The importance of DFM in the production process of SMT patch assembly
According to many years of electronic production experience in Dongguan SMT processing plant, the design cost of the product accounts for more than 70% of the total production cost. The costs incurred during the specific production process, such as operating expenses, materials and labor costs, account for only 20% of the total production cost. %about. Therefore, the control of electronic production costs largely benefits from the effective control of design costs.
Circuit design engineers design circuit diagrams based on innovative ideas and planned product functions, but they don’t know much about production. If the design documents are directly taken to the production line as the only reference, then factors that are not conducive to the smooth progress of production will appear, and even cause a large number of scrap products. The result of this is of course terrible, so it is necessary to carry out design for manufacturability (DFM) before the SMT patch assembly production process.
What is DFM?
DFM is a part of the circuit design, the purpose is to optimize the design details to make the assembled PCB (printed circuit board) produced at low cost and more efficiently.
For patch assembly PCBs, DFM is usually carried out by the assembly manufacturer’s engineers before production, because the assembly manufacturer’s engineers have more say in production matters. They are more familiar with the production process of patch assembly and understand that even if it is very The positive significance of small design improvements for high-quality production is more obvious in mass SMD assembly products.
DFM can be applied to PCB bare board production, and can also be applied to SMD assembly production. The DFM inspection items in PCB bare board production include:
a. Board thickness;
b. Board size;
c. Wiring;
d. V engraved;
e. Line distance/line width;
f. Plate hole;
g. Surface treatment;
h. Gold finger;
i. Jigsaw, etc.
The DFM inspection items in SMT patch assembly production include:
a. Pad design;
b. Components direction;
c. Spacing of components;
d. Reflow soldering;
e. Optical positioning holes, etc.
Is DFM inspection important in SMT patch assembly production?
The answer to this question is “yes.” To analyze this problem, we must first take a look at the purpose of the DFM inspection.
In short, the purpose of DFM inspection is to solve the problems that may cause defects in the production process before the formal assembly and production. Then, the patch assembly production can proceed smoothly, and the product output will also be greatly increased.
The advantages of DFM inspection are mainly manifested in three aspects: improving product reliability, reducing production costs and shortening production cycles.
• Improve product reliability
Improving product reliability is believed to be the common goal of all original equipment manufacturers (OEMs). DFM inspection can ensure the realization of the design function and ensure that the core elements that may cause production defects have been reasonably corrected before the formal production. The result of this is to improve product reliability. For example, some defects in the reflow soldering process are actually caused by improper pad design. If the DFM engineer optimizes the design before assembly and production, these reflow soldering defects will not exist.
• reduce manufacturing cost
In the process of DFM inspection, the patch assembly process is also one of the items of DFM inspection. After DFM inspection, some unnecessary production steps will be omitted, thereby reducing production and labor costs. In addition, as the production process is simplified, related tools, equipment, and labor are also saved, and costs are naturally reduced, which is especially obvious in mass production.
• Shorten the production cycle
The earlier electronic products enter the market, the more benefits they will receive. As discussed above, DFM inspection is conducive to the smooth production of products, the production and application time is reduced, and the production cycle can be shortened. In the patch assembly production process, once it is found that there are no production parameters, it is necessary to gradually adjust the production parameters in the next production until it reaches the product standard. With DFM inspection, these processes are greatly reduced, which greatly shortens the production cycle and has the opportunity to quickly enter the market for the final product.