Concept of inspection speed 3

When inspecting items that are moving at high speed,

The key is how clear (blur-free and bright) the image can be obtained.

To be more specific,

The distance traveled during exposure should be less than one pixel.

is the key point.

 

In our experience, the limit for visual inspection is approximately 30 μm per pixel.

The first thing to consider is to make sure that this 30μm is not blurred.

 

And let's say you want to inspect a 100 mm length in 1.0 second.

 

Since the conveyor speed is 100 [mm/s],

Allowable image deviation 30【μm】÷Transfer speed 100【mm/s】＝Exposure time 0.3【ms】.

That is, assuming an exposure time of 0.3 [ms] (1/3,000 sec.),

We believe that if a bright image can be acquired, it can be inspected.

 

On the contrary, for the reason that bright images cannot be acquired,

When the exposure time is fixed at 1.0 [ms] (1/1,000 sec.),

Exposure time 1.0 [ms] × allowable image deviation 30 [μm] = transfer speed 30 [mm/s].

This means that the image will be blurred unless the transport speed is slowed down.

 

The first point raised,

To put it in perspective, "the distance traveled during the exposure should be less than one pixel."

Shorten exposure time

Slowing down the conveyor speed

and one more if possible.

Increase 1-pixel resolution

These three points are to be considered.