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Printed circuit boards (PCBs) can be classified based on many things, including their fabrication process, application, or design specifications. When choosing a PCB, factors such as stress, mechanical strength, electrical stability, and space constraints must be taken into consideration. Single-sided PCBs and double-sided PCBs are two such classifications that are based on which side the conductive copper and components are on. Space constraints, cost, and circuit density are factors that designers must consider when choosing between single-sided PCBs and double-sided PCBs. In this article, we will compare single-sided PCBs vs. double-sided PCBs and explore their appropriate applications.

Single-Sided PCBs
PCBs are used in the electronics industry to connect electronic components. Components are soldered on a PCB and are connected using conductive copper. A single-sided PCB is a type of PCB where the components and conductive copper are mounted on one side and the conductive wiring is on the other side. Single-sided PCBs are the first-ever printed circuit board technology and are widely used due to their simplicity in manufacturing.

A single-sided PCB consists of a substrate layer, conductive metal layer, protective solder mask, and silkscreen. The conductive copper layer is laid above the substrate layer. Electrical components are soldered on one surface of the board and the circuit is etched on the other side. As single-sided boards use only one conductive layer, there is no intersection or overlapping of conductive paths. Circuit realization using a single-sided PCB consumes a lot of space and is suitable for low-density circuit designs.

Single-sided PCBs are widely used in camera systems, calculators, radio equipment, power supplies, timing circuits, LED lighting boards, and printers. Single-sided PCBs are good for low-cost electrical or electronic circuit realization. However, circuit designers might struggle to create single-sided PCBs to realize complex circuits with space and size constraints. For such boards, a double-sided PCB is the best option.

Double-Sided PCBs
Single-sided PCB traces are present on only one side, while double-sided PCBs have traces on both sides with top and bottom layers. The components and conductive copper are mounted on both sides of a double-sided PCB, and this leads to the intersection or overlap of the trace. Double-sided PCBs are best for realizing high-density circuits that do not require point-to-point soldering.

In double-sided PCBs, there is a layer of conductive copper on both the top and bottom sides of the board. Vias are introduced to create traces on both sides of a double-sided PCB. The vias help in connecting the components between the top and bottom layers. Double-sided PCBs use two mounting technologies, through-hole technology and surface mount technology, for connecting the circuits on either side.

Through-hole technology: Leaded components are installed into pre-drilled holes on the double-sided PCB. The leads of the components are soldered to the pads on the opposite side.

Surface mount technology: Surface mount devices (SMDs) are precisely placed on the surface of double-sided PCBs.

Double-sided PCBs are often used in vending machines, cellphones, UPS systems, amplifiers, lighting systems, and car dashboards. Double-sided PCBs are best for higher technology applications, compact electronic circuits, and complex circuits. As the complexity of a circuit increases, the PCB type shifts from single-sided to double-sided to multilayered. Double-sided PCB production is also more complex than single-sided PCB production.

Below, we have a summary of single-sided PCBs vs. double-sided PCBs.

Designers must be well-aware of circuit space constraints, mounting technology requirements, and circuit density to decide between single-sided PCBs vs. double-sided PCBs. To design single-sided, double-sided, or multilayered PCBs, Cadence’s PCB design and analysis tools can be utilized.

As a parent, you quickly become used to an ongoing stream of questions from your child. On an almost daily basis, parents handle the most important questions of a lifetime. “Why? Where did I come from? How did I get here?” rank high on my personal list of favorites.

In the business of designing and [URL]<a href="https://www.jhypcba.com">producing printed circuit boards (PCBs)</a>[/url], the ability to ask the right questions can provide value and save money. Within the right environment, asking questions leads to a healthy exchange of ideas and perspectives. Those exchanges foster learning and innovation. The ability to ask questions may also prevent leaders and teams from making decisions that lead to unacceptable risk. In this article, we discuss the critical questions to ask a PCB Manufacturer to establish confidence that you will be getting an excellent product.

The Best Questions to Ask a PCB Manufacturer

Asking the right questions of a PCB manufacturer has roots in best practices and reflects both knowledge and credibility. The right questions allow design and engineering teams to move past surface issues such as availability and discounted costs. When asked the right questions, PCB manufacturers recognize that a team has credibility, knowledge, and insight.

General Business Practice Questions Can Be Revealing
Although asking a PCB manufacturer how many years they have been in business may seem simplistic, the response to that question sets the table for other questions about the type of boards they have produced and whether the products and services match the expectations of your team. For example, if a PCB manufacturer has fifteen years of experience producing rigid boards and has not produced another type of board, the manufacturer—despite 15 years of experience—probably cannot meet your expectations for producing rigid-flex boards, since they don’t have that experience.

Other questions to ask a PCB manufacturer include:

How many employees do you have?

PCB manufacturers that have the appropriate staffing levels have a better ability to sustain best practices when faced with producing larger orders.

What kind of education and training do your employees have?

PCB manufacturers should have the engineering expertise needed for reviewing quick prototype requests and for making recommendations to design teams. Questions of this type often disclose the ability—or lack of ability—of a PCB manufacturer to communicate effectively and to collaborate across different organizational levels.

What is your company’s manufacturing philosophy?

PCB manufacturers that place efficiency as a high priority concentrate on delivering products quickly at lower costs. In contrast, PCB manufacturers that value effectiveness begin with a stakeholder analysis and continue by factoring stakeholder requirements into their decisions.

Answers to the above questions can help your team formulate a budget while also showing if time-to-market predictions include stage-by-stage quality control.

Take Time to Ask PCB Manufacturers About Processes
Much of the difference between efficiency and effectiveness involves process control. The processes defined by a PCB manufacturer must align with the decisions that your team makes about the board layout, shape, type, materials, and components, and all of this impacts the sub-processes that make up each stage of the larger manufacturing process.

In addition, those processes must match the design specifications for precision and accuracy. Along with other processes, a manufacturer must have the ability to create correct positive and negative images, maintain the alignment of layers within multilayer boards, etch inner and outer layers, drill precise vias and mounting holes, and apply the optimal finishes.

Your team’s decisions about components might also impact PCB assembly stages. For example, a decision to use surface mount technology components requires the correct type of pick-and-place equipment. Any use of through-hole components also requires the appropriate wave soldering equipment. Some applications—such as aerospace or medical applications—may require a PCB manufacturer to have specific board cleaning procedures.

Solid processes should produce a balance between delivering products ahead-of-or-on schedule and ensuring that the quality of the product satisfies or surpasses stakeholder requirements. Any discussion about efficiency and effectiveness should focus on the ability of the manufacturer’s processes to meet schedules and demonstrate quality control. Questions should touch on the following:

The technologies that a PCB manufacturer uses

Their ability to review board and product designs

The level of error-detection used from the start of manufacturing to the end of manufacturing

Ask About Certifications and Compliance with International Standards
Most PCB manufacturers post certification information that demonstrates their commitment to and compliance with international standards. When interviewing manufacturers, ask about their compliance with the International Standards Organization ISO:9001 quality management standard. ISO 9001 certification shows that the manufacturer can meet or exceed the needs of its customers through a quality management system that includes company leadership, planning activities, operations, support, and performance management.

Look into a Manufacturer’s Compliance with Environmental Standards

Environmental sustainability has become a top priority for the electronics industry. Reputable PCB manufacturers enforce Restrictions of Hazardous Substances (RoHS) standards throughout the manufacturing process. RoHS regulations restrict the use of Lead, Mercury, Cadmium, Hexavalent Chromium, Polybrominated Biphenyls, and Polybrominated Diphenyl Ethers during fabrication. PCB manufacturers must have the ability to provide surface finishes that meet the RoHS requirements. When asking about RoHS compliance, also request information about the manufacturer’s ability to treat wastewater produced during PCB fabrication processes.

UL Listings and First Article Inspections

Another key certification for PCB manufacturers involves UL listings. Compliance with the UL listing service shows that manufacturers rigorously test products to protect against flammability and delamination risks. Questions about the capability of a manufacturer to test boards should cover the in-house procedures, the type of in-house equipment, and maintenance procedures.

Key parts of testing procedures include First Article Inspection (FAI) or the testing of the first one or two completed boards to ensure the correct use of materials, the appropriate quantity of materials, the correct application of component mounting, stenciling, and soldering technologies, and an inspection of printing, placement, and soldering. Additional manual inspections, automated optical inspections, and automated X-ray inspections allow manufacturers to check component polarity and locate scratches, open conditions, shorted conditions, incorrect components, missing components, insufficient solder, or excessive solder.

Make Sure the Manufacturer Complies with ISO 8402

Compliance with the ISO 8402 standard assures design teams that a manufacturer has the capability to trace any problems encountered with a board to a root cause. The ability to trace—or traceability—shows that a manufacturer can successfully check production processes, supply chain issues, or maintenance problems. Questions about traceability can cover processes such as the assignment of lot codes for materials arriving from the supply chain, the type of equipment used to perform chemical solution checks, and the assignment of lot and date codes to completed PCBs.

PCB manufacturers should also demonstrate compliance with IPC standards. Those standards cover all classes and types of boards and establish performance and quality levels. The IPC standards also describe quality expectations for the supply chain and the capability of manufacturers to source and trace critical components.

Ask Questions About Post-Fabrication Procedures

Problems with PCB production can occur between fabrication and assembly. Because an important part of quality involves the storage of PCBs after fabrication, IPC has issued the IPC 1601 standard to cover handling for boards. Your design team should ask if the PCB manufacturer uses climate-controlled storage and about the temperatures and humidities observed in the storage facilities. Along with requesting information about the storage facilities, your team should also ask if the manufacturer stores PCBs in a heat-sealed, vacuum-packed moisture barrier bag. Improperly stored PCBs can delaminate after reflow, crack, tarnish, and develop bad solder joints.