Q: What is chemical milling?

A:  Chemical milling, sometimes referred to as chem-mill or chemical etching, is a metal removal process applied to fabricated parts and raw materials in order to reduce weight. A few of its more significant advantages versus mechanical machining are the ease at which it can be applied to contoured surfaces and the selectivity that can be achieved when used in combination with a maskant (or chemical stop off).

Q:  What materials can be successfully chem-milled?

A:  Most metal alloys can be chem milled, including steel, brass, aluminum and titanium. TAM exclusively processes aluminum.

Q: What chemicals are used for chemical milling of aluminum?

A:  Unlike steel and titanium which requires usage of various acids (sulphuric, hydrofluoric), aluminum is milled using a solution of sodium hydroxide (caustic soda). The rate at which material is etched is controlled by chemical strength and solution temperature.

Q:  Are there any limitations on the type of aluminum that can be chem-milled?

A:  Aerospace parts are generally fabricated from 2000, 6000 and 7000 series aluminum. In most cases the aluminum must also be of MRS condition (minimal residual stress) unless it is plate material. Check with TAM before purchasing material if you're not sure.

Q:  What is the standard turnaround time for processing?

A:  TAM benchmarks itself against a 15-20 day lead-time. Flexible scheduling allows for the expedited processing of jobs in as few as 3-4 days depending upon shop load.