Eddy Current Component Testing Experts
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Practical applications issue
Tier One supplier determines origins of surface flaws in automotive components

A major Tier One supplier of automotive steering system components utilizes ibg crack detection systems to achieve zero defects for surface flaws on its produced components. The systems being used supplemented previous magnetic particle inspection because they provide much higher test reliability (avoiding human error) as well as significantly lower inspection costs.

Origin of flaws

Surface flaws detected by the system have been characterized and cataloged over time in order to determine what caused them and how they originated.

The findings are very illuminating. Of the defects uncovered by the eddy current system, A 61% originated at the steel I mill and arrived in this condition as expensive, high grade steel bar stock for this component. Processing of the bars at the plant caused only 27% of the defects. (Origins for 12% of the flaws could not be determined.) Once the sources of flaws were known, actions were undertaken to improve the quality of the incoming steel bar stock and to reduce internal causes of the flaws.

Of course, remaining flaws in the bar stock, and those developed by internal processing, still must be detected and sorted out by the eddy current system.

Closer look at steel mill origins

However, knowing the sources of the surface flaws has opened the way for new opportunities and strategies to accomplish additional cost savings beyond those already gained directly from the ibg eddy current test system.

Have you determined the origins of all rejects in your operations? Could it be that the processed metals, material mixes or alloys you are receiving have defects that impinge on your quality levels and costs of operations? Can you possibly find and eliminate all of them?

ibg has maintained that automated 100% testing for material properties and for cracks has become vital to components manufacturers. This Tier One supplier's experience has definitely proven our point.

Transmission gear assemblies tested for structure

Manual tests of transmission gear assemblies are performed by an ibg eddyliner® P16 instrument, testing each unit for correct structure after heat treatment. Applied after carburization and hardening, sample parts are tested for correct hard­ness, case depth and core hardness at each of four test positions (see illustration.

This testing utilizes the effective Preventive Multi-Frequency

Testing method of ibg, and is simply accomplished:

  • The test part is placed in a test fixture.
  • Coil heads are placed into the test position, which triggers the test automatically.
  • A sorting decision is indicated by a red or green lamp (while a printer provides hard copy).
eddydector® instrumentation provides 100% reliable detection

ibg's eddydector® instruments and systems assure ultimately reliable detection of cracks, seams and other surface defects as shallow as 0.05mm on mass-produced components.

Each application encountered by ibg is solved by developing an appropriate solution around a nucleus of advanced eddy current technology. May we work with you on your latest NDT challenge?

Automatic structure testing of CV joints
accomplished by ibg eddyliner® system

Testing the structure of CV joints for hardness, case depth (on stem), core hardness and hardness runout on the stem has been achieved with an automatic structure testing system utilizing ibg's eddyliner® P3 instrumentation. Testing at three positions (see diagram), the system utilizes two locations on the stem and one on the races inside the bell to confirm the structure of each CV joint.

This sort of testing also can be performed on tripots and other similar components, according to ibg General Manager Bill Buschur.

The procedure works as follows: CV joint parts enter the system via conveyor. Each part is then lifted into a test position by the I.D. coil, which tests inside the bell, followed by two other test coils that monitor the shaft positions.

Each joint is tested at three locations: on the shaft for hardness runout at the end; on the shaft for hardness, case depth and core

hardness at the spline; and in the bell I.D. for hardness of the races. All three of these tests require less than 0.7 second!

A graphic display on the control panel provides a view of each part configuration during testing.

BY BILL BUSCHUR
GENERAL MANAGER
Berg Engineering represents ibg in central Midwest

Jerry Berg has been serving industrial clients for over 30 years, with a focus on eddy current applications in the last decade. His firm, which numbers nine persons, serves industries in Illinois, Wisconsin, Minnesota and Iowa from its Chicago office.

Hardness testing equipment is Berg's background, and his firm has developed a strong base among such customers as John Deere and International Harvester. Acquainted with me prior to my involvement with ibg, Berg Engineering is pleased to be a new member of our team.

According to Jerry Berg, who investigated the current perception of ibg with several companies, ibg equipment has everybody impressed." Now it's Berg's turn to impress his customers with ibg capabilities.

Please welcome with us Jerry and his crew into the ibg organization.

2-channel eddydector system detects cracks on piston pins

Automatic, non-contact crack detection on piston pins (or wrist pins on a crankshaft) is performed by an ibg eddydector® system using a two-channel rotating head eddyscan® instrument. Rotating at 3,600 rpm, the system head tests 1,800 to 4,500 parts per hour (depending on length) running at 50mm/sec.

Both longitudinal and circum-ferential crack detection can be performed on the factory floor with this compact system, which includes separate control cabinets for test electronics and electrical components.

In this process, ground piston pins are fed to the test system horizontally via conveyor belt. After passing a demagnetizing coil, they are subjected to the rotating eddyscan® instrument,

which performs a continuous inspection for cracks. The parts are then sorted into a reject chute or on to the packaging station.
Easy changeover to different piston pin part diameters can be accomplished with exchangeable guide tubes in about 10 minutes.

New system detects cracks on axle shafts

Although test parts may differ significantly, and come to this test system randomly, a multiple channel eddydector® system ibg can test axle shafts for cracks at three different positions:

A- on the surface of the shaft

B- underneath the plane face

C- on the radius

Thus, three different parts, fed in mixed batches to the testing unit, are recognized and can be scanned for cracks in about 14 seconds each.

Conveyor-fed, the system unloads the shaft parts from the belt by means of a gripper, feeding and discharging each tested part via a pallet system. At the crack detection station, the part is clamped and

rotated at approximately 600 rpm. Multiple channels scan the whole cylindrical surface (A); including the radius, the plane face (B); and the radius (C) for cracks.

Following rotation, the tested part is repositioned on the pallet, while rejected parts are passed on to a separate internal conveyor belt. A version of this system includes a transparent protective cover, which can be opened easily for access to the test station

ibg NDT Systems Corporation, 20793 Farmington Road, Farmington Hills, MI 48336
Phone: 248.478.9490, Fax: 248.478.9491
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