P - Abrasives to Tumblers Flashcards
Material removing technique that uses particles of very hard ceramic material called GRIT instead of metal blades. Wears down the surface of metal through high friction.
ABRASIVE CUTTING
ABRASIVE CUTTING is also known as
GRINDING
Typical ceramics used for abrasive cutting of metals
ZIRCONIA
ALUMINUM OXIDE
SILICONE CARBIDE
CERAMICA
More expensive alternatives to ceramics used for abrasive cutting of metals
CBN (Cubic Boron Nitride)
DIAMOND
Reasons to use ABRASIVE CUTTING over blades
Cutting hardened materials
Achieving tight tolerances
Creating superior surface finish
Various shapes of abrasive grit
GRINDING WHEELS (flat circular disks)
GRINDING CUPS (bowls)
MOUNTED (on a metal shaft)
GRINDING STONES (rectangular forms)
Grit particles fracture as they interact with the workpiece, resulting in the grinding wheel to get smaller in diameter.
ATTRITIOUS WEAR
ATTRITIOUS WEAR leads the grinding wheels to effectively ____ _________
SELF SHARPENING
TRUE OR FALSE:
Grinding MUST be performed on dedicated machine tools, and NEVER on LATHE or MILL
TRUE
Describe “JOB ONE” when designing the layout of a machine shop
Place grinding machines as far away form other machine tools as possible
Wheels that use a form of “Glass” as the bonding agent, FELDSPAR and CLAY, which are mixed with moisture and grit, then molded and pressed into a wheel shape.
VITRIFIED
Wheels that use “Thermosetting Resin” as the bonding agent. Used in ANGLE GRINDERS.
RESINOID
Bonding agent used in THIN CUT-OFF wheels
RUBBER
Classifies grinding wheels under the ANSI standard B74. 13-1977. A different code is used for CBN(Cubic Boron Nitride) and Diamond.
WHEEL CLASSIFICATION CODE
Interactions between a workpiece and a grit particle that do not result in chip production. Polishes a surface and improves its finish.
CUTTING
PLOUGHING
RUBBING
Downside of interactions between a workpiece and a grit particle that do not result in chip production. Polishes a surface and improves its finish.
RESIDUAL STRESSES
Slowly relaxes residual stresses using moderate temperature over a long period of time, to not negatively reduce the desired hardness.
POST HEAT TREATMENT
Four categories of ABRASIVE CUTTING
GRINDING
FINISHING
POLISHING
BUFFING
Simplest and most dangerous of all grinding machine tools
BENCH GRINDER
Precision grinding machine dedicated to cutting flat surfaces
SURFACE GRINDER
Grinding process where the workpiece is placed between two centers, live and dead, and rotated by a “Driving Plate and Dog” for a concentric shape
CYLINDRICAL GRINDING
Grinding process second to CYLINDRICAL GRINDING or performed on its own. Workpiece rests on a blade and fed without slippage by an angled “Regulator Wheel”.
CENTERLESS GRINDING
Rejuvenation process for grinding wheels
TRUING
Device with a diamond tip which is drawn across the edge of the grinding wheel where it cuts it back to a straight surface concentric with the shaft.
DRESSING TOOL
FINISHING applied to flat surfaces
LAPPING
FINISHING applied to internal bores
HONING
FINISHING applied to the outside surface of circular shafts. Uses a pre-cut, curve-faced “Stone”
SUPERFINISHING
Flat slab made of bonded abrasive grit for LAPPING
LAPPING STONE
Flat slab made of grooved metal for LAPPING
LAPPING PLATE
Finishing process used on a bore with a cylindrical tool
HONING
Tool which is cylindrical in shape and carries a ring of rectangular stones around the periphery.
HONING TOOL
Finishing process performed using discs of material with very fine abrasive grit. Levels surfaces and removes pits, scales, and other imperfections.
POLISHING
Process to achieve a “Bright Luster” look. Removes fine surface scratches left after polishing.
BUFFING
Fluffy or edge-frayed to accept and retain the application of BUFFING COMPOUND
BUFFING WHEELS
Fine abrasive grit distributed throughout a stick of wax-like material
BUFFING COMPOUND
Abrasive grit can also be applied to a flexible surface to produce
COATED ABRASIVES
Most common COATED ABRASIVES
SAND PAPER
EMERY CLOTH
Large numbers of machined components need their sharp edges slightly softened. They are placed in a rotating drum containing abrasive media.
DEBURRING
A rotating drum containing abrasive media for DEBURRING
BARREL FINISHING
A drum which vibrates the abrasive media for DEBURRING
VIBRATORY TUMBLER
Specialist application for TUMBLERS
Polishing used brass firearm cartridges for reloading, where peanut or walnut husks rather than hard stones