FPI Inspection Basket for Turbine Fan Segments:

Application Overview:

Our customer manufactures jet engines and they needed baskets to hold their parts through a new FPI work cell (Fluorescent penetrant inspection) that cleans the parts and applies penetrating dye to reveal any imperfections or cracks.

Specific Requirements:

Our customer was developing a semi-automated work cell to 100% FPI inspect turbine fan segments before final assembly into jet engines.  The work cell has a U-shaped conveyor to move baskets loaded with parts through several stations.  The first station is an aqueous wash station to clean away any manufacturing dirt or debris. The next work cell station dips the basket full of parts into a tank of penetrating dye.  The third station along the conveyor is an air blow off chamber that removes the excess dye from the part’s smooth surfaces, leaving dye only in the cracks or imperfections.  The final station in the work cell is an enclosed booth where the parts are inspected under ultraviolet light.  Any cracks hold the dye which glows brightly under the ultraviolet light.  If the parts pass inspection, the basket of parts leave the inspection booth for a second pass through the wash cycle to remove any dye residue.  If any parts fail inspection, the parts exit the inspection booth on a different conveyor to be reworked or scrapped.  The U-shaped layout of the conveyor brings the finished parts back to the starting point so a single operator can both load and unload the conveyor.

Our Solution:

Properly designed baskets for FPI Baskets must hold parts in a very specific orientation so the dye coats the surfaces evenly and completely.  Good FPI basket designs also must have the absolute minimum of points contacting the parts, and the basket itself must a minimum of joints, both of which will trap extra penetrating dye and give false inspection readings. Our custom basket design accomplished all of these design requirements.  The baskets have internal grids that locate the arc-shaped parts securely with only four small areas contacting the parts.  The overall basket design is very open to allow extra dye to shed away.  Even the text on the identification tags have the letters laser cut through, not stamped or engraved which would trap unwanted dye.  Finally, the entire basket is powder coated with Black Nylon 11 to protect the surfaces of the parts from scratching and to bridge any small crevices between the rods that would catch dye.

Design Features shown here that could be Ideas for your Custom Basket: