The global competition in the field of manufacturing technology is increasing day by day. Engineers are finding ways to come up with the solution that can greatly decrease the cost of their product while maintaining or enhancing quality. In the domain of electronic and electrical engineering, Printed Circuit Boards (PCBs) are the core of hardware engineering and their cost greatly affects the overall cost of the product. Hence it is crucial that one find the cheap PCB assembler and PCB fabrication vendor that will provide good quality in reasonable price.
However it is observed that many suppliers providing cheap prototype PCB assembly will lower the quality and thus the user will suffer in terms of failure and noncompliance. There are different PCB assemblers providing different quotations to their customers, hence one should through check the portfolio and services along with terms and condition to save money cut down the PCB assembly cost. Hence the user must keep a good balance between cost and quality of PCB assembly. It is therefore necessary that customer must know it budget constraints and find assembler accordingly while in parallel optimize the circuit design or PCB layout at design stage so as to cut PCB assembly cost.
Now we will discuss some major techniques that can be used to cut PCB assembly cost while maintaining good quality.
1. Locate a reliable, professional, and “low-cost” PCB assembler.
Many PCB assemblers claim cost effective solution and services but they do not provide as they state. Hence first of all you should know completely about your project requirements and limits of your budget, then after this go for the detailed examination of a particular assembler / supplier. This will require effort in searching internet, visiting websites, reading blogs and checking comments and reviews of user but all this will help you in long run by locating a perfect assembler that meets your project requirements and budget constraints. You can then keep good ties with that assembler so that in more projects you can get more discount on your PCB assembly. While searching for PCB assembler you must keep following points in mind
Certificates:
A supplier or PCB assembler having certified documents showing his capability and capacity to meet your specific requirement is always reliable. Certifications like RoHS (Restrictions of Hazardous Substance) and ISO9001 (A international standard for QM) will always be useful in selection of PCB assembler. These certificates ensures that quality provided is up-to mark and that six hazardous materials are not used in the manufacturing of products and fabrication of PCBs.
Equipment:
While planning to choose the right PCB assembler, the equipment plays a very important role. The equipment like SMT components pick and place robots, high speed and accuracy will greatly increase the quality of PCB.
Component procurement:
At Rayming PCB, we deal lots of customers and we come to know that, time and money are the key points that every customers wants to save. This can be achieved by carefully selecting the PCB assembler that provides “Components Sourcing” services. Many times the customers do not communicate correctly with PCB assemblers which results in unexpected errors in components/parts selection. Hence if you want ensure good quality PCB in reduced cost, you have to find a PCB assembler that has links in local or foreign markets to procure cheap and good components and assemble them on PCB. In this way you will have time to concentrate on your project design.
Moreover, there are also other factors that can also help you to filter out PCB assemblers that do not fit the requirements. Some of these factors are lead time, MOQ (Minimum Order Quantity), shipping methods and obviously quotations and rates.
Just to mention a key point is the “labor”. Like in China, labor is not much expensive like in European countries and in US. So you can choose PCB assembler from China to greatly become cost effective while on the other hand parts cost are mainly dependent on US dollar rate. A slight fluctuation will not pose great effect in overall cost of PCB assembly.
2. Adjust the bare PCB layout design to cut cost
There are many parameters in PCB layout design that can be set by the user end to minimize PCB cost. These parameters are tested by the process name “Design for Manufacturability” DFM check. There are some PCB assemblers that provide this feature free of cost. You can choose that assembler to cut PCB cost.
Now we will discuss some of these parameters that can directly affect the cost of bare PCB. These are:
Number of Layers:
The higher the number of layers the higher the cost of PCB. It is that simple.
Number of Vias:
The higher the number of vias and smaller the diameter of via, the higher the cost of PCB will become. So while designing your PCB layout, carefully place each via either it is buried, blind or micro so that greater functionality of PCB can be obtained with minimum vias.
PCB Dimensions:
The smaller PCBs do not necessarily mean lower cost of PCB. Instead smaller PCBs are complex in nature and contains multiple layers that can increase cost. Hence a designer must carefully design PCB layout so as to keep balance in number of layers and PCB size. In case of SMT PCB size should be such that the PCB will fit exactly on pick and place machines of PCB assembler. The designer should have beforehand knowledge of its PCB assembler capability and constraints.
PCB Shape:
The shape of PCB can affect the PCB assembly cost. Usually the square or rectangular shape PCBs tend to be less expensive as compared to other special shape PCBs.
Surface Finish:
The quality of PCB is directly proportional to the electrical performance and ability of PCB to accept solder. Hence various types of finishing methods are used at PCB surface that include ENIG, OSP and HASL. This will restrict the solder pads from oxidization and increase quality. Choose the surface finish option that best fits your requirements.
These above discussed tips are based on our extensive experience in the domain of PCB fabrications and assembly. These points must be considered before selecting the right PCB assembler to cut cost and ensure quality.
3. Generate a Perfect BOM.
The very important thing while designing PCB layout is the generation of Bill of Material called (BOM). Many of us take it very lightly. But this BOM things is more important than Gerber generation.
The BOM is a file that a designer generates. The BOM files contains all the information necessary for the PCB assembler to procure components/materials and start PCB assembly process. An incomplete BOM can result in delays and improper components procurement that will result in time and money wastage. Usually the BOM must include, supplier name, manufacturer name, part number, quantity, reference designator, details of parts and package footprint details.
There are PCB assemblers that have their own form for BOM generation. If the designer fills that form and give to the assembler, than it will be helpful for assembler to understand and speedup the assembly process. It is also very important that the design engineer, must keep the “components replacement” in mind. And mention that replacement part number in the BOM. Many times when designing circuit, a particular IC package is discontinued and not further available in market, so giving a replacement option will help the assembler to avoid wastage of time finding the obsolete item.
4. Choose PCB Assembler having links with Components Wholesaler.
The cost of PCBA is directly and obviously proportional to the cost of components. As discussed above in paragraph “Component Procurement”, the customer/designer/user can rely on the PCB Assembler to procure electronic components that are cheap and readily available off the shelf. These PCB assemblers have links and PR to electronic components wholesalers, retailers and distributors and they can arrange very inexpensive components in large quantity like MOQ of 5,000 or 10,000 pieces. In such large amount some pieces can be counterfeit parts which can be ignored.
5. Adjust order quantity.
Another important aspect of cutting the cost of PCBA is the larger volume order. It is a common practice that when you order anything in large amount the cost per unit is low and when you order less the cost per unit will be high. The same is the case for electronic components like resistors, capacitors and ICs and same goes for bare and populated PCBs. So the cost is inversely proportional to quantity / order volume. Keep your quantity requirements in view and select the PCB assembler that fulfills your requirements. Considering prototypes development, in quantity of 1-10 pcs, the price per piece is obviously high and that cannot be avoided as compared to bulk order or larger volume order.
6. Lead Time.
It is commonly observed that the lead time shown by many assemblers are very attractive and on practical grounds it takes more time. Lead time means the time required by the assembler/manufacturer to ship your consignment to your destination. Hence you should ask the PCB assembler to let you know about the exact dates like starting of work date, date of payment, date of the components procurement and similar. In short if you want fast services you have to pay more and vice versa.
7. Never neglect inspection or test.
The inspection and testing like Automated Optical Inspection (AOI) and X-Ray inspections are very popular in PCB assembly process. These services are provided my some of the PCB assemblers and there are separate companies that only provide these services. So it will be very good if you select the PCB assembler that provides PCB inspection. However PCB inspection is very costly and it can apparently increase the cost per unit PCB, but in larger run this PCB inspection is useful.
These PCB inspection methods can assure high quality end product. In bulk manufacturing, The visual inspection, AOI and X-Ray inspection can be done few initial products/PCBs. This will help in identifying possible errors in the design and hence protect the whole lot or bulk to get faulty. In this way the design goes back to designer and rectified and then PCBs are fabricated and assembled in bulk.
The errors and fault types identified can be orientation and polarity errors in PCBs.
Conclusion:
It is always beneficial to keep long term business relationship with only one PCB assembler / manufacturer. Experimenting with many manufacturers cannot develop consistency in work. Hence try to develop strong mutual cooperation and trust to achieve better goals and give more business to your PCB assembler so in return you get discounted prices on your order. On the other side, if your existing PCB assembler is not fulfilling your requirements then it is time to look for suitable PCB assembler by rigorously following the steps as mentioned in this article.
