In most of the cases, it is better to have feeder bowls coated. Coatings can be either polyurethane spray coating, pasting of sheets on the bowl surface, teflon coating etc. The best solution lies in polyurethane spray coating. The advantages are firstly, in case of metallic components, the Noise Level can be drastically reduced by eliminating the Metal to Metal contact between the metallic bowl surface and the components. Another major problem faced by customers is of feeding oily components. Oily components reduce / eliminate the friction between the components and the Bowl track. As Vibrators work on the principle of Friction, this results in the components slipping and hence they are not able to feed properly. Proper type of coating can eliminate this. It is better to have a rough coating in case of oily components while in case of dry components, it is beneficial to have smooth coating. This improves the friction between the components and bowl, resulting in better movement of parts forward. Previously, PVC or polyurethane sheets were pasted to the bowl surface to act as lining. However, these have many disadvantages. First and foremost, in case the adhesion is not proper at any place, air bubbles get created and the whole sheet gets removed. Even if any adhesive is used, it gets removed in cases where there is oily residue on the components.

A few bowl feeder manufacturers in Europe have started using Polyamide bowls. These types of bowls have certain advantages like machining ease and repeatability but the disadvantages are the size (small) and type (conical). Step design bowls, which provide a lot of tooling flexibility, convenience and high loading volumes are not possible in case of polyamide bowls. Secondly, these bowls need to be machined on five axis CNC machines, making them costly to manufacture. However, in case the same bowl needs to be manufactured again, it is much easy to pull out the machining program and machine the bowl in the same way. However, some tooling needs to be hand made, which increases the labour content. Another advantage of polyamide bowls is that coating is not required as the bowl is not made of metal; the noise in case of metallic parts is less. Likewise, a disadvantage is that one cannot use oily parts on polyamide bowls as these bowls are smooth and the oily parts tend to slip and feeding is not proper. Hence, does it make sense to go for polyamide bowls? The answer is that only in case the parts are small and flat and many numbers of the same type of bowl are required.

Conical bowl is a bowl which is like a cone with the track welded to the inside of the cone. Conical bowls are required for certain types of components, which tend to overlap or are very flat. In these types 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 are most suitable for medical applications as firstly they can be welded in such a way that there is no crevice which can hold dust. Secondly, they can be fixed from the sides to result in much better working and to ensure that there is no dust present in the mounting holes for medical applications.

Most bowl feeder manufacturers usually use cylindrical bowls for most applications. The biggest advantage of cylindrical bowls is their low cost of construction, and tooling. Plus they are faster to make. However, the biggest disadvantage is that there are tracks one on top of one another, which results in jamming of parts between two tracks, removing of which requires manual intervention. Another disadvantage is that due to the tooling, especially in case of complicated tooling, the bowls becomes unwieldy and unbalanced. This results in the bowl not working properly on one side, resulting in either air jets required for pushing the parts forward at that particular area or else the minimum number of parts required in the bowl (for pushing the parts forward) increases. The loading quantity or the volume in cylindrical bowls too is much less, resulting in regular replenishment at short intervals. Though most bowl feeder manufacturers try to use cylindrical bowls, it is bound to create a lot of problems / hassles for the customer during long term usage. Hence, it is important to insist on the bowl feeder manufacturer not to use a cylindrical bowl and insist on a step / cascade type one. Some bowl feeder manufacturers call cylindrical bowls, outer pan types by having the orientation done on an outside track which is pitched downward to improve the separation and orientation of the parts. However, these become much more unwieldy and there is trouble with the parts moving properly at all places in the bowl, as indicated earlier. These too must be avoided. The best course of action is to ask the bowl feeder manufacturer to use a step / cascade type of bowl.

Vibrations have fascinated human beings since a very long time. Vibratory Bowl Feeders are around since the early part of the Twentieth Century. Till date no major alternative to a Vibratory Bowl Feeder has been invented. The only viable alternative is a Rotary Feeder which uses a motorised drive. However, it is definitely a very poor cousin of the Vibratory Bowl Feeder. For any part where a particular orientation is required, feeding through a vibratory bowl feeder is the only alternative. The first major distinction is that in a Rotary feeder, the parts which can be fed through a Rotary feeder are limited to certain flat caps where the diameter is more than the height, needles and rollers where the length is more than the diameter and any face can come out etc. As against this, in a vibratory bowl feeder almost any type of component can be handled. Second and most significant disadvantage of a Rotary feeder is that due to the positive pressure generated because of the rotating disc, the parts being fed are thrown against each other and against the wall of the feeder. This can result in damages to the parts. Compared to this, the parts do not get damaged in a vibratory bowl feeder. Even brittle and delicate parts can be handled in a vibratory bowl feeder. Thirdly, the speed or feed rate in case of a Rotary feeder can be as high as 40 metres per minute while that of a vibratory bowl feeder can be at the most 12 metres per minute. In fact, Elscint recently manufactured a Rotary feeder for flat drippers where the curved face was required to be up. A speed of 800 parts per minute was achieved for this 40 mm long flat dripper as against this, we could achieve a speed of just 200 parts per minute in case of a vibratory bowl feeder for the same component (for a different application where the speed requirement was much less). This is the only advantage of a Rotary feeder. Price of a vibratory bowl feeder is also much substantially less than that of a Rotary feeder.

Usually a vibratory bowl feeder is made suitable for one type of component. However, in case of need, the bowl feeder can be made suitable for a variety of parts / components. A large variety of parts can be fed through the same bowl feeder with some changeover tooling. However, though it is theoretically possible to accommodate any variety of parts in the same bowl with the requisite changeover tooling, it is not recommended for mainly two reasons. The first being that the changeover tooling will become very complicated, requiring a skilled operator to make the changes and secondly, the time taken for making the changes increases. Plus more the complicated tooling, there is always the chance of the operator making mistakes in the changeover. Hence, it is always better to have the total number of parts / components which are fed through the same bowl to be from the “same family” rather than from “another family”. Meaning if most of the parts are having length greater than diameter, then it is better not to include a part where the diameter is more than length in the same bowl. However, at Elscint, we have perfected the very easy changeover tooling even for parts which are not from the same family. But this is not possible with other bowl feeder manufacturers and hence it is better to stick to one family of components.

The speed of a vibratory bowl feeder is usually mentioned in number of pieces per minute. The maximum speed which can be achieved by a vibratory feeder is dependent upon the components being fed, orientation required, the tendency of the parts to come in the required direction, weight of the parts, the size of the vibratory feeder etc. However, the maximum speed at which a vibratory feeder functions is the same for any size of vibrator (if properly designed and manufactured). The maximum linear speed too which can be achieved is the same. A well designed vibratory feeder can achieve a maximum speed of 8 to 10 metres per minute. Even 10 to 12 metres is possible in case the vibrator and bowl are properly designed and also perfectly tuned.

In case parts relating to pharmaceutical or medical industry are required to be fed through a feeder bowl, certain points must be taken care of. First and foremost, the bowl needs to be manufactured in stainless steel (either 304 or 316 grade, as per customer requriement). Secondly, it should be full argon welded in such a manner that there is no crevice or gap anywhere as this can result in dust accumulating over there. Even the fixing of the bowl needs to be done from the sides or the bottom. The bowl should not be fixed at the centre as the mounting holes can hold dust. The removal of the bowl too has to be easy and fast so that in case any changeover of bowls (for different parts) is required, it is fast. It might also be helpful in case the bowl has to be autoclaved every now and then. For such applications, a stainless steel conical bowl with full argon welding is highly recommended with mounting from the sides. Some manufacturers provide cylindrical or step design bowls for such applications but they are not suitable for pharmaceutical and medical applications. Orientation tooling too needs to be fully welded to the bowl and cannot be fixed by screws for obvious reasons. In case a chute or gravity track is manufactured, it should preferably be made with stainless steel rods as this ensures that no dust accumulates in the same. The bowl should preferably be as shown in the enclosed photo.

Using a leveling screw for mounting stands made for vibratory bowl feeders is useful in many ways. First and foremost, it helps in leveling the stand in case the floor is not flat enough. In case the floor is not properly leveled, then the vibratory bowl feeder will be remains tilted on one side. This will result in the components not moving properly up the track in that area. If the orientation tooling is on that particular side, then the components will find it impossible to climb up on that side. The leveling screws help in reducing this possibility. Secondly, Elscint provides grouting arrangement on the leveling screws, which can help in grouting the stand to the ground. This is particularly useful in case of big vibratory part feeders, whose stands might have a tendency to jump / lose their position. Last but not the least, the leveling screws can help in providing a small height adjustment in case the stand does not have such a facility. Hence, it is always beneficial to have leveling screws for the mounting stands of vibratory bowl feeders.

The outlet height of a vibratory bowl feeder is between 100 mm to 500 mm, depending upon the model and the bowl used for the same. As a vibratory bowl feeder feeds to some machine or assembly operation, the required height, in the majority of the cases is more than this. Hence, there is a requirement of mounting the vibratory bowl feeder on a stand in order to match it with the machine or assembly table height. These stands can be cubical, single post, special, made of aluminum extruded sections etc. It always makes sense to purchase such stands from the bowl feeder manufacturer so that further work at the customer’s end is eliminated. In most of these stands, it is always beneficial to have a small extent of height adjustment. This ensures that minor adjustments at the time of integration are easy. In case the height adjustment required is just upto (+/-) 50 mm, this can be done by having this in the leveling screws below the stand. However, in most cases, the adjustment required is upto (+/-) 100 mm or even upto (+/-) 200 mm. This might be because the machine height is not finalized or if the bowl feeder is made to work for a variety of parts, with each part having a separate height requirement. In such a case, this adjustment can be provided with a height adjustment screw of appropriate length. Further in such a case, it is important that there is a provision to ensure that the screw does not rotate in 360 degrees, and proper provision is made for locking it. Elscint provides a keyway in the screw to ensure that it does not rotate and a proper locking arrangement is provided to ensure easy up and down movement as well as locking. The stands can be designed to not only mount the vibratory bowl feeder but also other things like hoppers, linear vibrators, gravity chutes etc. Further, if space is a constraint, one can opt for a single post stand which is a pillar type one as it helps conserve space. If not, then a cubical stand is most appropriate as it also provides some amount of storage space below the stand, where the tools and tooling of the vibratory bowl feeder can be stored.