IME 146 FINAL EXAM QUESTIONS & ANSWERS
Three different components of CNC machines - Answer -1. Program of Instructions
(G&M Codes)
2. Machine Control Unit (controller)
3. Processing Equipment (tooling)
What are the three main ways G & M code can be created for a CNC machine? -
Answer -manual programing, conversational programming, CAD/CAM programing.
What type of coordinate system is CNC milling G & M code based off of? - Answer -
Cartesian coordinate system.
Our Haas CNC machines have a closed loop positioning system. What does this mean,
and how does the closed loop system work? - Answer -closed loop system get
feedback to verify that the appropriate actions have occurred. In the closed loop system
a machine control sends a motion signal through a controller board to a servomotor.
This servomotor rotates causing the table to move in an opposite direction. Then an
optical encoder continuously compares and monitors the position of the axis to the
commanded position.
What is the purpose of the ball screw in a CNC mill's drive system? - Answer -turns
rotary motion from the servo motor into linear axis motion.
What is a fixture offset (WCS) used for in a CNC mill and what is the most common
alphanumeric code used to call up a fixture offset in a CNC program? - Answer -used
to provide a way for the CNC control to know the distance from the machine home
position and parts coordinate system. G54 "home location" is the most common
alphanumeric code used to call up a fixture offset in a CNC program.
What is the purpose of a tool length offset in a CNC mill? What alphanumeric codes are
used to set a tool length offset in a CNC program? - Answer -The stick out then tells us
the relative position of the bottom of the tool to the WCS. G43 is the code used to set a
tool length offset in a CNC program.
What is a G-code? Give two examples of commonly used G codes in a CNC program. -
Answer -preparatory codes that prepare the machine for a certain type of motion.
Commonly used G codes in a CNC program would include, G00 (rapid motion), and
G54 (Home locations).
G02, - Answer -Clockwise
G03 - Answer -(Counter-clockwise) cuts and arc or circle.
G01 - Answer -cuts in a straight line G03
, What is an M code? - Answer -An M code are miscellaneous codes.
Give two examples of commonly used M codes in a CNC program. - Answer -M06 (tool
change), and M30 (End program)
2½-axis CNC toolpaths - Answer -only the X and Y axes move simultaneously
3-axis CNC toolpaths? - Answer -XY&Z axes move simultaneously to generate the
surface profile.
purpose of the post processor in when using CAD/CAM software to program a CNC
machine? - Answer -makes the code for the appropriate machine tool brand.
What type of polymers are utilized in the injection molding manufacturing process? -
Answer -thermoplastics
What are the function of the runners in an injection mold? - Answer -allows the plastic
to flow from the nozzle to the cavity.
What is the definition of a short shot in injection molding? - Answer -molten plastic does
not fill the mold cavity completely.
What is one of the primary causes of a short shot? - Answer -having too little pressure.
When an injection molded part has flash on it what does this mean? - Answer -there is
a thin layer of plastic outside the mold cavity
What is the primary cause of flash on injection molded parts? - Answer -having too
much injection pressure
Why do injection molded parts require draft on their vertical edges? - Answer -so that
the parts can come out easily.
Why should sharp corners on injection molded parts be avoided? - Answer -leads to
stress risers and cracks.
What is the purpose of the sprue on an injection mold? - Answer -inject the molten
plastic into the mold.
What is the purpose of a gate in an injection mold and where should the gate be located
on the part? - Answer -minimize stress, and where the runner feeds the mold cavity
How do the non-traditional machining processes differ from the traditional machining
processes? - Answer -Non traditional machining processes cover the processes that do
not use shear stress as their primary source of energy to remove material. Non
Three different components of CNC machines - Answer -1. Program of Instructions
(G&M Codes)
2. Machine Control Unit (controller)
3. Processing Equipment (tooling)
What are the three main ways G & M code can be created for a CNC machine? -
Answer -manual programing, conversational programming, CAD/CAM programing.
What type of coordinate system is CNC milling G & M code based off of? - Answer -
Cartesian coordinate system.
Our Haas CNC machines have a closed loop positioning system. What does this mean,
and how does the closed loop system work? - Answer -closed loop system get
feedback to verify that the appropriate actions have occurred. In the closed loop system
a machine control sends a motion signal through a controller board to a servomotor.
This servomotor rotates causing the table to move in an opposite direction. Then an
optical encoder continuously compares and monitors the position of the axis to the
commanded position.
What is the purpose of the ball screw in a CNC mill's drive system? - Answer -turns
rotary motion from the servo motor into linear axis motion.
What is a fixture offset (WCS) used for in a CNC mill and what is the most common
alphanumeric code used to call up a fixture offset in a CNC program? - Answer -used
to provide a way for the CNC control to know the distance from the machine home
position and parts coordinate system. G54 "home location" is the most common
alphanumeric code used to call up a fixture offset in a CNC program.
What is the purpose of a tool length offset in a CNC mill? What alphanumeric codes are
used to set a tool length offset in a CNC program? - Answer -The stick out then tells us
the relative position of the bottom of the tool to the WCS. G43 is the code used to set a
tool length offset in a CNC program.
What is a G-code? Give two examples of commonly used G codes in a CNC program. -
Answer -preparatory codes that prepare the machine for a certain type of motion.
Commonly used G codes in a CNC program would include, G00 (rapid motion), and
G54 (Home locations).
G02, - Answer -Clockwise
G03 - Answer -(Counter-clockwise) cuts and arc or circle.
G01 - Answer -cuts in a straight line G03
, What is an M code? - Answer -An M code are miscellaneous codes.
Give two examples of commonly used M codes in a CNC program. - Answer -M06 (tool
change), and M30 (End program)
2½-axis CNC toolpaths - Answer -only the X and Y axes move simultaneously
3-axis CNC toolpaths? - Answer -XY&Z axes move simultaneously to generate the
surface profile.
purpose of the post processor in when using CAD/CAM software to program a CNC
machine? - Answer -makes the code for the appropriate machine tool brand.
What type of polymers are utilized in the injection molding manufacturing process? -
Answer -thermoplastics
What are the function of the runners in an injection mold? - Answer -allows the plastic
to flow from the nozzle to the cavity.
What is the definition of a short shot in injection molding? - Answer -molten plastic does
not fill the mold cavity completely.
What is one of the primary causes of a short shot? - Answer -having too little pressure.
When an injection molded part has flash on it what does this mean? - Answer -there is
a thin layer of plastic outside the mold cavity
What is the primary cause of flash on injection molded parts? - Answer -having too
much injection pressure
Why do injection molded parts require draft on their vertical edges? - Answer -so that
the parts can come out easily.
Why should sharp corners on injection molded parts be avoided? - Answer -leads to
stress risers and cracks.
What is the purpose of the sprue on an injection mold? - Answer -inject the molten
plastic into the mold.
What is the purpose of a gate in an injection mold and where should the gate be located
on the part? - Answer -minimize stress, and where the runner feeds the mold cavity
How do the non-traditional machining processes differ from the traditional machining
processes? - Answer -Non traditional machining processes cover the processes that do
not use shear stress as their primary source of energy to remove material. Non
