Cellular layouts

Group technology—An engineering and manufacturing philosophy that identifies the physical similarity of parts (common routing) and establishes their effective production. It provides for rapid retrieval of existing designs and facilitates a cellular layout. 

Step 2 Converting to a Process-based Layout. The next step involves converting the production area to a cellular layout by rearranging the process elements so that processing steps of different types are conducted immediately adjacent to each other. For example, machines are usually placed in U or C shape to decrease the operator s movement, and they are placed close together with room for only a minimal quantity of WIP. The process flow is often counterclockwise to maximize right hand maneuvers of operators. 

Several techniques are important to facilitate effective cellular layout design and production. 

Right-sized equipment. Conversion to a cellular layout frequently entails the replacement of large equipment (sometimes referred to as monuments) with smaller equipment. Right-sized equipment is often mobile, so that it can quickly be reconfigured into a different cellular layout in a different location. In some cases, equipment vendors offer right-sized equipment alternatives, and in other cases companies develop such equipment in-house. A rule of thumb is that machines need not be more than three times larger than the part they are intended to produce. 

Cellular layouts can pose safety challenges, however. It is important to ensure adequate egress is maintained in the cells and that equipment can be secured if needed. Also keep an eye out for tripping hazards during the design phase for example, the location needs to be such that cords can be secured or placed out of the way. 

In many cases the cell design is "all or nothing , in that all parts are grouped into a cell, and there is no allowances for prioritizing changes from a functional layout to a cellular layout. 

Machine cell justification is a trade-off between the benefits of manufacturing in a cellular layout versus the costs associated with under-utilization and movement of equipment. Under-utilization of equipment is created by the assumption that none of the operations required for a part family can be performed outside the cell (no inter-cell movement). This results in the purchase of additional equipment to satisfy the machine requirements of those parts not produced within a cell. The benefits used in the MAPFLO analysis are inventory reductions, scrap and rework reductions, and reductions in material handling. Reduced setup times due to design similarities in a part family are offset by an increase in the number of setups... 

This ability of team workers to assist each other is greatly enhanced by locating the team s operations in a layout that facilitates sharing the work. Group technology layouts or cellular manufacturing layouts complement the use of teams. These types of layouts allow team workers fast access to different parts of the process, so there is little delay in switching from one task to another. 

Fig. 5. (a) Classification of PVC grains and (b) typical cellular PVC grains—layout as in Figure 6a From Ref 13, courtesy of Elsevier Applied Science Publishers. 

Figure 9.26 illustrates the four stages of escape in a common traditional building layout. Whereas Figures 9.27 and 9.28 show how the various stages of escape in open planned and cellular planned internal layouts are applied. 

Cellular manufacturing layouts and autonomation can free workers to focus more closely on equipment maintenance (TPM), reducing the hkehhood of accidents. Additionally, new equipment may need to be purchased, which may be safer (or may not), but either way impacts safety. Additionally, the shift in chemical uses and locations can impact needed protections, exposure, and training. 

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