A number of factors can affect the cost of Hard Anodising so it is better for both buyer and supplier if these are clearly understood at the quoting stage.
Alloy Grade
First there is the Alloy Grade, not all aluminium is created equal some are easier to process than others. However there are some alloys that are classed as difficult to anodize such as the high-silicon casting alloys. These alloys can produce inconsistent results and take longer to process than others. There is plenty of information on the various aluminium alloys on the Aluminium Federation web site, so if you are planning to design an aluminium part it would be wise to select an alloy that is easy to process to minimise the cost of surface treatment.
Coating Thickness
For hard anodising, parts are generally anodised to around 25 microns thick however, due to the engineering nature of many parts, they are often required to be anodised to 50 microns or more. This is because thicker anodising requires longer tank time and consequently, greater energy.
Part Geometry and Masking
Items with complex profiles, that have blind holes, threads, etc. all require time consuming hand masking. As a general rule of thumb, parts with open profiles are easier and less expensive to anodize.
Batch Size
As the unit cost decreases with increasing batch size, this could be worth bringing up with your supplier, if you are purchasing in low volumes.
For Hard Anodising, visit www.poeton.co.uk/surface-treatments/anodising/hard-anodising/.
Post-Treatment Options
PTFE impregnation will add cost as it is another process step, but can provide dry lubrication. Dyeing anodize can also add cost as it is another process step, but can provide colour for identification or cosmetics. Only add these process steps if they provide a functional or operational requirement.
So, a clear and correct specification of all requirements is crucial for an accurate quotation on the very first attempt.