SMT assembly starts from solder paste printing that aims to place a proper amount of solder paste onto pad on which components will be soldered. The quality of solder paste printing is mainly determined by three elements: solder paste condition, scraping angle and scraping speed.
According to the customer’s BOM list, the purchasing department of the processing firm will make an inquiry, including PCB bare board, electronic parts, etc. Sometimes, PCB assembly costs and engineering costs will be included in purchasing quotation. It needs to cover about 5% of the material loss when purchasing the components, due to the reason of material loss, like resistance and capacitance disk loading material and SMT chip. For the small batch of PCBA, engineering costs are usually covered in quotation, including the costs of processing file, stencil, Changing SMT line etc.
High quality can never be obtained by SMT assembled PCBs unless solder paste is properly stored and applied. Solder paste has to be stored in a fridge to be kept in a low temperature and its temperature should be recovered to room temperature prior to its application on SMT manufacturing line.
1. PCB Board Size and Number Layers
The bigger the PCB board, the more the assembly cost would be. So we need to better utilized the board the save money. And a higher number of cooper layers would also raise the PCB production cost, so complex PCB design would definitely require more layers assembilies which need more cost.
2. PCB Board and Component Material
If you are cooperating with electronic contract manufacturers like us, you can tell us if you agree on using alternate brands of PCB materials with similar traits, so that we can use the PCB materials in stock instead of buying the specific assembly materials.
3. PCB Board Design Complexity
We always need to try our best to minimize the complexity of our PCB layout, because extra work on the PCB board would always raise the cost. So we need to fulfill our purpose and reduce the PCB layout complexity as possbile as we can.
4. PCB Assembly Order Volume
Larger quantities result in lower PCB assembly costs due to encomies of scale. So we would prefer high volume of PCB order so that we can save our time on setting it up. Most companies would offer you a good discount if the PCB order volume is big enough. So if you need 10,000 PCB assemblies in one year, it’s best to order them for one time instead of separate for mulitple times which would cost you more money.
5. PCB Assembly Lead Time
Whenever you ask us what’s the cost of the PCB assembly, the first question from us is what your expected lead time is. As we all know: Time is Gold. So a quicker turnaround time means the higher cost. Since the PCB manufacturers need to invest more resources to meet your requirements.