| Magnetic Analysis Corp., USA, the originator of the spinning probe rotary eddy-current tester, has launched the Rotomac� 9 non-destructive test system. The latest in MAC�s line of rotary testers, this technology is the method of choice to detect long, seam-type defects in wire, tubing or bar stock. Hot rolled and cold finished product can be tested in-line as part of a production process (such as cold drawing), or as a separate test operation. The Rotomac 9 features high-flaw resolution for today�s higher rpm rotaries, as well as a real-time, flat panel colour display of wave forms reflecting true phase and amplitude. The wider oscillating frequency range (50KHz to 1MHz), combined with the high-frequency capacity rotary mechanism and test probes, enhance the ability to detect unusually shallow defects (as small as 0.001� deep depending on the material under test).
Digital electronics and the flaw verify feature now permit more accurate differentiation between wanted defect signals and unwanted signals (such as those created by short handling marks or vibration). Up to four independent flaw channels can be included in the same rotary and instrument package. Signal amplitudes with their phases are shown as excursion spikes from the midpoint of the 360� polar display, clearly showing relationships between wanted and unwanted signals. A coincident linear display uses different colours to show the combined real-time vertical channel signals from each rotating test probe. The testing screen�s new hot key feature allows the operator to adjust the most frequently changed test parameters and revise, store or recall a set-up while still in test mode. Plus, the built-in Ethernet interface allows stored setups to be downloaded to the Rotomac 9 from a networked computer, especially useful when there is a change in the diameter or type of test material.
Amplitude or phase signals from any threshold can be brought out to any of four outputs for fused AC relay, TTL, or optically isolated switching. MAC�s datalog feature stores data on the threshold signals for each segment, piece or reject pieces only, allowing immediate print-out, later observation, or analysis from a networked computer via the Ethernet interface. The Rotomac 9 can be incorporated with the MAC 175 eddy-current encircling coil type tester where very short, intermittent defects can be detected, particularly useful for customers who must test copper tubing for heat exchanger applications. MAC�s rotary test systems can be used for continuous product or cut lengths. When defects are detected in the wire, alarms, flaw indicators, paint markers or other devices are activated. In parts forming applications, the tester signals a reject action on the appropriate piece after the cutting and forming operation. To test cut length product, the rotary is usually installed in a separate test station in conjunction with MAC centring and drive mechanisms (which position the rotary tester and move the bar accurately through).
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