Flexible Manufacturing and Industry 4.0, Automated Feeding Technology (pt 2)

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. 

 

Introduction

In the previous article we looked at various feeding systems that are available to provide products to the automation equipment. Currently the parts are placed onto the flexible system by operators making this a semi-automated process. The feeding of the parts can be automated to increase the throughput of the process over a longer period of time. 

The selection of feeding systems greatly impacts the efficiency of the manufacturing process. The parts that are to be fed to the assembly or printing system have a major impact on the selection of the feeding systemsVarious aspects that are to be taken into consideration will be dealt with in this article 

The challenges posed by the parts themselves are reviewed first after which the influence of the part material is reviewed. Additional aspects of the parts are then discussed to provide a good understanding of the various aspects 

 

Parts Overview

Parts come in a wide range of shapes. Most assembled products consist of multiple (individual) parts all with a specific function and shape. Some of the shapes pose a challenge for correct feeding and orientation (some are notoriously hard to separate and handle, e.g., springs).

An overview of different parts is included below. Each of these products provide their own challenge in separation, orientation, transport and loading (we will look deeper at the various aspects in the next paragraph).

 

Parts, Design and Handling

Given the wide range of parts available and their geometry, weight, point of gravity, material used, etc., a lot of factors come into play when designing an efficient feeding and handling system. Let’s look at some of the most important aspects.

Parts Characteristics

The part characteristics include the overall dimensions and geometrical aspects of the part. A smooth and round product (ball) is easier to handle than a part with additional protrusions. Let’s look at two (2) product types (see below).  

Both parts offer their own challenge. The springs can interlock and jam up the storage and separation. The cover part on the top is easier to handle but the shape of the cone may cause them to interlock (stick together). This is to be carefully reviewed before deciding on a feeding system.

 

Material and Composition of the parts

The material from which the parts are made is the next thing to consider. A hard-plastic part needs to be handled differently than soft plastic parts. Softer plastics may change shape when pressure is applied. The time for storage is also important as freshly produced products may behave differently than “matured” ones.

Storing a large number of products requires the material to be reviewed. With multiple products stored on top of each other, the pressure increases on the bottom parts.

The bottom parts experience the weight of the products stacked on top of them. Products may have different properties just after production (directly after forming or molding).

Some material require time to harden before they can be processed correctly. Plastics may show change in properties directly after forming. Different types of materials may have different behavior (e.g., semi-crystalline materials shrink more than amorphous ones, and fillers will reduce the shrinkage rate of any particular polymer to a degree that depends upon the type and amount of filler that is added).

 

Natural orientation of the part

The natural orientation of a part may be very different than what is needed for the assembly process (or next process step). Let’s use a simple part to review this aspect. A cubical shape has a natural orientation for the flat, larger side. But the next process step requires the parts to be on the smaller side.

For this example, we can actually use this in our advantage in (e.g.) a bowl feeder. As the parts tend to be on the flat side, most part will assume this position. This immediately has a positive effect on the output, most part arrive already in the desired position.
We can eliminate any part transported on the smaller side with the initial guide. We now have only parts with the correct orientation (most parts anyways due to the natural orientation of the part).

Any part not aligned correctly against the back side of the bowl feeder is to be removed as well. Here we can introduce a small alignment part. Any part not positioned against the side will be dropped back in the bowl feeder.

Only parts oriented and positioned correctly are then transferred. Now we can re-orientate the parts with a “ramp” where they are all rotated over 90° to have the correct orientation for the next process step. An overview of the (passive) orientation unit is shown below.

 

Weight and center of gravity

The weight of the part and its center of gravity may have a profound impact on the handling and feeding. The exit orientation of a bowl feeder depends on the part’s shape and mass distribution and this may prove a challenge for correct orientation. Some parts have a center of mass which tilts them, making it hard to transport them.

A reference image is included below. This part has a natural tendency to “tilt” to a specific orientation. This may prove to be a challenge to transport this part on a linear transport system.

 

Additional Aspects

Apart from the aspects described before, additional requirements and aspects may also have an influence on the part feeding process.

For some medical products particle generation is extremely important (limiting the number of particles generated during handling). This does not allow for some feeding systems to be used as the parts touch or rub against each other.

The accessibility of the operators to the feeding system may be important as well as accessibility to the manufacturing system itself.

Also, when parts are retrieved from different suppliers and have variation, the feeding systems need to accommodate these changes. This may require different feeding systems than when a single (plastic) part supplier is used.

Based on the aspects before, a great number of considerations have to be taken into consideration when designing, developing, or selecting reliable feeding systems.

An optimized feeding system can dramatically increase the Overall Equipment Efficiency (OEE).

 

Inclusion with the FMS (Flexible Manufacturing System) system

Having discussed the various types of feeding systems, we can now introduce the automated solutions to the flexible automation system.

At operator position 01, three (3) parts are inserted where we need different feeding systems. For illustration purposes will we introduce these three (3) feeding configurations.

The first part is fed using a bunker feeder, hopper, bowl feeder and a linear track. This replaces the parts originally retrieved from the green (storage) box.

When introducing the second feeding system, we can also remove the original operator position.

To automate the feeding of the second part we can use a similar configuration of the first part consisting of a bunker feeder, hopper, bowl feeder and linear track.

For the last past we can use a flex feeder system (or any feeder) where a vision system detects pickable parts and guides the robot to the part. The part is them picked and placed into the flexible system. This feeding system offers the most flexibility in feeding.

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 more, coming up next month! In the meantime, please 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.

 

Literature

Cohen,Y*, Faccio, M**, Galizia, FG **, Mora,C ***, Pila, F (2017) Assembly system configuration through Industry 4.0 principles: the expected change in the actual paradigms. Available at https://www.sciencedirect.com/science/article/pii/S2405896317334754 [Accessed on June 2020].  
NTN Corporation, Parts Feeder Guidebook, CAT. No. 7019 / E, Corporate publication  
Fanuc, Benefits of Flexible Part Feeding, Available at: https://www.flexibowl.com/benefits-of-flexible-part-feeding-fanuc.htm [ Accessed July 2020]. 

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