28. March 2010 10:46
Many times one needs to pick up a component with a pick & place for placing it in the required position for assembly or for further operation. For this, the part needs to be oriented and fed. A vibratory bowl feeder can take care of the orientation and feeding of the component. However, at the end of the bowl, one cannot just pick up the part with a pick & place, the reasons being
1. The pick & place device would, in most cases, fowl with the bowl.
2. If the part is picked up at the end of the bowl, then there are very less parts / components behind, which can act as a buffer. This means, the pick & place would need to wait for the parts to come to the pick up point.
To eliminate these possibilities, a linear vibrator or gravity chute should be used with a non-vibrating part and stopper to ensure smooth pick up. The advantage of using a gravity track is that it is cheaper to make and secondly, there are no running costs involved, however, the disadvantage is that some amount of back pressure is required. This means there will always be a dead stock in the chute. To eliminate this possibility and make the pick up smooth, a linear vibrator with a non-vibrating part is most suitable. The non-vibrating part acts as a nesting point for pick up ahead of the vibrating linear track.
16. March 2010 03:51
Many times one requires feeding components, one at a time and not one behind the other. Usually, components come out of the bowl feeder one behind another. For this purpose, a pneumatic escapement or singulator is required. It can work either mechanically through a cam operated system or else pneumatically by way of a single or double cylinder. The escapement or singulator stops one component and holds another. With a single stroke, one component is released while the one behind it is then stopped. This can find usage where the parts are to be packed in cartons, spouts are to be dropped into cartons, one part is to be picked up and operated upon. Further using an escapement with a gravity chute, one can use the stopped part for operations like drilling, tapping etc. The escapement can also be designed in such a way that on receipt of a signal from a relay / sensor or PLC, the escapement is actuated and a single component is released.
Usually, most manufacturers use two pneumatic cylinders for these types of escapements, one for stopping one part and one for holding the part behind it. However, some manufacturers provide escapements which work on a single pneumatic cylinder. This results not only in saving the running cost but also the initial cost. Elscint, in fact, not only provides escapements with a single cylinder but also provides an F/R/L unit and solenoid valve along with all the electrical inputs like transformer and other circuitry so that using it becomes very hassle free and easy for the customer. The operation of this escapement can be with the help of a 24 V DC signal.
9. March 2010 04:24
A Silo is an accessory which can be used along with a vibratory bowl feeder for providing higher capacities. Usually, the number of components which can be loaded in a vibratory bowl feeder is constrained by the weight and the volume of the components. In order to increase the loading capacity, usually auxiliary hoppers are provided. The disadvantage of auxiliary hoppers is the extra space which they occupy and plus the extra cost and electrical consumption and wiring required for the same. As against this, Silos offer the advantage of increased loading capacity and they do not require any Electrical Supply. The increase in height is also nominal. The overall table size also does not increase to that extent. Though the Silo has a lot of advantages, the only disadvantage is that it can only be used for certain components like needles, rollers etc. It cannot be used for components like screws, hooks etc. The Silo sits on top of the bowl and is an integral part of the vibratory drive unit.