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Recently, I visited many companies intensively to understand their needs for APS. At present, most of these companies have launched ERP systems. Then you may have doubts, there is also a planning module in the ERP system, so why do companies need APS? Let’s talk about the uniqueness of APS today.
As we all know, the model of ERP plan management is still MRPII, and its planning method still uses MRP and MPS to calculate material demand. This kind of production planning method that appeared in the 1960s using the simplest logic and with the help of computers according to the product BOM and process flow, obtained a production planning method that can be applied under general stable production conditions, and has been popular for nearly 40 years. However, the MRP method has the following obvious weaknesses:
- Defects of the BOM model
Product BOM (PBOM) only shows the affiliation and quantity composition of products and materials, but does not reflect the amount and location of materials used in which process, which may lead to excessive preparation of required materials in advance and cause unnecessary inventory costs.
- fixed lead time
The production lead time is affected by many factors and cannot be preset, such as batch size, production capacity, whether parallel movement, etc., so the production lead time is essentially the result of planning and scheduling.
- Unlimited ability
MRP performs all work on the assumption of unlimited capacity. In order to avoid unfeasible plans, manual adjustments are made through capacity demand planning (CRP). The gap between planning and execution is too large to match the resource capacity and production line rhythm of the production workshop. .
- Difficult to respond in real time
In the actual execution of the workshop, once the production order is not executed according to the plan or the plan has to be adjusted due to abnormal circumstances, the master production plan MPS needs to be adjusted manually. This manual closed-loop MRP is not an automatic closed-loop at all, and cannot adapt to the multi-variety and small-batch production mode. Changeable features.
- Resources cannot be monitored and scheduled visually
Managers cannot interact with the Gantt chart, and the results of adjustments are not displayed intuitively and in real time, and the plan (batch process) must be re-run to be reflected.
- Unable to do "what-if" analysis
The factory will inevitably have accidents such as insertion, cancellation, equipment failure, and material shortage. It cannot provide "What-if" scenario analysis and simulation functions such as pre-planning, simulation, comparison, and analysis.
- Algorithm optimization and multi-objective optimization are not supported
Decisions such as order priority, order merging and splitting strategies, process processing priority, and resource priority all use specific rules, which cannot achieve optimal planning and scheduling, and do not support multi-objective optimization of KPIs, such as ensuring order delivery rate Under the premise, how to minimize the cost of replacement.
- Unable to promise a reasonable delivery date
Essentially, the plan is inaccurate caused by the unlimited capacity of MRP.
Facing the changing international market, the above-mentioned shortcomings of MRP are becoming more and more prominent, and the planning model of traditional ERP is increasingly unable to adapt to the changing needs of enterprises. Advanced Planning and Scheduling (APS) came into being.
APS is an advanced planning and scheduling tool based on supply chain management and constraint theory, which includes a large number of mathematical models, optimization and simulation technologies, and has synchronous, real-time, and constraint-capable simulation capabilities for all resources,
including Factors affecting planning, such as materials, equipment, personnel, suppliers, customer demand, and transportation, optimize both long-term and short-term planning.
The core problem that the traditional APS solves is the executable of the production plan: a production plan that considers constraints, including material constraints, capacity constraints (machines, molds, tooling, etc.), human constraints, and process requirements constraints. This is also the " advanced " aspect of APS compared to MRP .
The "Smart Planning and Scheduling System" (SPS System) independently developed by Shangjian Intelligence adopts deep reinforcement learning , operational optimization algorithms and other technologies, which can independently improve decision-making capabilities, greatly improve various production indicators, and realize minute-level planning and scheduling .
In addition to the plan's executable problem, Shangjian SPS also solves the optimization problem of the production plan : under the consideration that the constraints meet the necessary conditions for production, comprehensively consider the highest order delivery rate, the largest production volume, the highest equipment utilization rate, the most balanced resource input, The most reasonable inventory and other issues, the pursuit of multi-objective optimization of order delivery rate, production cost and production cycle.
Therefore, compared with ERP, Shangjian SPS has the following characteristics:
- Add Manufacturing BOM
Shangjian SPS not only considers PBOM, but also establishes the relationship between materials, machines, molds, manpower and other resource elements and processes, so as to add more actual constraints to the model and increase the feasibility of planning and scheduling.
- variable lead time
Shangjian SPS supports a variety of strategies to shorten the lead time, including work order division, work order merging, process parallelization, smooth flow, adjustment of equipment, setting sequence, etc., to shorten the production cycle or changeover time.
- limited capacity
Shangjian SPS takes factors such as production capacity, materials, and resources into consideration, and carries out process-level operation planning with limited capacity , limited materials , and accuracy to the hour, minute, and second .
- Agile Plan Roll
Shangjian SPS can collect dynamic situations such as processing progress , equipment failures , material supply exceptions , and quality problems in real time , and automatically add relevant constraint rolling plan schedules.
- Support drag-and-drop Gantt chart interaction
Shangjian SPS supports drag-and-drop Gantt chart interaction, and automatically changes the affected tasks based on constraint propagation to ensure that the plan is adjusted.
- Support "What-if" simulation analysis
Shangjian SPS supports fast calculation of scheduling and comparison of multiple schemes under different input conditions, helping planners to make correct decisions.
- Multi-objective optimization based on operations research model and AI algorithm
Shangjian SPS uses a deep reinforcement learning algorithm and the powerful computing power of a computer. By simulating the occurrence of various situations, it can learn rich planning and scheduling strategies within a limited time. This is like AlphaGo Zero playing Go. Play chess or even play chess against yourself to continuously improve your level. The learned knowledge can be stored for reuse, achieving the goal of " offline learning, online application ", and achieving a fast and good result that takes into account the solution time and solution quality.
Shangjian SPS also supports the configuration of different target preferences , which can achieve more optimized results on the focused target, greatly improving the flexibility of decision-making.
- Fast and accurate commitment to delivery
On the basis of limited capacity and limited materials, through intelligent optimization strategies (such as smooth production, intelligent splitting, target balance, etc.), optimize the order production cycle, reduce production costs and inventory costs while ensuring delivery rates, and quickly answer customer inquiries Period, improve customer service level.
The relationship between APS and ERP is both related and different. One is the connection, APS is the supplement and optimization of the ERP planning system ; the other is the difference, the theoretical basis of APS is "constrained optimization theory"; ERP relies on MRP or MRPII, mainly based on The competency principle also has key differences in planning, as follows:
| rule | ERP | APS |
|---|---|---|
| Available to Promise (ATP) | static | dynamic |
| Plan Materials and Capabilities | order | at the same time |
| plan time period | section | continuous |
| organizational plan | Plan by function | Integration plan |
| direction of plan | unidirectional | two-way |
| Allocate supplies to customers | Can't | Can |
| constraint type | soft constraints | Hard and Soft Constraints |
| Manufacturing lead time | fixed | flexible |
| simulation ability | Low | high |
| planning speed | slow | quick |
| planning algorithm | Addition, subtraction, multiplication and division | Rules, mathematical programming, intelligent optimization, machine learning, deep learning, etc. |
APS is not a replacement for an ERP system. APS needs a closed-loop integrated system such as ERP system, which is only limited to the field of planning and decision-making . APS needs to extract basic modeling information such as production route, raw material supply, inventory situation, order situation, etc. from ERP to execute plan optimization activities. Then, import the optimal scheduling plan into the ERP system for operation. Therefore, APS is a decision-making system based on the ERP system (of course, APS can also manage basic data through its own data center) . APS cannot completely replace the ERP system, and the planning model used by the ERP system cannot meet the current needs. Changing the ERP planning model will cause changes in the entire system structure. By using the integration of APS plan and ERP system, the ERP plan can be optimized without affecting other ERP processes.
This also answers why enterprises need APS when they have ERP.