It is very expensive to decoratively surface finish existing magnesium alloys. As a result, most of this business goes to zinc and aluminium die castings or plastic mouldings. There is a significant market opportunity for a cost effective magnesium die casting alloy that has better die castability attributes than existing magnesium alloys, plus an improved as-cast surface finish that is suitable for decorative surface finishing operations. Together with its research partner CAST, AMT has developed AM-lite which fulfils these market requirements. AMT has also worked together with MacDermid Industrial Solutions to develop suitable electroplating technology and conversion coating technology for AM-lite.
What is AM-lite ®

AM-lite is a high surface finish die casting alloy suitable for applications that currently utilise zinc, aluminium or magnesium (alloy AZ91D) die castings, or plastic injection mouldings. AM-lite has significant cost advantages and other benefits when compared to these competitor materials.
Advantages of AM-lite ®

The key advantages of AM-lite in decoratively finished products over zinc alloys are its light weight, lower material cost per unit volume and lower reject rates in painting and powder coating. Compared to plastics the key advantages are electrical conductivity for electromagnetic shielding, thermal conductivity and metallic feel. When compared to aluminium die casting alloys the main advantage of AM-lite is a superior as-cast surface combined with improved and lower cost surface finishing characteristics. Compared to the existing general purpose magnesium die casting alloy, AZ91D, AM-lite offers improved die castability, better as-cast surface, improved recyclability and a superior substrate for surface finishing operations at significantly lower costs.
Advantages of AM-lite over AZ91D

The most commonly used magnesium die casting alloy, AZ91D, suffers a significant disadvantage in the cost of surface finishing of articles made from this alloy. High quality as-cast surfaces are difficult to achieve and surface finishing operations generally require additional processing steps leading to higher cost.

AM-lite, in combination with appropriate die design, die casting process parameters, and decorative coating technologies, overcomes this disadvantage. An as-cast surface finish that is superior to AZ91D can be readily obtained. At the same time AM-lite has excellent die casting characteristics with better die filling and surface feature reproduction than AZ91D. It also has a much wider diecasting operating window, leading to reduced cycle times in production and large potential cost savings. AM-lite is very easy to recycle and, in combination with the use of AM-cover and AM-converter technologies, the cost of external recycling can be virtually eliminated.
Electroplating of AM-lite ®

The electroplating process for AM-lite was developed by MacDermid Industrial Solutions, a global supplier of chemicals and technology to the surface finishing industry. Macdermid’s Bondal ® Mg process, that was specially developed for AM-lite, takes advantage of the alloy’s favourable surface chemistry to greatly simplify pre-treatment steps that are necessary before application of electroplated layers of copper, nickel and chromium. The pre-treatment for AM-lite involves one step more than is necessary for electroplating of zinc die castings but thereafter the process is the same as for the electroplating of zinc and surface finishes of equivalent high standard can be obtained.