Flexible assembly systems

Flexible assembly systems with industrial robots... 

Flexible assembly systems with industrial robots can be divided into three principal basic types with specific system structures ... 

There are two typologies of linking flexible assembly systems permanent and flex-link sequences. Linking with a permanent linking sequence means that each assembly system is linked in a set sequence to each other, such as with longitudinal transfer systems (see Figure 7). The permanent linking sequence allows these assembly systems to execute only a smaller number of assembly tasks with different assembly sequences. They are therefore suitable for the automated assembly of variants and types with comparable assembly sequences and several similar products or components with comparable assembly sequences. 

The assembly systems introduced by Henry Ford were effective for high-volume production of a single product type with dedicated machines and material handling systems. To respond to the changing market and increasing variety desired by the consumers, more flexible assembly systems have been introduced. Such flexible systems use all purpose machines or robots to handle a variety of tasks in a station associated with the multiple product t3 pes. In addition, the assembly systems have also taken on more complex, non-serial configurations (Hu et al. 2011). 

The only manual process in this system is adjustment of the reflow profile based on the results of soldering an assembly. The last step in the process would be to test the finished prototype board. This system could also be used for very small volume production runs, and aU components as described are available. With a change from milled boards to etched boards, the system can be used as a flexible assembly system. 

Extremely flexible assembly system (many product variants) and therefore most common. 

Flexible assembly systems use programmable, robotic devices to compose previously manufactured components and/or sub-assemblies into a complete product of unit of a product. A number of transfer mechanisms, feeding devices, robot types and end effectors can be utlilized in order to achieve a general assembly system (see 6.2F). 

The product volume, number of variants and process capability requirements support the application of flexible assembly system for the product. 

Highly structured, 3-D nanoparticle-polymer nanocomposites possess unique magnetic, electronic, and optical properties that differ from individual entities, providing new systems for the creation of nanodevices and biosensors (Murray et al. 2000 Shipway et al. 2000). The choice of assembly interactions is a key issue in order to obtain complete control over the thermodynamics of the assembled system. The introduction of reversible hydrogen bonding and flexible linear polymers into the bricks and mortar concept gave rise to system formation in near-equilibrium conditions, providing well-defined stmctures. 

Flexible Pharmaceutical Manufacturing and Assembly System Design... 

FLEXIBLE PHARMACEUTICAL MANUFACTURING AND ASSEMBLY SYSTEM DESIGN... 

When designing a flexible manufacturing/assembly system (FMS/FAS), the design team should consider the following steps ... 

Flex-link assembly systems, with either programmable work heads or assembly robots, allow more than one assembly operation to be performed at each workstation and provide considerable flexibility in production volume and greater adaptability in designing changes and different product styles. 

The various types of automated assembly systems euise due to the combination of the different t5rpes of assembly stations and work transfer devices, which, in turn, ate dependent on the requirements of the workpieces to assemble. HexibUity, that is, being adaptable to different conditions euid assembly tasks, should also be a characteristic of assembly systems. An adequate configuration of the assembly station as well as respective work transfer devices will help meet the different flexibility requirements. 

For transfer systems to flex-link systems, flexibility is achieved in the way the individual stations of an assembly system are linked—for example, for a junction in the material flow or the evening out of capacity fluctuations and/or technical malfunctions of the individual assembly stations. 

Due to flex-linking, the number of linked assembly stations can be very high without impairing the availability of the whole system. Flexible modular assembly systems with well over 80 assembly stations for automated assembly of complex products are therefore not uncommon. 

The movement towards automation of manufacturing and assembling sequences takes place progressively. Mechanized facilities can be automated only if specific prerequisites are fulfilled emd if employing complex industrial goods seems profitable, llecause assembly systems require maximum flexibility, the degree of automation is still relatively low. 

The essence of flexible, modular assembly systems is that all subsystems are constructed in a modular way. The modularity pertains not only to the actual assembly stations and the sequencing devices, stands, and so on, but to the work transfer devices, control and regulation. The variety of combinations made possible by the module allows the automation of a wide range of assembly tasks. The modular conception of these systems ensures... 

Flexible, modular assembly systems (see Figure 4) usually work in cycles of a few seconds and are often used for the automated assembly of product variants for large to medium numbers of units. The principle of the flex-link assembly stations is applied for flexible, modular assembly systems because this is the only way to realize flexibility in the linking of individual assembly stations. Longitudinal transfer systems are used as work transfer devices. In order to prevent individual cycle times, technical malfunctions, capacity fluctuations, and other factors of certain assembly stations from affecting the next stations, a buffer function in the transfer line between the assembly sta-... 

Figure 4 Flexible, Modular Assembly System. Source teamtechnik)...

The largest number of industrial assembly robots is used in flexible assembly lines (see Figure 5). Flexible assembly lines are more or less comparable to flexible, modular assembly systems with regard to construction, features, and application. The cycle times for flexible assembly lines generally vary between 15 and 30 sec. The main area of application for these systems is the automated assembly of products with annual units of between 300,000 and 1 million. 

Assembly robots can also execute several assembly processes within an assembly cycle. This allows a high level of utilization for the assembly system, in particular for smaller amounts of workpieces, which is important for economic reasons. Depending on the cycle time range, an assembly robot can be allocated with a maximum of five to six assembly procedures in a flexible assembly line. 

A large number of the industrial applications of flexible assembly cells are conducted as island solutions, that is, without being linked to other assembly stations. Flexible assembly cells as assembly islands are used for the automated assembly of subassembly components or simple products with usually less than 20 different parts. This system works best technically and economically with cycle times from 25-120 sec. This allows it to be applied in situations requiring an annual number of units to be assembled of between 50,000 and 500,000, depending on the scope of the assembly tasks and the number of shifts with which the system will be run. 

Particularly for small annual workpiece amounts, it is economically necessary to assemble several different products or components in one flexible automated assembly system in order to maintain a high level of system utilization. Because sometimes very different assembly processes must be realized, a linking structure (flex-link sequence), independent from certain assembly processes, is necessary. Assembly systems of this type are able to meet the increasing demands for more flexibility. 

Over the past years, automation technologies have been evolving dramatically in terms of flexibility and user-friendly operation as for their use in assembly systems. Automated devices, especially industrial robots, have also become less and less cost-intensive. Prices have been reduced up to 50% in some cases. For this reason, the scope for rationalization and application in assembly is as promising as ever. 

Figure 12 Layout of a Flexibly Varying Assembly System.

Figure 42 Final-Assembly Cell with Flexible Clamping System.

---