Telecurso 2000 - Metrologia - 04 Paquímetro

Summary

This educational video explains the use of calipers in precise measurement, focusing on various types such as the universal, dial, depth, and digital calipers. Viewers learn the principle behind the Vernier scale, a tool that enhances measurement accuracy by allowing fractional readings. The video also demonstrates how to calculate the resolution of a caliper to ensure precise measurements. Practical applications are covered, including how to select the right type of caliper based on the measurement needs. Overall, it provides a comprehensive guide to using calipers in metalworking and metrology, ensuring users can measure with confidence and accuracy.

Takeaways

• 😀 Paquímetro is a measuring instrument used to detect linear measurement errors, including external, internal, and depth dimensions.
• 😀 The instrument consists of a fixed scale with a movable cursor that slides with minimal slack, providing precise measurements.
• 😀 Paquímetros are used for measuring small quantities, with a resolution of 2/10 mm, 1/128 inch, or 1/1000 inch.
• 😀 The scale on the paquímetro includes a Vernier scale (or nônio), which allows for measuring fractions smaller than the smallest division of the main scale.
• 😀 There are different types of paquímetros, including the Universal, Universal with dial, Depth, and Digital paquímetros, each serving specific needs in various industries.
• 😀 The Universal paquímetro is commonly used in metal mechanics for external, internal, and depth measurements.
• 😀 The Digital paquímetro provides rapid error-free readings and is ideal for statistical control, helping to avoid parallax errors in measurements.
• 😀 The Vernier scale was invented by Pedro Nunes and Pierre Vernier in the 16th century and allows for more accurate measurements by using a secondary scale.
• 😀 The formula for calculating resolution in a paquímetro is based on the number of divisions on the Vernier scale relative to the main scale's smallest unit.
• 😀 Paquímetros with specialized features, like hooks for depth measurement or dual scales for gear teeth, help with very specific measurement needs in metal mechanics.

Q & A

What is the purpose of a caliper, and how does it work?

A caliper is a tool used to measure linear dimensions, such as external, internal, and depth measurements. It consists of a fixed scale and a movable scale (Vernier scale) that slides over it, allowing the user to measure with high precision.

What is the Vernier scale, and how does it enhance the accuracy of the caliper?

The Vernier scale, or nônio, is an auxiliary scale that allows users to measure fractional divisions of the main scale. It was invented by Pierre Vernier and Pedro Nunes and increases the accuracy of measurements by enabling users to detect smaller increments than those on the main scale.

What are the main types of calipers mentioned in the video?

The video mentions several types of calipers: the universal caliper, universal caliper with a dial, depth caliper, dual caliper, digital caliper, and height gauge.

How does the digital caliper improve the measurement process?

The digital caliper allows for quick, error-free readings and is especially useful for statistical control, eliminating parallax errors that can occur when reading a traditional scale.

What is the purpose of the height gauge in mechanical work?

A height gauge is used to trace parallel lines to a reference plane and for geometric control of parts, making it essential for precision work in mechanical engineering.

What is parallax error, and how does the caliper avoid it?

Parallax error occurs when the scale’s readings are misinterpreted due to the angle at which the measurement is viewed. The digital caliper helps avoid this error by providing a clear, direct digital readout.

How is the resolution of a caliper calculated?

Resolution is calculated using the formula: resolution = fixed scale unit (UF) divided by the number of divisions on the Vernier scale (NDN). This determines the smallest measurement the caliper can accurately measure.

Why is it important to use the correct type of caliper for different measurements?

Using the correct type of caliper ensures accurate measurements, especially when dealing with specific shapes, such as conical pieces or parts with varying diameters. Each caliper type is designed for a particular kind of measurement.

What types of measurements can a universal caliper be used for?

A universal caliper is used for measuring external dimensions, internal dimensions, and depths, making it a versatile tool in mechanical and precision work.

What is the difference between a simple depth caliper and a depth caliper with a hook?

A simple depth caliper is used for measuring the depth of holes or recesses, while a depth caliper with a hook is specifically designed to measure more complex depths, such as those with varying diameters or retracted features.