Bowl Feeders

Chapter One – What is a Bowl Feeder?

A bowl feeder is a mechanism for supplying small parts and components to a production line or for sorting bulk items for rapid use. A self contained bowl feeder system has a bowl that sets on a spring loaded base that moves vertically. Small parts and components move along the edge of the bowl.

Bowl feeders are a very flexible form of parts feeder able to handle parts from ones that are the size of pill to parts as large as six cubic inches. Though bowl feeders take up very little space, they are capable of arranging, selecting, feeding, and sorting parts in a very cost effective way.

This brief YouTube video, from Feeding Concepts, Inc.(FCI), shows the uses of a bowl feeder in a packaging operation.

The effectiveness of a bowl feeder is measured by its output rate, part orientation, and the space it fills on the production floor. Bowl feeders can have an output rate between 200 to 1600 parts per minute.

Chapter Two – How are Bowl Feeders Used?

Bowl feeders are a vibratory mechanism used as a material conveyor and automation equipment that is essential for several manufacturing processes, such as: automotive, chemical processing, electronics, food and beverage, foundry, glass, mining, packaging, pharmaceuticals, railroad, and recycling.

With a bowl feeder, parts are forced along a circular inclined track inside the bowl. The length, shape, and size of the track is chosen to meet the exact size of the part and has a special coating designed to match the shape and size of the material.

How Bowl Feeders Are Used:

Feeding:

Bowl feeders can be designed with a simple plain feed or tooled and engineered for special part orientation, positioning, and selection. These factors are controlled by a variable speed controller with a normal electrical supply.

Automation:

Bowl feeders are a cost effective method for replacing manual labor. They are used for automatic feeding of parts to an assembly workstation and positioning of high volume parts. The feeder is placed under a hopper that provides a continuous flow of material.

Counting:

A counting bowl feeder counts an exact amount of parts to be placed in a process or for packaging.

Pick and Place:

In pick and place, parts are directed to the work station in the correct position to be securely assembled, such as orienting a screw for placement. The video below, from Deprag Feeding Technology, briefly explains pick and place technology.

Inspection:

Vision inspection systems check parts as they leave the bowl feeder. Ones that do not fit the parameters programmed into the PLC are removed as rejected.

Chapter Three – How does a Bowl Feeder Work?

The term bowl feeder is a general description given to devices that feed parts for multiple and different applications. Basically, a bowl feeder uses mechanical vibrations or centrifugal force to move parts along a conveying track to an assembly, shipping, inspection line, and other operations.

The unique design of bowl feeders does not make it possible to describe all of the features of every type of bowl feeder. There are commonalities between bowl feeders, which include the bowl and base plate.

How a Bowl Feeder Works

The image below highlights the basic features of an ordinary bowl feeder unit.

Hopper:

The hopper is the storage area for parts prior to being sent to the feeder bowl. It eliminates overloading or insufficient quantities in the feeder bowl and can be monitored by a level control switch.

Feeder Bowl Diameter:

The diameter of a bowl feeder is the central element of the process. Its design has to fit the type of material that it will convey. A crucial factor in the design of a bowl feeder is the diameter of the feeder bowl, which should be ten times the length of the part to be fed. In correct feeding, parts make contact with the bowl track.

Base Unit:

The base unit is the drive unit for the feeder system. It is selected according to the materials that will be fed, which includes their size, weight, length, and the number of parts that will be in the bowl.

Linear Feeder:

Linear feeders accumulate and orient parts from the feeder bowl to be moved to assembly or other machines. The four types of linear feeders are vibratory, conveyor, airveyor, and gravity.

Feed Rate:

The feed rate is the number of parts that will be moved over a set period of time and is expressed in parts per minute. It depends on the configuration of the parts, the need for positioning, how many tracks there are, and the size of the unit. An important step in determining the feed rate is a thorough examination of the part being fed.

Factors that determine the feed rate include:

• Part dimensions
• Metals or materials of the part
• Positioning of the part
• Part weight
• Present production processes
• Purpose for bowl feeder installation – efficiency issues

Feeder Bowl Level Control:

Feeder bowls will only operate properly if the number of parts in the bowl is the correct amount. Too many parts may damage the parts, while too few parts will slow the process. Sensors monitor the number of parts in the bowl to be sure there is the right amount.

Feeder Track Detection:

Feed track detection is designed to prevent jamming and clogging. Sensors turn off the track if it gets too full. The image below, from Performance Feeders, has a sensor at the entrance and discharge of the feeder.

Amplitude Controller:

The amplitude controller monitors the rate of the vibration on a bowl feeder. If a bowl feeder does not have a controller, it will run at its maximum output, which necessitates the use of a variable rate controller to keep vibrations uniform.

Noise Reduction:

Noise in a bowl feeder is caused by the movement of parts in the bowl. It can get so loud that workers have to wear noise reducing gear, such as decibel reducing earmuffs. Sound enclosures are used to reduce noise levels created by the bowl feeder process.

Chapter Four – Types of Bowl Feeders

Bowl feeders are divided into various parts depending on how they move material. Though all types have a bowl, how parts and materials are moved from the bowl vary depending on the purpose and function of the bowl feeder.

Types of Bowl Feeders

Vibratory:

Vibratory bowl feeders are the most common and the ones that are most readily found when searching on the internet. They use a system of vibrations to move parts to the exit chute, linear track, or an assembly machine. A vibratory bowl feeder is like a workhorse and seldom needs maintenance. In cases where a vibratory bowl feeder is moving oily, greasy, or dirty parts, it may need to be regularly cleaned.

Centrifugal:

Centrifugal bowl feeders are more complex than vibratory bowl feeders. They are used in high speed operations, where vibrations are not fast enough and cannot be used. Parts inside the bowl are moved in a circular direction by centrifugal force that pushes them to the edge of a conical shaped disk inside the bowl, as can be seen in the attached video.

Conical:

Conical bowl feeders, or cascade bowl feeders, are a type of vibratory bowl feeder with a cone shaped bowl. Parts are positioned on the inside wall of the bowl to reduce part circulation and abrasion. The process is used for parts with a simple geometry. They have an open cavity design for use in clean rooms, the pharmaceutical industry, and food processing.

Chapter Five – Types of Bowls for a Bowl Feeder

The central feature of a bowl feeder is its bowl, which can come in varying sizes and shapes. The most common bowl designs are cylindrical, conical, stepped, and polyamide.

Types of Bowls for a Bowl Feeder

Cylindrical:

Cylindrical bowls offer a constant feed but have a restricted capacity. They are used for very small parts, as can be seen in the image below.

Conical:

Conical bowls have a higher capacity with a diameter that helps in pre-separation. They can have an increased number of tracks and track widths.

Outside Track:

Outside track bowls are used for operations where exact part orientation is required and a higher feed rate with multiple lines. The track is angled downward for parts to separate more quickly. When parts buckle, they fall into the inside bowl.

Stepped:

The feeding track on a stepped bowl is wider making it ideal for pre-oriented parts. It has a larger bowl that prevents parts from getting jammed.

Polyamide:

Polyamide bowls are made of plastic, which allows parts to slide more easily and avoids the problems of steel on steel. The properties of plastic allows for greater flexibility for shaping of the bowl and increased noise reduction.

Bowl Materials:

Bowls are typically made from cast aluminum, plastic, certain grades of steel, and stainless steel.

Track Configurations

High Negative:

Negative tracks have a negative angle for flat nonuniform parts.

Positive:

Positive tracks are at an angle that is less than 90o between the track and wall.

Multiple:

Multiple track bowls have several tracks along the side of the bowl.

Radius:

Radius form tracks have a groove and are used for cylindrical parts.

V Shaped:

V shaped tracks have a groove of varying angles depending on the requirements of the part.

Negative:

In negative tracks, the distance between the wall and track is larger than 90o and is used for caps and rectangular stamped parts.

Chapter Six – Industries that Use Bowl Feeders

Many industries rely on bowl feeders for speeding up productivity and assembly. They have become an essential automation device. The number of production processes that use bowl feeders is wide and varied. Their easy use and lack of maintenance has made them an ideal choice in helping speed up production.

Uses for Bowl Feeders

Automotive Industry:

The speed of automotive production requires parts to be fed with the proper orientation and able to handle a wide variety of sizes and shapes. Cascade bowl feeders are used to supply small components, such as screws, bolts, and dowels. Large parts are fed using an outside track bowl feeder, as seen in the image below.

Electronics Industry:

The electronics industry uses bowl feeders for sorting and positioning of electrical components, such as pins, tubes, and fasteners.

Pharmaceutical Industry:

One of the specifications for the pharmaceutical industry is cleanliness. Bowl feeders have to be able to move materials without any concern for contaminates and are designed to exacting specifications, which include special metals. an important qualification is their ability to meet Food and Drug Administration guidelines. To meet the cleanliness requirements, bowl feeders for the pharmaceutical industry are made using stainless steel grades 304 and 316L.

Ordnance:

Bowl feeders can be engineered and designed to handle explosive materials. The attached video is sorting bullet casings.

Food Production:

Food production is constantly looking for methods for improving productivity. Bowl feeders have become an integral part of the industry’s changes. The biggest problem, with food production, are the stringent regulations regarding contaminants and sanitary conditions. Food bowl feeders can move 500 pieces per minute at sizes ranging between 30 to 50 inches.

Packaging:

The consumer packing industry is ever changing as new lids in a variety of shapes and sizes are produced. Engineering feeders to meet the ever developing demand is a challenge for the bowl feeder industry. Systems need to be easy to change and adjust.

Cosmetics:

An essential part of the cosmetics industry is the appearance of the container. Feeder systems for cosmetics have to be efficient to avoid part recirculation and avoid irregularities. Parts have to be in perfect conditions after going through the bowl feeder process.

Conclusion

• A bowl feeder is a mechanism for supplying small parts and components to a production line or for sorting bulk items for rapid use.
• A bowl feeder uses mechanical vibrations and centrifugal force to move parts along a conveying track to an assembly, shipping, inspection line, and other operations.
• There are a vast number of industries that use bowl feeders as a method of automation.
• Bowl feeders are divided according to their method of moving materials.
• The central feature of a bowl feeder is its bowl, which can come in varying sizes and shapes.