Surface finish in manufacturing

Surface finish in manufacturing

Surface Finish


For many engineering applications, the finish on a surface can have a big effect on the performance and durability of parts. Rough surfaces generally wear more rapidly and have greater friction coefficients than smooth surfaces. Typically, roughness is a dependable predictor of mechanical part performance, as irregularities tend to form nucleation sites for breaks or corrosion. Conversely, roughness may encourage desired adhesion


Surface finish is one of the essential quality control parameter to ensure that

functional surfaces of manufactured parts conform to specified standards. Surface finish of

parts can significantly affect their friction, wear, fatigue, corrosion, tightness of contact

joints, positioning accuracy, etc. Surface finish is an important factor for manufacturing process monitoring and quality control inspection. A change in any part of the production process will result in a change in one or more measurable parameters of the component. 


Surface finish in particular is very sensitive to changes in production, even alteration in the

composition of the material or hardness of surface will be reflected as a change in the texture of the machined component. Tool wear, strains in the material and incorrect machining conditions can all leave their mark measured at the end of the chain of production processes;it is an important control means.


In many engineering applications surface finish is closely allied to function, particularly when the surface of interest is having relative motion with another surface (a function which has been very aptly described as ‘its neighborliness to adjacent surfaces’).

One may find enormous engineering applications of mating components that require control of surface finish.


Controlling Surface Finish:

Often, the failure of an engineered part originates at the surface as a result of either an isolated manufacturing-related issue or gradual breakdown in surface quality. Therefore, finishing operations have been widely adopted as the ideal methodology for generating a desired surface finish on various machined and fabricated parts.

Precise roughness is challenging and costly to control in manufacturing. Lowering the roughness of a surface will usually raise its manufacturing costs significantly. This results in a trade-off between the manufacturing cost of a part and its performance.


Surface Finish and Product Function:

There are a variety of considerations, and they may even vary for different stages in the manufacture of a particular part. For example, we may have a surface finish requirement on a casting that ensures the finish is good enough that the allowance made for extra material that will be machined off in a future step is sufficient. If the casting is too imperfect, the trough of an imperfection may be below the expected machined surface of that future step.

Another important consideration is friction. Reducing surface roughness typically reduces friction which can be critical to reducing wear and increasing efficiency of sliding parts.

The required surface finishes are very much determined by the function and use of the component. Ship’s propellers start out with fairly high surface finish standards but in actual use they erode pretty quickly. Optical and especially components used with X-Rays have some of the finest surface finish requirements achievable.

The goal of the designer is to specify surface finishes that are as coarse as possible but will still function within the part’s desired operating parameters. The goal of the machinist is to achieve surface finishes on parts that are as good as those required by the designer, but not better as that results in the cheapest to manufacture parts. It’s important for designer and manufacturer to agree on exactly which parameters (Ra, Rz, etc..) are to be used for inspecting and parts acceptance.


The measurement of engineering surface finish is becoming increasingly important due to the benefits incorporated with it. The benefits of measuring surface finish:

to quality and cost- control are as follows:

■ The efficiency of the manufacturing process is improved through performance


■ The number of parts rejected by the customer (scrap) due to inferior surface finish is


■ A part is manufactured with the maximum permissible roughness, thereby reducing

manufacturing costs.

■The part quality is enhanced by optimizing surface finish.


In CUBII we are caring about surface finish inf machines and its’ parts because we appreciate the importance of surface finish process and how it affects the performance of the machines so you can have an idea about our machines in the website: 


This machine you can see a video for it and know more about our production: