Real time x-ray

A Real Time X-Ray Inspection System is introduced to replace Film X-Ray. The main objective is to reduce the consumption of film and to reduce the environmental pollution due to lead intensifying screens and chemicals. Other benefits are the reduction of space to storage X-ray data and the shorter inspection time, which gives a faster feed back to production. 

The efficiency of gas turbines is limited by the maximum allowable turbine inlet temperature (TIT). The TIT may be increased by cooling of the blades and vanes of the high pressure turbine. Cooling channels can be casted into the components or may be drilled afterwards. Non-conventional processes like EDM, ECD or Laser are used for drilling. Radiographic examination of the drilled components is part of the inspection procedure. Traditional X-Ray film technique has been used. The consumable costs, the waste disposal and the limited capacity of the two film units lead to the decision to investigate the alternative of Real-Time X-Ray. 

In this paper the technical specifications of a Real Time X-Ray system are given. The procedure for inspection is explained briefly. The resolution of film and of Real Time X-Ray inspection are compared. The basic equipment needed to inspect Real Time X-Ray data is defined. 

The lead time for making a image by film X-Ray is 10 to 15 minutes. Where about 2 minute are needed in inspection by Real-Time X-Ray. Another advantage of Real-Time X-Ray is the feature that the effect of manipulating the part or changing the setting of the X-Ray tube can be observed directly. This is often used in investigating quality problems. 

Real Time X-Ray images are stored on CD ROM/XA. Compared to film the volume for a storage is reduced by a factor 50. Retrieving is easy since information of the location is given in the directory of the diskette. Normally the directory name is the shop order and the file name is the serial number of the part. The directory and file names can be customised. 

The resolution of images of the Real Time X-Ray system depend on the material thickness and on the settings of the system. While setting up the Real Time X-Ray inspection of parts the resolution is compared with the resolution aehieved in film bases X-Ray as used over the last years. It is demonstrated that the sensitivity of Real Time X-Ray meets the specification of DIN 54109 Bildgtitteklasse II. 

An advantage of Real Time X-Ray is that since only one section of the part is inspected at the time the X-Ray parameter settings can be optimised per section. At the same time each section is irradiated almost perpendicular which gives less distortion in the image of the top and the bottom section of blades. 

In Real Time X-Ray inspection a positive image is used. It takes an operator who is used to the negative image of film X-Ray less than one hour to get used to a positive image. 

By introduction of Real-Time X-Ray the consumable costs and the waste disposal problems are reduced. The capacity of the system allowed an increase of production volume without the need for a investment for an additional film X-Ray unit which would have been needed otherwise. 

Doering, E.R. Basart,. I.P. Gray,. I.N. Three-dimensional flaw reconstruction and dimensional analysis using a real-time X-ray imaging system. NDT-I-E International, Vol. 26(1), 1993, pp. 7-17. 

The tests concluded that it was possible to use real time X-ray to inspect incoming frozen fish blocks 100% and giving a completely accurate assessment of the quality of the blocks to enable the factory to calculate the correct purchase price as a function of the bone content. 

Once the feasibility of using real time X-ray as an inspection method was established, it was decided to proceed with the design of a system equally suited for control of incoming frozen fish blocks and for developing inspection procedures. These inspection procedures are, when completed, to be the basis of the inspection standards for the complete concern. 

Ten Grotenhuis, E., van Aken, G.A., van Malssen, K.F., Schenk, H. 1999. Polymorphism of milk fat studied by differential scanning calorimetry and real-time X-ray powder diffraction. J. Am. Oil Chem. Soc. 76, 1031-1039. 

Van Malssen, K., Van Langevelde, A., Peschar, R. and Schenk, H. (1999). Phase behavior and extended phase scheme of static cocoa butter investigated with real-time x-ray powder diffraction. Journal of the American Oil Chemists Society, 76(6) 669-676. 

Stahl K, Hanson J (1994) Real-time X-ray synchrotron powder diffraction studies of the dehydration processes in scolecite and mesolite. J Appl Crystallogr 27 543-550 Stefan PM, Krinsky S, Rakowsky G, Solomon L, Lynch D, Tanabe T, Kitamura H (1998) Small-gap undulator research at the NSLS concepts and results. Nucl lustrum Methods Phys Res Sect A-Accel Spectrom Dect Assoc Equip 412 161-173... 

Pladous RC, Polansky D, Berger H, Bueno C, Vosberg CL, Betz RA et al (1991) High-density glass scintillator for real-time X-ray inspection. Mater Eval 49 1419-1421... 

We investigated the structure formation during the isothermal crystallization (annealing) process from the oriented glassy states of PET using real-time X-ray scattering and thermal measurements. The results obtained are as follows ... 

The objective of this contribution is to review the improvements in the combined use of real time X-ray scattering and dielectric relaxation techniques experiments for a better understanding of polymer crystallization. 

Post-test real-time X-ray inspection of the mechanical time-dependent and time-independent testing revealed that the extent of alloying into the sample was greater than anticipated and in some cases extended throughout the entire gage section of the tensile bars. It was concluded that the interactions were limited to the Si Phase of the material and that there was no difference between samples affected by alloying versus those that did not. Additionally, an experimental approach was taken to limit the extent of the thermocouple interaction. The results of this study and the approach will be presented and discussed. 

Figure 3. Real Time X-ray of a Sample showing Interaction...

Figure 8. Real time X-ray image of sample with interaction showing that the alloying did...

Further analysis was done to note where the alloying was within the cross section of the material. A sample where a Pt thermocouple was used where alloying was known to occur from post real time X-ray analysis was sectioned. Back-scattered images were taken in the SEM and the presence of Pt was highlighted this way. It was seen that the Pt was staying in the melt-infiltrated phase of the material. This can be seen in Figure 9. 

---