Especially for new designers, it is necessary and important to learn the guidelines to save cost for your first prototype PCB manufacturing
Design for Manufacturing and assembly are the integration of product design. The aim is to design a product that can be easily achieved and can be manufactured in a economic way. so there are some guidelines or tips which can be considered.
Especially for new designers, it is necessary and important to learn the guidelines to save cost for your first prototype PCB manufacturing.
The circuit board foundation, sometimes referred to as the base, comprises the substrate (or core) and the laminate. The substrate is the non-conductive dielectric material, typically chosen based upon the dielectric constant, dk. Laminates when used in conjunction with substrates provide the copper foil or surface material. However, laminates may themselves be used as core material in some board constructions.
Substrates are typically dielectric composite structures that are comprised of epoxy resin and paper or glass weave (sometimes unwoven), which may be supplemented by ceramics to increase the dielectric constant. Substrates are made to meet certain property requirements, like the glass transition temperature (Tg), which is the point where heat causes the material to deform or soften, and may be customized. However, there are a wide variety of standard substrates from which the majority of PCBs are fabricated. These include FR-1 thru FR-6, CEM-1 thru CEM-5, G-10 and G-11, Aluminum or insulated metal substrate (IMS), Polytetrafluoroethylene (PTFE), RF-35, Polyimide, Alumina and flexible substrates Pyralux and Kapton. FR-4 is by far the most commonly implemented of these substrates.
Laminates are manufactured under pressure and consist of cloth or paper layers and thermoset resin. Just as with substrates, laminates can be made to meet custom requirements or properties. Properties of interest for laminates include tensile and shear strength, the coefficient of thermal expansion, CTE, and Tg. Dielectrics commonly used for laminates include FR-1, FR-4, polytetrafluoroethylene (Teflon), CEM-1 and CEM-3. Also common are pre-preg materials FR-2 thru FR-6, CEM-1 thru CEM-5 and G-10.
Together the substrate and laminate define the basic electrical, mechanical and thermal circuit board properties that, when used in conjunction with an accurate board type, enable you to make the best selection of PCB material for your design.
Circuit boards may be classified in a number of ways:
The first three criteria above are poor candidates on which to base your selection as they are not based on circuit board material properties. While bendability and strength are good physical criteria, they do not provide guidance on your board’s ability to function as desired. Electrical functionality is based on PCB function, which makes it a good criterion for design-based circuit board material selection. According to function, PCBs may be classified as the following board types:
The board types above can be used to select the circuit board material best suited for your design.
For any designs for manufacturing, the important design principles or rules is to help the designer or developer reduce their cost or reduce the difficulty of manufacturing of the PCB, and here below are a listing of these principles. The following are some suggestions or tips for designers to make a cost-effectively printed circuit boards.
As a matter of fact, about 60%-75% of manufacturing costs of the PCB or other products (quality of materials, production processing, and products assembly, etc.) are determined by design decisions. so it makes the designs so important for your projects in a cost effective way.
Reduction of the amount of the parts or components is a good chances for reducing the manufacturing cost, less parts means less purchases, processing time, assembly difficulty, testing etc. It ease the processing process and in 90% it can reduce the assembly cost. In general, it reduces the level of intensity of all process related to the final finished product during its processing life.
The standard components are normally in stock and easily sourced. resistors, capacitors in 0603,0204, which are easily purchased in many different channels. Standard components are less expensive than custom-made items due to the cost in delivery, customs etc in custom-made components.
What’s more, the high availability of these components reduces product lead times. As we all know, it will charge tax for the customized components or imported components, and some are forbidden in local market, absolutely it will cause extra cost to your final products.
Some Tips on PCB Design for Cheap Manufacturing
Some designs are with special requirements, in very strange shape,with many slots or v cut lines, In general, excessive tolerance, surface-finish requirement, very small hole size, small track space, or heavy copper weight and so on are commonly found problems that result in higher than necessary production cost.
Select a good combination between material and design of fabrication process to minimize the overall manufacturing cost.
As stated above, there are a number of physical characteristics or properties that can be used to identify circuit board materials. These characteristics are important and may be used for in-depth substrate and laminate analysis. Additionally, they may be used as metrics for comparison, which is done below. In the following table, common substrates and laminates used to form the foundation of PCBs are compared according to dielectric constant (dk) and ability to withstand heat (Tg):
Circuit board material comparison
The above table does not list all possible combinations of circuit board materials. However, it does provide circuit board materials that can be used for standard and special PCB board types and can, therefore, help you make the best selection for your design. As previously mentioned, there are additional circuit board properties that you should include in an overall evaluation of a PCB material. This evaluation should be done in conjunction with your CM to ensure that your design requirements align with your CM’s capabilities.