Complex & Pressure Tight Aluminum Castings

Products for the pump, compressor, transmission, hydraulic and pneumatic industries demand leak free castings. Le Sueur Incorporated specializes in manufacturing complex, pressure tight castings. We have the experience, tools and unique manufacturing processes to ensure leak free castings of extremely high integrity.

Tools and Processes to Ensure Pressure Tightness

Pressure tightness refers to the ability of the casting to hold a specified internal pressure for a specified time. Below are just some of the tools and processes we use at LSI to ensure the supply of high integrity castings:

  • Magma Simulation: Every new part is simulated prior to tooling construction. This ensures that potential leak areas are detected early in the casting development process, remedied, and tooling is developed using the best design practices possible.
  • Casting X-ray: Digital/Real-Time Radiography (DR), Computed Radiography (CR) and Film Radiography.
  • Leak Testing: LSI offers Air Decay (also referred to as Pressure Decay), Mass-flow and Underwater Testing to ensure supplied castings meet a castings intended pressure testing requirement.
  • Metal Spectrometer: LSI uses an Optical Emission Spectrometer (OES) to verify the chemistry of our purchased alloys, and to verify individual melting furnaces throughout the manufacturing facility.
  • In-house Heat Treating: To improve mechanical properties of our Sand and Permanent Mold castings.
  • In-house Machining: Including component assembly and customized testing.
  • Liquid Penetrant Inspection:Used for crack detection (Also referred to as Dye Penetrant Inspection)

LSI’s Aluminum Casting Process and How We Get It Right…


Early engagement with LSI's process dedicated engineering staff is essential to achieve a mutually successful project. These engineering professionals assist our customers in the product development process by incorporating the most advantageous tooling and aluminum casting practices. Together with our customer, a product design is evolved for the selected casting and manufacturing processes to produce the most cost efficient and robust part.


Le Sueur Incorporated implements an unbiased approach to the aluminum casting process selection. We specialize in permanent mold casting, sand casting and die casting and use this experience to recommend the most effective method for your project.


To minimize or eliminate internal shrinkage porosity, properly designed runner, gate and riser systems are all critical to achieve pressure tight and leak free castings.


As a die casting cools, shrinkage porosity may form in heavy mass or isolated areas of a casting. This is due to thinner wall sections of the casting and gates "freezing off" preventing the continued pressure and feeding of the heavier mass areas as these areas continue to cool. Shrinkage porosity may result in leak paths or exposed porosity on a machined surface.

The remedy.....Squeeze Pins. When the casting is cooling in the mold and the aluminum is in the semi-solid state, LSI uses Squeeze Pin Technology to deploy specially designed pins directly into the part. Squeeze Pins displace material in the casting under very high pressure. The displacement of material significantly increases the pressure in the mold cavity in a localized area. This extreme pressure improves the casting integrity in areas of a casting requiring minimal porosity.

For many product designs, Squeeze Pin Technology is the solution to achieving a repeatable pressure tight and leak free casting. Le Sueur Incorporated's Die Casting Engineering Staff assist customers with product design specifically for utilizing this technology.


Vacuum Assist aids in evacuating the air in the mold cavity as the metal is being injected into the mold at very high speeds (milliseconds). Also, after a part is extracted from the mold during the die casting process and the mold is in the open position, a die coolant/lubricant is sprayed on the mold cavity surfaces.

Vacuum Assist helps reduce gas caused by residual die lubricant in the mold cavity prior to the aluminum entering mold. This minimizes gas porosity from forming during the solidification stage. Vacuum Assist is an absolute necessity in the aluminum die cast process when producing pressure tight and leak free die castings. All new die castings produced at Le Sueur Incorporated are cast using Vacuum Assist.

Learn More About Our Ability to Cast Intricate and Pressure Tight Projects

Le Sueur Incorporated specializes in producing dimensionally complex, pressure tight aluminum castings and thermoplastic injection molded components. We offer complete in-house precision machining, finishing and assembly. Please contact us to learn more about our capabilities and how we can best assist with your casting needs!

Complex and Pressure Tight Casting Channel Plate Face

Complex and Pressure Tight Casting Horton Clutch

Complex and Pressure Tight Casting JD Manifold

Complex and Pressure Tight Casting TK 4 Cylinder