There are various types of bowls which can be used, namely, step, cylindrical, conical, outer track etc. All of these types have certain advantages and disadvantages inherent to their design & construction.

Cylindrical bowls – The biggest advantage is their low cost of construction and tooling. However, the disadvantage is that there are tracks one on top of another, which results in jamming of parts between two tracks, removing of which requires manual intervention. Another disadvantage is that due to tooling, especially in case of complicated tooling, the bowls becomes unwieldy and unbalanced. This results in the bowl not working properly on one side. The loading quantity or the volume in cylindrical bowls too is much less, resulting in regular replenishment at short intervals.

Step bowls - Step design bowls provide a lot of tooling flexibility, convenience and high loading volumes. Secondly, it is possible to provide irregular and complicated bowl tooling and shapes in case of step design bowls. As such there are no disadvantages of using step type bowls except that they are costlier to make. These can be used for any type of components. As there is no track on top of another, the problem of jamming of components between two tracks does not arise.

Conical bowls – Conical bowls are suitable only for certain types of components, which tend to overlap or are very flat. In these type of bowls too, as there is no track on top of another, the problem of jamming of components between two tracks does not arise. Conical bowls are most preferable in case of medical applications as they can be made to ensure there is welding crevice or gap anywhere in the bowl. Conical bowl can be fixed from the sides to result in much better working for medical applications.

Outer track bowls - These are also costlier to make but have some advantages like high loading capacity, optimum area for tooling. In case there is a requirement for high speed and complicated orientation, then outer track bowl is the only solution. However, the disadvantage is the high cost of such bowls. Further as the outer track bowl is an cylindrical bowl on the inside and therefore there are tracks one on top of another, which results in jamming of parts between two tracks, removing of which requires manual intervention.

Going through the above information, it can be concluded that step type bowl is the best for most parts being fed, not only from the point of view of the bowl tooler but also from the customer’s usage point of view.

In case of single coil vibratory bowl feeders, the coil is mounted centrally (either one coil or else two coils). The advantage is that one requires only a single coil, thus reducing the cost and secondly, the coil can be made powerful enough so that the same one can be used across models. However, there are certain major disadvantages of having a single or even two central coils. It leads to excessive vibrations at the centre, which reduce as the part moves away from the bowl centre. This results in a huge wastage of energy. Due to the eccentric and powerful load, there are possibilities of the springs and bolts breaking on a regular basis. To offset the extra load, the bowl needs to be made heavy or else extra counter weights need to be added to the bowl to balance it, further making the bowl needlessly heavy. The vibrations too are abnormal and heavy, resulting in damage to the parts being fed or resulting in a wrongly oriented part coming out. The bowl life too reduces due to this.

            In case of multiple coil vibratory bowl feeders, the coils are mounted on the periphery of the vibratory bowl feeder (three or four coils). However, for this the coils need to be correctly designed for each and every model. But the advantages are that firstly there is no extra energy wasted, thus saving on energy costs and secondly, the coils being on the periphery of the vibratory feeder, the vibrations are equally transferred to the bowl, leading to better performance of the vibratory bowl feeder. Secondly, being on the periphery, one can design the bowl having a slightly bigger diameter, which is not possible in case of a centrally mounted powerful coil. Further the chances of the springs and bolts breaking are drastically reduced, especially in the case of full wave vibratory bowl feeders. The bowl can be designed to be light weight and cast aluminium bowls can also be used. The life of the vibratory feeders and the bowl too is much more in case of multiple coils mounted at the periphery of the vibratory feeder.  

The number of components which can be loaded in a vibratory bowl feeder is limited either due to the volume or weight of the components. Volume is especially important in case of rubber or plastic components and weight when the components are metallic.

In case extra loading capacity is required, then the choice is to either use a bigger bowl feeder or else to use an auxiliary feeding unit like a flat vibratory hopper or elevator, silo etc. These auxiliary equipments can increase the loading quantity tremendously and the bowl feeder can become a totally man-less operation requiring refilling at longer intervals.

A Silo as well as a stock feeder is used to hold extra parts for replenishing the supply in a vibratory bowl feeder. While a stock feeder is set to operate automatically by a signal from a level control switch, thus eliminating either a deficiency or an over-supply of parts in the bowl, a Silo is mounted on the bowl itself and the components keep on percolating down from the bottom of the Silo into the bowl.

Thus a Silo and a stock feeder are competing products and while deciding on which one to opt for, the following points require consideration –

1.      Dimensions / sizes of the parts - In case of Silo, only certain parts like Needles, Rollers etc. It cannot be used for components like screws, hooks etc. Any size / dimension of parts can be accommodated in a hopper feeder.

2.      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 and this is its real limitation.

An Elevator feeder as well as Stock feeder is used to hold extra parts for replenishing the supply in a vibratory bowl feeder. They are set to operate automatically by a signal from a level control switch, thus eliminating either a deficiency or an over-supply of parts in the bowl.
The number of components which can be loaded in a vibratory bowl feeder is limited either due to the volume or weight of the components. Volume is especially important in case of rubber or plastic components and weight when the components are metallic. In case extra loading capacity is required, then the choice is to either use a bigger bowl feeder or else to use an auxiliary feeding unit like a flat vibratory hopper or elevator, silo etc. These auxiliary equipments can increase the loading quantity tremendously and the bowl feeder can become a totally man-less operation requiring refilling at longer intervals.

Thus an elevator and a stock feeder are competing products and while deciding on which one to opt for, the following points require consideration –

1.      Weight of the parts / components – The loading height of a stock feeder is usually around 400 mm to 700 mm above that of the vibratory bowl feeder and that of a elevator is between 500 mm to 700 mm from the ground level. Hence, in case of heavier parts, it is preferable to opt for an elevator so that operator fatigue is reduced and the parts can be easily loaded at a lower height. In case of small plastic parts or other light weight parts, a stock feeder is ideal.

2.      Volume / loading capacity required – Volume in case of stock feeders or hoppers can range between 15 litres to 50 litres while that of elevators range between 50 litres to 200 litres.

3.      Running cost – Elevators work on 0.25 HP to 1 HP motors (depending upon their size and component weight while stock feeders or hoppers have a linear vibrator drawing power of just 10 VA to 400 VA (depending upon its size).

4.      Replacement parts – The only parts which need be replaced in case of stock feeders are coil, controller and spring plates of the linear vibrator. The prices of these spares are very less. In case of an elevator, belt, gear box (or its components), bearings etc. might require replacement over time.

5.      Space required – Stock feeders / hoppers use much less space and additionally are kept at a height, thus reducing the total foot print. Vis a vis elevators require much more space.

6.      Life – Life of both are usually the same and they last for many years.

7.      Cost – Obviously, the cost of a stock hopper is much less than that of an elevator

Thus, an elevator feeder has obvious advantages over that of a stock feeder or hopper but its initial cost, space required and running cost is much more than that of a stock feeder. Hence, the decision whether to opt for a stock feeder or a elevator depends upon the loading capacity required and weight of the parts to be fed.

An Elevator feeder is used to hold extra parts for replenishing the supply in the bowl. Elevators are set to operate automatically by a signal from a level control switch, thus eliminating either a deficiency or an over-supply of parts in the bowl.

The number of components which can be loaded in a vibratory bowl feeder is limited either due to the volume or weight of the components. Volume is especially important in case of rubber or plastic components and weight when the components are metallic. In case extra loading capacity is required, then the choice is to either use a bigger bowl feeder or else to use an auxiliary feeding unit like a flat vibratory hopper or elevator, silo etc. These auxiliary equipments can increase the loading quantity tremendously and the bowl feeder can become a totally man-less operation requiring refilling at longer intervals.

In addition to the increased capacity, the biggest advantage of a elevator feeder is that the loading can be done at a lower level as compared to that of a bowl feeder. An elevator feeder can be of various sizes and dimensions and types

These types of elevators can be provided either in Stainless Steel or Mild Steel. In case of mild steel, it is preferable to use a coating or lining like the Elscinthane PU coating from the inside. Coating is also required in case of metallic components when can otherwise make a lot of noise in the hopper.

A level controller for controlling the component level has to be provided. This is controlled by a level sensor mounted on the hopper itself. This provides a start / stop operation, thus resulting in increased efficiency of the downstream equipment like vibratory bowl feeders as well as centrifugal / rotary feeders.

            Elevators ensure that the quantity of components loaded in the bowl always remains the same (with the help of the start stop function of the level controller) and hence can help in achieving better functioning and working of the bowl feeders.

             While ordering an elevator feeder, is should be ensured that the supplier has provided a small adjustment for the outlet height so that any change in the bowl height in the future is taken care off. Secondly, it is preferable to opt for mounting the elevator on castors so that movement is easy. However, in case of castors, there should be separate locking arrangement so that the elevator does not move if somebody pushes it by mistake.

Normally vibratory bowl feeders are made for either bolts or nuts due to the intrinsic nature of the tooling required for each type of component. Both cannot be fed in the same bowl feeder. However, this is now possible with the help of a very complicated tooling but with slight changeover tooling. Bolts from size M 4 to M 14 and Nuts from M4 to M30 can be fed through the same vibratory parts feeder. This can help fastener manufacturers attain a lot of flexibility and adaptability with regard to their vibratory bowl feeders. In order to feed the nuts, the tooling for the bolts needs to be removed and replaced with a different type of tooling which will be used for feeding of the nuts. Of course, side adjustments for accommodating various nuts and bolts will still have to be done for the various sizes.

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.

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.

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.

When it comes to accommodating various parts in a single bowl, then caps of various sizes are easy to accommodate in a single bowl with simple changeover tooling. For tooling a bowl for caps, three things are required. First being “wiper” which ensures that only a single cap moves forward while the ones on top of each other fall back in as well as those resting on their edge too fall back in. Then comes the “scallop”. It is the part with which the caps with the open side facing ground fall back into the bowl while the ones with the open side facing sky move forward. The third one is the part for ensuring that the caps coming out as “open side facing sky” are turned 180 degrees to make then “open side facing ground”. For accommodating various sizes of caps in a single bowl, the “wiper” needs to be adjusted up or down to ensure that only a single cap moves forward while the one on top of each other fall back as well as those resting on their edge too fall back in. Then the “scallop” needs to be changed as per the diameter of the cap. The third adjustment i.e. that for turning / twisting the caps in 180 degrees, too needs to be changed. However, Elscint has developed an innovative tooling for twisting the caps in 180 degrees that it need not be changed from cap to cap. The same tooling can accommodate a wide variety of caps. However, in case there is a huge variation in the diameters of the caps, then a slight adjustment is required. Elscint can accommodate caps having diameter from 15 mm to even upto dia 100 mm in the same bowl with this innovative tooling.