24. July 2010 06:44
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.
15. July 2010 08:00
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.
6. July 2010 11:51
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.