Not to mention that discrete mode of production of electronics, automotive industry production patterns and processes of chemical, pharmaceutical industry in the basic mode of production on the huge difference, even if the same electronics, automobiles, or belong to the pharmaceutical, chemical different enterprises, and their mode of production the details are still very different. An ERP system, maintaining the status quo were all able to accept such a difference? Technically very difficult! Had for each industry to develop a specific product version, it is necessary. But the industry, the enterprise version to be able to sit back and relax inside it? Large version of the industry in general are still unable to meet the industry-specific differences in the details of categories of businesses, such as the pharmaceutical industry is subdivided into 'drug agents' and 'API', differences in production methods or large, should be subject to development of more sub-version of a small category. However, different enterprises in the same category also has its own production characteristics for the secondary development of different enterprises would be analogous to the production of the enterprise features of each writing process. Not to mention that any changes to production systems must be invested heavily in human resources, software companies can not accept frequent and complex secondary development requirements, not to mention a change in production process, once the software is still very difficult to deal with! A lot of the production process for each Ge Jitian will be changed, while the software vendors can not rewrite the code every day. Strain should only requirement is to reduce the company - the production process modeling and the actual approximation, probably almost on the list. The key is users will not be satisfied? Still using no up, losses too great. So, apart from some institutions of the theory of the researchers, the current domestic ERP vendors have not yet crossed the detailed production process modeling attempt this first threshold.
The establishment of production model, so that the software companies to accept the detailed production process, this is indeed a lot of trouble, but not impossible to accomplish, the real difficulty is the next step: According to the model and the production of requests are detailed operating plan, which is detailed production scheduling. The real bottleneck in ERP technology took place here.
For detailed production scheduling result is that 'production planning', is for each person for each device production resources work plan. Operation plan must be met in the production process can not have the slightest error. First of all, between the processes must meet specific logical relationship, and require that certain procedures must be continuous, at the same time, or interval, etc., this is an operational plan for the most basic requirements. Second, the operations plan must satisfy the resource capacity constraints, a resource at a time could only do one thing, production scheduling can not have the resources to conflict. Finally the operating plan must meet the material supply constraints, there is no production of raw materials can not start. In other words: work plan must meet a variety of complex constraints. TOC Theory of Constraints has long been, just need more advanced algorithms and mathematical theory, in this regard the need for long-term investment will pay off. Therefore, domestic theoretical circles, little of this research.
With the theory, calculated in accordance with TOC plans to meet the production process requirements is not on the list? Unfortunately, this is far worse. Now we are in a hypothetical example to illustrate.
An ERP production scheduling system, it is well accepted by all the production details of an enterprise, and calculate a set of production scheduling, print a copy to all the productive resources into the organization of work of the operational plans. Now, by an experienced teacher to the old scheduling decision is not the ERP planning system can be used, he will do?
First, he will go check the timing of each process to see if the order between them and logical relationship is not consistent with the logic of production process requirements; secondly, he will observe the planned arrangements for each resource is not a reasonable Is there a time to do two live this conflict situations; the last time he wanted to see in the plan be able to supply the materials. These are no problem, he must admit: This plan is a 'feasible' plan, and that is the basis of this plan will be able to complete production tasks.
However, there is a critical thing, the old scheduler according to their customary practice of the division, but also developed an operational plan by hand, he plans a contrast to these two and found a problem. The plans can be hand-eight hours to complete all the work, while the computer program takes 9 hours. Or you can manually program the completion of a computer program 8:00 to 9:00 spots. The reason is: The computer processes the order of a few arrangements, while possible, but unreasonable, but the old divisions under long-term experience in scheduling has long been clear that the arrangements at this time what procedures should be first, after which, and which in parallel is better, the results can be completed in less time plan. This is an optimal arrangement, but the computer did not find this method of organization, so the computer is given a 'viable', but 'bad' program! Ideal computer should automatically calculate a better plan than the hand is more optimized scheduling program outcomes to guide people how they work. This software, in order to reflect the 'enterprise resource planning' power. Otherwise, it can not meet the optimal scheduling of production in the enterprise ERP or can not be replaced by hand.
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