For many types of industrial applications, the more traditional rigid borescope is more than adequate. For the price, rigid borescopes provide a superior-quality viewed image, usually at a lower cost than flexible borescopes. However, there are situations where rigid borescopes are not an option: for example, in viewing cavities in the human body, or for the inspection of mechanical parts with curved surfaces, or for viewing around obstructions when doing behind-the-wall building inspections. For these jobs you will need a flexible borescope.
Choosing a Flexible Borescope
Because a flexible borescope must be capable of “flexing” or bending, the technology used to deliver the viewed image is different from that used in rigid borescopes. Whereas rigid borescopes can make use of a series of lenses to transmit and relay light, flexible borescopes usually make use of fiber optic fibers to transmit the image. The major drawback of flexible borescopes is that this use of fiber-optic elements reduces the image quality.
When evaluating a flexible borescope for possible purchase, do not be tricked into thinking that a model that incorporates more fiber optic elements will automatically give you a better image. What you really need is an image where you can distinguish small details clearly. So, all other things being equal, choose a flexible borescope that provides you with the greatest degree of contrast in the viewed images.
Types of Flexible Borescopes
In particular, one type of flexible borescope will give you higher contrast: a flexible borescope that uses “leached” fiber optics. In these types, the fiber-optic filaments are not joined together (“fused”) but are kept separate from each other, which keeps the individual fiber optic elements from interfering with each other — this interference, commonly called “cross-talk,” is what reduces image contrast. Remember: you want a flexible borescope that gives a high degree of contrast in the viewed image.
Another criteria to use in evaluating which type of flexible borescope will be most suitable for your needs, is to consider the amount of control that you will have over the end-tip. This is the end that is inserted into the viewing area, that contains a lens and is also the end where the light shines out. Some flexible borescopes do not have a tip that can be controlled independently — these are called non-articulating flexible borescopes. If, for example, you’re going to inspect a drain pipe in your home, this type of flexible borescope would probably do the job just fine.
On the other hand, there are situations where you might need to be able to move the end-tip around once you have reached your viewing area. Flexible borescopes with a controllable end-tip are called articulating borescopes. The simpler models allow the tip to be moved to the right or to the left — these are called 2-way articulated flexible borescopes.
Better models will allow you to move the tip right and left as well as downwards and upwards — these are called 4-way articulated borescopes. Suppose, for example, he needed to inspect the interior of your automobile wheel well — perhaps through a small hole. You would, no doubt, need an articulated model, as this type would allow you to simply insert the borescope through a small hole, move it into position, and then move the tip around to examine the area thoroughly.