How to Ensure Punctual Delivery of PCB Circuit Board
Short lead time in PCB industry requires production management to control the whole production process from order to production. This requires ERP system to provide production scheduling and product management in order to ensure production lead time and customer response speed. Therefore, the most critical competitive advantage of PCB lies in the following aspects: engineering research and development, production management, material control, manufacturing, outsourcing processing and so on, especially WIP (in-process) control and management of on-site production management. If the WIP control is improper, there will be many mismanagement phenomena, such as loss, stagnation and rotation, inaccurate WIP quantity, delayed replenishment, increased number of wire changes, unclear delivery date, etc.
There are many kinds of PCB products, which are generally differentiated according to the number of layers, such as single sided PCB, double sided PCB, 4-layer PCB, 8-layer PCB, 10-layer PCB, etc. PCB products processing materials, process flow, process parameters, testing methods, quality requirements, etc., will be through the preparation of production instructions (MI) to the production department and external units to issue processing instructions.
For the 4 layer PCB and below products, the process is relatively simple, the production process card can be completed from the beginning to the end, without changing the process or changing the process card in the middle.
As for blind buried orifice boards with more than six layers of PCB, different inner and outer layers have different circuit diagrams, technological processes or process parameters, and different auxiliary equipment such as dies, films and so on are also used.
It is necessary to use different production instructions and related documents, and different production process cards will be made in the production process to control the production process and quantity of different inner and outer layers.
In the production process, the multi-layer PCB board will have different inner coding. In the production process, it must be distinguished by different coding, and different production process cards to control its production progress. PCB is the transfer and transfer of auxiliary products through the production of LotCard, commonly known as excessive. Because of the large number of on-line products and miscellaneous models, it requires simple, fast and fault-tolerant operation of over-counting, scrapping and repairing. In the process of implementation, I deeply feel that general ERP products are basically unable to deal with the business of coding, over-counting, scrapping and replenishing the inner and outer layers respectively.
Generally speaking, the more detailed the production plan, the richer and more valuable the information it gives, and the more difficult it is to calculate accordingly. The rougher the production plan, the less information and the lower the value. However, the process flow involved in PCB is often complex. The production of engineering data and MI for a PCB multilayer board with complex process often takes a long time to complete, and the delivery time required by customers is often very urgent. For the production management of PCB manufacturing industry, it belongs to the process-based manufacturing mode, so Run Card scheduling management technology will be adopted. Therefore, when scheduling, we must pay attention to the following characteristics of PCB production process:
Reflux processing
PCB processing is a representative process processing, which is different from the mechanical assembly processing mode. It mainly consists of one kind of raw material input, and then the auxiliary material input and processing technology are all processed around the main raw material. And because of the emergence of multi-layer board technology, the circumfluence production (i.e. repeating one or a certain processing process) in PCB industry is also more and more common.
Cutting and Pressing
Whether the front part of the substrate processing or the back part of the PCB board output, must experience a link is continuous cutting. In order to meet the needs of follow-up processing, the front section of the fabric is invested in a large amount of raw materials. In order to meet the needs of follow-up processing, it will be continuously cut into a reasonable size for follow-up processing. The other process is pressing. Whether the front processing of the substrate or the back processing of the multi-layer plate, the pressing work needs to be carried out, that is, two plates with the same area and shape are pressed together, especially in the case of multi-layer plate pressing.
For the characteristics of cutting and pressing, that is, how many raw materials are needed to process a certain number of finished products, the number of large plates is converted into the number of small plates, and the input of raw materials is calculated accordingly. But in the case of waste/waste, combined with the proportion of father and son, sometimes the workload of PCB plant will increase and the process is not smooth and incoherent.
Monolithic scrap
Unlike the scrapping of the assembly industry, the scrapping of PCB includes not only scrapping (excluding scrap products), but also so-called monolithic scrapping. The reason is that the pressing process is usually carried out for the board, a board will generally produce a different number of final monolithic products. When a defect occurs in the pre-pressing process, resulting in a poor quality on a single panel A or B, the manufacturer can not simply discard the board, but continue to use the material, but will record a single scrap quantity for the single panel.
For example, a large plate A can be eventually cut into 16 pieces of small PCB board, and the current processing process due to process problems, resulting in a point on the board damage, so the batch of processing results in the scrap number of large plate is 0 (no scrap of the whole piece), and single scrap is 1. This amount will be accumulated backwards along with the process flow for production statistics and final product output. At this time, it should be noted that the number of scrap monolithic will be inherited by double-decker after passing through the cooperation industry. Because when the single panel A and B are pressed together, the projection of the bad points on the A panel will also cause the bad points on the B panel, and the resulting double-decker panel will not be able to be used at this point, resulting in the same number of single scrap.
Finally, PCB industry is a kind of OEM industry. The design changes of products are very frequent and often change versions. Once the customer changes the version, the manufacturing instructions and process cards also need to cooperate with the changes, and even some changes may occur, some unchanged.
