The mystery of low-cost PCB Panel design
2018-11-23 21:18Writer: qyadminReading:
PCB panel is a combination of several PCB unit boards with various possible connection modes, as shown in the figures below.
Typical, when a hardware designer a PCB, he considers the electrical signal and the layout of the components on the circuit board, focusing on the function of the product. Less consideration is given to PCB manufacturing and assembly. To make PCB production smooth, especially for SMT assembly, special attention should be paid to PCB assembly design.
I. Purpose and Significance of the Panel
1. Improve SMT assembly efficiency. The more PCB unit boards a panel contains, the less the average time for a single PCB to transfer and run in orbit, and the higher the utilization rate of pasting equipment, which can greatly improve the production efficiency of SMT.
2. Improve the quality of SMT production to prevent bad problems in the production process. PCB components distribution density is big, some components such as edge connectors outline may be beyond the edge of PCB, before the completion of the reflow soldering and the wave soldering, all these components are removable, so you need to have additional break-away rails and increase the area of the whole panel, to prevent these edge components influenced by external factors and reduce the assembly quality.
3. Easy to operate and prevent damage. The panel is also designed to facilitate the operation of the production line. The assembly of a PCB needs to go through many steps. The finished PCB or semi-finished PCB should be put into the turnover box and these PCBs would be transferred, stored and transported by the turnover rack. These operations require a specific process edge to prevent component damage on the PCB board.
II. Types for Panel Design
No matter what kind of PCB, it usually needs to adopt a panel structure. However, there are many ways to design the panels. Sometimes it is difficult to determine which way to use and the number of panels.
PCB panels are usually made in many ways, such ABAB, ABCD or AAAA. It is not easy to generalize which type of panel is good, which needs to be determined by considering the density and distribution of components on the board as well as the configuration of equipment. All these types of panels have their own advantages and disadvantages.
Combination panelization (AAAA):
As a common method, AAAA combination panelization is the most massively-used panelization method. Lots of advantages contribute to its present leader status. Firstly, this type of panelization is compatible with all circumstances, with no considerations to be taken of SMT manufacturers fabrication conditions and product combination. Secondly, order panelization isn't influenced by manufacturing number, allowing the maximum number of panels effectively based on the maximum number of SMT equipment so that it leads to highest manufacturability among all combinations of panelization. Thirdly, printing quality won't be decreased due to the influence of pad orientation of special components in the process of printing stencil design. Finally, operating difficulty won't be accumulated owing to the different orientations of panels in each run of the whole procedure.
Combination panelization (ABCD):
This type of panelization features some advantages. Firstly, it is suitable for the manufacturing model containing multiple PCB combinations in products like household appliances and toys. Secondly, it is beneficial to production efficiency improvement and cost shrinking so that products turnover and semi-finished products stock can be greatly reduced, which is capable of meeting customers' requirement of fast shipment.
However, this type of panelization features disadvantages as well. On one hand, in the process of assembly line work, products differentiation is difficult to manage, leading to product chaos. On the other hand, when one board among the combination suffers bad quality or even scrap, the overall number of panelizations will go down and it's bad for manufacturing remediation.
III. Factors Which Affect the Price of Panel:
1. The fee of substrates and the film. For the sample order, we PCBWay defaults if the panel of size less than 100*100 mm shouldn’t contains the number of single PCB which exceeds 10 pieces. For example, if the customer places a sample order, his requirement is that the size of the panel is 100*100 mm, but 14 single boards are included in the panel, then we need to charge the substrate fee and the film fee.
2. The number of drilling holes. If the number of holes required by the customer exceeds our prescribed amount, the fee will be increased. For example, by default, the number of holes should not exceed 500 for each area of 100*100 mm. If the number of holes required by the customer is more than 500, then we will increase the cost according to certain rules.
3. The number of V-cutting. If the number of V-cutting required by the customer exceeds our prescribed amount, the fee will be increased. For example, by default, the number of v-cutting should not exceed 10 for each area of 100*100 mm. If the number of v-cutting required by the customer is more than 10, then we will increase the cost according to certain rules.
4. Electrical testing. As for the electrical test, different orders will have different test charge standards. If the standard is exceeded, then the cost will increase.
5. Emergency fee. Under normal circumstances, our products will arrive at the customer within 3 days after the customer pays the order, but if the customer needs to be urgent, we will charge a certain fee.
The above is mainly about the designs of rigid PCB panels. For flexible PCB, the production mode may be different, and the requirements of panels will be different. Anyway, panelization is designed to satisfy the requirement of SMT assembly and the security operation, after the completion of the assembly or to return to the veneer assembly of finished products, so whether hard or soft board, the panel design should not only consider the assembly strength requirements, also want to consider the points of production after the completion of the panel request, can meet these two points, is good panel design.