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  1. because I am not using flying shears or rotating knives. the web needs to stop to be sealed, then drawn and stopped again for the next bag to be sealed. This document is very helpful and relevant to me. Thanks for that. .
  2. Hi. thanks for this. This article is actually not mildly but fully related to my application. Such bag making machines is exactly what we manufacture. Am just trying to upgrade control techniques to make the machine logic control more self sufficient and reduce operator skill and intuition required to run these.
  3. The only problem with real time analogue response is that there is always a certain degree of continuous acceleration deceleration scenario. While this is absolutely comfortable with reels that are not extremely heavy or large in diameter, in this particular area the problem arises that unless an expensive eletronically controlled breaking or tension creating mechanism is not applied, the reel maintains its angular momentum even as the motor slightly decelerates causing the web between the reel and the rubber rolls pulling the web to loosens effectively causing them to first loose their tracti
  4. Guys, off topic. Wanted some information on PID Control Loop for Motor Speed Control. Can PID Control Loop help in averaging out or say smoothen the motor speed output when the input speed reference is continously oscillating. Again, the oscillation being caused by the part mentioned in the earlier query. the Dancing roller which is connected with a potentiometer that gives a 0 to 10VDC signal to a VFD. Normally, cheaper machine manufacturers just dont care about fine tuning. Motor speed keeps on oscillating with the oscillating input reference. Some level of averaging in actual speed is achi
  5. No No. Much Simpler. Its a actually a plastic bag on roll making machine. so theres basically a reel of plastic at the unwind side, the servo motor draws lengths as per the operator setting and seal and perforate at that point, and then those bags are rewound into smaller rolls, say 10 bags per roll or 20 bags per roll for consumer use. This is where the above dancing roller swingarm comes into effect. as the servo motor starts and stops to draw the appropriate length and seal the bag, the rewind process is a continuous one and it is neither feasible nor efficient to stop the rewind process ev
  6. Ok. So the point of 70N force is 520mm away from the rotational axis. and each consequent point is at a distance of 100mm. The only reason I want to get a rough estimate of the weight or force exerted on the tape when all 5 rollers are engaged, is because this particular machine will involve processing a web with perforations at certain intervals and if the force exerted is beyond a certain accepted limit, the web or tape will tear from the perforation causing the machine to stop, create lots of wastage and loss of production. Plus the machine runs at about a 120 metres per minute, its no
  7. Yes. I absolutely understand the mechanical disadvantage part, albeit practically, as we use this kind of a lever in our industrial machines everyday. So with every rise in the level above 90 degrees, the effort to lift it increases as the web will require more and more tension to lift the lever further because it doesnt stay in a vertical 90 degree rise and fall situation. But, quite frankly, that is something way too theoretical and not really required in the calculation in the concerned practical application as the use of this kind of lever in our machines, though absolutely necessary, is n
  8. Hi guys, I have not had a formal education in physics. But I am designing a machine which involves the use of dancing rollers. i.e. rollers fixed to a swingarm that rotates on an axis at one end. multiple rollers are attached through which a flexible web. eg. paper, plastic film etc will pass through. I want to know how much force would be required to lift the swingarm up. I am attaching a diagram with the weights the swingarm exerts downward at each point through which the web will pass. I am attaching a file which marks the rotational axis, as well as the weight in Newtons exerted by the sw
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