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Eddy Current Sorting Devices for Parts

ibg Eddy Current Ball Sorter

High Speed Test System for Automatic Structure Test on Balls

Precise and rugged mechanics for the 3-shift use in harsh industrial environment

ibg ball sorter with optional support for the instrument

What would the world be without ball bearings? And what would the ball bearings be without balls? A mass product, however with high demands on a successful heat treatment and correct use of material. Soft balls or balls out of a wrong material assembled in a crankshaft bearing? The consequences for you as manufacturer can be serious when balls of a complete batch are faulty or a material mix-up occurred. Even a single case costs money and gnaws at your reputation.

Would it not be desirable to easily 100% guarantee that only balls with correct material properties are assembled into the bearings? In this case we can support you with our well-proven ball sorting machine.

The ibg ball eddy current sorter combines the well-proven Preventive Multi-Frequency Technology PMFT and Simultaneous Harmonic Analysis and latest fully-digital stage of development (still faster test times, enhanced frequency range and harmonic analysis) with a very fast and precision test mechanics.

It is available as a plug-in standard product in two versions:

  • for small balls (1.5 – 6.0 mm)
  • for large balls (6.0 – 25.0 mm)

Depending on their diameter, small balls may be tested at speeds of up to 10 balls per second. The version for bigger balls may run at up to 6 balls per second.

Reliable solution with impressive test speed


The balls are fed through a tube to the bunker of the eddy current ball sorter or smaller balls directly into the bunker. A transport disk with pockets, takes the balls from the bunker and moves them below a structure probe which tests each ball.

A fast solenoid is installed for sorting the balls to OK or NG in order to meet the high test speeds. Sorting is always active.

The distance of probe to ball is diameter-dependently and set by means of two micrometer screws for the X-and Y-values as per a table.

A lockable cover prevents unauthorised access. In addition there is a switch box with PLC, operating elements and the power supply.

A rotary knob under the cover with digits controls the number of test parts per second via the motor speed. Maximum setting means ten parts per second are tested. Setting is achieved with the help of a speed table.

A signal light on the switch box with two LEDs serves as remote control. The red light is on in case of standstill of the machine, the green light is on when the machine is working. The red light blinks in case of malfunction and the transport motor is stopped immediately.

Scope of supply

  • an eddy current test instrument of new generation, e.g. eddyliner® S digital as a table top device or installed on an arm
  • the test mechanic with parts feeding, transport disks, structure probe, discharge chute, cabling and switch box with control electronics

Principle of function

Testing of balls for correct material properties is always based on our eddy current structure technology PMFT. Balls which do not correspond to the correct properties are rejected. To achieve this, a certain quantity of OK-balls with correct material quality is fed into the test system as reference parts. Afterwards, each test part is compared with this reference data. Any discrepancy sorts the parts to NG. From a physical point of view the permeability curves of the test parts are compared with the permeability curves of the reference parts.

ibg ball eddy current sorters can be installed either at the beginning or at the end of your ball production process: at the beginning it is possible to stop the production early in the process when wrong material is involved and so avoid unnecessary expense. At the end, you test your finished product and guarantee that OK-balls only are packed or mounted.

BTW: still larger balls with diameters >25mm can also be tested and we supply tailor-made solutions with proven mechanical concepts and performance data.

ibg Eddy Current Ring Sorter

100% Zero Defect Test of Bearing Rings for Correct Heat Treatment at High Test Speed

Preciseibg ring sorting device for the structure test on rings – as a stand alone unit or integrated into a production line

The core of the test: ibg rectangular coil. In the background: the star-shaped singling wheel.

Ball and roller bearings are subject to great and greater demands in our high-tech world. Besides the balls and rollers the rings work under severe loading demands. They can withstand the stresses long-term when the heat treatment process was successful and they have the specified hardness and case pattern.

Heat treatment is a complex process with many parameters responsible for the perfect product, so the rings must be tested for a wide defect spectrum. Rings can be too soft or too hard, annealing or quenching can be faulty or did not happen, decarburisation may occur or the rings in the furnace lie on top of each other so that they are only partially hardened. Quite apart from the “worst case” when a not-hardened "green" ring gets amongst the god parts.

What could be more appropriate with regard to product quality than to 100% test the rings after heat treatment for correct structure non-destructively. The established method is the eddy current method. The permeability curves of the test parts are compared with the permeability curves of the reference parts (OK parts). Any deviation means a mutated structure and the part is sorted not-good.

Such a complex error naturally shows differences in the permeability curves at different locations. Thus a multi-frequency test is recommended for the eddy current structure test in order to be able to detect all deviations. The ibg Preventive Multi-Frequency Technology PMFT and Simultaneous Harmonic Analysis and the latest fully digital development step with optimised test times, enhanced frequency range and harmonic analysis is first choice.

Until the introduction of the fully digital Preventive Multi-Frequency Technology PMFT, the test time was so long that relatively large test parts like bearing rings could only reasonably be tested statically, so that all eight test frequencies took part in the test result. As the popular bearing ring types are produced in large numbers a 100% zero defect test requires a rather immense test and thus cost and effort. Often it was therefore omitted. Introduction of the fully digital Preventive Multi-Frequency Technology PMFT was the beginning of a new era. Due to the significant reduction of test time now a dynamic test of bearing rings is feasible without concessions regarding test reliability.

We have used this technology for the development of the ibg eddy current ring sorter, and designed for your bearing ring application an automatic test system with a test speed of maximum 90 parts/minute and a parts range of outer diameter: 30-120mm, width 9-35mm.

Thus the ibg ring sorting opens up absolutely new opportunities to you on the way to a quick and cost-saving production-accompanying 100% test of a large spectrum of your product range!

The perfect duo: our testing instrument eddyvisor® S and the ring sorting unit

Test process

The parts roll down the inlet rail which is adjustable to ring width to the diameter-specific escapement and transport wheel. A height-adjustable star wheel is driven by a gear motor and cycled. It moves the individual rings with constant speed through the rectangular encircling test coil.

The test trigger point is recognised by a light barrier in the middle of the test coil and processed by the PLC. It triggers the test part type such that all eight test frequencies flow through the test part and are evaluated. The relating 3rd and 5th harmonics are also evaluated at the same time by the ibg eddy current test instrument. The exact setting of the trigger point is important and considerably eased by a graphical display of the test part by the single frequencies in the test instrument software. When the test result is OK the flap to the NG discharge closes and the OK part rolls to the next process step on a rail adjustable to ring width. This active OK parts sorting is perfected by monitoring the sorting gate. As an open sorting gate is the resting state the NG parts are always sorted to the NG discharge to the bad parts container without any further action (failsafe).

The complete test unit is mounted inclined, thus the rings move by gravity through the inlet and outlet rail.

The ring sorting is designed for integration in a production line or as upgrade with a conveyor. Gapless part feeding is recommended to achieve the maximum test speed. It is also possible to use it to test individual parts and feed the rings by hand.

Scope of supply

  • ibg eddy current test instrument eddyvisor® S, latest generation and a rectangular test coil and a second one as compensation coil
  • test mechanic with feeding of parts, escapement and transport wheel, test coil, NG parts chute with sorting gate, cabling and switch box with control

Eddy Current Sorting Gates

Universal, Fast and Cost-Saving 100% Structure Test of Small and Medium Batches

UNISort 10 HD

UNISort 40 HD

Manufacturers and refiners of components who have to handle small and medium batches know the problems: automation is not thinkable due to high investment for such quantities, and manual handling is too cost-intensive due to labor costs. A compromise must be found. If it has to be a 100% material test the ibg sorting devices UNISort 10HD, 25HD, 40HD and 63D could be your solution. Together with one of the ibg eddy current test instruments eddyvisor® S, eddyliner® S or eddyguard® S and the appropriate coils, this semi-automatic test “out of the box” which can realise cycle times of approx. 1 part/sec. with one employee. The test parts (diameter 1-60mm) are put manually in the coil, testing is done automatically as well as sorting to OK chute or NG chute is also automatic.

Our eddy current sorting equipment is ready to work within minutes and can be switched to other part types very quickly. Best suitable for testing smaller and medium batches and it is often used for “first responder jobs” as it is easily transported. Adding a suitable feeding and escapement enables it to be used in automatic mode when demand increases. The UNISort is controlled by the ibg eddy current test instruments, a separate control is not needed. The power for the UNISort 10 / 25 / 40HD is taken from the power supply of the test instrument. The UNISort63HD has an own power supply. The UNISort serves as fixture for the test coil and is a sorting gate at the same time. The sorting flap is monitored by a proximity switch. Together with the coil monitoring of the ibg eddy current structure test instrument malfunctions of the test equipment are recognized.

ibg eddy current sorting devices are designed for the rough application in an industrial environment. Resistant ceramic components are used among others in order to fulfil the sophisticated conditions in foundries and heat treatment shops ensuring a long lifetime of our products. Should it happen that something is worn after years you may rely on a quick repair and availability of spare parts. The standard scope of supply offers ibg UNISort devices in four different sizes (up to 10mm, 25mm, 40mm and 63mm part diameter) which are available for quick delivery. Custom sorting devices are available for special geometries or larger test parts.

UNISort 25 HD

UNISort 63 HD

ibg UNISort:

  • large testable parts range
  • applicable immediately and universally
  • works with all ibg structure test instruments
  • long lifetime due to high-quality components and easy exchange of wear parts
  • non-stop operation
  • capable of being integrated in automatic test systems
  • reliability due to sorting gate monitoring
UNISort 10 HD UNISort 25 HD UNISort 40 HD UNISort 63 HD
Weight of the Unisort 3 kg 4 kg 8 kg 13 kg
Tension 24 VDC
Ambient temperature – 10 to + 60°C
Protection class IP 55
Max. part temperature 50°C

ibg NDT Systems - Designers and manufacturers of state-of-the-art NDT eddy current testing equipment, instruments, sorters and systems for automotive, bearing and other metal components including fastener, forged and cast parts, hard metals, precision stamped parts, etc.