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ENDOSCOPE VERSUS BORESCOPE 

Definition of terms related to the industrial field

 

A borescope is a technical device used in industrial applications to view the interior of technical hollow bodies. The term "endoscope" is used in the medical field. All information about SCHÖLLY's medical endoscopes can be found in the endoscope section of this website.
This article is about the use of borescopes in the technical environment. There are rigid and flexible borescopes. They differ in design and purpose.

Rigid Borescopes

The rigid borescopes are characterized by a rigid shaft. The image and light transmission often takes place by means of a rod lens system. The smallest borescope in SCHÖLLY's product range has a diameter of 1.8 mm.

SCHÖLLY's borescopes also include high-temperature borescopes (shown on the left). These are additionally equipped with a cooling jacket as they are used at temperatures of up to 2000°C. Boroscopes are used for drill holes and openings with straight access according to their design.

Flexible borescopes (fiberscopes)

Flexible borescopes have a movable, flexible shaft with which hard-to- reach places in a test object can be reached. In contrast to rigid borescopes, flexible borescopes transmit images through structured, flexible fiber bundles, also known as image bundles. Image bundles consist of individual fibers. Each fiber transmits one pixel from the objective to the ocular. The flexibility and mobility of the probe is guaranteed by the image bundle system and the plastic coating. Due to the technical design, the flexible borescopes can be manufactured in smaller working diameters than rigid borescopes.

 

The smallest diameter of SCHÖLLY fiberscopes starts at 0.35 mm. 3000 individual fibers are used for image transmission with this fine fiberscope. Due to the small diameter, fiberscopes in the range of 0.35 mm - 2.4 mm belong to SCHÖLLY's micro borescopes.

Fiberscopes are used, for example, for the inspection of miniaturized components with holes in the lower millimeter range or for bent accesses.

Fiberscopes can be equipped with a mechanically deflectable tip for better orientation. The deflection is realized by a lever system and Bowden wires. Fiberscopes with angled tips are available from SCHÖLLY in diameters of 3.4 mm. They are suitable for the optical inspection of larger cavities.

Video endoscopes are another variant of the flexible borescopes.

Rigid borescopes and flexible borescopes (= fiberscopes) can be used for direct and indirect visual inspection. For indirect visual inspection, borescopes and fiberscopes are combined with modern camera technology and test images are digitized. This has the advantage, for example, that not only a single snapshot is taken by the inspector, but that the image can be viewed by several people on one monitor, the image can be processed for better error detection or saved for documentation. The more complex the visual inspection and the more important the duty of proof is, the more indirect visual inspection is recommended.

 

When is a borescope and when is a fiberscope used?

This section deals with the use of borescopes and fiberscopes for direct visual inspection.
Whether you use a borescope (rigid borescope) or a fiberscope (flexible borescope) for direct visual inspection depends from a technical point of view on the diameter of the bore hole or access. Flexible borescopes ( micro borescopes) are used for bore holes between approx. 0.4 mm and 1.8 mm. In this working diameter no rigid borescopes are available for direct visual inspection. 

You can choose between rigid and flexible borescopes for bores or openings from 1.9 mm upwards. Which one you choose depends on whether the access to the inspected area is straight or bent. It is generally recommended to use rigid borescopes wherever possible. Due to their construction with rod lenses, they deliver a high optical image quality. Flexible borescopes with fiberoptic design, on the other hand, can be built in even smaller working diameters than rigid borescopes In the diagram you can see the available working diameters of flexible and rigid borescopes.

 

Flexible and rigid borescopes from SCHÖLLY depending on working diameter

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The choice of the right borescope also depends on other factors: How prominent is the defect, do you conduct random checks or 100% tests, how many different components, bore holes or materials do you inspect? The higher the inspection requirements, the more likely it is to go for indirect visual inspection. Read more in the article Direct or Indirect Visual Inspection.