After creating the mold, we take it to the Foundry.
- At LA Aluminum, we melt only the best certified aluminum alloy ingot. Our specialty is casting alloy A356, though others are no stranger to us.
- Ingots are placed in our electric or gas crucibles and heated to approximately 1,350 degrees Fahrenheit. Our melting capacity is 5,600 pounds per hour.
- We preheat the molds and coat the internal surfaces with a refractory material. Next, we ready any inserts and assemble any cores.
- Temperature control is critical in all aspects of the pouring process. Thermocouples and infrared temperature sensors are used to ensure optimum temperature control.
- The first castings poured from a new tool are called first articles. The first articles must pass our quality department inspection and tests prior to being sent to you for evaluation.
- Once your approval is received, the molds are ready for full production.
We specialize in permanent mold casting (also referred to as gravity die casting or permold), using static pour, tilt pour, or reverse tilt pour casting method variations.
- Permanent mold casting or gravity die casting refers to the use of gravity to feed molten aluminum into a reusable mold or die.
- Using the static pour method, the preheated molds are closed and installed into a stationary base. Molten aluminum is poured into a spout located at the top of the mold. After a set amount of time, the mold is opened and the part is removed.
- When the tilt pour method is used, molds are placed horizontally into a hydraulic actuated tilt machine. Aluminum is poured into cups attached to the mold and an operator initiates the machine to tilt vertically to allow aluminum to fill the mold cavity. After a set amount of time, a programmable control positions the mold horizontally where the part is removed.
- In traditional tilt pour, the mold parting line is perpendicular to the floor during the solidification process whereas with reverse tilt pour the parting line is parallel to the floor. Reverse tilt pour is ideal for radial type castings, such as wheels, hubs, compressor housings, automotive structural castings and cookware. This method is not limited to radial type castings; it’s also been used to cast parts like high performance brake calipers.
Steel and sand cores
- Some part designs call for the use of a steel core or sand core (also called shell core) to hold the inner dimension or hollow section of a part.
- Steel cores generally operate mechanically in the mold and are reusable.
- Sand cores or shell cores are placed in the mold before closing. This is also referred to as semi-permanent molding.
- We remove the sand core from the aluminum part by breaking it apart using a vibratory process sometimes called "shake out."
Heat Treating And Aging
- After removing gates and risers, the inlets are sanded as required before being carefully loaded into specially designed heat treat baskets and staged to be heat treated.
- Our Drop Bottom heat treat and age oven heat treat ovens are certified for uniformity of temperature annually.
- The amount of time in the heat treat and the temperature are critical factors since the temper of the alloy is determined in this process. We typically heat treat parts to a T51 or T6 condition. The heat treat process is verified by testing the hardness of the castings per your specification.
View Heat Treat Equipment table, Foundry Melting Equipment table, Foundry Casting Equipment table, and Shell Core Equipment table