Defective troubles regarding screw fastening are classified, and the countermeasures on screw fastening device troubles are explained.

(1)Screw fastening defects and the factors classified

Screw fastening defects can be classified as the following.

Of the above, below are the screw fastening device related defects.

a) Errors on screw fastening work

	・	Improper controls on the automated screw fastening unit
	・	Defective screw fastening (Misalignment, Oblique fastening, etc.)
	・	Screw positioning error

b) Inadequate screw fastening tool

	・	Wear and damages on screw fastening bits
	・	Wear on screw chuck
	・	Inadequate maintenance on fastening tool

(2)Examples of screw fastening device trouble countermeasures

1)Screw fastening device (in case of pneumatic driver) trouble countermeasures

	（1）	Since the driver receives reactive forces during screw fastening, it is likely that some functional errors may occur at some usage intervals.
	（2）	In many cases, the problems are attributed to rotational motion instabilities due to wear on rotational shaft, foreign objects adhesion, rusts, and seizure. Apply lubricant oil and repeat forward and reverse rotations.
	（3）	Check air supply pressure of the pneumatic driver.

2)Countermeasure examples on inadequate screw fastening tool

	（1）	With an assumption that the screw driving bits are subject to wear deformation, maintain spares and periodically (quantity base managed) replace the bits.
	（2）	Screw chuck related parts are the same as the (1) above.

3)Management techniques for the stable operation of the screw driving device

In order to maintain the stable operation of the automated machinery, not only proper management of the automated machinery itself, but preventative measures such as quality control maintenance of assembly parts and finished goods will be effective.

[Examples of Managed Items]