MET 2065 (metal manufacturing tech) - Lecture #4

How do metal finishes affect product marketability?

They enhance appearance, which impacts customer satisfaction.

What protective functions do metal finishes serve?

They protect against contaminants and abrasion.

What is the purpose of identification in metal finishes?

To provide a means of recognizing different finishes.

What are the types of abrasives used in metal finishing?

Emery, aluminum oxide, silicon carbide, crocus, and diamond dust.

What is the function of emery as an abrasive?

A natural black abrasive used for various grinding applications.

Why is aluminum oxide considered a good abrasive for high carbon and alloy steels?

It is synthetic and effective for tough materials.

What is Grain Size in abrasives?

It is determined by the size of individual grains used in the abrasive material.

What is the purpose of buffing in metal finishing?

To produce a smooth, bright finish through mechanical polishing.

What does sandblasting achieve in surface preparation?

It removes materials from surfaces and produces a matte finish.

What is hot dipping in surface preparation?

Coating metal by dipping it in molten aluminum, zinc, lead, tin, or lead-tin alloy.

What is electroplating?

A process where a thin layer of metal is deposited on a surface through electrochemical means.

Describe flame spraying as a surface preparation technique.

Melted (metals, alloys, or ceramics) coating material is sprayed onto a surface and interlocks with the surface upon cooling

What is sputtering in surface preparation?

A vacuum process where argon ions strike a target to deposit particles on a material.

What are organic coatings in surface preparation?

Paints, varnishes, lacquers, enamels, and epoxies applied through various methods.

What is aluminum anodizing?

An electrochemical process that forms a protective layer of aluminum oxide.

What is electrobrightening?

Electrochemical process where the aluminum
is the anode in an electrolyte that dissolves
the oxide film, as quickly as it’s formed. Color may be added.

What is chemical blackening?

A process that applies a black oxide coating to ferrous metals.

What is the function of a wheel dresser in grinding?

To true the grinding wheel and remove glaze or foreign materials.

What is precision grinding?

An economical method to remove excess material and finish hardened steel with high accuracy.

What is surface grinding?

A method using reciprocation or rotary motion to grind surfaces flat.

What is the difference between traverse and plunge grinding?

Traverse grinding moves the workpiece past the wheel, while plunge grinding rotates the workpiece in contact with the wheel.

What is centerless grinding?

A grinding method where the work does not have to be supported against centers as it rotates against the grinding wheel.

What are the three types of centerless grinding?

Through feed, infeed, and end feed.

Describe through feed in centerless grinding.

Work is fed continuously into the gap between the grinding wheel and regulating wheel, suitable for simple cylindrical shapes.

What is infeed in centerless grinding?

Work is fed into the gap until it reaches a stop.

What is end feed in centerless grinding?

Both wheels are dressed to the desired shape.

What is internal centerless grinding?

The grinding wheel is inside the bore, with multiple regulating wheels outside the part.

What is the purpose of a diamond dressing tool in precision grinding?

It dresses the grinding wheel to the precision required.

What is a drill press?

A power-driven machine that holds or supports the workpiece and a cutting tool to drill, cut, shave, or grind material.

How is the size of a drill press determined?

Size is twice the distance from the centerline to the column.

What are the main parts of a drill?

Point, shank, body, and flutes.

What is the function of the point of a drill?

This part of the drill is the cone-shaped end that does the cutting.

What is the purpose of the lips on a drill?

They are the cutting edges of the drill.

What does the heel of a drill refer to?

The portion of the point back from the lips or cutting edge.

What is the shank of a drill?

The portion that mounts into the chuck.

What are flutes on a drill?

Spiral grooves that run the length of the drill body, forming the cutting edge and allowing chip removal.

What is the function of body clearance on a drill?

It reduces friction between the drill and the wall of the hole.

How is drill size indicated?

By numbers, letters, inches and fractions, or metric measurements.

What is the purpose of cutting fluids in drilling?

To absorb heat and act as a lubricant.

What is countersinking?

Cuts a chamfer in a hole to allow a flat-headed fastener to be inserted.

What is counterboring?

Cuts a cylindrical relief larger than the pilot hole for socket head screws.

What is reaming?

The production of holes that are extremely accurate in diameter with a fine surface finish.

What is tapping in drilling?

Cuts internal threads using a feed handle to apply downward pressure.

What should not be done with a drill press when tapping?

Do not use a drill press to turn a tap, as it will break the tap.