Mechanical Finishing
To impart a subtle change to the appearance of components, to remove slight surface imperfections or to create an individual aesthetic finish Graph have the capability of applying various mechanical finishes to components prior to anodising. These mechanical finishes alone or in conjunction with some chemical pre-treatments can create very pleasing finishes which will improve the overall appearance of work.
Mechanical Textures
Bead blasting
This is a versatile process which will create a ‘textured’ finish on the component. The grades of media which can be employed and blasting pressures can be adjusted to produce a texture range from ‘coarse industrial’ appearance produced using a blend of coarse grit, to a subtle ‘fine soft’ texture by using fine glass bead or stainless shot.
Linishing or Brushing
This is a highly popular finish which is particularly good for fascias and enclosures. This is a process by which a ‘grain’ effect is applied to the component. The grain can be coarse but more popular is the fine brushed finish (320 grit) similar in appearance to that on brushed stainless steel. When ‘stock size’ bar has been used for components and a minimal metal removal is permitted this process can significantly improve the appearance of components.
Graph have both manual and automatic machines allowing us to accommodate not only standard bar but slightly more complex parts.
Vibroing
Commonly used in industry as a method of de-burring components, this process can also be used to impart a smooth to the touch yet mottled effect providing the correct media is employed.
All the above finishes can be used alone or in conjunction with some of the supplementary chemical pre-treatments detailed below to impart a good aesthetic quality to components.
Chemical Pre-Treatments
Etching
This is an alkaline process which will remove the surface layer of the component. The longer the immersion the greater the metal removal. This process results in a fine ‘matt’ finish. It should be noted that this finish will change dimensional tolerances on surfaces including holes and this should be bourn in mind if specifying such a finish. Also this finish will not remove or disguise deep mechanical damage.
Brightening
As the name would suggest, this is a process which imparts a smooth bright finish to components. The luster can be altered by immersion time and alloy. The alloy used should be selected carefully if this process is intended to be used as some alloys are unsuitable for this process.
The variations of the mechanical finishes in conjunction with the chemical finishes are vast and it is preferred practice to obtain a sample of the required finish and carry out trials to perfect finish prior to production.