Control of Monitoring Device - Workers (employees) eyes - Visual Inspection

[tom2517]

Yes, we have studied the quality cost of reject. There are plenty defective parts that do slip through the inspection, which is why we employ another set of inspection workers at our warehouses prior to shipment. My company spend quite a bit of money on visual inspection.

As for magnification, it is an excellent idea and we have bought similar equipment 5 years ago.

For cross training and rotation plans, unfortunetely, it probably won't work in my factory. First, the workers know what they are getting into, it's the only job they are going get to do. Why? this particular job is not skilled based so it is low pay and generally for young people who are not well educated and can't find office jobs. Other types of work in the factory required better education.

Rotation plans is great, but as you can see above, it is not exactly a job people are lusting after, so the fact is turnover rate is high in this job and we can barely find enough to fill the current rotation.

We have thought of moving the factory to China but in the end, the idea of quality is low in most mainland Chinese's mind that even if we can find plenty people there, the productivity might not be better compare to Taiwan.

[Claes Gefvenberg]

In Reply to Parent Post by tom2517

The product is small, between 15cm to .5cm. They all look the same and what we are looking for are tiny imperfections, thus it is straining to the eye.

Yes, that sounds like an eye strain recipee. Question: This is a bit far fetched, I know, and it's entirely possible that visual inspection is the only way to do this, but have you considered alternatives? Sorting via gauges or something? What sort of imperfections are you dealing with?

In Reply to Parent Post by tom2517

I know no 100% visual inspection is ever 100% effective, I've tried it for a day myself and I know after a couple hours, they all pretty much look the same to me.

I hear you. I have been there too, and I recognize the feeling. Even if your life depended on it there is just no way to keep the concentration up in the long run. Defects will slip past, and the only known cure is to prevent them form occuring in the first place. Can the manufacturing process be improved?

/Claes

[Jim Howe]

Most plants I have worked in have two breaks a day. Morning break is 15 mins and is usually half way between start and lunch. Afternoon break is 10 mins. and is halfway between lunch and quit. These were planned and paid for breaks not included in the restroom or personal breaks most employees take anyway.
I supervised PC board inspectors who used stereo microscopes from 4 to 10 power. Talk about eyestrain. We tried all kinds of magnifying equipment but evetually returned to the scopes. however we found that layer inspection of circuit traces was well suited to overhead magnifiers.

[Caster]

In Reply to Parent Post by tom2517

....I brought this issue to upper management before but they don't want to listen...

Interesting problem....why is final visual inspection always the lowest paid, least skilled, least desireable, highest turnover job in a plant? I guess management reasons that the customer will find the problems anyway.

For some authoritative work to help persuade your bosees, please consider the American Society for Non Destructive Testing. They managed to write a 62 page book about visual testing. It talks about rest periods and duty cycles.

http://www.asnt.org/shop/merchant.ihtml?pid=1137&step=4

Caster

[tom2517]

My factory's products are rubber parts, and most needs to be bend one way or the other to check imperfections inside, so no machines that we know of can do that automatically.

If all the production process goes well, the demand on inspection wouldn't have been great, unfortunetely, the production units has plenty of problems on their own. Sure, we are also trying hard to improve that part of the process, but until the production can make perfect products day in and day out, my unit still need to check piece by piece.

Good for you Jim, I am only talking about 5 min. break once in the morning and one in the afternoon and my management is already balking at that.

Thanks Caster, I will take a look.

Tom

[Ingeniero1]

No question that after a while the inspectors will become ineffective. Worse, the variation among inspectors alone can be a detriment to consistent product quality.

As an alternative, you can have a rather inexpensive camera display the ‘enlarged’ image on a monitor and do the inspection looking at the monitor. Better yet, you can buy software that you can train to look for specific characteristics.

Yes, I developed and implemented several such projects to inspect nicked threads, slightly scratched very small (0.25 x .06 area) sensors, and other similar applications - 21 years ago.
If the technology was available back then, when we primarily used 8-bit microprocessors for most control applications, I am sure that this is much more easily done today.

Alex

[M Greenaway]

What about an AOI system, and get rid of the 'people' inspection for good ?

[Viki N.]

Did you ever try a halo light (florescent magnifier). Those work pretty well and are inexpensive ($75 to $400 approx). They aren't quite as strong, up to 3.5X but may be worth looking into.
Viki