empty box inside a carton

[Jimmie_Ohio]

Here's how I would do it, since weighing "is out of the question":

1) Sense the presence of material in each box.

2) Sense the presence of all boxes in the matrix of boxes just prior to loading.

3) Sense that AFTER loading, no boxes remain at the pick-up point. For example, no box was dropped, etc.

4) After loading, also sense that the area around the carton is clear. For example, no box or boxes got "half-loaded" or missed the carton, dropping off somewhere in the vicinity of the carton.

For every operation, check that the sensor is "clear". For example, during the "window" when nothing is to be sensed, the condition of the sensor should be opposite to when it is "made". This will be a check for a faulty sensor.

If money allows or practicality demands it, use a vision system during the appropriate steps in this sequence instead of a "sensor".

 

[Eric Nelson]

I am supposed to modify a machine which puts these boxes into a carton, there is no space to put a weighting system inside the machine

So put it OUTSIDE the machine. As Ron pointed out, "To load a box it must sit upon something, why not a scale conveyor?". The box has to exit the machine at some point, so weigh it there. Weighing will be the easiest, cheapest, etc. method by far... :nodi:



-Eric

 

[Peter Nachtwey]

Does an empty box sound different if you thump it?

 

[curlyandshemp]

I am asking this question because i think that someone may encountered this situation.

i am searching for a sensor that can detect the abscence of a box inside a carton. the carton contains 50 boxes, 25 in each side.
and the 25 are arranged in 5 by 5. if there is a sensor that can detect emptyness so i can tell that the carton is fully packaged or not thus i will be sure 100% that our production line gives excellent quality.

i did not use weighting system because i need online check that will not glued the carton, so it will go out opened.

thank you all for your help.

Sounds like an application for an checkweigh conveyor with a reject station, providing the weight of each fully loaded box is fairly consistent.

Ian

 

[tragically1969]

like i said i dont know what range you are working with, 500mm is big ask of any sensor excluding a photocell of course

 

[tragically1969]

I do not think a capacitive sensor would work, it just detects if a material is within a certain range. It can not "see" into a carton with 50 boxes and detect one missing. Short of an x-ray vision system not sure what could, hopefully someone may know of something.

QUOTE]

They can if you use one of the teach capable sensors, teach it to see through the box and detect a mass on the other side.

I have used capacitive sensors behind metal panels to detect an operators hand for start signals

As the boxes are arranged on either side of the carton use an array of sensors arranged at the correct spacing to detect a missing box

Of course none of this will work at 500mm range so its all pretty pointless really !!

 

[jjkisner]

Would this work? I had an in house demo they seem to work well.

http://www.cognex.com/products/Checker/default.asp

 

[rsdoran]

And I thought I rambled on

NO real information about the machine or the process has been provided.

NO serious questions have been answered by the OP, except the little thing worrying about sensor failure.

The OP stipulated from the beginning "I CANT".

What exactly are y'all providing information for?

 

[sinanissa]

I am sorry for not replying.

first the machine is a casepacker that packs 50 boxes of 10 cigarettes packets/box inside a carton, 25 on left and 25 on right.

at the fill in stage, the carton is closed from one side, and the other is opened to let the boxes entered in.

after the carton is assumed fully filled, the carton start to move towards the glueing station (hotmelt). in this area, i am supposed to put an xray sensor

Short of an x-ray vision system not sure what could, hopefully someone may know of something

or

Strike the carton and measure the frequency of the sound it makes.

if this happened, then i can program the PLC not to glue this carton if a box is missing.

as for an external solution, we have 10 inductive proximity detectors on the output of the machine, that detects the 5 rows on the left, and 5 rows on the right. but if the carton material is big, the sensors will detects that all carton is empty, if i used large range detectors it will have an interference between each other and may not detect an empty row or box. (inductive proximity switches detects the foil inside the packets.)

please if any one know more about sound sensors that can detect 10 cm of emptyness for a 50cm of packets, please tell. I think this solution is healthy.

thank you all for your suggestions.

I can not redesign the machine. I do not know anything about

scale conveyor

. more information will be helpful.

 

[Jimmie_Ohio]

first the machine is a casepacker that packs 50 boxes of 10 cigarettes packets/box inside a carton, 25 on left and 25 on right.

I think this solution is healthy.

Sorry, but I couldn't help noticing the irony...:nodi:

Perhaps a truly "healthy solution" is to ship the cartons out empty after all.

 

[sinanissa]

i did not mean any irony. but i work on this problem months ago, and until now. i did not reach anything.
I even think that it is impossible to do.

strike the carton means strike it with sound, then measure the time it takes, because sound speed verifies from a tobacco material to air.

 

[curlyandshemp]

Definitely sounds like an application for a checkweigher. One pack of cigarettes missing from a box of 50 is well within the limits a checkweigher can detect.

check out http://www.ricelake.com/docs/browse.php?categoryID=451

 

[highvoltage8471]

If there is no room for a scale, the next best thing would deffinately be a vision system. I have made one that was mobile for sensing missing threads on screws before that you could easily set up above the machine and point down at the product. It worked well, and could be programmed for different applications. I don't know how much is in your budget for this application, but it does not take up much room and is affective.

 

[sinanissa]

the carton is not not fully opened, and i can not put a vision system their. i am sorry highvoltage but thanks you.

curleyandshemp, i am now visiting the site.

 

[sinanissa]

thank you curleyandshemp for the website, i will put as plan B, but i still if availables sensors that i can put it inside the machine without redesign it.