Technical Articles

For most foundry processes the commonly accepted standard for the nondestructive testing is SAE International specification AMS 2175.  Although better known for delineating the frequency and inspection criteria for Radiography, Magnetic Particle and Penetrant Inspection, AMS 2175 also devotes substantial sections to quantifying the standards for Visual inspection. 

Slots and fins are common features that appear often on Investment Cast parts and typical of configuration that can be incorporated into a design with minimal impact on the cost.  There are, however, some basic rules-of-thumb for the design of slots and grooves to help keep them from becoming cost drivers.

One of the special capabilities of the investment casting process is the production of castings with internalized features, passageways or undercuts.  O’Fallon Casting has four techniques available to produce internal detail:  mechanical tooling, soluble wax cores, pre-formed ceramic cores and imbedded pre-formed tubing.  We’ll expand here on each of these four techniques.

Blind holes and pockets are common features of investment casting designs. They serve to lighten the part, provide designed clearances and are examples of the type of detail that can often be provided by the investment casting process at negligible cost to a customer.

A common question asked by Design Engineers in concurrent engineering is whether a particular hole in a part is castable?  To answer that question requires an analysis of the four dimensional components that constitute the description of the hole: diameter, length, diametrical tolerance and locational tolerance.

CAD systems have made the designing of parts both better and quicker and have a positive impact downstream from product design.  Also known as Digital Product Definition (DPD) the MBD revolution in design has had both good and bad repercussions for the foundry industry.

O’Fallon Casting provides its customers with a better alternative and consistently legible option for the application of variable part marking information on castings:  Laser Engraved Part Marking.    This OFC technology eliminates customer complaints and rejections of castings for poor legibility of manually applied vibro-peened or ink stamped part marking.

Geometric Dimensioning and Tolerancing of Castings

One of the primary benefits provided by the Investment Casting process is that part detail can very often be furnished at negligible additional cost.  Engineers frequently take advantage of this “free” capability by incorporating cast lettering and marking into their part designs.

Surface Texture of Investment Castings