Anodize Finish

Anodize Finish

The Macfab team provides one-stop solutions to the challenges manufacturing and plating. We deliver parts ready for our customer’s immediate use including anodizing.

Anodizing aluminum is an electrochemical reaction that applies a layer of material onto the aluminum part.  The advantages of anodizing include:

  • Increased corrosion resistance
  • Increased wear resistance
  • Lowers electrical conductivity
  • Lasting color
  • Can be applied to aluminum, magnesium and titanium

The Types of Anodizing

PropertiesType-I
(Chromic Acid)
Type-II
(Sulphuric Acid)
Type-III
(Hard Anodize)
ApplicationsDecorativeDecorativeCorrosion Resistance
Corrosion ResistanceGoodGoodExcellent
Coating Thickness0.08-0.25 µm2.54-25 µm12.7-80 µm
Wear ResistancePoorModerateExcellent
PorosityLowModerateHigh
Environment impactNoYesYes
AppearancePrimary CoatClear or ColorsHard clear or black

Anodizing aluminum is an electrochemical reaction that applies a layer of material onto the aluminum part.  Comparing to Allodizing a part, this process requires the part to be machined undersized to account for the addition anodizing to the part, using a vendor that delivers the part complete reduces issues by compensating for the part growth from the anodizing process.

A clean part is placed in prepared solution.  The aluminum part is positively charged, making it the anode; simultaneously, a negative charge is applied to a metal plate in the solution.  The current passing from the plate to the aluminum work piece bonds chemically to the aluminum part.

Anodizing can be done as a hard coat anodizing (Type III).  This offers high corrosion protection and improves wear performance for mechanical parts exposed to high frictional heating.  The anodizing is controlling the thickness of the Aluminum Oxide barrier layer.  Did you know that Aluminum Oxide is nearly as strong as a diamond?  While aluminum is most commonly anodized, it is possible to apply this process to magnesium and titanium.

The anodize process also allows for colors to be absorbed into the chemical structure of the part.  Short of grinding on the part, the color will not peel or scratch away from the part.

Design considerations for a successful part:

  • Remember to account for anodized growth for tight tolerance connections
  • Corners have a minimum radius of 0.020”
  • If part has esthetics requirements, a deburring or polishing operation should be done prior to anodizing
  • Also consider a location that does not require the anodizing, as the part will need to be fixtured to the electrode to complete the process.

 

Macfab offers complete anodizing services, your one-stop shop for ready to use components and assemblies.