CNC Precision Measurement & Quality Control 1 — Questions and Answers
Question 1: What tool is commonly used to measure external dimensions with high accuracy?
- Caliper
- Micrometer (Correct answer)
- Depth gauge
- Ruler
Correct answer: Micrometer
A micrometer is a precision measuring instrument commonly used to measure external dimensions with very high accuracy, typically to thousandths of an inch or hundredths of a millimeter. Its fine-pitch screw mechanism allows for extremely precise adjustments and readings. This makes it more accurate than a caliper for many critical dimension measurements.
Question 2: What does SPC stand for in quality control?
- Standard Performance Chart
- Statistical Process Control (Correct answer)
- System Process Code
- Sample Pattern Control
Correct answer: Statistical Process Control
SPC stands for Statistical Process Control, which is a method used in quality control to monitor and control a process using statistical techniques. By collecting and analyzing data from a process, SPC helps identify variations, predict future performance, and ensure that the process remains within acceptable limits. This leads to consistent product quality and reduced defects.
Question 3: Which instrument measures internal dimensions precisely?
- Outside micrometer
- Vernier scale
- Inside micrometer (Correct answer)
- Height gauge
Correct answer: Inside micrometer
An inside micrometer is a precision measuring instrument specifically designed to measure internal dimensions, such as the diameter of a bore or the width of a slot. Unlike an outside micrometer, which measures external features, the inside micrometer has measuring faces that expand outwards to contact the internal surfaces. This allows for precise measurement of internal features.
Question 4: What is the function of a dial indicator?
- Measures angles
- Checks electrical current
- Measures displacement or alignment (Correct answer)
- Applies cutting force
Correct answer: Measures displacement or alignment
A dial indicator is a precision measuring tool used to measure small linear displacements or variations in surface flatness, concentricity, or alignment. It converts linear movement of a plunger into rotational movement of a needle on a dial, providing a visual reading of deviations from a reference point. It's essential for checking runout, parallelism, and other geometric tolerances.
Question 5: Which measurement tool can provide readings in both metric and imperial units?
- Protractor
- Laser scanner
- Digital caliper (Correct answer)
- Feeler gauge
Correct answer: Digital caliper
A digital caliper is a versatile measuring instrument that can measure external, internal, depth, and step dimensions. Its digital display allows for easy reading and often provides the option to switch between metric (millimeters) and imperial (inches) units with the press of a button. This dual-unit capability makes it a highly convenient and widely used tool in various industries.
Question 6: What is runout in machining?
- Temperature variation
- Rotational misalignment (Correct answer)
- Material roughness
- Tool wear
Correct answer: Rotational misalignment
Runout in machining refers to the deviation of a rotating part or tool from its true axis of rotation, indicating a wobble or eccentricity. This rotational misalignment can lead to uneven cuts, poor surface finish, premature tool wear, and dimensional inaccuracies in the machined part. Minimizing runout is crucial for achieving high precision and quality in machining operations.
Question 7: What does a go/no-go gauge determine?
- Electrical conductivity
- Thermal resistance
- Dimensional conformity (Correct answer)
- Color coding
Correct answer: Dimensional conformity
A go/no-go gauge is a simple, fixed-limit gauge used for rapid inspection to determine if a part's dimension falls within its specified tolerance limits. The 'go' side must fit, and the 'no-go' side must not fit, quickly indicating whether the part conforms to the required dimensions without providing an exact measurement. This tool is ideal for high-volume production quality control.
Question 8: Why is calibration important in measurement tools?
- To beautify tools
- To improve grip
- To maintain measurement accuracy (Correct answer)
- To increase temperature
Correct answer: To maintain measurement accuracy
Calibration is the process of comparing a measurement instrument's readings against a known standard to ensure its accuracy and reliability. Regular calibration is essential to compensate for wear, drift, or environmental factors that can affect tool performance. This guarantees that all measurements taken are precise, trustworthy, and meet required quality standards.
Question 9: Which quality control document outlines the steps for inspection?
- Work order
- Tool setup sheet
- Inspection plan (Correct answer)
- Maintenance log
Correct answer: Inspection plan
An inspection plan is a specific quality control document that details the steps, criteria, and methods required for inspecting a product or process. It outlines what needs to be checked, how often, and against what standards. This ensures consistent quality assurance and adherence to specifications, unlike other documents which serve different purposes.
CNC Precision Measurement & Quality Control 1
What tool is commonly used to measure external dimensions with high accuracy?