Study Guide P: Abrasives(Tumblers) Flashcards by Zany Unknown

What is the other name for ABRASIVE CUTTING?

GRINDING

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What is used instead of metal blades in ABRASIVE CUTTTING?

GRIT

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Since grains vary in size and frim course to very fine what does GRIT number mean?

Large numbers refer to fine grain and vice versa and the size of the mesh used

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How is an ingot of a cermaic material made?

Created in an electrical furnace, crushed and sorted by passing fragments through mesh screens

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What are typical ceramic materials used for abrasive cutting?

SILICONE, CERAMICA, ZIRCONIA, and ALUMINUM OXIDE

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What are other expensive alternatives of abrasive cutting ceramics?

CBN (CUBIC BORON NITRIDE) & DIAMOND

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Name the main resons to use ABRASIVE CUTTING rather than traditional machining

Cutting hardened materials, Achieve tight tolerances, and Creating superior surface finish

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What are the different shapes of ABRASIVE GRITS?

WHEEL(circular shape) , CUPS (bowl shaped), MOUNTED (metal shaft), and STONES (rectangular forms)

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Describe the process of AABRASIVE CUTTING.

Its the wearing down of surface through high friction and if done with a GRINDING WHEEL the GRIT with its irregulat faceted shape it will always produce chips

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As the CERAMIC GRIT progressivly gets smaller in diamter as broken GRIT is shed the name of the process?

ATTRITIOUS WEAR

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What are the 3 types of fractures when ABRASIVE CUTTING?

Micro fracture, Grain fracture, abd Bond fracture

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Becuase of ATRICOUS WEAR the grit paricles are smoothed off overtime basically making it …

SELF SHARPENING

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What is an IMPORTANT NOTE when doing GRINDING?

YOU MIUST DO THEM ON DEDICATED MACHINES, NEVER ON A LATHE OR MILL, the serious issue being if the grit gets into the ways of the machine

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When designing the layout of a machine shop what is JOB ONE?

Put the GRINDING MACHINES to one side away from other machines

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What must be needed to form a GRINDING WHEEL?

A BOUNDING AGENT

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What are the different trypes of BONDING AGENTS?

VITRIFIED (FELDSPAR and CLAY), RESINOID (PHENOLIC or POLYIMIDE), and RUBBER

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What type of grinding wheel can be used that is suituble for dedicated machine tools?

VITRIFIED wheels, since these wheels are dimensially stabe and are resistant to oils, acids and water but respond poorly to mechanical or thermal shock

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What type of GRINDING WHEEL is good for POWER TOOLS?

RESINOID “Thermosetting Resin”, since the wheels are more flexible than vitrified and are more resistant to shock. They also are reinforced with a mesh of glass fiber to hold larger chucks should breakage occur

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What is the common power tool that uses a RESINOID WHEEL?

ANGLE GRINDER

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What type of GRINDING WHEEL is used for THIN CUT-OFF wheels?

RUBBER, and these wheels only act as a saw and are not capable of precision work, or prolonged usage but good for countouring situations such as smoothing body filler

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What is used to classify GRIDNING WHEELS that is defined in the ANSI standard?

WHEEL CLASSIFICATION CODE, and goes left to right as ABRASIVE TYPE - GRAIN SIZE - GRADE - STRUCTURE - VITRIFIED BOND

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What are the other interactions between a GRIT PARTICLE and workpiece?

Cuting by an individual grain, Ploughing by an individual grain, and Rubbing by an individual grain

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Since GRRINDING produces RESIDUAL STRESSES that are tensile residual stresses what are the ways to minimize them?

You can grind the piece gently or do POST HET TREATMENT by heating the workpiece progressivly over time

What are the 4 basic categories oof ABRASIVE CUTTING?

GRINDING, FINISHING, POLISHING, and BUFFING

What is the most common grinding machine tool and why is it the most dangerous machine with its "siren song"?

BENCH GRINDER, and the danger is if the gap grows to 1/2"

What is the safer GRINDING MACHINE that has a CNC and MANUAL variant?

SURFACE GRINDER, this version is much safer for basic reason being the operaters hand is never near the wheel and the wheel(which is heavily guarded) is installed parallel to the mahcine front and not perpendiculary

What is one of the most common areas for precision grinding?

To create shafts that have ot hold barrings meaning tight tolerances

Descride the first process of two CYLINDRICAL GRINDING

Workpiece is placed between an alive and dead centers, then rotated by a "Driving Plate and Dog" that is driven independently of the workpiece but in the same direction while coolant is used to keep the workpiece within acceptable temperature limits

What is the machine that does CYLINDRICAL GRINDING?

CYLINDRICAL GRINDING MACHINE, which also is able to reciprocate the spindle back and forth and has no exposed ways and all bearings are sealed, with debris and shed drit being filtered from the recirculating coolant stream

What is the second stage process?

CENETERLESS GRINDING, can be perfomed as a stand alone process

Describe CENTERLESS GRINDING

It is a process that doesn't require a clamp or other holding devices but instead the workpiece rest on a blade and is driven around and fed without slippage

Since a GRINDING WHEEL doesn't alwyays rin true or evenly it must go through a rejuvenation proceess called what?

TRUING

What is the tool used in TRUING?

DRESSING TOOL and it has a diamond at its tip

Describe the TRUING process

You take the DRESSING TOOL and draw it across the edge of the grinding wheel where it straight cuts the surface conentric wit the shaft

What is a broad category of abrasive cutting that is performed after cutting?

FINISHING

What are the different ways FINISHING can be applied?

On flat surfaces (LAPPING), internal bores (HONING), and outside circular shafts (SUPERFINISHING)

What are the two different types of slabs used in LAPPING?

LAPPING STONE made of bonded abrasive grit & LAPPING PLATE made of grooved metal, and are used in conjunction eith cutting slurry or paste

What is the simplecest form of LAPPING?

Done by hand to sharpen a blade

What is automated LAPPING done on?

LAPPING MACHINE

How does a LAPPING MAHCINE perform lapping?

The vehicle is a fluid whih is either pre charged with grit particles (cutting paste) or simply carriers the particles that are naturally shred and the a machine does large circular motions wiht superimposed smaller swirls.

After LAPPING is done what is the result of the surface of the workpiece?

Only a very small amount is removed (typically 0.0005") but the resulting surface is very flat and smooth

What process is done after grinding for mainly cylindrical bores (insinde holes) for engines and hydrolic actuators?

HONING

What is the tool used in HONING?

A HONING TOOL

What is unique about the HONING TOOL?

It is cylindical in shape and carries a ring of rectangular STONES around the periphery that are attched in a complaint (non-rigid) manner, such as springs or clips, leaving them free to jpstle and adjust position as they interact with the workpiece

How is HONING done?

It uses the HONING TOOL and the motion invloleves oscillaiton, reciproction, and rotation and uses flouids for cooling (no "vehicle")

What is used to measure shaft diameter on-the-fly during SUPERFINISHING?

Air guages, measures the back pressure of an air stream

What is performed using disc (or semtimes belts/straps) of material infused with very fine abrasive grit?

POLISHING, produces Brushedd or Lined look

What is the purpse of POLISHING?

Attemting to level surfaces and remove pits, scale and other imperfections

What process is used to achieve Bright Luster?

BUFFING

What are the tools used in BUFFING?

BUFFING WHEEL (a cloth disc) & BUFFING COMPOUND (wax like material added to the BUFFING WHEEL)

What are the different types of BUFFING COMPOUNDS?

EMERY, STAINLESS, TRIPOFF, WHITE ROUGE, JEWELERS ROUGE, and PLASTIC

What is an abrasive grit tha can lso be applied to flexible surface to produce this

COATED ABRASIVES

What are the two most common COATED ABRASIVES?

SAND PAPER (mostly carpentry) & EMERY CLOTH

How are COATED ABRASIVES made?

Constructed by sprinkling grit over a cloth or paper substrate, and then using a multi-layered approach to hold the grit in place and protect it from water and oil intrusion.

What is another use for ABRASIVES?

in DEBURRING applications

What are the different types of machines that can do DEBURRING?

BARREL FINISHING MACHINE (containing abrasive media) , VIBRATORY TUMBLER(uses vibrations), and TUMBLERS (peanut or walnut husk used)