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Why printed circuit board manufacturers use plated slots ?

Printed Circuit Board Plated Slots

Slots are holes, which are either plated or non- plated-through. So, plated slots are holes plated in copper. And we use them for electrical connections on the PCB. A through slot is the one that goes to the entire depth of the board, starting from one end to another. Whereas a PCB outline or edge also has plating called side plating.

printed circuit board manufacturers use plated slots for components packaging, however, non-plated slots are also in practice. But, PCB with multiple layers have only plated-through slots.

Why Prefer Plated Slots?

PCB assembly involves different designs and components, and you would often see round holes to accommodate the round components or square as well. A round hole suits a PCB with through-holes. However, certain components are compatible with the blade or rectangular leads, so the round or square holes are not ideal in that case, and this is where a plated slot works.

When the pin size becomes large, the rectangular connectors work with plated-through slots rather than round holes. Like, they are ideal for the DC Jacks. Though you can use the round holes for small connectors and rectangular pins, plated slots are better because they take less space on the PCB, unlike the round holes.

Difference between Plated And Non-Plated Slots

Plated slots have copper plating in the circuit layer, whereas it opens in the solder mask.
On the other hand, non-plated slots don’t have copper plating in the circuit layer, besides, it does not open in the solder mask.

Design of Plated Slots

There is a specific way to show plated holes on the Gerber, like:

    • You have to put the copper pads on the upper and lower solder mask.
    • Then you insert a milling slot in the mechanical layer.

Designers prefer a mechanical layer to put slots in the Gerber and it involves two possible options to do it.;

Use of Flashes Having the Right Size Slot

Drawing a slot with a 0.50 mm thick line, as it helps designers to check it visually to ensure that there is enough tolerance between copper and the PCB edge. Remember that a line’s center is considered the edge of the slot.

Then you have to join the slots with the PCB outline into the Gerber, and it should be parallel to the copper layer. However, the copper layer should also have a PC Board outline to stay on the safer side.
The mechanical layer in this case has different names, depending on the system. It also depends on milling as it should be there. However, you can use another layer in the absence of a mechanical layer. Use the README file to avoid any doubts regarding the right file.

Don’t always define slots in a legend or a copper layer because they could be misinterpreted. Show large slots in the legend or copper layer, however, the outline should be precise. Don’t forget to write the text SLOT in the center.

Creating a Drill File

You can also define the plated slots through drill files as it is a precise way, however not all CAD software allows this option. But, defining through the drill files involves the X and Y or the slot width and length, instead of a complete row of holes that overlap.

Understanding A Small Slot In The PCB

The size of the smallest slot varies, depending on the type of the PCB, like if it’s flex, rigid, or rigid-flex. The width of the smallest slot is 0.50 mm for a rigid and flex-rigid PCB, and the length is often 1.0 mm.

These sizes are so due to more thickness of the PCB, besides, the slots are created through the NC milling that is mechanical. As, the grooving cutter of NC is 0.50 mm and its length is twice the width, like 1.0 mm.

On the other hand, the thickness of the flex PCB is less, and you can make slots through a laser machine. Designers prefer the smallest slot because the bigger slot’s length becomes more which is twice its width.

Milling Of the Cutouts Or Slots

You have to use the round NC grooving bit for the milling of slots in the rigid PCB, and it’s just like the CNC machine. However, the inner corners of the slots are made round instead of sharp. Whereas the PCB edge is created to the center of the border.

Which Industries Can Use the Plated Slots?

Mostly the thick or multilayer PCBs have plated slots, and such boards are ideal for different industries, including aerospace, consumer electronics, computer, and telecommunications. As these slots don’t take much space, they are cost-effective in terms of making. A board with both plated slots and round slots is also ideal for multiple electrical connections.

Frequently Asked Questions

What Is A PCB?

PCB stands for a printed circuit board having different electrical components, holes, and other features. Various industries use PCB boards to provide the electrical signals to run different devices or electronics. A PCB board can be embedded, single or double-layered, or can have many layers like up to 60 plus.

What Is The Definition Of A Plated Slot?

A plated slot is a hole in the PCB with copper plating. It is not round, so it is ideal to accommodate the leads with rectangular pins. You can use such a slot for electrical connections and component packaging
The slot goes throughout the circuit board that’s why we call it a plated-through slot.

What Is Edge Plating?

If plating is done on the edges of a PCB, we call it edge plating. Besides, you can also call it the side plating of a circuit board. It goes from the upper layer to the lower layer of the PCB, extending to an edge of the perimeter.

Which Circuit Board Should Have Plated Slots?

Generally, the multilayered PCBs have slots with plating also known as plated-through slots. However, there are also non-plated slots, depending on the PCB design and its application.

Do I Need A Lot Of Space For Plated-Through Slots?

Plated slots are mostly rectangular, hence they don’t take much space on the PCB like the round slots. So, such slots are ideal when you run short of space on the PCB, and where you need to use the rectangular Jacks.

What is a Copper Layer?

PCB has different layers of which one is a lamination made of copper foil, and it is attached to the circuit board with some adhesive. The copper layer is essential for a two-sided PCB, including copper on both sides. But, PCB boards with more than 60 layers of copper are available by different companies.

What is Solder Mask Layer?

The green color on the circuit board is a solder mask and its surface is called the solder mask layer. The purpose of the solder mask is to cover the exposed copper to prevent users from the electric shock upon contact. Though it is mostly green, other colors are also available.

Final Thoughts

PCB manufacturers use plate slots for components packaging, however, the non-plated slots are also in practice. But, PCB with multiple layers has only the plated-through slots. Certain components are compatible with the blade or rectangular leads, so the round or square holes are not ideal in that case. This is where a plated slot works.

Plated slots have copper plating in the circuit layer, whereas it opens in the solder mask. Non-plated slots don’t have copper plating in the circuit layer, besides it does not open in the solder mask.

The size of the smallest slot varies, depending on the type of PCB, like if it’s flex, rigid, or rigid-flex. The width of the smallest slot is 0.50mm for rigid and rigid-flex PCB and the length is often 1.0 mm. Engineers use cad software to make Gerber files for different types of slots including plated through and non-plated through slots.

Would like to know best practices for Plates Slots or printed circuit board assembly? Email us at sales@pnconline.com

What is High TG In PC Board Fabrication?

The making of PCB involves different steps, technologies, and terms, and TG is one such term that refers to the Glass Transition Temperature. High TG PCB is the board made at a high temperature. We will discuss this topic in detail, including the TG value, features, applications, materials, parameters, and much more.

What is High TG PCB?

If a PCB’s temperature goes beyond a set TG value, its condition will change. Like, the solid board will turn rubbery, affecting a PCB’s function. Depending on where you use a PCB, the temperature of the application should be at least 10 to 20C less than the PCB temperature.

Understanding TG Value

TG means Glass Transition Temperature like there is a certain limit of this temperature for PCB and that specific temperature is the TG value. TG value helps in understanding the PCB material, and you can find which temperature is required for its service.

Secondly, it helps you to find the condition of the PCB material, like if it’s solid, flexible, or solid-flex.

High TG PCB and Its Features

You have to choose a high TG Printed Circuit Board for your application carefully, because it involves multiple features, including thermal, electrical, mechanical, and chemical features.

Thermal Features: they include the TG or Glass Transition Temperature, thermal conductivity, thermal temperature’s coefficient, and decomposition temperature. TG is the temperature at which the state of the PCB material changes. But, when the board cools down, it gets back to its initial condition.

Electrical Features: they include the surface resistance, electrical power, volume relativity, and the dielectric constant and loss tangent.

Chemical Features: the chemical properties of a high TG PCB include the moisture absorption and the methylene chloride resistance of the PCB material. The TG PCB should be able to resist moisture if it’s near water.
Mechanical Features: the mechanical features are also important to know regarding the TG PCB. They include the flexural and peel strength, and the young’s module.

Suitable Materials for High TG PCB

A PCB has two materials, including laminate and substrate. The substrate includes epoxy resin, glass, or paper weave. The substrate should be compatible with the TG. Some common substrates that we use for a high TG PCB are;

  • CEM-1, 2, 3,4, and CEM-5
  • G-10 and 11, FR-1 to FR-6
  • Aluminum
  • Knapton
  • Pyralux

The last three materials are flexible.

The laminates should also be compatible with your TG PCB in terms of strength and temperature. Some common laminates are:

  • FR-1, and FR-4
  • CEM-1, CCEM-3
  • Teflon

Criteria for High TG PCBs

Printed circuit boards with a high TG value are based on certain criteria as described below:

  • The selection of a PCB, depending on the components like it can be single or double-sided PCB or embedded.
  • The stack-up PCB with a single layer or several layers
  • The design of such boards can be based on a module or it can be custom
  • The strength of the board also matters, like it should be robust either electrically or mechanically
  • PCB’s bendability also helps to classify the TG PCB, like if it’s hard, flexible, or hard-flexible
  • The electrical strength also helps classify the TG PC Board

Generally, manufacturers use bendability and strength to classify a TG PCB‘s physical properties.

Where Can You Use The High TG PCBs?

You can use the high TG circuit boards in intense conditions, as the environments with high-vibration devices. They are also suitable for applications with shocks, chemical components, and high temperatures. Like, missiles and car parts often come up with chemicals. So, the suitable industries for high TG PCBs include aerospace, telecommunications, military and defense force, automobile, and down-hole drilling.

What to Consider While Designing a Rigid PCB?

You must hire a professional PCB manufacturer for the right design, manufacturing, and assembly of these boards. The engineer must know the kind of environment that suits a TG PCB to function precisely. Below are a few examples to help you understand it.

Commercial Use

Many telecommunication companies use the best materials for mobile devices to enable them to bear high shocks. Like, the phone should not get damaged easily when you drop it.

Auto Industry

PCB has to be safe under a car’s hood as it’s mostly vibrating, so a shock or crash might happen. Hence, a rigid PCB is the best solution in this case.

Aerospace Industry

The flying machinery always needs the high TG PCB because there is intense vibration, like in the jet engine, as there are thousands and millions of micro-vibrations in one minute. So, equipment related to aerospace should be able to tolerate extreme temperatures, like from -45°C to 85°C.

Other Applications

These boards are also ideal for solar power equipment, such as power inverters and cogeneration equipment. As these boards resist temperature, they work well in many industries. Like, one of its applications involves Lead technology, like the medical, computer, and telecommunication industries.

The TG PCB is also used in broadcasting, like booster stations. Besides, the fire detectors and burglar alarms also need such boards.

Use of High TG Flex PCB

It is clear from the name that a flex PCB can adapt any design or shape to get compatible with certain products. Like, they can tolerate intense environments better than rigid PCBs. You can use the high TG flex PCB in defense and military, aerospace, medical equipment, consumer electronics, auto, wireless networks, as well as industrial equipment.

What To Consider While Designing a Flex PCB?

You must hire a professional PCB manufacturer for the right design, manufacturing, and assembly of flex PCB. The engineer must know the kind of environment that suits a TG PCB to function precisely. You should see if:

  • You need a flex PCB for an ordinary environment or an extreme environment like an explosion. Whereas the cell phone has a normal environment.
  • The environment should be free from any moisture before installing a high TG circuit board.
The Design Process

The design of a high TG PCB involves different steps, such as

  • Using the right software, like CAD, Eagle, Altium Designer, etc.
  • You must know the power requirements to suit different components on the PCB. You should also consider a specific plan for noise reduction caused by a TG PCB.
  • Preparation of the stack-up plans documents as it is essential for making the best TG PCB.
  • The floor layout for a PCB with proper sections, including components. Like you can place them together or separately.
  • TG PCB should be complete in terms of a power plane and ground details. These details ensure proper routing for signals.
  • The board should be compatible with patterns in terms of sizes. All components should be well-placed to help a PCB function the right way.
  • It is important to design routs for high-frequency signals, as the route should be clear for a flawless signal transfer. This step involves vias, as they help in proper signals. You need the reverse via and signal via in this case.
  • You must follow the 3W-rule to increase the traces’ distance which helps to reduce the coupling effect.
  • Another rule to reduce the coupling effect is the 20 H rule.
  • In the end, check the routing guidelines to see if you are doing everything the right way.
Specs and Design Parameters

The fabrication of a high TG PC Board Fabrication involves certain parameters and specs, depending on the application. Some standard parameters are described below.

How Many Layers Do You Need

Designers prefer the even number of layers while developing the high TG PCBs. But, the odd numbers of layers are also suitable in certain applications.

Dimensions of PCB

The PCB dimensions depend on its application. Like, you need a large circuit board for a broader application. Besides, there should be enough space on the board to place the electrical components.

Well-Finished

The high TG PCB should be well-finished, and the material depends on where you want to use this board. Like, some common materials are;
HASL, or hot air leveling – It is ideal as it is cheap and can be stored for longer.
OSP, or organic protective surface
Immersion silver – It gives a smooth surface, and it is cost-effective. It has many storage limitations
Immersion tin – It suits the SMT

Immersion gold – It can be stored for longer with a few limitations.

ENEPIG, nickel palladium – It can be stored longer, but it involves a complex process.

Solder mask – It protects the PCB from environmental elements.

Weight of copper – You must also consider the weight of copper like it includes both initial and finishing copper. Generally, the weight is 1 oz. to 1.5 oz. or 5 oz. It also depends on the layer and board thickness.

Assembled PCB thickness – The TG PCB thickness depends on its material and type. Like, if it’s flexible, hard, or a hard-flex board.

Distance between layers – The distance or spacing of electrical components and layers should be equal for high-frequency signals. As it reduces the coupling effect.

Via sizes – The drill aspect ratio and the hole size should also be appropriate. Generally, the PG PCB can have either plated-through or non-plated through holes, depending on the placement and layout design.

Board quality – The board should have a high-grade material to ensure an effective function during application. Besides, you must check the quality of the TG PCB to evaluate its performance in terms of specs. Like, you should test its lamination, vias, copper plating, solderability, finishing, components, and cleanliness.

Interested to know more about PCB TG or PCB Assembly? Email us at sales@pnconline.com

HOW DOES SMT ASSEMBLY WORK

HOW DOES SMT ASSEMBLY WORK?

While modern designs for electronics get smaller, more designers depend on the technique of surface mounting. After the 80’s, this technique became famous and hasn’t stopped being the dominant PCB assembly technology for electronics production.

Almost all of the devices in your pocket – either an iPhone xs max or a smartphone – has probably been produced using surface mount technology (SMT). Most of those components in your vehicle or Transportation today have probably been assembled using SMT.

PCB assembly
PCB assembly

What is Surface Mount Technology (SMT)?

Assembling electronics with SMT involves assembling electrical parts using automated equipment that places components on the printed circuit board (PCB).

Manufacturing devices using surface mount technology (SMT) essentially imply electronics assembly using machine tools. In contrast to traditional THT procedures, SMT elements are put directly on top of the PCB rather than soldered to a radial or axial lead. SMT has been the most commonly utilized method in the business when it comes to ethernet interfaces.

Placement and Assembly of Components:

The components to be assembled are inserted into the pick and place feeders or trays. Intelligent software applications guarantee that components are not unintentionally swapped or misloaded during the config file. The SMT pick and place machine then autonomously takes each part from its tray or reel using a pressure pipette and puts it in its proper location on the panel using accurate X-Y cross pre-programming. Our equipment can assemble up to 24,000 parts per hour. Just after SMT assembling has been finished, the PCBs are transported to soldering reflow ovens.

Soldering Components:

The reflow-soldering technique is utilized for series manufacturing orders. This method involves placing PCBs in a nitrogen assisted environment. It is then progressively heated with hot air when the solder paste melts, and the flux vaporizes and attaches the parts to a PC Board. The panels are cooled down after this step.

SMT ASSEMBLY
SMT ASSEMBLY

Solder Paste Usage:

A few of the initial stages in SMT manufacturing is the administration of the solder paste. Solder paste is squeeged through aperature openings in a stainless steel stencil.  Once the squeegee passes over the stencil, the PCB is lowered and travels to the next operation, solder paste inspection, known as SPI. After the solder paste has been verified, the PCB’s move to the SMT pick and place machine.

AOI System in SMT:

AOI visual inspections should be carried out for virtually all manufacturing orders in verifying the quality of completed panels or to capture and rectify an error. The AOI section analyzes each Printed circuit board with multiple cameras and analyzes the look of each circuit to the proper, pre-defined sample image. They will either fix the error or remove the panel from the device to examine it further. The AOI visual management guarantees consistency and precision in the manufacturing process of the SMT assembly.

SMT Components that are not Suitable for Auto Pick & Place:

While most components are placed automatically, others are not installed. This can be for several reasons. Some of them are,

Ø Thermal stress:

Other circuits may be too resistant to thermal and are not perfect materials for soldering reflow temps. These materials must be installed manually to protect them following the usual assembly procedure.

Ø Too light:

Specific components are not substantial enough and, consequently, have a low bulk ratio for conventional soldering automated placing equipment.

Ø Rugged solder joints:

Many components, like connection leads, require a stronger solder joint. Some components are soldered manually to enable this.

This enables rapid examination and repair of components that may be at risk of layout for infringements before the soldering oven is passed.

Surface mount technology benefits:

As with cross-holes, both advantages and drawbacks are included with SMT. Let’s start with some SMT design advantages:

1.   Efficiency:

Thanks to SMT technology, designers can now transform complicated circuits into smaller PCB’s.

In contrast with using the storage on a PCB more efficiently, the SMT board is quicker to increase its overall capacity.

2.   Fewer mistakes:

SMT assembly is very reliant on technology and not so very dependent on people. SMT is a far less error-prone procedure since it’s nearly fully automated.

3.   Cost Accessibility:

These are some of the reasons for the SMT module was to reduce cost. SMT needs far fewer holes in the circuitry. This substantially reduces manufacturing and handling expenses. Furthermore, SMT is much more able to produce large quantities, thereby improving the unit cost.

SMT Disadvantages:

As with other production processes, SMT design has certain drawbacks. The most important is that it needs considerably more eye for detail than a complete construction. Even if the process is substantially automated, your specifications must still be fulfilled to create quality. This is mainly the responsibility of the inventor and the producer of the electronics equipment.

There may also be problems when SMT can be used to put parts on a PCB that works under circumstances that include:

  • Machine stress
  • Ecological stress
  • Stress of temperature

This issue may be addressed by mixing SMT with complete processes to achieve both advantages. That’s correct — on the very same pitch, you may utilize both!

What is the SMT-SMD Difference?

The distinction between SMD & SMT is that SMD relates to the electronic element placed on a Board. SMD is an integrated circuit.

Surface mount technology (SMT) refers in contrast to the way electrical components are placed on a printed circuit board.

SMT refers to Surface Mount Technology and is the complete technology used to place and solder electronic parts on printed circuit boards or PCBs such as resistors, condensers, transistors, electronic components. The devices utilized are also known as surface mounting devices (SMD), surface-mount devices. It should be pointed out that SMT does not have to preserve for constituent pins utilizing holes, and SMD is considerably smaller than by-pass technology.

SMT features:

  • Parts do not have connections or short leads alone;
  • On the same edge of the PCB, the top part of the device and the solder joint;

SMD features:

  • miniaturization;
  • No plumage (flat / short plumage);
  • authoritative Parenting for PCB assembly mounting;

Uses of Surface Mount Technology:

SMT mounting was developed to produce a better, more robust electrical product.

Many typical uses for surface mounting technology are shown if you look around your workplace or home area. Anytime you need a commodity, turn to the surface mount Device structure:

  • Shorter
  • Thinner
  • Faster
  • Most potent

While an SMT assembly is still utilized in some situations or even in specific places aboard.

Summary:

Utilizing the surface mounting technique for electronic engineering, electronic modules are integrated using automated machines which put various elements onto a PCB.

Contrary to typical technological procedures, SMT components are put directly on the surface of the printed circuit board rather than soldering to a lead. Although an SMT device may seem quite complex, it operates extremely fast. The base of the SMT machine utilizes a tiny vacuum head to collect the parts before putting them accurately in the circuit. These devices, known as “pick” and “place” devices, pick up bits from a periodical and position them on a vacuous circuit board. It is important to remember that the correct programming of these devices plays a significant role in efficiency and durability.

SMT Assembly Technology

SMT Assembly Technology

Any piece of commercially manufactured electronic equipment these days is packed with tiny electronics. Instead of utilizing conventional components with wire leads, such as those used in home building and kits, these components are placed directly onto the boards’ surface, and many are very small.

What is Surface Mount Technology?

It is also known as SMT, Its a printed circuit board component installation process in which the components are mounted and linked onto the board’s surface utilizing batch solder-reflow procedures. Part leads are placed into plated through-holes and waves connected from the bottom, to fill in the holes and connect the components. Compared with plated through-hole insertion method, SMT offers the benefits of greater packing densities, better reliability, and lower cost. SMT is presently the most popular method for producing low-cost, high-volume consumer electronic assemblies.

Surface-mount technology is the name of the technique used for manufacturing an SMD. Most of the industry has moved away from using the traditional THT construction method of putting wire leads into holes on the circuit board to insert parts. Both surface mounting and through-hole mounting may be utilized on the same board for components that are not appropriate for surface inserting. Parts of SMT are often small than their through-hole frame since they have fewer or no lead.

Surface mount technology is used in almost all commercially produced equipment today since it provides substantial benefits during PCB manufacturing and allows much more electronics to be packed into a much smaller area due to the lower size of SMT components. Aside from the size, surface mount technology enables automated PCB assembly and soldering, resulting in substantial gains in dependability and significant cost reductions.

It is not necessary for component leads to travel through the board during PCB construction. Instead, soldering components directly to the board is quite acceptable. Consequently, surface mount technology was created, and the usage of SMT components grew quickly as the benefits of SMT components became apparent. In today’s electronics manufacturing, surface mount technology is the most often utilized technique for assembly. SMT components may be manufactured highly tiny, and several kinds, especially SMT capacitors and SMT resistors, are used in the billions.

SMT implementation on a PCB

The surface mount technology is used in the production of printed circuit boards. Surface mount technology refers to the assembly of electronic components by automated devices that put them on the board’s surface. In contrast to traditional PCB components, which are welded to the conductor, surface-mount components (SMT) are placed directly on the PCB surface, as is the case with conventional through-hole processing. When it comes to electronic assembly, SMT is the most widely utilized method in the business. In SMT assembly and production, surface mount technology is nearly entirely utilized. Surface mount technology allows more electrical components to be encapsulated in a small area.

Surface mount components are small and often perform well, and may be used with automated machines that select and place components, which removes the need for human involvement during the assembly process in many cases. Also difficult to install automatically, are the wire components since the wires must be pre-formed to ensure that the holes are spaced properly, and though in that case, there may be problems when the components are placed.

The majority of components on the circuit board are automatically positioned during PC Board fabrication. Some may need human intervention on rare occasions, although this is becoming less common. Some connections and other components have traditionally required supplemental installation, although manual placement is becoming less common. In today’s world, PCBs are frequently built to reduce or remove the issue make adjustments to incorporate parts that can be eventually put into the board.  Furthermore, several surface-mounted versions of components have been developed by component manufacturers, allowing for nearly completely automated production of most circuit boards. Technology using surface mounts PCBs must be selected with care, considering factors such as cost, electronic properties, or TGA (thermal expansion coefficient). During the development of a surface mount board (PCB), the kind of SMD element to be utilized dictates the type of PCB material to be used.

Pros and Cons of SMT

Pros

  • Better signal transmission:

The construction frequency may reach up to 5-5-20 solder joints per square centimeter when the PCB is bonded on both sides which are very high. High-speed signal transmission is possible with SMT printed circuit boards because of their short circuits and low delays.

  • Miniaturization:

Surface mount electrical components have a geometric dimension and volume much less than composite parts with through-holes. In general, through-hole interpolation parts may have their size and volume reduced by 60 percent to 70 percent, and few parts could have their size and volume reduced by 90 percent. Meanwhile, the weight of the components may be reduced by 60-90 percent.

Effect of high density:

The circuit’s distribution parameters are reduced because there are no or few leads on the element.

  • Less expensive materials:

Due to the improved efficiency of manufacturing equipment and lower packaging material usage, most SMT components cost less to package than THT components of the same kind and function. As a result, SMT components have a lower selling price than THT components.

  • Production method and cost:

There is no need to bend, shape, or shorten the components’ lead wires when placed on the Printed Circuit Board, which speeds up the process and increases manufacturing efficiency. The processing cost of the same functional circuit is less than that of through-hole interpolation, which may decrease overall manufacturing costs by 30% to 50%.

Cons

  • Repairs may be more challenging in small spaces.
  • It does not ensure that the solder connection will be able to resist the potting chemicals. When thermal cycling is done, connections may or may not be broken.
  • Although solder melts at high temperatures, components that produce much heat or carry many loads should not be surface-mounted.
  • This implies that parts that directly engage with the client should be physically bound to the hole rather than linked via it.
  • Since solder connections in SMT need less solder, the dependability of solder junctions becomes a source of worry. In this case, the development of voids may result in solder joint failure.
  • Surface-mounted components should not be used for components that produce significant quantities of heat or carry heavy loads because solder melts at high temperatures.
  • The majority of SMT component packages cannot be placed in sockets that allow for the simple installation and replacement of defective parts.

Method of surface mounts assembly

When electronic devices are placed to the surface of a printed circuit board using adhesive, surface mount technology is referred to as surface mount technology. It reflow solders the surface-mount assembly to the plate, essentially welding it together. Several components are selected during the design stage, and the printed circuit board (PCB) is produced using software tools, which prepares the ground for the surface mount assembly process to commence.

Preparation and examination of the materials:

Prepare the SMC and PCB and inspect them for faults. PCBs are often equipped with flat brazing pads, which are generally made of tin-lead, silver, or gold-plated copper and are referred to as pads.

Preparation of the template:

In solder paste printing, the steel mesh is utilized to hold the solder paste in a fixed location. It is manufactured in line with the layout position of the plate on the printed circuit board (PCB).

Print of solder paste:

The solder paste printer is the first piece of equipment to be placed throughout the production process. The purpose of this machine is to put solder paste to the suitable solder plate on the printed circuit board with a template and scraper. SMC and PCB solder pads are connected with solder paste using this method, the most widely used method.

Equipment’ locations:

Following confirmation that the PCB has the appropriate amount of solder applications, the board goes on to the next stage of the production method, which is assembling the parts. A vacuum or clamping nozzle is used to extract each component from the packaging. The visual system then checks the component before putting it at high speed in a preset location.

Inspection of the first component:

When it comes to first assembly or first piece inspection (FAI), subcontractors confront various difficulties, one of which is the time-consuming process of verifying client information. This is an important stage of the process since any mistake, if left undiscovered, may result in a significant amount of rework being required.

Soldering with reflow:

The assembled PCB board is subsequently transferred to the reflow welder for further processing, where it is heated to a suitable degree, allowing all of the electrical connections between the component and the PC Board to be established. This is done by bringing the assembly up to a suitable operating temperature.

Cleaning and Inspection:

After welding, thoroughly clean the board and inspect it for flaws. Rework or fix any flaws, then store the finished object. The most common SMT-related equipment and additional optical testing devices are SPI machines that are capable of being linked to the machine’s location to adjust the component position and connectable SPI machines that may be used to modify PCB alignment layouts when the printer is linked to it.

PRINTED CIRCUIT BOARD ASSEMBLY
PRINTED CIRCUIT BOARD ASSEMBLY
ICT Testing VS Flying Probe Testing - PCB Assembly

ICT Testing VS Flying Probe Testing – PCB Assembly

PCB Assembly
PCB Assembly

Flying Probe testing and In-Circuit Testing (ICT) are excellent choices for testing the quality of circuit board construction. Both tests detect the expected problems before the circuit board gets into mass production and assemblage. Both tests are a fantastic way of assessing your end product.

Testing of Circuit Boards:

PCBs are getting progressively advanced to fulfill the technical requirements of our digital era. Automatized testing of a board before the mass manufacture permits you to find out faults before mass manufacturing. In-Circuit Testing (ICT) and Flying Probe Testing can assist you in finding out these fundamental issues in the examining process:

  • Bonding Problems
  • Lamination
  • Copper Quality
  • Hole Wall Reliability
  • Electric conduction
  • Electrical resistance To Environmental Factors

In-Circuit Testing (ICT):

In-Circuit Testing equipment can find out 98% of PC Board constructing problems and is among the most best-selling options. It functions by placing the electric circuit board on the mend with a series of investigations to examine the different characteristics of the circuit board. It cannot just check for constructing defects but also operation functionality.

In-Circuit Testing is an effective instrument for PCB testing. It applies a bed of nails in-circuit examination equipment to approach the circuit knobs of a circuit board and determine the performance of every part. It can also test a few functionalities of digital laps, though the complexity attached can make it economically preventative.

In-Circuit Testing is most appropriate for testing productions that are more highly developed and high-volume. All the same, the up-front prices and growth lead time with IC testing are more advanced and more durable, respectively, than those of flying probe testing (FPT). This is as your producer must expressly create a customized IC testing fixture for every PCB.

The bang-up thing with IC testing is that after the instrument is formulated, costs per unit incline to be more down than with flying probe testing (FPT) as it entirely takes approximately 1 minute for a single test cycle. Flying probe testing (FPT), it can take up to 15 minutes per circuit board.

Flying Probe Testing (FPT):

Flying Probe tests (FPT) are some of the times known as “fixtureless in-circuit tests.” They yet utilize probes to try out lineaments on the PCB, but rather than a fixture, the investigations run to the test dots thru a programmed software system. Hence the examination “aviates” where it is required. This choice is most beneficial for low-volume and PCBs yet in maturation because of its versatility.

Contrary to an IC Testing machine, Flying Probe Testing (FPT) does not use a bed of nails mend. As an alternative, it utilizes a small quantity of portable and fixed probes to make a well synchronic in-circuit test of the big top and bottommost of your Printed Circuit Board. It is manufactured of high-precision goads — a few machines utilize as a couple of as 4 goads, although others can use as much as 20 per PCB side. They are programmed to adjoin component pins and execute electrical and operational tests to check if the circuit board is sound for the field.

Flying Probe Testing (FPT) is most appropriate for products that are in the immature stages of evolution and are low-volume grades. It needs no traditional tooling, and customization for each PCB is followed through programming utilizing the CAD data files you provided to the maker. With flying probe testing (FPT), costs-per-unit are more advanced equated to in-circuit testing because of more elongated test round periods per board (about 15 minutes)

In-Circuit Testing vs. Flying Probe Testing:

They both are good in their way, but they both have slightly different properties for testing circuit boards. In-circuit testing vs. flying probe testing depends on the following factors.

  1. Product pattern:

An effective quality test program (also recognized as adequate ‘coverage’) will count the choice of your Computer-Aided Design (CAD) data files and schematic drawings.

The CAD information file is utilized to bring forth the standard test program, which assures that data is sourced from the master design instead of any blue-collar interpretation of additional data. Good choice of populated and unpopulated sample PCBAs are essential for calibrating the test programs, ‘debugging,’ and creating any mends, so the assemblages physically accommodate as they were specified. Therefore thinking about product pattern for a bit, what are the main differences between each examination solution you might prefer to keep in mind?

  • In-circuit testing will need at least a 50 thou broad test pad per net, which has been organized into the PCB direct and utilized to aim for the determined test investigation. Double-sided mends can be expensive, so these had better, ideally, be on the same side entirely of the PCB.
  • Like those proposed by some other companies, flying probe testing machines can examine the ends of parts, pads, and exposed vias to get an approach to the electric network mesh.
  1. Coverage:

As we discuss ‘coverage,’ we look up to how much of the electric circuit you are competent to test. Both in-circuit testing and flying probe testing follow out what is known as a ‘manufacturing defects analysis’ or MDA, which permits the absolute majority of the most mutual process defects that are expected to fall out. These can let in: open electric circuit (due to depleted or defective soldering), short electrical circuits, resistless component measurements (resistances and electrical condensers), junction rectifier and electronic transistor orientation, and standard supply electric potential measurements. , given that these components are mutual to both testing programs, what puts them apart?

  • In-circuit testing can also provide restricted analog and digital measuring, which flying probe testing cannot due to the restricted number of investigations.
  • In addition to the vector-less examination, ICs that are integrated circuits can include a few powered (albeit familiar) operational testing to ascertain the soldering of flags to the PCB Assembly by a non-contact capacitive investigating or plate. In many cases, flying probe testing is restricted to just vector-less tests.
  • Almost all flying probe testing systems will propose a few forms of restricted optical inspection, which adds up coverage for those factors that cannot get at electrically. In-circuit testing mends usually will not offer the choice of optic inspection.
  1. Cost:

The programming cost will hinge upon the complexity of the assemblage but is generally as-is for either test result, potentially about £2000 more or less. As it comes to additional charges affiliated with the test, all the same, there are a few significant differences to have in mind:

  • The fixture prices of flying probe testing are typically zero, but in-circuit testing mends, in contrast, can flow to an extra of about £4000.
  • The evolution lead time for the flying probe testing is generally less than 7 days, but in-circuit testing can have up to 6 weeks for mending, construct, and programming.
  • In the consequence that your product pattern alters in any case, it will just need a program alteration. In the case of in-circuit testing, it could quickly require a new mending if any part or examine pads have been affected.
  • The actual machine test time is generally less than 60 seconds, which signifies that it is perfect for working promptly through bigger batches. At the same time, flying probe testing can accept a lot of minutes, which intends that it is often more suitable for little sets.
  • The velocity of in-circuit testing also means that it is comparatively cheap, frequently coming in at lowers than £1 per unit. Whereas flying probe testing is a somewhat more tedious process, and so can cost about £50, or more, per assemblage.

Final Words:

On the whole, the option between In-Circuit Testing and Flying Probe Testing will hinge upon many essential components of your project. Mainly these include:

  • Anticipated masses
  • PCB pattern/complexity
  • Budget
  • Lead evolution times

While making the PCB contract with the manufacturer, you should have a perfect understanding of every test system, which will only be better for your particular needs. For more small-scale circuit boards that do not need a lot of examination or circuit boards acquired in low masses, the flying probe testing system might be the most beneficial option. On the other hand, enormous groups of circuit boards and composite boards will require the velocity and extended capacities of in-circuit testing.

Frequently, printed circuit boards manufacturers will practice a combination of both testing systems to present you with the most effective results. As flying probe testing will be utilized for standard testing during the image stage of the circuit board development, so will transition the volume of the testing system to the In-circuit testing system for the entire production.

Merely by keeping in mind the expected benefits and the basses of the in-circuit testing vs. flying probe testing, is difference between the two programs, you should experience a much better ordered to choose the best testing scheme for your PCBA assemblage and both testing services are available at PNC.

Contact us at sales@pnconline.com to fulfill your customized testing requirements.