Gear Cutting Flashcards
What are certain KEY FUNCTIONS that gears do?
REVERSING THE DIRECTION OF ROTATION, ALTERING THE ANGULAR ORENTATION OF ROTARY MOTION, CONVERT ROTARY MOTION INTO LINEAR MOTION (and vice versa) , and to alter GEAR SPEED RATIO
What are the two types of methods of MACHINING GEARS?
GEAR GENERATING & GEAR FORM CUTTING
The methods to mahcine gears can also do what?
Do FINISHING
Describe the process of GEAR GENERATING?
It is done by the relative mation of the gear cutting tool and the generating mation(or rottion) of the workpiece
What are the PRIMARY gear generating processes?
HOBBING AND SHAPING
Describe the process of HOBBING.
Gear teeth are progresively generatted by a a series of cuts using a HOB. Where the HOB and workpiece are roatating but the HOB is being axially fed across the face of the blank
What is gears does HOBBING create?
Spur gears, helical gears, and many special gear forms
What is the main limitation of HOBBING?
Can only be used to craete external gears
Describe the process of GEAR SHAPING.
The workpiece rotates in contact with a reciprocating cutter
What are the types of reciprocating cutters used for GEAR SHAPING?
PINOIN SHAPED CUTTER, MULTI TOOTH RACK SHAPED CUTTER, and SINGLE POINT CUTTER
What cutter was used to create staright teeth on a gear?
A PINION SHAPED CUTTER
How is the process of GEAR SHAPING done with a RACK SHAPE CUTTER?
Typical has 6-12 teeth that reciprocate in the gear blank and once its done cutting throughit disengages and returns to its starting point to begin another cut
How is SHAPING done with a SINGLE POINT CUTTER?
The cutter reciporcates to make succesuvely deeper cut until the predetermined depth is reached
What types of gears do GEAR SHAPERS mainly make?
Internal gears, shoulder gear, and many other gear types that HOBBING cannot produce, as well as non enveluped shape such as a cam and gear on the same shaft
What is GEAR FORM CUTTING and the TOOL used?
Uses formed tooth cutters that have the desired shape(or profile)
What are the 2 types of GEAR CUTTING?
BROACHING & MILLING
Describe the BROACHING PROCESS and why is it used?
The BROACH and the gear blank are pushed or pulled relatively to each other to quickly remove material and is used since its the fasts method to machine gears
Why would you do normal BROACHING?
To create internal gears
Describe the process of POT BROACHING.
Performed on a speciall machine tool that has a hollow broaching tool asssembly called a POT and the gear blanks are either pushed down, pushed up, or pulled up through the pot to create the external gear teeth
Describe MILLING used in the video
Uses the reltive motion between a multi edge cutter and workpiece to generate shapes and usually mill each gear tooth individually
Describe GASHING and why its used
Used to create produce large corse pitch internal or external spur or helical gears.It involves plunging the the rotating cutting into the blank to rapidly remove metal
What are the 2 processes that can be done after SHAPING/CUTTING a gear?
HEAT TREATMENT to create the required hardnness and FINISHING which is done to nullify any distortion
