Where the
world gathers for metal finishing
Q&As since 1989


-----

Anodizing during manufacturing of industrial digital cameras

2005

Dear sir,

We are manufacturing Industrial digital cameras. We are very much concerned with aesthetic properties and also some close tolerances.
One of the dimension in our component is 38H7/g6, which is very precise sliding fit. But after anodizing this fit would not be there.

Material used: Aluminium 6351 He30 T6
Overal dimension: 75 mm Sq x 25 mm

Questions are,
1) For how much time a component should be dipped in the solution during anodizing process to get the exact required dimensional tolerance?

2) Is there any relation between dipping time, dimensional tolerances and alloy?

Thank You Sir,
Regards,

Pramod P T
Soliton Technologies - Bangalore, Karnataka, INdia

---

2005

The anodising time depends on the current density,alloy and thickness of coating required.

Rough guide for pure aluminium
Thickness=(Current density amps/dm2 x Time (min))/3

Generally 30 % of the anodising thickness would be increase in dimension.

Jabasingh Immanuel
Sundaram Clayton - Chennai, Tamilnadu, India

---

2005

Dear Sir
If the precleaning is done for aluminium with alkaline etch ,the component may lose its thickness in microns and as well the mechanical finish done on it. And during anodising aluminium oxide build up will increase the thickness approximately at the rate of 1/2 microns per minute.

Thanking you
with regards,

Kansdaswmy Raveendhran
Euro Process - Coimbatore, Tamil Nadu, INDIA

---

Dear sir,
You have to do trails and fix the precleaning time for your dimensional requirements. In the outside area you will get 40% increase in the dimension and in the Inside bore or drill holes you will get only 25 -30 % increase. If your coating thickness required is less than 15 microns it will be difficult to maintain the dimentions consistently.By doing proper precleaning with accurate time and maintaining all precleaning process parameters you can maintain your dimensions after anodising.

ELANGOVAN
ANODISING - BALAJI ENTERPRISES, COIMBATORE, INDIA
2005