An old saying goes in manufacturing: "Cost, quality, and delivery: pick two." Is that always true? Actually, manufacturers can create a lower-cost, high-quality product with reduced lead time—even for complex products such as printed circuit boards. In this post, we will discuss the importance of PCB components on the bill of materials.
To smooth the actual PCB fabrication process, PCB designers must work closely with their manufacturers as well as component suppliers. The page regarding the BOM is between customers and manufacturers should be exactly the same, so each component needs to have comprehensive documentation: manufacturer and manufacturers’ part number, a quantity per assembly, a reference designator, and a part description. The last must include general information like commodity type, package size, and a component footprint.
Designers should select components for availability first, then unit cost, and then package size. Standard component packages from standard manufacturers will tend to have the highest availability—use these whenever possible.
SMT components tend to be smaller and less expensive, and can be mounted to both sides of a board, increasing flexibility in design. For all the most rugged applications, SMT components should be considered before through-hole components.
Everybody wants to buy things with the best price. In this post, we will tell some tips to save your PCB manufacturing cost as much as possible.
Equipment Capacity: Factories should provide you with the capacity calculations of each piece of equipment and for each step in the manufacturing process. This should focus on the equipment to produce your product only. You should have a written process flow about which equipment they will be used. This will flag you which machines need to pay for. For example: If your products don’t need a clean room, then fabricating in a clean room is a waste of money.
Equipment Maintenance: Factory should have a clear maintenance plan for all the machines which is posted on the machine. You should select a machine on the line which will produce your product then review the maintenance schedule and sign off by the maintenance engineers. If the factory has a tool shop then ask for the tool maintenance records. For example: A stamping tool should have a record from the tool maker for every time it is shimmed, sharpened or punch is replaced. Another reason to check the tooling is because sometimes you will find the supplier is not making your parts or part of the production is being outsourced.
It is critical to visit the production line prior to mass production.
SMT technology is largely used during the fabrication process of electronic devices. It is able to generate mass-produced, smaller, lighter boards with fewer fabrication steps and less setup time, reducing cycle times and fabrication complexity. That’s why PCBs use SMT technology are less expensive and more cost-effective for use in electronics or other products. However, things have two sides; EPCB lists some disadvantages about SMT board construction as follows:
1. Construction of prototypes or manual fabrication is more difficult.
2. Board repair of components is more challenging, not easily done by manual means.
3. Use breadboard materials for construction are not available for SMDs.
4. SMD construction is not suitable when there are requirements for high power or large high-voltage parts.
5. Thermal cycling potting compounds can damage SMD solder connections.
6. Capital outlay for SMT equipment is considerable.
7. SMT design requires more advanced skills than traditional through-hole methods.
8. Not all components are available as SMDs. In such cases through-hole design will remain the only alternative.
The PCB is the centerpiece of a design. To reduce PCB fabrication cost, here are some specific techniques to keep in mind:
A blind via connects an outer layer of the PCB with exactly one inner layer. A buried via connects two inner layers, and contains no contact with outside layers. These techniques are characteristic of high density circuit boards, and add greatly to their expense.
A minimum of three board fiducials shall be provided located in a triangular pattern as far apart as possible on the PCB. Fiducials located near the corners of the PCB are preferred.
Aim for the smallest board dimension and the fewest number of layers. Minimize the amount of gold and copper.
Allow the board fabricator to design the multi-up pallet for smaller boards.
Ensure that the fabricator knows the material specifications of the PCB laminate by indicating this in the fabrication drawing. For RoHS assemblies, the laminate must have a Tg greater than or equal to 175 degrees C.
Not every fabricator will be able to replicate a particular laminate stack-up. Up front, define the minimum trace width, the minimum distance between traces, and the smallest hole diameter.
Placing fiducials on the top copper layer of a board allows pick-and-place vision systems to detect boards more accurately.
To be continued…
SMT technology is largely used during the fabrication process of electronic devices. It is able to generate mass-produced, smaller, lighter boards with fewer fabrication steps and less setup time, reducing cycle times and fabrication complexity. That’s why PCBs use SMT technology are less expensive and more cost-effective for use in electronics or other products. However, things have two sides; EPCB lists some disadvantages about SMT board construction as follows:
1. Construction of prototypes or manual fabrication is more difficult.
2. Board repair of components is more challenging, not easily done by manual means.
3. Use breadboard materials for construction are not available for SMDs.
4. SMD construction is not suitable when there are requirements for high power or large high-voltage parts.
5. Thermal cycling potting compounds can damage SMD solder connections.
6. Capital outlay for SMT equipment is considerable.
7. SMT design requires more advanced skills than traditional through-hole methods.
8. Not all components are available as SMDs. In such cases through-hole design will remain the only alternative.
The PCB is the centerpiece of a design. To reduce PCB fabrication cost, here are some specific techniques to keep in mind:
A blind via connects an outer layer of the PCB with exactly one inner layer. A buried via connects two inner layers, and contains no contact with outside layers. These techniques are characteristic of high density circuit boards, and add greatly to their expense.
A minimum of three board fiducials shall be provided located in a triangular pattern as far apart as possible on the PCB. Fiducials located near the corners of the PCB are preferred.
Aim for the smallest board dimension and the fewest number of layers. Minimize the amount of gold and copper.
Allow the board fabricator to design the multi-up pallet for smaller boards.
Ensure that the fabricator knows the material specifications of the PCB laminate by indicating this in the fabrication drawing. For RoHS assemblies, the laminate must have a Tg greater than or equal to 175 degrees C.
Not every fabricator will be able to replicate a particular laminate stack-up. Up front, define the minimum trace width, the minimum distance between traces, and the smallest hole diameter.
Placing fiducials on the top copper layer of a board allows pick-and-place vision systems to detect boards more accurately.
To be continued…
