CNC machining Flashcards
Q: What is the difference between NC machining and CAD/CAM?
A: NC machining involves programming steps at the machine terminal (G-code), while CAD/CAM uses a CAD model to generate machining paths, later converted to G-code by a post-processor.
Q: What is a Numeric Control (NC) machine?
A: NC machines are machines with an integrated computer that controls mechanical movement, commonly used for metal cutting, milling, and lathes.
Q: What are G-codes?
A: G-codes are commands used in NC machining to control machine movements, such as G00 for rapid traverse or G21 to set units to mm/min.
Q: What are the main physical components of NC machines?
A: NC machines are electrically controlled, using servo motors with integrated encoders for precise position feedback, ball screws for motion control, and various feedback systems (closed-loop or semi-closed loop).
Q: What is the purpose of ball screws in CNC machines?
A: Ball screws provide low friction motion, allowing for higher speeds and precision, and are commonly used in CNC machines, unlike lead screws which have higher friction and backlash.
Q: What is the CNC control loop?
A: The CNC control loop continuously monitors velocity and position, using feedback to correct errors and compensate for backlash or slippage.
Q: What is the role of the Man Machine Interface (MMI) in CNC machines?
A: The MMI allows users to input machine parameters, edit G-code, monitor machine operations, and handle alarms and service functions.
Q: What is the purpose of a post-processor in CAM software?
A: The post-processor converts a CAM-generated toolpath into G-code specific to the machine’s controller, considering factors like tool-bed size and reference points.
Q: What are NURBS in CNC machining?
A: NURBS (Non-Uniform Rational B-Splines) are mathematical representations used to define smooth curves and surfaces efficiently in CNC toolpath interpolation.
Q: What are PID controls in CNC systems?
A: PID controls adjust the CNC machine’s movements by correcting errors (proportional), steady-state errors (integral), and overshoot (differential) to improve precision.
