Based on an Article Published 12/2011 by: En Hong, Honogwei Zhang, Reuven Katz, John S.Agapiou Presented by: Vadim Tutaev & Boris Sheendlin

The need in internal threads inspection *Account for approximately 50% of all joints produced in mechanical systems. *Used across all fields of industry. *Affecting safety, precision AND reliability of the assembly. *Have a wide variety of sizes, depths, and shapes. *In case of mass production assembly, dysfunction will results in a loss of time and money.

The classical inspection of internal threads # contact gauges & Go/No-Go gauges : -subject to operator interpretation -depends on the operator’s skill -cause mechanical wear -Require maintenance and calibration. # Visual inspection -Internal threads are hard to visually inspect # CMM - can not measure the whole surface of the thread - can not reach the internal surface of the thread # Thread-Pitch gauge - requires direct touch that may damage the thread - can not examine long threads

Possible defects in internal threads Discontinuities Burrs Pores In engine Blocks such Defects may affect Engine performances and Even cause accidents Burrs

Finding the starting point of a thread # Determines the Quarter in which the beginning of the thread begins # Detects the Orientation of the thread (right hand\ left hand) # Measures “PS” distances using 4 beams for the operation # More beams being used- more precision in the location.

Motorized laser-based periscope The device: # motorized periscope that rotates a 45° inclined mirror to allow for a laser beam circular scan. # The sensor attached to a precise linear stage to move the periscope in and out the threaded surface.

CCD camera with “sight pipe” The device: 1) conical mirror at the tip imaging the 360° view of the inner surface of an internal thread. 2) Camera and illumination are attached to the far end of the sight pipe. 3) a linear stage that moves the probe into the threaded hole. 1 2

# Find angular position of internal thread starting point. # Reduce measuring time and cost when inspecting mass produced parts. # Measure the internal long threads of small diameters. # Allow the inspection of 100% of threads used in safety-related parts, such as brake cylinders. # Capable of evaluating tool wear. # Detect internal flaws found on thread surfaces. The advantages of the mentioned non-contuct inspection methods

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