How to Evaluate A PCB Manufacturer or A PCB Assembler
Many of us may have faced problem while finding a right PCB contractor for their project. This is because there are lots of PCB fabrication and assembly houses working drastically and constantly striving to improve their systems and processes. But you are obviously looking for a PCB contractor that can fulfill your demands. A PCB manufacturer and assembler having excellent experience and perfection in end product in the domain of mobile phone circuit board fabrication and assembly may not be able to give the same excellence in your desired requirements let’s say 3 phase Rectifier board fabrication and assembly. So being an OEM (Original Equipment Manufacturer) searching a right partner ECM (Electronic Contract Manufacturer) that can provide you what you desire is not an easy task. You must know what you want.
What are your needs and desires,you must have clear list of requirements that you would expect from your ECM. As PCBs are implemented in various industrial sectors like automobile, home automation, mobile phones, aerospace, defense, medical and many others, so it is highly important that you know your industry and you find a PCB contractor (ECM) that belongs to same industry. Like if you are not an OEM but a normal hobbyist or a student doing some experiments than you may not need a very long lasting PCB partner and you don’t need mass production of PCB either. You just need a few prototypes and for that you would do a basic research about different PCB suppliers and choose any one of them that best suits you.
However in the case of OEM, a company like Foxconn which is an ECM of the world renowned OEM named Apple Inc. is an example. Similarly those giant enterprises that are looking to expand their business worldwide, they search for a highly reliable Contract Electronic Manufacturer (CEM)alternately called as ECM. These OEM or ODM (Original Design Manufactures) are the ones which focus solely on the Research and Innovation perspective and their headquarters are in the country of origin. Their outlets i.e. factories or production lines and assembly lines are mainly in countries where the labor is cheap, electricity prices are low, overhead charges are low and where the world market or customers or population is high. These OEMs do a thorough research by looking deeply inside the selected few CEMs out there in the market. The key aspects of CEMs/ECMs that they analyze are 1- Product 2- Capabilities 3- Equipment 4- Component Procurement Sources 5- Services
1- Product:
The most powerful strategy to evaluate any ECM is through examination of their products. The end product is the indicator of a CEM’s capabilities, quality level, product value in the market, the industry it deals in and customer’s demands of that product by reviewing their customer’s feedbacks. The following are the main indicators of the product being developed by the CEM which are highly helpful for OEM to analyze and take decision.
For OEM before making any hypothetical perception about the CEM, it must take a look at ground reality i.e. “Quality” of the actual output of that CEM in the form of end product they make. There are already well known standards against which the quality of the product can be judged. These are
| Cpk | Process Yield |
| 0.5 | 86.8% |
| 0.8 | 98.4% |
| 1.0 | 99.7% |
| 1.2 | 99.97% |
| 1.33 | 99.99% |
1A1- Cpk Index: It is the measurement tool of the capability of process to make product that falls within the prescribed limits of the customer specifications. The Cpk index of less than 1 means the process is incapable to meet the requirements. The Cpk index of less than 1.33 means it needs some improvements in the process. The Cpk index of 1.33 or more means the process is capable and meets specifications limits. A typical Cpk Index chart is shown on right.
1A2- SPC: The Statistical Process Control (SPC) is the method of analyzing the statistical quality data collected in the form of product or process measurements or readings from various machines or instrumentation. The data is used to evaluate, monitor and control a process. This is also known as Statistical Quality Control (SQC).
1A3- Control Charts and Six Sigma:
The DMAIC (Define, Measure, Analyze, Improve and Control) based approach of using Six Sigma methodology in enhancing the product yield and to reduce discarding cost. This tool can be used to analyze any parameter within Upper and Lowe Control Limits i.e. UCL and LCL of PCB production run like any defect for example short circuit inside the inner layer can be plotted. Then the manufacturing process can be improved and then again this tool is run on statistical data to bring values with prescribed UCL and LCL. An example chart shown below is the quality improvement chart for PCB defects. Yet another strong statistical tool related to six sigma is Taguchi approach to attain higher six sigma level.
1A4- Total Quality Management (TQM):Another yet significant tool for analyzing the product quality is the application of TQM in that particular CEM/ECM. The TQM is nothing but the creating the permanent culture or environment where employees can improve their abilities and skills so that they do things right the first time and eliminating waste and defects from operations.
1A5- Engineering Change Order (ECO): The ECO can be a modification of the components, circuit module or assembly, or working algorithm or anything that will have effect on end product or manufacturing process. The OEM must analyze this parameter of CEM that how well they follow their ECO rules.
1A6- Other quality affecting parameters like calibration of equipment, AQL level, consistent use of ESD protection, File and record management like BOM and other important data management are the parameters that OEM must analyze before selecting CEM/ECM
1B- Industry of CEM/ECM:
It is vital that the OEM must know about their own industry. If the OEM belongs to mobile phone research, design and manufacturing industry then it must look for only those CEMs having experience in this industry. Other CEMs who are Guru in opposite industries like automobile or aerospace may not be able to handle project properly.
1C- Production Cost:
Most of the times many qualified and competent CEMs are only rejected because of their high production cost and high service charges. So it is important that the OEM should know about its budgetary constraints and then look for CEMs that fall in it range. The following aspects must be considered while evaluating CEM.
1C1- The quotation given by the CEM must be integral and it must not have any hidden charges. The OEM must ensure that CEM delivers what it claims and be responsible for what they promise to deliver.
1C2- The labor charges must not be high, infact the cheap hard working labor is always beneficial.
1C3- The cost of land to develop production facility in CEM’s country is reasonable enough
1C4- Utility charges and other overheads are within limits of budgetary constraints of OEM
1C5- Ensure constant cost reduction on frequent reorders.
2- Capabilities:
Another very crucial aspect of analyzing the CEM Company is by analyzing its capabilities. The following are the main aspects of capabilities
2A- Certifications:
The written or documented proof of any company’s capability is its certifications. It is not enough that they have certifications it is also equally important that how well they comply with these certifications and implement it in their organization. Important certifications that a CEM must have are RoHS, UL, and ISO9001:2015
2B- Technology: The utmost important aspect of analyzing a PCB supplier/vendor/CEM is by analyzing and researching about types of machines, technological equipment they have at their facility. The latest state of the art PCB fabrication and PCB assembly machines are always highly appreciated. Also the trained manpower to run these machines are of prime importance. Common sense aspects of analyzing the technology of your PCB partner are
2B1- Make sure that the technological machines being used at their manufacturing and processing setup meets your requirements.
2B2- Make sure that they own these machines/equipment
2B3- Research their capability to adapt to the technological advancement in the PCB market and that they can be the leader in future technology growth.
2B4- Checkout the types of PCB assembly machines they have like BGA and CSP soldering capacity
2B5- Miniature small SMT components like 0201 and 01005 soldering and repair capability
2B6- Reflow oven and Wave soldering capacity
2B7- Check that they are willing to provide design reviews and DFM services
2B8- Check that they implement SOP integrally.
2C Equipment: The production, fabrication and assembly of PCB process is not possible without proper “Equipment” in place. Make sure they have following capable equipment
2C1- Automated Optical Inspection (AOI) Machine
2C1- Automated X-Ray Inspection (AXI) Machine
2C3- Flying Probe Testing Setup
2C4- In Circuit Test (ICT) setup
2C5- High speed and accurate automated pick and place robot for component assembly
2C6- Multilayer PCB manufacturing prerequisite equipment like photo plotter, etching, lamination, cutting machines, V-grooving tools, panelizing tools, etc
3- Component Sourcing:
Another parameter of prime importance is the supplier from which this CEM procures or source components from. The procurement source of ECM/CEM must be legitimate and not dealing in counterfeit parts. The components must be inexpensive and good quality. The CEM must have good relationships with renowned global suppliers of electronic components
4- Services:
Lastly the most important thing is their services. The CEM must be judged on the following points as far as the services are concerned
4A- Lead Time: The lead time is always desired by many clients to be as short as possible. However you as an OEM/client/customer must not be in haste. Good things always take their time to complete. Give your ECM to take it time to work on project then deliver once and without any errors. You can get information about a particular CEM lead time from their website where they claim or to get real time line figures just read the customers feedback.
4B- Tracking Your Order: Tracking number provided by your long term or short term PCB partner is always satisfying. You can see where your product is and you can have mental relax while the parcel comes to your door step. Make sure that your potential CEM offers door to door services and get information regarding freight or customs charges if any
4C- Responsiveness: Many PCB suppliers/ ECMs / vendors claim 24/7 customer services. This terms has become widespread and famous. However ground reality can be different. Again go to the PCB supplier’s customer feedback on their website to see what they say about their responsiveness.
Conclusion: Summing it all up, we can say that the evaluation or selection of your PCB partner is not a piece of cake especially when you are looking for long term relationship. However for short term purpose, you can superficially check the company’s profile, customer reviews and match your requirements to what they deliver and take decision. But for long term relationship with your PCB vendor you can follow the guide in this article to easily evaluate or select reliable PCB vendor.
