Die Castings can now be prototyped in production alloys using Trilore's ME casting process and match critical mechanical properties.  We start the process with your 3D CAD file, as with the standard plaster mold process, and create a master model from it using CNC machining.

  The ability to cast in different aluminum alloys means not having to compromise between mechanical properties, thermal conductivity or alloy compatibility.

Tighter tolerances means significantly less machining of parts; indeed, in many cases machining is eliminated, reducing the costs of secondary operations.  See tolerance page for details on tolerance control provided by ME.

  Rapid response tooling means when your quantity needs increase, Trilore can meet those increases with ease.

Trilore's ME process was developed to meet a need in the die cast prototype market for a process that provided analogous parts for testing prior to the release of data for production die casting. The most important attributes identified as we developed the ME process were:

Mechanical properties

Dimensional tolerances

Surface finish

Cost of tooling and castings

Lead time

After 2 years of development, the ME process achieves the best mix of these attributes. Below is a summary of the expectation a customer can have for ME castings for each attribute when casting with die cast alloys:

It is understood that if one specific alloy is used in different casting processes, conventional thermodynamics says that the only way to change mechanical properties is to change the rate of cooling of the alloy. This might occur during the casting process, or in a subsequent heat-treat process after the cast process. There are some additional methods now available such as the HIP process or the addition of grain site promoters, but typically the rate of cooling of a part determines mechanical properties. In the simplest terms, faster cooling means smaller grain structure, and smaller grain structure means better mechanical properties.

If you look at the rate of cooling between the different casting processes, the die casting process appears to provide the best overall mechanical properties at a cooling rate to solidification of 10 to 12 Degrees C/second. A higher cooling rate will create depleted silicon zones that reduce mechanical properties. Lower cooling rates may cause low density (porosity). Other casting processes have different cooling rates. Typical rates for various section thicknesses are as follows:

Die Casting :             12 - 500 Degrees C/sec

ME Casting:              .8 – 2.2 Degrees C/sec

Permanent Mold :     .3 – 1 Degrees C/sec

Sand Casting:           .1 - .5 Degrees C/sec

RPM:                          .05 - .2 Degrees C/sec

When the DCS (dendritic cell spacing) of typical die castings and castings made with the ME process were compared, the DCS of ME castings where about 4 times greater than those of the die casting of comparable section thickness. Please note the comparison was made at comparable depths within the sections of the castings, and below the chilled surface of the die-casting. This means that in the as-cast condition, the mechanical properties of the ME casting were significantly lower than those of the die-casting using the same alloy. However, due to the lack of trapped air in the ME casting, we have the capability of heat-treating the casting to increase mechanical properties. Typical mechanical properties of test bars poured along with the castings are as follows for 380 alloy:

                                                       Die Casting (Book values)      ME Castings

Tensile Strength (ksi)                   46                                               33

Yield Strength (ksi)                       23                                               21 - 26

Elongation (%)                              3.5                                              2.5 – 3.5

Typical dimensional tolerances for ME castings are as follows. (Please note these are to a nominal tolerance based on the first part(s) poured, see Tolerance page)

+/- .007 inches for the first 8 inches (+/- .18 mm to 200mm)

Add an additional .0005 inches per inch for every inch over 8 inches (.012mm for every additional 25.4 mm)

Core and parting lines are + .010 inches, - 0.00 inches for the first 8 inches

These are typical of standard NADCA allowances for die-castings with the exception of the core and parting line dimensions. The ME molds are plaster molds that are assembled by hand, so the parting lines created by additional plaster pieces used to make features that are not in die draw tend to be slightly less accurate than what can be achieved in die castings but closer than what can be achieved with any other casting process.

It should be noted that holes less than 3/8 inch in diameter or any feature that is required to be better than .015 inches to true position is machined into ME castings to assure meeting dimensional requirements.

The typical as-cast surface finish of ME castings is 64 micro inches. The biggest difference between a die-casting and the ME casting is the area around a core pull feature. For example, an undercut feature on a die-casting would have a core pull scar at the beginning of the undercut (picture a hole with a core scar around the diameter of the hole). The ME casting will have a core scar stepped away from the undercut feature that also extends to the parting line of the mold.

The standard lead time quoted for the ME casting is 4-5 weeks for the first as-cast parts after receipt of a finished casting database. The typical times for the various processes in the tooling and casting process are as follows:

Creation of a master pattern: 1-2 weeks

Creation of the tool used in the foundry: 2 weeks

Time to make the initial castings 1 week

The timeline for the actual casting process includes making the plaster mold (1 day), pouring the metal into the mold (1 day), grinding the casting (1 day) and finally the heat treat and final inspection of the part (2 days).