In my current job, we use several inspection machines that utilize some old fashioned but certainly accurate mechanical counters. The operators, load the machines with jumbo rolls of finished fabric and inpect them meter by meter, by unrolling the roll and creating several smaller ones.
After finishing inspection, they type the meters for each roll inspected in a small self adhesive label and stick it on the fabric and also write down the number of deffects that were found on each roll. Although this procedure is not very time consuming, it happend many times, to write down the wrong data on the label. The result led to dissapointed customers that received the wrong amount of meters or deffects. Some years ago, I decided to write down my own code to automate this procedure. I actually rewrote from scratch some routines of a ready made software writen for a similar application and altered its code in order to automaticaly capture the meters of each roll and classify it according to the number the deffects that the operator found. For each deffect found, the operator had just to press an approriate deffect button and the rest of the job was done by the software.
After finishing inspection, they type the meters for each roll inspected in a small self adhesive label and stick it on the fabric and also write down the number of deffects that were found on each roll. Although this procedure is not very time consuming, it happend many times, to write down the wrong data on the label. The result led to dissapointed customers that received the wrong amount of meters or deffects. Some years ago, I decided to write down my own code to automate this procedure. I actually rewrote from scratch some routines of a ready made software writen for a similar application and altered its code in order to automaticaly capture the meters of each roll and classify it according to the number the deffects that the operator found. For each deffect found, the operator had just to press an approriate deffect button and the rest of the job was done by the software.
The actual problem was the way to capture the data of the mechanical counter and automatically do the calculations for classifying the fabric. The solution was to create a small data aquisition system, that counted the pulses generated from a rotary encoder (instead of a mechanical one), translate them into linear meters and send them through RS232 to a PC. Although I used a ready made solution at that time, later I tried to make a small aquisition system of my own and install it into other machinery.
I used a 16F628A microcontroller and a small HD44780 LCD screen to print the data. Although this is something I made a couple of years ago, a friend of mine found it really interesting and I decided to demonstrate it here.
2 comments:
I've been thinking of implementing something like this at work. I'm the head of a department where the sewing of a lot of materials is done and we have quite an inventory of rolled goods (60+" wide heavy rolls of materials down to small .75" nylon binding tapes). As the lead, I've found it to be a daunting task lining up the physical inventory counts with what our MRP system says my floor stock has. I would love to build something like this to at least get a baseline number for what we're actually using versus what the BOM says the finished part is supposed to. What sort of encoder do you use? Where do you get the wheels for them?
Cheers,
Jesse
Hi Jesse & thanks for your comment.
Well, the basic problem I faced was that when we used linear meters as the primary measuring unit, we had to keep different skus if the fabric was cut even 1 cm less than the targeted width. So, for example we produced canvas 62" (157.5cm) and we had SKUs for 156.8 , 157.9 ,157.5 etc. Since all the above were accepted by the final customer, the easy way out was to use square meters insted of linear meters, as the primary measuring unit and only keep one SKU.
Maybe you should think of this approach too. Having less SKUs, makes easier to keep your physical inventory in sync with your ERP's data base.
Regarding the encoder, you have many solutions. You can buy one like mine. It is an "Autonics ENC" rotary encoder and it is the only one I found that has the wheels attached to the shaft, or find a cheaper encoder (I've used an ELTRA encoder effectivly) and get a wheel suitable for the shaft. To say the truth, finding a suitable wheel is really easy, once you know where to look for it. I' ve found one, in a shop shelling materials for industrial trolleys but if you go in a mega shop like "Leroy Merlin" you can find many different types of wheels for your application.
rgds,
Panagiotis
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