A Guide To Measuring Surface Finishes

The finish, or surface texture of a finished component can be viewed differently from two different perspectives. For the designer, variations of surface texture would affect the functionality of the component. If the designer wishes to change the component’s functionality, the surface texture specification must be altered. From the machinist’s point of view, the finish is the end product of the manufacturing process and it can be altered by modifying the manufacturing process. Read on to find out more about measuring surface finishes and the various parameters involved!

Variations In Surface Finishes

Surface finishes contains the troughs and crests that comprises the surface and the direction of the surface. Through the usual machining processes such as grinding, milling and turning, uneven sections are being imparted onto the component’s surface. Moreover, other factors such as the vibration, speeds, condition of the machine tool and the choice of machine tool can also affect the extent of these irregularities. As a result, these factors must be carefully controlled.

Components Of Surface Finishes

Surface finishes can essentially be classified into 3 segments:

  • Roughness: Roughness stems from the usage of cutting tool that leaves a mark with a distinct depth and width. Also, in the cases of grinding, the abrasive granules on the wheel can also leave a groove on the surface of the component that is being produced.
  • Form: Form can be attributed to a lack of straightness or flatness in the machine’s cutting tool, resulting in the component’s surface finish being affected. This results in a systemic deviation from the specified requirements whenever the machine is being used.  
  • Waviness: Waviness of a component is defined as small variations in the length between the cutting tool and the produced component during the manufacturing process. These variations are caused by the instability of a cutting tool due to vibrations. The source of vibrations can be internal such as the motor of the machine or even externally induced due to the operations of other machines nearby. The waviness of the component can be measured by a contour measurement device.

How To Measure Surface Finishes

All of the above-mentioned surface finish components exist simultaneously and each condition is checked
separately. By measuring these components, the search for the origins of the error can be narrowed, allowing its effects to be reduced or eliminated. There are many instruments available in the market that would enable you to measure these 3 components, such as a pocket-sized, battery-powered gages. Its low price allows for the measurement of a small number of roughness parameters at an affordable cost. Furthermore, these instruments are also very flexible and are very easy to use. If you require more complex parameters to be measured, more precise equipment but expensive that involves powerful computers would be required!

At Willrich Precision Instrument, we provide a large selection of surface roughness testers and form measurement that would definitely meet the rigorous needs of your business! Browse through our exciting inventory and shop for quality surface roughness testers today. If you need assistance with any product purchase, call us at 866-945-5742 or email us at sales@willrich.com today.

by George Chitos

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