PCBA industry is an industry with high degree of informatization in China at present. The general view in the industry is that ERP+MES+APS realizes enterprise informatization management. At present, large-scale enterprises have implemented ERP, and many enterprises have introduced MES system. APS is expected to be the next big import.
Why do I need to import APS?
The trend of manufacturing industry is small batch, multi-variety and customized production. APS is an important tool to improve production efficiency and customer service level.
APS’s help to businesses can be analyzed in both the long and the short term
Accurate long-term planning can improve material purchasing, reduce material inventory, reduce material shortage and improve on-time delivery rate
Accurately evaluate capacity and give reasonable and achievable delivery time forecast. Improve on-time delivery rate to avoid repeated delays and customer dissatisfaction
Make production and delivery plan in balance, balance production load and reduce material and finished product inventory
Provide more accurate long-term planning, so that enterprises can prepare early for future production. How many workers do we need to hire? Do you need to purchase equipment? Customized molds? Outgoing orders? These all need data to make basis, cannot rely on guess.
Reduce WIP: because software scheduling is more efficient, shorter WIP can be used. Manual scheduling. In order to cope with online anomalies and simplify planning changes, the method of increasing WIP between processes is usually adopted. WIP between processes is usually 12 to 24 hours. After using APS, the delay of working parts is shortened to 1-4 hours, which greatly reduces the number of WIP in process and shortens WIP.
Continuous and consistent maintenance of model data
Evaluability of the plan: when using APS scheduling, IE maintenance time, the system schedules according to the model, which is convenient for evaluation and efficiency analysis, and provides the basis for process improvement.
Don’t rely too much on employee experience and avoid scheduling errors
Respond quickly to changes in demand and avoid frequent firefighting plan switches
Optimize the plan to reduce emergency switching and improve equipment utilization
There are some common features and difficulties in the production scheduling of SMT. This paper takes PlanMateAPS as an example to show how AP systems deal with these problems
APS noun explained:
Model: the production scheduling requirements of the enterprise are described to the system in a data table, and the system is scheduled according to the model. The model consists of several sections
Products and BOM
Main resources: equipment and production line, main production resources. Production tasks are chronological on the main resource and cannot overlap.
Ancillary resources: tools, fixtures, manpower, etc. that constrain production.
Production process: product production process, each product goes through multiple processes, each process needs to select main resources and auxiliary resources.
Scheduling data: scheduling data are the orders and constraints that need to be completed, including customer demand, work order, inventory, work order form, etc.
Task: work order flows through each process on the process, arranged on the main resource, and forms a task (non-split) on each process.
The results of scheduling are shown in the gantt chart, where the vertical axis is usually the main resource and the horizontal axis is time. Each rectangular box is a work task. The arrows indicate the flow between the processes.
SMT scheduling requirements and solutions:
PCBA production processes generally include: radium carving (bar code engraving), SMT(single or double face), AI (horizontal, vertical), ICT (unscheduled connection, independent test to schedule), tin furnace (wave soldering, selective soldering, etc.), moulding (PCB cutting and molding), assembling and other processes. Each product process can be different, and constraints between the processes can be defined.
Typical SMT production process and equipment
In the PCBA industry, process time is usually partially overlapped, which is EE relationship in PlanMate, as shown below:
The system will plan the appropriate start and end time according to the production length of the process before and after.
Each product process in PlanMate allows multiple optional resources to be defined, resource priority can be defined, and system scheduling selects resources according to priority.
As auxiliary resources in PlanMate, steel mesh, fixture and workers are first defined in the model. The list and quantity of auxiliary resources should be defined for each product process. When scheduling, the system will meet the constraint conditions and not exceed the quantity of resources. Example:
There is only one row of steel mesh, only one line