CIRCOGRAPH Sensor systems Rotating Head Ro 35 P Rotating Head Ro 35 L

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1 CIRCOGRAPH Sensor systems Rotating Head Ro 35 P Rotating Head Ro 35 L The optimum rotating head for eddy current testing of metallic semi-finished materials in the diameter range: Ro 35 P 2 to 35 mm Ro 35 L 5 to 35 mm High throughput at testing speeds of up to 3 m/s Minimum retooling time for dimension changes by lateral access Very compact design, overall length of only 345 mm Sturdy, breakdown proof design Ro 35 P with 2 or 4 test heads performed as pin, particularly suitable for largely high flaw resolution together with high precision material guidance Ro 35 L mit two or four test heads performed as levers, particularly suitable for integration in production machines, e.g. drawing lines Roller guide on option, overall length mm Registered trade-marke Rotating Head Ro 35 L/Ro35P with roller guide

2 Features Highly sensitive, contactless testing for mainly longitudinally oriented surface flaws Electronic clearance compensation in the entire diameter range from 2 (5) to 35 mm with CIRCOGRAPH DS With CIRCOGRAPH CP without clearance compensation Longitudinally oriented surface flaws can be detected as from a flaw depth of around 30 µm High throughput without untested gaps: testing speed of 3 m/s at 9,000 rpm when using four test heads with a track width of 5mm each Fast and easy dimension change, snap-lock nozzles, self-clamping adjustment of test heads Improved test head protection thanks to a reduced distance between the entry and exit nozzles Compact design with a length of only 345 mm without the attached roller guide when material guidance is guaranteed by installation in the production machine Optional compact roller guides extend the overall length by only 63.5 mm With small testing diameters the use of the optional roller guide supports material centering Compressed air terminal for blowing the test heads free Application Non-destructive eddy current testing of metallic round materials (wires, bars and tubes) for surface flaws in conjunction with the CIRCOGRAPH electronic testing and evaluation system and a suitable transport mechanism Test material diameter range from 2 to 35 mm resp. 5 to 35 mm Requirements for test material and ambient conditions: surfaces as devoid as possible of scale and protruding burr Test heads with track width [BS] Ro 35 P 1,5-2,5-5 mm Ro 35 L 2,5-5 mm 2 variants of the motor control are offered for operation with the Ro 35 P/L: Motor control MOC E Fixed speed of 4,500 rpm 50 Hz mains connection Motor control MOC S Fixed speed of 9,000 rpm switchable to half rotational speed Straightness 2 mm/m Manually brake as standard Max. material temperature + 80 C; blow-free unit connection recommendedt Electrically brake as option with MOC SB The rotating heads Ro 35 PL can be connected to CIRCOGRAPH DS electronic unit with two or four channels (see leaflet CIRCOGRAPH DS 6.430) and to CIRCOGRAPH CP 1-channel (without electronic clearance compensation, see leaflet CIRCOGRAPH CP 6.412) /49

3 Operating principle The transmitter system Ro 35 P/L operates in accordance with the eddy current principle in conformity with DIN Rotary probes rotate at a short distance and at a high speed around the longitudinally moved test object and helically scan its surface without physical contact. Sondenrotation Probe rotation Rotiersonde Rotating probe The rotary probes scan discrete points, merely registering a small portion of the overall surface at any given moment. In relation to the relatively small registered material surface, every material flaw that the probe passes over represents a large fault. Therefore, the rotary probe detects extremely small material flaws with a high resolution. Each time the rotary probe passes over, extended material flaws generate a signal so as to ensure that the full length of the flaw is indicated. If a suitable material transport speed ( test speed ) is chosen, the probe s test tracks follow without untested gaps so as to ensure complete scanning of the material s surface. Riß Crack Fig. 1 Rotating probe on material flaw Rotiersonde Rotating probe Sondenwirkbereich Effective probe area Abtastspuren Scanning tracks The maximum test speed is the result of the revolution speed, the number of probes and the probe track width. With two probes offset by 180 resp four probes offset by 90, the tracks follow in succession without gaps or overlaps when the test object is transported forwards by two resp. four track width in every revolution. The signals picked up by the probes are transferred from the transmitter system to the electronic test unit for evaluation. The field current for powering the probes and the probe output signals are transmitted without physical contact by rotary transformers. The electronic unit consists of a process-controlled electronic testing and evaluation unit featuring interactive operation and convenient display and documentation possibilities. Gesamtfehlersignal Overall flaw signal Fig. 2 Scanning track and flaw signals 1 4 Abtastspuren Scanning tracks Fig. 3 Scanning tracks, four probes offset by /49 3

4 Structure Besides the rotating head, which scans the test material and which generates the eddy current signal, a CIRCOGRAPH electronic test unit, a motor contol unit and two connecting cables are needed for a complete testing system. The rotating head Ro 35 P/L consists of the following obligatory components: Rotating head Ro 35 P/L 2 resp 4 test heads (adjustable according to a scale) Protective nozzles Motor control Test and control cables, motor cable The following are optionally available to improve adaption to the conditions of the testing task: 2 roller guides Sliding table Tilting table (without roller guide only) Special guide unit Main voltage adaption Sensorsystem Ro 35 P/L without roller guide Motor control MOC E CIRCOGRAPH CP Sensorsystem Ro 35 P/L without roller guide Motor control MOC S (SB) CIRCOGRAPH DS Bild 4 Structure of a test unit /49

5 Rotating head Ro 35 P/L The rotating head consists of the following components: Bearing case One chamber envelops the test zone. Three-phase drive Indestructible drive featuring a standard squirrel-cage motor connected to an external motor control. Rotating head electronics The electronic system of the rotating head amplifies the probe signals and the field current and is fitted in a sturdy box on the side of the bearing case for easy servicing. The cables to the test electronics are connected by means of MIL connectors. Start-up protection when the bearing case is open Hollow shaft with contactless rotary transformer Hand brake to considerably reduce the run-out time Three-phase drive Start-up protection Bearing case Rotating head electronics Hollow shaft Fig. 5 Rotating head Ro 35 P/L Bearing case open Protective nozzles The protective nozzles perform a dual function: Centring the test material in the test zone to a dimension that can be balanced out by the clearance compensation. Breakdown protection for the test heads, particularly during fit-in and exit of the test material provided the straightness and end conditions are met. Fig. 6 Protective nozzles with nozzle holders, assembly tool positioned /49 5

6 It is imperative to use diameter-adapted protective nozzles. Nozzles with the same nominal dimensions must always be used. For breakdown and safety reasons, operation without protective nozzles is forbidden. Protective nozzles are available in the following nominal diameters (NM = nominal diameter): 2,0 to 8,0 mm: material diameter + 0,1mm > 8,0 to 15 mm: material diameter + 0,5 mm > 15 to 35 mm: material diameter + 1,0 mm Protective nozzles can be ordered or can be produced by the customer according to a drawing. Please enquire about a special guide unit, particularly for use with highly sensitive materials such as Cu tubes, polished surfaces etc. Generally, no additional roller guide is recommended when using special guide units. Fig. 7 Protective nozzles Ro 35 L, nozzle holder with replaceable nozzles, schematic diagram NM 5 to 36 mm Fig. 8 Protective nozzles Ro 35 P, nozzle holder with replaceable nozzles, schematic diagram NM 2 to 36 mm /49

7 Motor controls Motor control MOC E Fixed speed of 4,500 rpm, 50 Hz mains connection Motor control MOC S Speed of up to 9,000 rpm switchable to half rotational speed Fig. 9 MOC E MOC S Roller guide Roller guides are recommended whenever the material transport drivers cannot be set up directly before and after the transmitter system. The roller guides offer two advantages: In the set up mode, a calibration piece featuring comparison flaws can be comfortably held in a central position outside of the test line and the electronic test unit can be adjusted easily because the rotary probes periodically scan the test flaw and the signal is displayed practically statically. The roller guides improve centricity, particularly in the lower dimension range, and reduce vibrations. The roller guides are fitted on the rotating head on the entry and exit sides. Diameter adjustment by hand wheel. The complete diameter range of the Ro 35 P/L is covered by two roller sets: Ø mm Standard roller set Ø 2-8 mm with additional roller set Fig. 10 Roller guide /49 7

8 Tables If guide units are positioned particularly close together, a sliding or tilting table facilitates replacement of the nozzles and maintenance work. Tilting and sliding tables are conceived as special accessories for test lines. Fig. 11 Sliding table which moves transverse to the test line Fig. 12 Tilting table featuring a swivel axis parallel to the test object axis /49

9 Technical data Ro 35 P/L Diameter range testing material 2 (5) to 35 mm, continuously adjustable Revolution speed rpm with motor control MOC E or rpm with motor control MOC S/SB Type of test Test heads with pin type probes for Ro 35 P with lever type probes for Ro 35 L Probe track width: Ro 35 P Ro 35 L Test speed for gapless (5 mm track width) Dimensions Mass Power supply Drive Useful bearing life at max. speed (depending on ambient conditions) without physical contact adjustable according to a scale two, offset by 180, with one probe each, or four, offset by 90, with one probe each 5 mm, 2,5 mm, 1,5 mm 5 mm, 2,5 mm 1.5 m/s at a speed of 4,500 rpm, 3.0 m/s at a speed of 9,000 rpm see dimension drawing approximately 70 kg 3 x 400 V three-phase for the drive, if the supply voltage differs, adaption via an isolating transformer Three-phase motor, n o = 1425/2850 rpm, P = 1.4/1.8 kw Typical operating hours Grease lubrication rpm rpm app. app h h Roller guide (option) Standard Additional Mass Dimensions Ø 4.5 to 35 mm Ø 2 to 8 mm approximately 3.8 kg See dimension drawing /2002 9

10 ca ,5 63, ,5 343 Fig. 13 Dimension drawing /49

11 , Fig. 14 Dimension drawing /49 11

12 Should you have any special problems please contact: INSTITUT DR. FÖRSTER Prüfgerätebau GmbH & Co. KG Postfach D Reutlingen In Laisen 70 D Reutlingen Phone +49 (0) Fax +49 (0) or one of our agencies abroad Order-No OUTSTANDING! FÖRSTER DQS-REG.NO the first German manufacturer of eddy current equipment with ISO 9001 certification Information and illustration may be subject to change Edition 03/2002 Author Sy