Die Casting Consultant

Midson has been hired as a die casting consultant for a range of projects, such as providing hands-on expertise for the prototyping and commercial production of die castings. Techniques utilized included conventional die casting, vacuum die casting, squeeze casting and semi-solid casting, producing parts from a range of alloys including aluminum, copper, magnesium and steels.

Another example of consulting projects involves providing companies with technical and commercial evaluations of novel die casting technologies.

As a die casting consultant, Midson has also been hired to provide expert analysis to assist clients in obtaining and defending patents.

Metal Casting Expert

An example of Midson's work as a metal casting expert is a recent project with University College Dublin, Ireland (UCD). Midson was hired as a metal casting expert to market and develop the CDC Process, a technique patented by UCD that produces functionally gradient materials from two metals or alloys. Producing castings from two metals provides engineers with the flexibility to design components with different material properties at selected locations.

Working with the metal casting experts at University College Dublin, Midson participated in the production of castings made from different pairs of alloys, as shown in the table below.

Eck Industries (www.eckindustries.com) was identified as by The Midson Group as a licensee of the CDC Process, and is presently developing a commercial application involving the casting of an OEM aluminium metal-matrix composite brake disc for a mid-size truck. The central part of the disc, which attaches to the wheel hub, is cast from monolithic aluminum A356, while the outer part is cast from a Duralcan composite, to provide the wear resistance needed for the friction surfaces.

As example of Midson's work as a metallurgical consultant involved identifying the origin of detrimental porosity in aluminum-silicon-magnesium squeeze castings. As a metallurgical consultant, Midson has access to a number of metallurgical evaluation techniques, and several were used in this project. The photograph on the right shows a high magnification view of one of the pores taken in the scanning electron microscope. Pores of this type could have originated from several sources, such as:

Entrapment of air
Entrapment of die or shot sleeve lubricant
Turbulence during die filling causing folding and entrapment of foreign material

To obtain more information about the pores, Energy Dispersive Spectroscopy (EDS) chemical analysis was performed. The EDS spectrum from the pore (see right) indicates the presence of aluminum and oxygen. The table below lists the quantitative analysis, showing that 7.4% oxygen was detected at the surface of the pore. EDS analysis of the base metal showed that, as expected, oxygen was not present in the alloy.

It was concluded that the pores were originating from air entrapment due to inadequate venting, and a recommendation was made to the caster to increase the size of the vents in the die. After the vent size was increased by about 50%, the castings were found not to contain the pores, confirming that the pores were indeed caused by inadequate venting.

Steve Midson is an expert on many aspects of semi-solid casting. He has been involved in the commercial production of thousands of semi-solid castings.

Midson has been hired by several organizations to provide detailed technical and commercial information on thixocasting, rheocasting and thixoforming processes. Read our article on the topic for a list of 20 rheocasting processes.