Flexible Manufacturing and Industry 4.0, Automated Feeding Technology (pt 1)
AAE (Grauel) pushes technical boundaries. We provide high tech printing & assembly solutions. We support smart printing and manufacturing with Smart Industry technologies and solutions. This series of articles provide background information on how these developments are supported.
In the previous article we saw how the company introduced a flexible manufacturing system (FMS) to their assembly process. This was done as they require further automation in the future and want to be prepared for a wide range of products.
As a second automation step, an ultrasonic welding (us welding) system was integrated onto the FMS where two parts are ultrasonically welded to form a single (assembled) part. The FMS uses flexible shuttles allowing optimization of the loading (onto the shuttle) and ultrasonic welding time.
Individual processes can be optimized, contributing to high quality output (compared to a fixed time for each process step as present on hard manufacturing system).
In this article we will take the automation of the production process to the next level. The feeding of parts (for operator position 1) will be reviewed.
The second article will focus on the challenges the parts themselves may pose for correct automation. An overview of a configuration for an automated feeding process is included in part 2 of the article.
For a better understanding of the challenges involved in selecting the correct feeding system(s), we will review the feeding functions and general feeding types in this article.
Let’s start by reviewing the current situation. Operator one places three (3) parts on the shuttles of the Flexible Manufacturing System (indicated by the green, purple and yellow boxes). We will review how we can automate this process.
Note: since the ultrasonic welding process has been automated (see our previous articles on this subject), the product flow has been changed. This adds an additional product to the automation.
A lot of factors are to be taken into account to introduce correct and reliable part automation. This is not an easy task and requires a lot of experience. Your automation supplier or part feeding system supplier can be a great source of information and support.
The basics of the feeding system are dealt with in the next paragraph.
Feeding System Functions
Part feeding systems generally take parts from bulk and position them for inclusion into an automation system. This is done in various steps which are schematically listed below:
Some functions can be combined but we will review the individual steps for clarification. A short description of the functions is listed below:
- Bulk Storage: unit that collects and stores parts. Parts are deposited in bulk (normally from the production process). The autonomy time (*1) is often specified here.
(*1) time that a system can run without refilling or adding products
- Separation: unit that takes part from bulk and presents them as individual parts. This is also referred to as “singulation” in later articles.
- Orientation: unit that orientates the parts in the required direction for further processing.
- Transport: unit that transports the parts in a controlled way to the assembly or printing machine.
- Loading: separate piece of equipment, typically a handling system operating at a portion of track that is under no vibration or pressure.
Note: loading methods will be reviewed in a later article as the parts are transferred to the automation equipment at this stage (as simulations are a useful tool, we will review this first before dealing with loading).
Feeding System Types
There are a wide range of feeding systems available to support the various functions. Common types are described and shown below, for information purposes reference image are included (note that some feeding types may have a different configuration):
Step Feeders (bunker feeder)
This unit provides the parts from bulk in small batches to the next process. Component / parts are gathered in a large collecting bin. From this bin, multiple parts are taken by an elevator system to transport them to the adjacent process. This is the first step in separating the parts and providing them in a controlled way to the next process.
Even though the parts are provided in batches, there may still be a large variation in the number of parts supplied. An addition processing step in the separation (and controlled supply) may be needed.
This is a vibrating unit that can be positioned after the step feeder / bunker feeder. Parts are provided in small batches by the step feeder and are then further separated by the hopper. The parts can then be fed to the next process in an even more controlled way. A vibrating hopper is generally used upstream (before) of a vibrating or centrifugal bowl in order to control the parts supplied thus increasing its autonomy (e.g., operating time).
Bowl Feeders / Vibrating Feeders
A unit that consists of a bowl with a spiral track internally. The parts that are provided to the bowl travel from the bottom to the top on a track due to the vibration of the bowl.
Controlled feeding of parts to the bowl increases the efficiency (if a large number of parts are dropped altogether in the bowl, it can easily jam up). Different bowl types (shape and materials) are available for different parts.
Centrifugal Feeders / Rotary Feeders
A unit that consists of a conical central driven bowl / rotor, which is surrounded by a circular bowl wall. The parts provided are separated using rotary force where high speed pulls the parts outside of the bowl.
Several types of central driven bowls are available for various shaped parts. A constant supply of parts (amount) will positively affect the output of the centrifugal feeder. Typically, centrifugal feeders can provide parts at a higher output speed than bowl feeders*1.
*1 a generic statement, speed of a centrifugal or bowl feeder depends on many factors (see also next article dealing with product materials, shapes, etc).
As orientation of the part is frequently done after the bowl or centrifugal feeder, we look at orientation here. A wide range of possibilities for correct orientation are available (active and passive). Parts can be oriented based on the shape of product, center of gravity, inclusion of a vision system with active rotation unit, etc. A wide range of options are available for correct orientation.
A basic system for separation, alignment and orientation is shown below.
Parts are separated based on their (initial) orientation. In this case only parts that arrive on the long flat side will continue, other parts will be dropped back in the bowl. The next step is to ensure all part are aligned. Parts that are not correctly positioned (against the back wall) will be dropped back into the bowl. We now have correctly aligned parts all in the correct orientation (flat).
At the last stage, the parts will be oriented into the correct position. In this case, they will be placed upright (small side). All parts now existing the (bowl feeder / centrifugal feeder) system will always have the same orientation.
Note: We will look orientation a bit more in depth in the second article as the parts themselves play an important role in the way they can be orientated.
These systems are used when step feeders, bowl feeders or centrifugal feeders are not suitable, these are typically used for more fragile parts. These feeders enable smooth handling of components. The parts are transported gently on conveyor tracks/channels lined with soft / suitable (brushed) material.
This unit transports parts from the bowl (centrifugal / vibrating) to the automation equipment. This includes transport systems such as vibrating rails, gravity rails or conveyor belts. These systems maintain the orientation of the components. Linear feeders also provide buffer storage upstream of the automation equipment to provide a constant supply of parts.
Flex feeders / Any feeders
This is typically a flexible bulk parts feeder (e.g., hopper) with an integrated bulk storage bin. Parts are provided in small and controlled batches from the storage to the part feeder. The part feeder further isolates the parts (e.g., transport by vibration).
A robot using a vision system is normally included for part detection and handling. The vision system identifies pickable parts and instructs the robot for correct pickup. The parts can then be placed into the automation equipment directly (loading function is integrated here). Multiple types of robots can be used, a SCARA* robot is included here.
Selective Compliance Assembly Robot Arm
With flexibility in mind (also looking at Industry 4.0), flexible feeders provide a good solution for a wide range of products and shapes. Stay tuned for part 2, coming up next month! In the meantime, consider following Grauel, a brand of AAE, on LinkedIn for weekly updates and extra content.
‘Manufacturing and Industry 4.0, Automated Feeding Technology – Feeding Systems to the Flexible Manufacturing System (pt 1). By Ivo Brouwer – Business Developer Production Automation at AAE b.v.