Advantages and Disadvantages of variant Process Planning

Advantages of the variant process planning approach include:

• Efficient processing & evaluation of complicated activities and decisions, thus reducing the time and labour requirements.
• Standardized procedures by structuring manufacturing knowledge of the process planners to company's needs.
• Lower development and hardware costs and shorter development times. This is especially important for small and medium-sized companies whose product variety is not high, who have process planners and are interested in establishing their own process planning research activities.

Therefore, variant systems can organize and store completed plans and manufacturing knowledge from which process plans can be quickly evaluated.

The obvious disadvantages of the variant process planning approach include:

• Maintaining consistency in editing is difficult.
• Adequately accommodating various combinations of material, geometry, size precision, quality, alternative processing sequences, and machine loading among many other factors, is difficult.
• The quality of the final process plan generated depends to a large extent on the knowledge and experience of the process planners. This dependence on the process planners is one of the major shortcomings of the variant process planning approach.

A number of variant processes planning system have been built up. One of the most broadly used systems is computer-aided process planning, built by McDonnell-Douglas Automation Company under the direction & sponsorship of Computer-Aided Manufacturing-International (CAM-I). This system might be used to generate process plans for prismatic, rotational and sheet metal parts.

The other popular variant process planning system is MIPLAN, developed in conjunction with the Organization for Industrial Research (OIR) and Genera Electric Company (Hourzeel, 1976). The MIPLAN system accommodates both rotational and prismatic parts and is based on the MICLASS coding and classification system for part description. A very comprehensive group technology based system developed by OIR is called MULTI-II. It consists of a number of task-oriented modules including :

• MultiClass II for group technology classification and retrieval
• Multigroup II for group technology analysis
• Multitrieve II for design retrieval
• MultiCats II for automated time standards
• MultiTrack II for tool tracking and inventory control