Between the MRP there are two kinds of differences, the usage and design differences.
The MRP design profile points out that it has high production flexibility, there is a high degree of order tracking. This system needs high data accuracy and lots of computer use. As well there is high schedule flexibility and a changeable organization of the shop floor.
About the usage features, we can say that the production lead time is very long and the production batch size is large. This system is focus in the labor resource efficiency. The inventory levels with the MRP are large and the set-up tine is averaged. | Area | MRP | JIT | OPT/TOC | BAM | Design Features | Production flexibility | High | Narrow range | High | High | | Order tracking | High degree | None | Fairly high | Low | | Data accuracy | High | None | High (limited areas) | High (limited areas) | | Computational needs | Lots | Minimal | Some | Some | | Scheduling flexibility | High | Poor | Good | Good | | Shop layout | Flexible | Restricted | Flexible | Flexible | Usage Features | Production lead time | Very long | Very short | Medium | Variable | | Production batch size | Large | Small | Vary | Smaller | | Resource efficiency focus | Labor | Materials | Bottleneck | Constraint | | Inventory levels | Large | Minimal | Medium | Medium | | Set-up time | Averaged | Minimized | Adjusted | Minimized |
Just in Time * It seems to be the least – cost production control: Reducing inventory levels and reducing manufacturing lead times. * It is a repetitive process. JIT is a very product inflexible, highly repetitive process. * It works with production orders of the same size (KANBAs) * It was created focus on getting the materials in and out of the production line as fast