Tire cord splice sensor

I looked at RKO but don't need high tech or expensive.

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The trade-off is generally cost vs reliability. Simple and low-tech could turn out to be more prone to false positives and missed splices.

That said, Terry's suggestion is a good one. Just about all the photoelectric manufacturers offer some form of analog sensor. You might als be able to use a color detection sensor to pick up the change.

Similar to what Terry said Keyance has a line of Laser Sensors that you can tune on the sensor itself with a simple teach function. It is basically the same principle. Your looking for a difference in recieved light or reflective light. Not sure if reflective will work. Will probably be less stable than a thru beam.

Banner has a similar line but if the light level shift is small the Keyance will detect it better. I have used these to detect splices in plastic sheets.

I've seen something similar to this done before in a cloth finishing plant. We needed a way to detect splices in the cloth, which was similar to blue jean pocket material and about 60 inches in width. What worked well for us was basically a laser micrometer measuring the thickness of the cloth as it wrapped over a very solid steel roller. The laser micrometer was set to trigger an output on any thickness over the nominal thickness of the cloth. Our line speeds weren't quite what yours is, but this was 15 years ago, so I'm sure detection speeds are better. This may not be the cheap solution you were looking for, but I thought I'd throw it out for thought.

Try Keyence

how about posting picture of the product so we don't have to guess? (ie. thickness, transparency, shape and consistency of the edge etc). could be just sensor array and few lines of code.

Jim767; your application seems straight forward. Working for RKB I would make the assumption that our 1032 or 1032B would work, but we would want to verify on your product itself. Since our unit is not cheap compared to simple photo-eyes and other low end solutions, it may be worth your time to investigate. Our product uses capacitive technologies originally patented by us which provides our customers with a very reliable, accurate and durable detection sensor. Our technology is self calibrating to any grade changes you my have. With over 3000 installs worldwide, we can ensure success with our technologies and we will stand behind them.

If your product does not change and it is the same basic makeup run after run, you may want to look into an ultrasonic solution. They range from 500 to 1500 USD depending on the company you look at. Pepperl+Fuchs Inc make an ultrasonic unit for about 850 USD. While we have replaced many ultrasonic units, most of these have been directly related to paper web processes or multi-web processes. If your product does not change, then this solution may be the solution that you require. Photo-eyes are usually unreliable for many reasons and have proven not to be effective solutions for 100% splice detection. Of course, I wont say they don’t work, but overall from customers we deal with, the feedback is not so good for photo-eyes. As a manufacturer of web inspection using phototransistor technologies, we have indepth knowledge of the capabilities of this type of sensor. If your company is putting in the splices, and you want photo-eye sensors, then it is best to use a dark colored tape if tape is used or a significant contrast type splice marking. If splice tape is used and you run into reds, pinks and sometimes clear tapes, photos eyes will not receive a significant contrast difference to send a signal off. Since photo-eyes are sensitive to the red region of light, reds, pinks, etc.. will absorb that part of the light spectrum and thus provide a lower signal to noise ration. Clear tapes may not provide significant contrast at all compared to the noise level (noise being the electronic signal normally generated by the product itself).

Steve Bailey posted a reply to you that mentioned my company thus my reason to come online. In his reply he stated “Try RKB; http://www.rkbopto.com/; I have used their products for splice detection in a paper application. I can't remember the exact model, except that it was a capacitive sensor and the sensitivity had to be adjusted regularly to compensate for variations in humidity.” While we appreciate the recommendation, he did state that he was adjusting the sensitivity too compensate for humidity. Our unit is an auto calibrating unit and should not require any adjustment until “old age” when the coils may start to leak which would be far down the road. If Steve has humidity issues, I would suspect an improper installation in an environment the unit was not designed for. As with any capacitive device, moisture will affect sensing. Since we have never been informed of this issue, it is hard for me to make any serious comment on why Steve has issues requiring adjustments. We have never been contacted about an issue regarding this from this user. We don’t even know what equipment it may be installed on, if installed by an OEM, installed in a proper location on the machine or even sold by us direct to the company Steve is with. While we have many units in MA where Steve is from, no one has contacted us about any issues which we would address immediately.

In short, Jim767, if you go cheap you may try ultrasonic first. I think photo-eyes would end up costing you more money in the long run either in type of sensor you buy as well as possible customer complaints or damage to other processes your material is used in or made from should splices get by. If you still have some issues in reliable splice detection may I suggest you contact us to discuss to see if you can help. Our website is www.rkbopto.com or www.splicedetector.net. Good luck with your search and we hope you find a reliable solution.

jim767 said:

Cord is a fabric which varies in width from 50" to 60" which has individual strands spaced 1/16" apart and held together with a strand which goes back and forth laterally. You can actually see through the fabric as it is running on the line. The area of the splice would be more dense since you have overlapped two pieces.

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This might work....

http://www.keyence.com/products/sensors/fiberoptic/fu/fu_features_3.php

The only problem, that I might see, is that if the product changes the density of the strands changed drastically, then it may need to be recalibrated.

-MUR

My immediate thought - if you had your hand on the cord you would feel the splice passing.
Does the cord run over rollers, perhaps the splice makes a sound as it passes or you can pick up a change in thickness with a transducer attached to a roller riding on top of the cord.

Two mfgs come to mind, Keyence does a lot of laser and visual type sensing, and http://www.sesensors.com/ for ultrasonic sensors. The ultrasonic may be cheaper. They used to be Hyde-Park but now looks like Schneider bought them.

Response to bdobbie

While we appreciate the recommendation, he did state that he was adjusting the sensitivity too compensate for humidity. Our unit is an auto calibrating unit and should not require any adjustment until “old age” when the coils may start to leak which would be far down the road. If Steve has humidity issues, I would suspect an improper installation in an environment the unit was not designed for. As with any capacitive device, moisture will affect sensing. Since we have never been informed of this issue, it is hard for me to make any serious comment on why Steve has issues requiring adjustments. We have never been contacted about an issue regarding this from this user. We don’t even know what equipment it may be installed on, if installed by an OEM, installed in a proper location on the machine or even sold by us direct to the company Steve is with. While we have many units in MA where Steve is from, no one has contacted us about any issues which we would address immediately.

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bdobbie, it's been twenty years since the application I mentioned. I doubt that any of the machines that used your company's product are still in operation. Given that your company is still in business, I would expect that your products have evolved and improved over the years. Given also the time lag between now and when I had any hands-on experience with your company's products, it's entirely possible that my memory of the details may be faulty. My experience in the intervening years has been that capacitive sensors are more difficult to apply properly than inductive sensors, so that inherent reservation about capacitive sensing technology may be affecting my memory of the application.

Thanks for the follow up Steve. Appreciate it. Yes, it has been a while since you work with it and we are pleased that you mentioned it to Jim767 after so long. We certinaly have improved it over the years and continue to work on that approach as well as others inspection approaches. Are you still working in the paper or conversion industry? Again, thanks for the mention and hope all is well with you.

With the cost and time required to set up the sensors it may be worth looking at a vision system such as the Cognex Checker or other units on the market. They may cost more initially but may save time in set up and provide future changes easily.

OK so you find the splice
NOW WHAT
Shutdown and cut it out or what??

Dan Bentler

I don't know what your tolerances are for this material or how tough it is, but this an inexpensive approach that I have seen used to detect splices of thin metal strips.

The metal strip is run through a set of guides and then through an EDM'ed slot that is only slightly larger than a single thickness.

The slot is mounted on a block with roller bearings on a set of rails. The slotted block is spring loaded against the movement of the strip.

A simple prox detects the block in the normal position.

When a splice comes down the line, it can't fit through the slot and it pushes the block off of the prox, stopping the press or machine.

Of course your machine is moving at about 5 ft/sec and it may not be able to stop in short distance. We only needed a few inches.

If that cord is pretty tough, you might be able to use a variation on this technique. Instead of an enclosed block, maybe a flag that pivots out of the way. I have also seen magnets used instead of springs.

Just an idea, may be of no use, but sometimes throwing out an idea may provide inspiration.