Transmission Casting Leak Test Cell
Demonstrates InterTech’s Test-Centric Assembly Advantage

InterTech coined the phrase “test-centric assembly” to describe the upfront consideration of real-world test requirements in test-intensive assembly operations that is proven to lower production line inefficiencies. In this Sprocket Support Transmission Casting Leak Test example, InterTech's encyclopedic knowledge base on
fixture design enables superior test instruments to deliver their promised performance.

InterTech's fixture solutions are as versatile as the design challenges that each unique product application presents.

Sprocket Support Leak Test Application Details

Production tester must guarantee that aluminum castings meet quality specifications and that rejects are automatically segregated to meet 6-Sigma mandate.

Test Requirements
Specifications call for leakage testing to a limit of 10 sccm (standard cubic centimeters per minute) at 1 bar (14.5 psig) pressure, at a rate of 120 pph. The tester also must accommodate six variations of the same test part.

The test part is an open-ended cylinder, 115mm long with an 185mm OD, divided into two sides by a crosswise center partition.

Within each side, two narrow concentric ring chambers are defined by the part’s exterior wall and two circular inner walls cast into the partition. Sealing surfaces essential for isolating each chamber are located around the sides of these walls, deep inside the test part, close to the partition.

All four chambers vent individually through ports in the cylinder’s outer wall. These vent passageways need to be tested for blockage before participating in the leakage test.

Test Process & Solution
The InterTech design features a single fixture that conducts all tests.

The machine operator simply places the test part in the fixture. Automatic testing begins with the fixture extending into the part through both open ends to seal all four chambers, while a sealing head mates against the four external vent ports.

Two InterTech M-1075 Mass Flow testers simultaneously pressurize the inner ring chamber on one side and the outer ring chamber on the opposite side, first checking for blockage and then measuring leakage. Both M-1075s then pressurize alternate outer/inner chambers and repeat these measurements.

Accepted parts are automatically pin-stamped with test date then removed by the operator. Faulty parts, left unstamped, are automatically ejected from the opposite side of the machine and accumulated on a roller conveyor for sealant application and retesting. In retest mode, the roller conveyor’s accumulating gate is lowered automatically so repeat rejects drop off into a scrap bin.

Special Features

• Difficult internal sealing challenge combining clearance and alignment problems were met with a unique arrangement of compression-expanded ring seals.
• Sensors verify part type by “reading” surface grooves machined into the test part, halt the test if a wrong part variation is inserted.
• Fixture is positioned at waist height at the front of the machine for easy loading/unloading without operator bending and reaching.
• Rejected parts are automatically segregated.
• Built-in table folds down to hold reprocessed parts container, automatically switches system into retest mode.