grinding. The profile truing attachment is used to impart a particular shape into the form grinding wheel, which is then used to impart a particular shape into the workpiece.
rate of traverse		Speed at which the truing tool travels across the grinding wheel. The truing tool rate of traverse is typically controlled by a hydraulic feeding mechanism.
regulating wheel		A wheel, usually made of plastic or rubber bond, used during centerless grinding to rotate the workpiece and pull it through the operation. The regulating wheel controls workpiece rotational speed and feed rate.
rough grinding		Relatively aggressive cutting or grinding done with little regard for surface finish.
roundness		The quality of a cylindrical workpiece characterized by the entire length of the workpiece having the same diameter relative to a common axis. All points on the exterior surface of a perfectly round cylindrical workpiece are equidistant from the axis of the workpiece.
scoring		Also called pick-up, a centerless grinding problem that occurs when excessive pressure from the work rest blade causes tiny chips to fuse to the blade. Scoring often occurs when the blade is too hard for the grinding operation.
squared		Directly aligned with the surface of another object. The work guide at the rear of the regulating wheel must be squared with the regulating wheel.
standard truing unit		A system used to true a grinding wheel in centerless grinding. This system uses a diamond dresser to true the face of a grinding wheel for straight cylindrical parts.
stock		Raw workpiece material that is removed during a grinding pass or operation.
through feed		In grinding, the movement of a workpiece as it travels through an operation.
throughfeed grinding		A method of centerless grinding in which the regulating wheel and work guides feed the workpiece past the grinding wheel in a straight line. Throughfeed grinding is used primarily to grind straight cylindrical workpieces with no obstructive features.
tolerance		An unwanted but acceptable variation from a specified dimension. Accurate setup of a centerless grinder ensures accurate workpiece tolerance.
truing angle		The angle formed by the truing device that matches the regulating wheel angle of inclination. The truing angle creates a slightly convex regulating wheel face, which enables a complete line of contact between the regulating wheel and workpiece during centerless grinding.
whipping		Also called chattering, the occasional unwanted vibration between components. Whipping is often caused by kinks or bends in a part.
work guide		A device used in centerless grinding that prevents the workpiece from moving too far toward either the regulating wheel or grinding wheel. Work guides help maintain consistent workpiece diameter during throughfeed grinding.
work rest		A part of a centerless grinding machine that supports the workpiece as it is ground. Work guides are mounted to the work rest.
work rest blade		A device, usually with an angled edge, that supports cylindrical parts during centerless grinding. The above-center positioning of the work rest blade produces concentricity of the workpiece.
work speed		The rotational speed of the workpiece. The regulating wheel rotational speed determines work speed.