Magnaflux

Magnaflux Quasar is used to test a range of ceramic parts. Applications include: 

• Oxygen sensors
• Catalytic converter cores
• Grinding wheels

Quasar Detects All Structurally Significant Defects

Magnaflux Quasar detects all of the structural defects that occasionally appear in ceramic parts including:

• Cracks
• Chips
• Inclusions
• Incomplete sintering
• Incorrect powder mixture

Quasar Provides Better NDT

Since a part's resonance pattern contains a measure of the structural integrity of the whole part, a single Quasar test can replace other NDT methods that typically focus on specific defects. Quasar replaces dye penetrant inspection used for cracks. It also replaces or complements visual white light inspections for chips and significant dimensional variations, and it can detect the inclusions or incomplete sintering that are sometimes detected using candling. Magnaflux Quasar can also replace many of the lab tests used to confirm correct density, sintering, and powder mixture.

Special Considerations

Quasar testing can be used for all production parts made of materials that are stiff enough to resonate. While Quasar can be used with most ceramic parts after complete sintering, it cannot be used for parts in the green state. Using Quasar for partially sintered parts is generally problematic because the parts are so soft that they do not resonate well.

Quasar testing will only detect structurally significant defects, that is, defects that are severe enough to cause a part to fail prematurely in service. As a result, Quasar will not detect surface crazing that does not weaken the part.

In application to symmetrical ceramic parts such as balls and rollers, Quasar can use an alternate resonance testing method based on the symmetry of the part. This method is somewhat less sensitive to defects than Quasar's pattern recognition method, but it has the advantage that it is not statistics-based, so the presence of defects can often be determined without the need for training of the computer algorithm using a Training Parts Set.

Benefits

The benefits of using Magnaflux Quasar for production volume ceramic parts include:

• Reliable detection of all structurally significant defects in a single test
• Results that can predict part life by correlating to failure testing (e.g., tensile or fatigue tests)
• Computer based accept/reject decisions, not subject to human judgment
• Reduction in scrap, since cosmetic defects are not rejected
• Dry process eliminates need for post-inspection treatment

Ceramics Economic Case Study

Description

The part is a ceramic oxygen sensor tested at 1000 parts per hour. The plant operates 3 shifts per day, 5 days per week and produces 5,000,000 sensors per year. The plant is located in the US and all costs are in US$.

Quasar allows the elimination of the 5000 psi "proof test" from the current inspection regime.

The Quasar system consists of 3 manually loaded Quasar 3100 NDT Systems. The total cost was $300,000.

The cost savings are tabulated below.

The Quasar cost per part is based on capital amortization over 2 years. It does not include labor because the Quasar load/unload operation is incorporated into the existing operator cycle, with no added manpower. In addition to the reduced NDT cost, the scrap rate was substantially reduced for additional savings. More important, the number of defective sensors received by the ultimate customer was reduced by a factor of 40.