Communication

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Taking good pictures requires attention to detail in several areas. Key areas include avoiding bright backgrounds, keeping parts organized, proper distance between the camera and the subject, taking many pictures, cleaning parts carefully, avoiding shadows and reflections, and holding still while depressing the shutter button. Following are several images that illustrate these key areas.

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The photographer should avoid excessive contrast between the subject and the background. Here is an example of a dark object photographed against a bright background. Cameras often have an automatic exposure control and adjust exposure downward when light is bright. If the specimen is dark and the background is bright, the camera may adjust to give a good picture of the bright background, leaving the specimen too dark to see details clearly. The picture of the returned oil pump is too dark and doesn‘t show a lot of detail.

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This is the same lighting but the oil pump has been placed on a black mat, decreasing the contrast and the light coming into the lens. Notice how the camera has automatically opened up to show the details of the pump much better.

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Communication

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In failure analysis work it is important to keep each part in its original position. Even bolts should be kept in their respective positions. Some technicians use a piece of cardboard or a piece of paper with a simple drawing to keep parts organized. Other ideas include tagging, taping or writing on parts to identify their relative positions.

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When taking pictures, the analyst should treat the viewfinder image as the finished picture and adjust the camera position until the picture has the desired look. While an overall picture is needed to orient parts for the viewer, this view is too far away and there is too much unnecessary background in the picture.

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This picture is a better overall view of the pump parts. There is little unnecessary background, the background is dark, the picture is filled with the pump parts and the parts are sharp and in focus.

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Communication

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During examination, the analyst should take many pictures of the parts. Facts may be visible in one picture that are not seen in another picture, and some pictures are excellent while others are just fair. Or there may be need later on to look at areas not inspected on the first try and if the parts are no longer available, pictures become very valuable. Vary the angle, lighting, distance and background while taking many pictures.

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If there are numbers or letters on the parts, they should be included in the pictures. Areas with residues or colors present should also be photographed.

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Pictures of how the parts fit together are helpful when considering how wear marks and grooves developed.

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Communication

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Using a dark background makes dark areas such as the suction screen become clearly visible because the camera adjusts to available light. Using dark background with dark parts usually produces best results. The general principle, stated earlier, is to minimize the contrast between the background and the subject of the photograph.

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When parts have recessed or protruding areas, it is difficult to get a close up picture and keep everything in focus. The analyst should pay careful attention to keeping the area of interest in focus. Additional lighting is often needed to illuminate recessed areas or disperse shadows.

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While filling the viewfinder with the specimen to get the desired picture, avoid getting so close that the picture becomes blurry and out of focus. With a digital camera, the image can be reviewed immediately, and if the image is blurry a new picture can be taken. The important idea when taking pictures up close is to be sure the viewfinder image is sharp before taking the picture. Move further away if the viewfinder image is blurry.

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Communication

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Parts with high and low areas and smooth surfaces are also difficult to photograph. Angled, three-dimensional pictures are usually better in these cases than straight down, two-dimensional shots. This is an overall shot of one of the oil pump gears for orientation.

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After getting the orientation picture, the next pictures should be close up to get maximum surface detail. Take care with close up pictures that the camera is not so close to the subject that the picture becomes blurry.

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Mating parts may also need to be photographed. This is another overall shot. Note that the background is black, the part fills the picture and it is in focus. Surface details are easy to see in this picture.

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Communication

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Here, the analyst is trying to record the surface features from the other end of the gear in the previous figure. What’s wrong with this picture? It is overexposed, making it difficult to see surface details. It is easy to accidentally overlook one of the many key areas when taking pictures, This is another good reason for taking many pictures while examining failed parts.

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In this picture, the analyst is trying to record the surface features on the end of the gear teeth. Are the surface features clearly visible? The gear fills the picture, it is in focus, but there are some bright reflections present which make it hard to see surface features.

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Rearranging the lighting on the part has removed the bright reflections so the surface features are much more visible. This is a better picture for failure analysis work and communication.

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Communication

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If contaminants, resides or oil films are present on a part as it is received, the part should be photographed before it is cleaned. This picture shows facts about the oil film as well as the part. After the as received condition of the part is recorded, rinse off the oil film or contaminants and photograph the surface features of the part.

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Notice that scratches are now clearly visible because oil has been removed. Even clear liquids can hide high and low surface features. In this picture the lighting is good, there are no shadows or bright reflections, the part fills the picture and it is in focus. This is a good picture for failure analysis and communication.

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Did shadows or poor lighting cause this gear picture to be too dark? Lighting is the same as on earlier gears, but there is a white background beneath the gear. The camera adjusted for bright background and this left insufficient exposure for the darker gear.

It is possible to electronically brighten a digital photograph, but it is best to record a quality photograph. Digital photographs that have been electronically “adjusted” may be suspect. Don’t use “adjusted” images in failure analysis reports without noting that the picture is not an original photograph and stating how it was “adjusted”.

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Communication

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This is the same gear that was shown earlier with a black background. Notice again how a bright background darkens the gear image and makes surface features more difficult to see.

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Some students have asked if there is an inexpensive way to take digital pictures through a microscope so that pictures can show the tiny facts. The answer is yes. Put the digital camera lens directly on one of the microscope eyepieces and use the camera instead of the eye. In some cases the analyst may have to zoom the digital camera or raise or lower the microscope to bring the image into focus. The camera then will function like an eye.

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For instance, one day, one of the Applied Failure Analysis instructors felt a “bite”. A quick inspection of the affected area revealed a small, black insect that could not be easily identified. The instructor, who was working at one of the microscopes in the lab, decided to have a closer look at the offending insect.

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Communication

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Here is the insect viewed at slightly larger than normal size — about what could be done using the zoom feature on a digital camera. It is still hard to determine what kind of insect it is and whether it is heavily “armed”.

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Here one of the Applied Failure Analysis instructors is demonstrating the technique used to obtain photographs with higher magnification than available with the digital camera alone. After placing the specimen under the microscope, the camera is carefully placed on one of the objectives. The image can be brought into focus using the focus on the microscope and the zoom feature on the camera. Once a suitable image is obtained, capture it with the camera.

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Here is a closer view of an image captured through one of the objectives on the microscope. With care, a very good quality image is possible. Sometimes, the combination of magnification in the microscope and zoom in the camera will not allow the analyst to capture a full screen image. Some of the corners of the image may be dark because they are out of the field of view. The quality of the images produced this way depends largely on the patience and skill of the photographer.

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Communication

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Returning to the mystery insect, here is an image made through the microscope with a digital camera. The insect was “incapacitated” prior to photographing it.

Notice that with care and patience, it is possible to obtain very good quality photographs such as the one shown here. Experimenting with lighting, magnification level and camera zoom is necessary to get the best results.

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Increasing the microscope magnification or camera zoom allows even further magnification of the subject.

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Additional magnification reveals that the insect is equipped with a formidable set of “jaws”. It appears that the “bite” experienced by the instructor was actually a bite and not a sting.

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Communication

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Magnified views of common objects often look very strange. It is often fascinating to view such photographs. Here it is possible to see the segmented antennas of the insect as well as its compound eye. The “neck” region appears to be almost fuzzy looking.

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The compound eyes of insects have a strange appearance. Imagine looking at this view if it were further magnified to show details of only one eye. Would it be possible to identify what was being observed if the observer hadn’t seen the earlier, lower magnification pictures?

The point is – highly magnified objects often appear different than expected. Be very careful when looking at magnified views. Preconceived ideas easily arise and incorrect conclu-sions are frequently drawn if the analyst is not completely sure of the identity of the subject of the photograph.

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Here is a final view of the insects jaws – the source of the irritation. Once digital images are captured it is easy to highlight areas such as the circled area in this photograph. Of course, text can also easily be added.

It is up to the analyst to make sure that any photographs used in conjunction with failure analysis reports are clearly identified and that there is no room for error in interpretation. Make sure that each photograph makes its point clearly. When doing failure analysis, take many photographs, but use only those that clearly support the analysis results.

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Communication

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When taking digital photographs, be aware of the picture file format. Some picture file formats produce very large size files. Using these in reports makes the report file size very large which can make sending the report electronically difficult.

With the proper program, it is possible to convert picture files from one format to another, compressing them to a much smaller size as in the example here. The analyst needs to find a program that can manipulate picture files to make the most efficient use of digital photos in reports.

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Sometimes, it may be necessary to compress a picture file while maintaining the same file format. This is also possible with the proper computer software.

When picture files are compressed, they lose “information”. The analyst should be careful when compressing picture files that so much information isn’t lost that the picture loses its effectiveness in presenting details of the findings in the report.

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Remember, if facts aren’t gathered and recorded carefully, it will be difficult to follow the “road signs” to the root cause. It will also be difficult to help others understand the facts if good pictures aren’t acquired and saved for communication work.

Pictures are also good for legal evidence in case arguments occur. Memory is a much less effective tool in court than pictures. Make sure however, to retain original copies of the photographs. Photographs that have been “touched up” may not be admissible as evidence.

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Communication

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The analyst should remember that Preconceived Ideas can occur any time from first problem awareness to last problem correction. Be careful not to stray from the facts found during failure analysis.

By following the Eight Steps of Applied Failure Analysis, the analyst will stay organized, find key facts, build an accurate time line, find the most probable root cause, and communicate effectively with others.

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Printed in USA 9/2004