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NDT Talk


Seminars/Workshops on 2002 schedule

ibg will be on the road again in 2002, holding our Seminars/ Workshops in several North American cities.

Presentations at the seminars are technical in content and cover a wide range of eddy current com­ponents testing applications and solutions. Your application or ones similar to yours are likely to be included or discussed. Examples of both material properties testing and crack testing will be presented, as well as some theory and rules for doing successful testing.

We invite you to attend any of these scheduled below:

Mo., March 18 Cambridge,Ontario, Canada
Tu., March 19 Ann Arbor, MI
Th., March 21 Indianapolis, IN
Fr., March 22 Chicago, IL

If you wish to attend, please contact Laurie Gerben at ibg (248-476-9490) to make arrangements.

Elsewhere in this issue, we are providing examples of the efficiency and effectiveness of eddy current NDT test systems, including parts such as piston rods, piston pins, ball pins and gears. I'd also like to call your attention to a new video we have available of a system that tests cast iron cylinder liners for cracks and pores (replacing visual inspections). The entire cylinder liner can be tested, including the I.D. and O.D. surfaces and the faces. Also, the induction hardened I.D. surface can be tested for correct hardness and case depth.

NDT monitoring of gear hardening process nets huge savings

A major automobile manufacturer was using destructive testing (cutting, embedding, grinding, polishing, microexamination) to confirm the hardening of 11 different very-high-volume transmission gear components, which had been carburized and hardened in a continuous heat-treating furnace. In this process, if the furnace malfunctioned, complete containers of gear parts had to be scrapped, even if most of the parts were OK.

Once an ibg system with an eddyliner®P16 test instrument was installed, a yearly savings of over $387,000 could be realized. The savings included 2,250 man-hours, 8,250 cut parts and 500 saw blades.

The system consists of a test coil with a bushing (for exact positioning) for every test part. Simply by pressing a button, the operator connects the test instrument to a test position and gets a result within split seconds.

This is a prime example of the efficiency of eddy current NDT testing. Three systems are now installed.

Automated test system for water pump shafts is integrated online

ibg was tasked by a well known manufacturer of bearings to inte­grate eddy current testing into an existing system that feeds water pump shafts to grinding machines. Three test positions--for hardness and case depth each--were required.

The solution was to place the eddy current test after the pump shafts have been put on a conveyor belt by a gripping device. The parts are now on an incline, on which they roll to a stopper. From there, they are moved into the ibg test coil pneumatically. The coil incorporates the three individual test positions.

An eddyliner® P3 then carries out measurement at three positions in series. If the shaft has correct hardness and case depth at all three positions, it is returned to the conveyor belt and is passed on to the grinding machine.

If one of the three positions detects wrong hardness or case depth, the part is fed to a separate container.

The test rate is less than 3 seconds per part. Parts with diameters 12-20 mm and lengths of 75-112 mm can be tested on the system.

(top) Shaft parts flow from right to left, while NOT-OK parts are shunted into two boxes in foreground (one for dimension rejects, the other for hardness rejects).

Two types of water pump shafts (left) are tested by the eddy current system.

Compact system tests piston rodsfor cracks and seams following grinding and superfinishing

Up to 20 piston rods per minute are examined for cracks with this system utilizing ibg eddydector® and eddyscan® H2/25 equipment.

Processing parts with diameters 8-33 mm, 250-650 mm in length, the system scans rods longitudinally and transversely.

Compactly set up within a steel frame superstructure, the system transports parts on synchronously-running v-rollers to a non-contacting, rotating probe disk where the testing takes place. Adjustments for differ­ent diameters are carried out by setting the rotating head to the correct height (by means of a rotating crank) and changing the probe disk.

Not OK parts are diverted to a lockable rejected-parts chute.

Within the system, the eddydector® detects cracks, seams and other surface defects at mass-production rates. The eddyscan® H unit is especially designed to monitor cylindrical parts. As with many other components for today's vehicles, automated 100% testing is vital for component manufacturers to achieve zero defects in parts subjected to such processes as heat treating, machining, grinding and superfinishing.

Precise transport (upper photo) sends rods toward rotating probe disk, shown in close-up at right in lower photo (protective cover has been removed).

Hardness testing of piston pins at one per second

The automatic testing of piston pins for hardness after grinding is accomplished by an ibg system utilizing our eddyliner®P. Testing parts with a radius of 18 mm to 28 mm (lengths 55 mm to 100 mm), the compact design of the system

enables it to be simply integrated into production lines at positions following the grinding process.For testing, each piston pin is stopped instantaneously in position by a stopper in the vertical test coil. Testing for hardness is then done at eight frequencies (in 0.128 seconds) according to ibg's Preventive Multi-Frequency Test (PMFT) method. After testing, the parts are passed to an OK chute or N-OK parts container according to the sorting decision.

Not OK parts are diverted to a lockable rejected-parts chute.

The ibg PMFT protocol enables eddy currents to reliably detect all hardness and structure defects due to incorrect heat treating, including those not statistically predicted or not previously encountered. It provides 100% testing for zero defects at production line speeds.

Close-up (above) shows piston pin after 0.128-second test for correct hardness following its release to the sorting gate. The next pin can be seen about to enter the coil.

(top right) Plaque above each gear position in eddyliner® system indicates description of gear for simple set-up and testing.

(lower right) Console of system accommodates 11 different gear components for testing.

"Twin station" system detects cracks and clogged/missing cotter pin holes on ball pins

At the rate of up to 5,400 parts per hour, an ibg system tests 12 types of ball pins via a two-channel eddydector® unit and twinned test stations. Crack specification is for a depth of 0.25 mm, width of 0.10 mm, and length of 3.75 mm.

The system works in this manner: The parts are fed in pairs to a rotary indexing wheel, which takes them to the test station, where they are put into rotation while the eddydector® unit performs the testing for cracks.

At the same time, the cotter pin holes are tested. From there, they are forwarded to the OK or N-OK chutes, depending on the decision of the detection station.

Changeover to different part types is carried out easily, within a few minutes, via change parts-which remain easily accessible.

Ball pins (shown in drawings) fed to this rotating wheel (photo above) are tested and then forwarded to a chute, in fore ground, depending on the sorting decision of the eddydector unit.