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Main aspects of the PCB industry - PCB Design, Manufacturing & Assembling

Main aspects of the PCB industry – PCB Design, Manufacturing & Assembling

In this article, you’ll get to know the fundamentals of PCB manufacturers and how our company “PNC Inc.” is unique from other manufacturers in the United States.

What are the three main aspects of the PCB industry?

According to our experience of more than 50 years as the leading PCB Company in the industry, we can easily write that three main aspects in the PCB industry for which most clients look for are:

PCB Design
PCB Manufacturing
PCB Assembly

Design, Manufacturing, and assembling of PCB is a systematic method for examining the parts and components which is needed to execute. It included obtaining costs of a commodity and seeks to cut costs before actual development begins. There are specific manufacturing, design, and assembling principles required to be following during the PCB process execution of any electrical or electronics part. Eventually, a final design concludes the series with a review among the most common issues related to the PC Board or Printed Circuit Board.

Until continuous description, it is important to explain how the word ‘manufacturing design’ is used when speaking more generally and when talking more directly about PCB output. In general, design for manufacturing and assembling may lead to the simplification and optimization of a model or theoretical design in anticipation of their production. As these words are used to describe PCBs, they also imply a more straightforward study of possible production problems.

Ideal Design can Help PCB Fabrication:

The purpose of addressing the nature of manufacturing and assembling, in general, is to decide how a commodity can be produced and installed most cost-effectively. Manufacturing is to be done in a way to reduce the total cost and, more evidently, assembly design is required to be done to reduce commodity inputs, capital operating costs, and labor reduction. The emphasis is both on applying standards to lower manufacturing costs and also aim to shorten the product creation period. The fusion of these methods is often widely called manufacturing and assembly design for Mil-Spec PC Board.

Rules of PCB Manufacturer and Assembly:

After the conceptual Circuit Board Fabrication design has been developed, the company is required to research opting towards the most economical way of executing the PCB fabrication. The construction of a prototype or the development of a new version of a product could require a conceptual design. Once a conceptual design has been developed, a designer review will analyze the design’s bill of materials.

Try to use fewer parts in a design:

Reducing the number of components in PC board manufacturers is a simple aim with clear advantages. It would minimize construction costs and assembly difficulty, while not as obvious, it is of great advantage. When PCB assemblies are supplied using devices, for example, they are restricted to the number of modules they may be supported in a single port.

Being aware that if use many parts are used by pick and place machines in circuit boards fabrication will contribute to non-assembly. Cost savings are obvious. For example, if a design needs a resistance of 20K ohms, and 10K ohms resistance has been already used in the design, it might also be easier to use two 10K ohms resistors in sequence if this reduces the amount of time the computer picks and places simulation.

In the same way, you can speed assembly time up and transfer portions of the test requisites to the IC maker in search of regularly integrated circuits that can combine part of the specification into one IC. Having in mind the number and form of PCB components is perhaps the most significant move towards reducing total PCB manufacturing costs. In a term, the elimination of a component for the final design would decrease BOM costs, minimize purchase costs, production time, test time, and workload assembly feedback.

Use Original Components:

The use of composite materials will dramatically reduce construction time and expense. It goes without saying that defining a specific custom approach would significantly raise the initial cost of every product which may render a concept unfeasible. In addition, the use of more generic materials will shorten the supply chain of a commodity and mitigate supply issues. The fact that their measurements are easier checked until they are included in a PCB design specification is another advantage to prefer electronic interfaces.

Use Multifunctional Parts for Printed Circuit Design:

When an electric power part may be used for many uses in a model, the designer must take account of it. For instance, utilizing a container that can also act as hot in a design can give considerable cost control. A further definition of a dual-use mechanism through the use of a blockade as a link to ground from PCB board assembly.

Install all PCB Assembly Directions:

If practicable, all the board companies would plan all pieces to be assembled from the same side of an assembly around one axis. This is also referred to as a “Top Down” assembly in which all parts from top to bottom are placed. The use of this kind of single-sided assembly method saves time when a product is turned and rotated during assembly. As for all of the design choices, PCB design engineers would then have to consider whether producing a smaller PCB fabrication with components placed on every s sides of the board safer is compared with developing a larger PCB.

Advantages of PCB Manufacturers and Assembly:

• Fewer pieces ought to be handled and recorded.
• The expense of billing products should be minimized.
• The cost of handling can be reduced to some degree.
• Labor and input of electricity should be reduced.
• The total production period may be reduced to significantly increase manufacturing productivity.
• Lower sophistication results in greater efficiency.
• Increasingly competitive products should be.
• High Replacement margins are achieved.

The Circuit Printed Boards Manufacturers and prototype PCB manufacturers should have a simple way to reduce the next design bill. The advantages of reducing the number of designs are evident. Materials will become more viable as they are cheaper and less vulnerable to loss, however by lowering the number of materials used in the production of product costs, paperwork needs will be decreased and the work required for SMT assembly. All these factors contribute to lower manufacturing costs and encourage either better commodity or price profits at more affordable prices.

In addition, the processing period is shortened so the goods can be delivered to customers in less time. An optimal printed circuit board may be built with the right PCBA assembly considering all the above implementation of these objectives.

At PNC Inc., You’ll get your PCB done from any of the following design tools of your choice as we have an in-house facility available for all the tools.

• Cadence Allegro v16
• OrCAD Capture v16.3 & OrCAD PCB Designer v16.3
• PADS v9
• Signal Integrity Analysis: Hyperlynx

You will get the following deliverables from us:
• Gerber, drill files & PCB File
• Assembly and fabrication files
• Formal drawings on your (client) desired format

Why you should choose us & why we are better than others in the Market?

At PNC Inc., we have got the facility of executing all the design, manufacturing, and assembling in the same building. In this way, you don’t have to visit different places to check the progress of your work. You’ll get all the things done in the same building at our Nutley, New Jersey facility. That’s why we are a “one-stop-shop” and providing all the services under the same roof.

metal core Printed Circuit Board

Can a metal core Printed Circuit Board from PNC solve your thermal challenges?

A metal core (MCPCB) is a PCB with an aluminum or copper sub straight laminated directly to the PCB. Metal core PCBs are becoming the go-to solution for small footprint, high power components such as ultra high brightness LEDs. The metal core in the PCB acts as integral heat dissipater, conducting heat away from components through the thermally conductive metal core to a remote heatsink.

Although UHB LEDS applications are the most common use of MCPCBs, PNC has fabricated Metal Core PCBs for compact DC to DC converters, high power MOSFET and solid-state relay applications along side their standard Printed Circuit Board Fabrication.

What makes the MCPCB from PNC such a unique thermal management solution is that the heat transfer path from the component to heatsink is underneath the components, out of the way. For this reason, a MCPCB is the only cooling choice for LEDS, since the top of the LED must be unobstructed to emit light. For more complex layouts like DC to DC converters, the metal core can provide cooling to all the components in the circuit, eliminating the need for multiple small heat sinks or a complex and expensive machined heat dissipater, laid across several different height components.

Another advantage of a MCPCB is that there are several options for removing the heat from the metal core. For lower power designs the radiation and convection from the large surface area of the core can be enough to maintain a stable circuit temperature. If more cooling is needed,the PC Board can be mounted directly to a heat sink located anywhere under the PCB, or even on the edges of the PCB, giving the product designers the freedom to make their product smaller, thinner and easier to assemble.

How are Metal Cored PCBs fabricated?

The metal core is the foundation of the MCPCB; the most common core material used at PNC is aluminum. Aluminum is only about 50% heavier than FR4, so it does not significantly affect the overall PCB weight while it significantly increases the PCB stiffness. Aluminum conducts heat over 700 times better than FR4, which is essentially a thermal insulator. So even a thin aluminum core dramatically improves the heat transfer capability of the PCB. Typical aluminum cores used by PNC are between 1 mm and 2mm thick.

One disadvantage of a MCPCB is that the aluminum core is an electrical conductor, meaning that it is difficult to route a via through the core without creating a short circuit. Each via must be drilled out oversized, filled with epoxy, and then drilled again for the plated via. In general, double sided boards with FR4 and copper laminates on both sides of the metal core should not be considered unless the two sides are independent, or can be connected without vias, such as through a cable. For the same reason, through-hole components cannot be used with metal core PCBs, so choose a PCB Manufacturer like PNC that can guide you through the process.

metal core printed circuit board
metal core printed circuit board

One sided, single layer MCPCBs are by far the most common configuration and are typically used for simple high-powered circuits such as an array of high power LEDS or power resistors.
For more complex circuits, PNC can add one or two additional laminate and copper layers, although the more layers that are added, the less effective the metal core is at removing heat, because there are more insulating layers of FR4 between the component and the core.

There are three methods to transfer the heat generated by a component like an UHB LED to the metal core in the PCB
1. Thermally conductive laminate
2. Milled openings in the laminate allowing direct component contact to the metal core
3. Plated heat transfer vias under the components

Typically, a MCPCB is fabricated using thin, thermally conductive laminates. These thermally conductive laminates are only 6-8 times more conductive than FR4 but they can transfer heat from a component if the laminate is thin and the heat transfer area is large enough. Typically, the heat from the components is conducted first to wide copper traces on the surface of the PC Board, which spreads the component’s heat over a wider area on the thermally conductive laminate. The heat is then transferred over this wide area down through the thermally conductive laminate and into the metal core.

For power components with larger footprints than an LED, such as DPAK and QFN packaged components, a more effective cooling technique is to mill a hole in the laminate underneath the component location. A thermal pad or thermally conductive epoxy can be used under the component to create a low resistance path to the core.

For multilayer boards, the best route is to use thermal vias to conduct the heat from the component thought the layers down to the copper layer closest to the metal core. The heat is then transferred from this copper layer down through the thermally conductive laminate to the metal core.

If you are designing a high-power circuit and want to increase component reliability or decrease the size of the product, talk to the experts at PNC. They can help you design a metal core Printed Circuit Board that will keep your circuit cool.

TOTAL-CONCEPT

Total Concept Company

PNC’s expertise in design, manufacturing printed circuit boards, PCB assembly, and Box builds in one 70,000 sq./ft. facility makes us the ultimate total concept company. PNC’s unique manufacturing facility is just that, a PCB assembly usa manufacturer located in Nutley, New Jersey. PNC has been a vital supplier of electronics in the PCB industry for over 50 years and serves the military/defense, medical, aerospace, automotive, RF/Microwave, industrial and consumer sectors. Having these capabilities all in-house stream lines the turnkey process under one PO which is invaluable to our customers.

ELECTRONIC DESIGN

Being able to design in-house has its importance when designing for PCB manufacturing as well as prototype pcb assembly and production PCB assembly. Our designers have an edge in designing for PCB manufacturing since they are knowledgeable of the PCB manufacturing process. Designing for manufacturability eliminates defects, delays and process issues. Our design tools used are Cadence Allegro, OrCAD Capture, OrCAD PCB Designer and PADS. Our deliverables are Gerber, drill files, PCB File, schematics, Assembly and fabrication files and Formal drawings on customer format.

Having the capability to manufacture printed circuit boards, pcb contract manufacturing, in the same facility also has its benefits for prototype pcb assembly and production PCB assembly. While the printed circuit boards are in process of being fabricated, our pcb assembly division can work in parallel creating pick & place data, SMT Stencils, work instructions, AOI programing, selective soldering programming, and pre-pare testing procedures to expedite the PCB’s once the hit the SMT assembly floor. The work in parallel process makes for an efficient seamless transition from PCB manufacturing to Assembly.

TOTAL-CONCEPT-PCB
TOTAL-CONCEPT-PCB

After the PCB’s clear final inspection, they are transferred to the PCB assembly department. For a pcb assembly manufacturer in a total concept configuration, logistically you gain 1-2 days shipping time, since you do not have to outsource the PCB’s as well as a time savings of not have to perform an incoming inspection. PNC’s Assembly division is comprised of multiple high speed SMT lines with 13 zone re-flow ovens, 3d AOI, 3D X-ray, thru-hole stations, selective soldering, and rework stations. If required, PNC can perform Flying probe, ICT and functional testing to ensure a robust and error free PCBA.

Another SMT assembly service with-in our total concept company is box building. The PCB assembly never leaves the facility eliminating any ESD issues from incoming inspection handling. Our expertise in box building varies from small plastic snap together housing, medium sized metal enclosures to rack builds. If provided with a system test procedure, PNC testing engineers and technicians can perform the functional and burn in testing. When looking for total concept printed circuit assembly companies, we are here to help.

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Printed Circuit Board thickness considerations and requirements

How Do You Select a Printed Circuit Board Thickness?

Selecting the correct PC Board thickness for your product requires balancing of three often competing aspects of the design: manufacturability, electrical performance and mechanical constraints. Modern PCB fabrication techniques at PNC give the PCB designer great flexibility in specifying the PCB lamination stack-up and gives them the option to design a PCB in a thickness other than the typical choices of .031”, 062” or .093”.

Manufacturing considerations in selecting a PCB thickness

To understand how to specify PCB thickness, it is important to understand how PCBs are fabricated. Most multilayer PCBS from 2 layers to 40 layers are constructed of these three basic materials.

  • Core – a fully cured fiberglass panel usually with copper foil on both sides. It is essentially a two-sided Printed Circuit Board. PNC stocks cores in a variety of materials and thicknesses, down to 3 mils thick.
  • Prepregs – fiberglass sheets impregnated with uncured epoxy resin. This resin will cure and harden when subjected to heat and pressure during the lamination process. It is the functional equivalent of double-sided tape. PNC also stocks prepregs in a variety of materials and thicknesses.
  • Copper foil – used to create conductive layers. Copper foil thickness is chosen by the amount of current the traces in each layer of the board will need to carry.

Multilayer boards can be manufactured in a variety of thicknesses by mixing standard core thicknesses with standard prepreg thicknesses. The lower limit of PCB thickness is set by the number of layers and the minimum available core and prepreg thicknesses. Copper foil thickness also plays a small role in overall PC Board thickness.

Providing you want to stay with the standard thicknesses, I’ll give you an example of PNC’s standard core thicknesses based off the core copper thickness. Let’s take an .062 and compare the stack-ups. See Figure  below:

Stack-up for an .062 multilayer:
062 thick PCB (002)

 

 

 

Notice to achieve the .062 overall thickness, the core thickness needs to be compensated based on the copper weight of the design. When using 1 oz copper we would use .038 core and .035 core for 2 oz. Also, the amount of pre preg would need to be adjusted as well to get to the thickness required. This is just one example when trying to determine overall thickness of your PCB.

The maximum PCB thickness is usually governed by something called the drill aspect ratio, which is the ratio of a drilled holes depth vs its diameter. When a hole is drilled, the deeper the holes becomes the harder it is to guide the drill accurately (because the drill deflects as it is pushed through the material) until you eventually reach a limit where you can no longer guarantee that the resulting drill hole will be centered in all the pads through the PCB. This is also referred to as drill wander in the PC Board fabrication world.

The aspect ratio for a through hole is the (board thickness) / (drill hole diameter).

Typically, the ratio is limited to approximately 10:1 This means that for a .062” thick board the smallest through-hole drill size is .006” which is the minimum drill size available at PNC. For a .093” thick PCB the smallest drill hole size will be .009” As board thickness increases, more complex via creation techniques such as laser drilled microvias are required to maintain the required pad density under components such as BGAs.

PCB thickness considerations for high speed circuits

One of the assumptions an electrical engineer makes when designing a circuit is that the PCB itself does not contribute any impedance to the circuit. However, in high-speed PCB design the integrity of the signals is definitely affected by the physical characteristics of the PCB.

Unfortunately for the designer the primary sources of parasitic capacitance and inductance of a PCB are affected by board thickness in conflicting ways, forcing the designer to carefully consider the trade-offs.

Vias

PCB vias can introduce both inductance and capacitance to the high-speed circuit. Parasitic inductance and capacitance of a via both increase proportional to board thickness.

Capacitance between layers
The capacitance between traces on different board layers or between traces and the ground plane are inversely proportional to the thickness of the dielectric between them. More space between layers will reduce parasitic capacitance and ensuring that all high-speed signal traces are the same distance from the ground plane will help impedance matching between them.

Crosstalk

Crosstalk between signal traces can be minimized by routing the PCB traces further apart and reducing the dielectric thickness between PCB trace and reference plane.

Mechanical Constraints

A PCB is ultimately a mechanical component of the product and is therefore subject to a variety of mechanical constraints. The PCB or PCBs must fit within the product envelope. This often requires that a PCB be as thin as possible. On the other hand, PCBs are subject to the torqueing forces from cables connected to the board edge and external connections. Preventing board failure during assembly or in use requires a circuit board fabrication thick enough to withstand these forces.

Finally, PCBs in the field are subjected to both vibration and shock. For example, large PCB panels can vibrate in several different modes when subjected to vehicle vibration, causing fatigue and eventual failure of solder joints. The rule of thumb is to get the resonance modes of a PCB to be 10X the input vibration. This requires designing thicker, stiffer PCBS and by careful placement and design of the PCB mounts.

These are the three most important considerations in selecting a PCB thickness. To optimize a PCB design, the PCB designer needs to understand all of these requirements and constrains on the PCB lamination stack-up, and have the flexibility to choose a PCB thickness that balances these often conflicting constraints. The team at PNC can help you design a PCB that meets your needs at a competitive cost and lead time.