Surface finsh for anodizing

[asimpson]

I am working on a prototype product in aluminium 6082-T6. Machined cube about 4" with flat faces and rounded corners.

I wish to clear anodize and would like to achive a smooth, flat blemish free finish that wont show finger marks too badly.

What would be a good surface roughness to achive this? I am concerned about machine marks and blemishes caused by polishing.

Dont want to bead blast or linish.

Thanks

 

[tbuelna]

By "finger marks" do you mean fingerprints resulting from skin residues left on the surface when the part is handled with bare hands? The oil of fresh fingerprints reflects light well, so they tend to catch your eye. Rather than a smooth surface texture, if you want to obscure fingerprints you should use a very rough surface texture. Something like diamond knurling on the cube surfaces would obscure fingerprints very well, since there would only be contact with skin at tips of the knurl points.

Clear anodizing produces a somewhat matte surface finish. But it won't obscure texture features of the base metal surface, such as machining marks, grit blasting or sanding scratches. If you want a smooth, uniform surface texture you might consider giving the part a vibratory tumble finish before anodize.

 

[IRstuff]

My laptop has has a matte aluminum finish, which does extremely well at not revealing fingerprints.

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[asimpson]

In my experience anodising anodizing gives variable results and I cannot give a specification for the effect I wish to achieve as there is a separation between machine shop and anodizing. To machine without marks can be expensive . I don’t know how smooth a surface is required. I am looking for a smooth and blemish free surface. Not highly polished.

Anybody know of a reference I can go to for anodized finish like RAL code painted colour? Only in this case there is an element of surface roughness , texture and visual appearance.

Trial and error seems to be only method available to me at the moment. I do not have my pick of vendors due to my geographical location.

The anodising shop can do some pre-treatment to obscure surface blemishes. Textured bead blasting which is not the effect I desire. Linishing with a sand belt produces a grain in the surface which is prone to finger marks and oil.

Polishing the surface seems to bring out machine marks. Perhaps a different grit size or polishing process should be used.

Perhaps some other process will produce the effect I want. I just don’t know because I cannot un-ambiguously define it.

 

[tbuelna]

If you want to remove machining marks and leave a smooth surface with a uniform texture, then give the part a vibratory tumble finish with a suitable media.