The Tomlinson recorder is associated with the measurement of-
Surface finish
Let's analyze the question about the Tomlinson recorder and what it measures. The question asks to identify the measurement associated with this instrument. We are given four options: Surface finish, Surface perpendicularity, Stiffness, and Hardness.
Understanding the Tomlinson Recorder
The Tomlinson recorder is a historical instrument used primarily in the field of metrology. Its main purpose is to measure and record the characteristics of a surface, specifically its texture or roughness.
How the Tomlinson Recorder Measures Surface Finish
The Tomlinson recorder works by using a stylus that traverses across the surface being measured. Any vertical movement of the stylus, caused by the surface irregularities (peaks and valleys), is mechanically or optically magnified and recorded on a smoke-glass plate or paper chart. This recorded trace provides a magnified profile of the surface texture, allowing for the assessment of its roughness or finish.
Analyzing the Options
Let's look at each option to see which one aligns with the function of the Tomlinson recorder:
- Surface finish: This refers to the texture of a surface, including its roughness, waviness, and lay. As explained above, the Tomlinson recorder is designed to measure and record surface texture profiles.
- Surface perpendicularity: This is a geometric tolerance that describes how close a surface is to being exactly 90 degrees to a datum feature. Instruments like coordinate measuring machines (CMMs) or autocollimators are used for this, not a Tomlinson recorder.
- Stiffness: Stiffness is a material property that describes how much it resists deformation under load. This is typically measured using mechanical tests like tensile or compression tests, not surface measurement instruments.
- Hardness: Hardness is a material property that describes its resistance to indentation or scratching. This is measured using hardness testers (e.g., Brinell, Rockwell, Vickers testers), not surface profile recorders.
Based on the function of the Tomlinson recorder, which measures surface irregularities and provides a profile of the surface texture, the measurement it is associated with is surface finish.
Conclusion on Tomlinson Recorder Measurement
The Tomlinson recorder is a classic instrument specifically developed for assessing surface finish by recording a magnified profile of the surface texture. Therefore, it is associated with the measurement of surface finish.
| Instrument/Method | Associated Measurement |
|---|---|
| Tomlinson Recorder | Surface finish (roughness profile) |
| CMM, Autocollimator | Surface perpendicularity |
| Tensile Tester, Compression Tester | Stiffness |
| Hardness Tester (Brinell, Rockwell, Vickers) | Hardness |
Revision Table: Key Concepts for Surface Measurement
| Term | Definition | Related Instruments |
|---|---|---|
| Surface Finish | The texture of a surface, including roughness, waviness, and lay. Affects friction, wear, and appearance. | Profilometers (stylus type, optical), Tomlinson Recorder, Surface Comparators |
| Roughness (Ra, Rz) | Measure of the finely spaced irregularities on a surface texture. | Profilometers |
| Waviness | Measure of the more widely spaced irregularities on a surface, typically caused by vibrations or deflections during machining. | Profilometers, specialized instruments |
| Perpendicularity | A geometric tolerance defining how close a surface or feature is to being 90° to a datum. | CMM, Autocollimator, Square with indicator |
| Stiffness | The rigidity of an object; the extent to which it resists deformation in response to an applied force. | Tensile testing machine, Compression testing machine |
| Hardness | Resistance of a material to permanent indentation or scratching. | Brinell, Rockwell, Vickers, Knoop hardness testers |
Additional Information on Tomlinson Recorder and Surface Metrology
The Tomlinson recorder is considered an early form of a mechanical profilometer. While more modern electronic and optical profilometers are now widely used, the Tomlinson recorder was significant in its time for providing a quantifiable record of surface texture. Its operation relies on mechanical amplification and recording, distinguishing it from later electronic methods that use transducers and digital recording.
Measuring surface finish is crucial in manufacturing as it impacts the performance, lifespan, and appearance of components. Different manufacturing processes produce distinct surface finishes, and selecting the appropriate process often depends on the required surface finish specifications.
Understanding instruments like the Tomlinson recorder helps in appreciating the evolution of metrology techniques and the fundamental principles behind measuring surface characteristics.
Important Questions from Surface Roughness
The Centre Line Average (CLA) method for surface finish measurement is also commonly referred to as the _______ value.
Which of the following instruments is used to measure the surface roughness?
For which surfaces, is a spirit level used for testing straightness ?
Mecrin instrument assesses -
The average height from a mean line of all ordinates of the surface, regardless of sign, is the _______.
