Tag Archives: PC Board fabrication

How Is PC Board Designed In KiCad

How Is PC Board Designed In KiCad

There are many free and open-source PC Board design software packages out there, but KiCad has become one of the more popular ones due to its combination of low cost and flexibility. As with most design software, it does take some practice to learn how to use it, which is why we created this guide on how to design PCBs in KiCad.
Whether you’re just getting started or want to review your skills, this guide will get you up and running quickly, allowing you to create your first PCB in no time.We’ll walk you through starting a new project, designing your circuit, creating the Gerber files to send off to your manufacturer, and much more.

Step 1: Open The File

To open up your chosen schematic file you need to double click on it. This will bring up your schematic editor, and also provide you with access to other tabs as well as additional views of your schematic. If you have more than one page in your project, they will appear separated by tabs that can be accessed at any time.

The first thing you should do is get rid of all unused components so that there is no clutter or confusion when designing your circuit board. You can do this by selecting each component individually and pressing delete or right-clicking on them to select Remove from Project from the menu.

Remember not to select any electrical connections you may have made during your design process because these are required for our circuit board to function correctly. When you are done removing everything that isn’t needed, save your project file under a new name so that you don’t lose what you’ve already done.

Step 2: Save Your Work

To save your work as you go, you must keep your progress handy. You can do so by clicking Save on KiCad’s main toolbar, or by using the CTRL+S on your keyboard.
As you work, you’ll want to save your work often. To do so, click File>Save Project (at the top left) or use the keyboard shortcut Control + S on Windows/Linux and Command + S on Mac.
Before saving, make sure that you haven’t included any hidden layers by clicking Layers>Show/Hide>Hidden Layers and making sure all layers are checked. It’s also helpful to set up a backup location for your project files.
If you choose to Save a project before compiling it when creating new projects, KiCad will automatically create backups of your files before compiling them into an output file. If something goes wrong during compilation, simply open one of these backups and continue working from there. The next time you compile, KiCad will overwrite your old backup with a new one.

Step 3: The Project Tree

You’ll notice that on your right-hand side, there’s a list of nodes. This is where you keep track of all your libraries, schematics,PCB designs and pcb fabrication files. The project tree will start with just one node called Unnamed; click on it and give it a name. That way you can return to it quickly and easily.

By default, designs are displayed as hierarchical project trees of symbols, footprints, and 3D models. Clicking on an object displays its properties in a panel at the left.

Right-clicking on any object opens a context menu for modifying it. It is also possible to create new project folders and objects from within KiCad using these menus.

There is no limit to how many objects or projects you can have in KiCad. When creating or editing the schematic sheets or PCBs, remember that the current sheet refers to either sheet 0, the top sheet, or sheet 1, the bottom sheet.

Step 4: Board Settings

The software is now configured for new designs. If you’re happy with all of your settings, click OK to save them and make sure that Configure Project for Manufacturing is unchecked. We want our design files to be suitable for creating prototype boards, but we don’t need any extra vias or silkscreen layers as those would just be an unnecessary drain on our budget.
The part of KiCad you’ll be focusing on is called Board, and it’s located under Preferences > Board. Click on that, then click Save as Default Project, then click OK. Now, any new projects you create will use these settings by default.
You’ve already got some elements selected in our schematic; now let’s check out how to add components from libraries. This is done using something called Footprints. For each component you want to add, different types of Footprintsdetermine their size and placement on your board.
To get started, find your library folder in Documents >KiCad Library> Components. There should be two folders inside here, such as footprints_1_0 and footprints_1_4. The former is used for older versions of KiCad while 1_4 has newer parts available.
Find one you like and double-click it to open up its details page. Here you can see a list of all the possible ways that components could be placed on your board, along with their respective sizes. Scroll down until you find one that matches your needs, and then right-click on it.
Once you have chosen a footprint, go back into your schematic editor and place your cursor where you want it on your board. It doesn’t matter where exactly, just somewhere near where you think it might fit nicely. Right-click again and select Add to Selection.
All instances of that component will now appear highlighted, allowing you to easily move them around without accidentally dragging another object instead. Move them around until they look good, and then press Ctrl+S to save your work.
Repeat steps 3–5 for each other component you want to add. When you’re finished adding everything, click File > Export Gerber Files… A window will pop up asking you where you want to export these files to.Choose your preferred file type before clicking Save.

Step 5: Trace Settings

To ensure your traces have sufficient space between them, you’ll need to change several settings in KiCad. If you’re working with 2 mils (0.002 inches) traces, choose Min trace width / Min clearance 0.2 mm and Min spacing 1 mm from under Advanced Tracing on the left side of the Project Properties dialog box.
If you’re using 5 mils (0.005 inches) traces, select Min trace width / Min clearance 0.5 mm and Min spacing 1 mm instead. For 10 mils (0.010 inches) or 20 mils (0.020 inches) traces, use 2mm/4mm as appropriate for those sizes.
Note that these values are set per layer, so if you want to use different values for top and bottom layers, simply click on the Top or Bottom layer in the Project Properties dialog box before changing these values. Once you’ve made your selections, click OK to save changes.
Now that you’ve got your trace size set up correctly, let’s move on to via size. Vias are used to connect one layer of copper to another through plated holes. These connections allow us to route signals through our board by allowing us to go from one layer to another without going all the way around (which would waste space).
The reason why we have two types of vias is that they serve different purposes depending on where they’re placed. Printed Circuit Board Blind vias are located inside a hole, which means they’re not visible from either side of our board. On the other hand, buried vias can be seen from both sides.

How Is PC Board Designed In KiCad
How Is PC Board Designed In KiCad

Step 6: Fabrication Output

You’ve created your schematic, laid out your board, and routed everything beautifully. Now it’s time to order those fab files. For now, let’s focus on getting these fab files ready for manufacturing.

  • Use DRC to ensure there aren’t any issues with trace width/spacing or via holes.
  • Add solder mask.
  • Add silkscreen.
  • Check for manufacturability (is your design feasible?).
    Export Gerber files.

Step 7. Exporting Gerber Files

Now that you have everything drawn up, save your schematic and board files. You will be using these files when it comes time to order your board. Start by going File > Save or hitting Ctrl+S.
To save Gerbers, you must create and name an output folder. Go ahead and do that now. After your boards are all laid out, you’ll be able to export them as Gerber files.
If you’re doing more than one layer of a board, like if you have an inner ground plane, then make sure that you select a Separate file per layer for Gerber, otherwise, they won’t work.
Also, make sure that you check every single box under File Options except Place component origin at the lower-left corner of pad/hole. This option puts components off-center on pads and is only useful if you plan to manually place components later.
Once you have checked those boxes, go to File > Export Gerber Files. A window will pop up asking where you want to save your Gerber. Name your project or whatever makes sense for what you’re making and click OK.
Then another window will pop up asking which layers you want to export. Select All Layers and click OK again. Finally, a third window will appear with progress bars telling you how long it will take to generate your Gerber. It can take anywhere from 10 seconds to over an hour, depending on how many layers you have selected and how complex they are.
Would like to know more about printed circuit board assembly? Email us at sales@pnconline.com

Printed Circuit Board Routing Practices after Auto Routing

Printed Circuit Board Routing Practices after Auto Routing

In electronic design, PCB routing is the positioning of conductive pathways on a printed circuit board before final soldering and interconnection. The purpose of PCB routing is to have an arrangement where signal traces connect electrically to components and other signal traces while avoiding the signal crosstalk and maintaining short electrical paths between the components.
You can have a manual PCB through computer-aided design software or the use of specialized routing hardware, such as manually controlled routers or auto-routers.

How To Reset Your Board After Auto Routing

If you’ve used an auto-router, but you’re not happy with its results, you can fix it in different ways. Moreover, if you know what a DRC is, you can use it to override certain errors that auto-router made.
DRC means the Design Rule Check which you can perform by running an ERC or Error Report Check. The ERC will report all of your errors on your design file on a text file. It will then tell you how many errors are found in each layer.
You can then go into each layer and manually change any error that was reported by using the P-CAD’s drag function to move components around until they fit perfectly within their pads or tracks. This is also known as drag fitting.
When everything fits perfectly, save your design as a new version so that you don’t accidentally erase anything important. Once saved, run another DRC and see if it finds anything else wrong with your board layout. If not, continue with another step to check for shorts between traces/pads/vias/traces, etc.
After fixing these issues, perform another DRC again. Now that everything looks good, export your Gerber files. Make sure you select the top copper layer only and then hit OK. Your Gerber files should now be ready to send off for PC Board Fabrication.

How To Manage Multiple Copies Of The Same Net

In printed circuit boards, nets are electrical connections between different parts of a design. For example, if you have an LED that is connected to the ground and another net that connects to a microcontroller through various resistors, there will be two nets connecting these two components.
You need to route one copy of each net in your board file in order for it to be used in your design. Having too many copies can make it difficult to update or change an element of your circuit board design.
In case you have several copies of a net, they will all be shown in different colors. But, you should always try to join them together instead of having multiple copies. The PCB editor provides a Merge Nets option which can do that for you. To use it, just click on it in one of your nets and select another net for merging. You can do that with as many nets as needed. When finished, press OK and then Save Board to save your changes. You can easily learn it through various video tutorials available on the internet.

How to Manage Tight Spaces in PC BOARD Routing

The key to successfully routing a PCB with tight spaces is in visualizing what you’re doing. If you can see it, you can do it. Once you have a clear picture of your goal, there are several techniques to deal with PCB obstacles that make it possible to route those hard-to-reach traces. Here are some tips on managing tight spaces.

Place your components as close together as possible: This will leave plenty of room for routing at either end of each component lead.

Put components with shorter leads toward one side: This allows more space for routing on other sides, where longer leads might overlap.

Use right-angle headers instead of straight headers when possible: They’re easier to route around obstacles because they have a narrower footprint. If you can’t use the right-angle headers, place them closer to an edge than a corner.

Use large-pad ICs instead of small-pad ones when possible: Large pads make it easier to route around them without accidentally overlapping their neighbors.
Put components with longer leads toward one side: This allows more space for routing on other sides, where shorter leads might overlap.
Place through-hole components near an edge: This leaves plenty of room for routing on other sides, where smaller holes might overlap. It also makes it easier to access component pins from both sides.
Route clockwise around obstacles when possible: Clockwise routing tends to be smoother than the counterclockwise routing because it keeps your drill bit moving forward rather than backward.

Tips On Hard-To-Route Pins, Vias, Signals, Planes, And More

One of the biggest advantages of auto-routing tools is that they save you a ton of time by automatically planning out your board’s signal paths. Though these tools are very convenient to use, there are certain types of signal paths that can be very difficult for them to handle.
Here’s a quick rundown on some common hard-to-route signal paths and what to do about them, so you can make sure your PCB design doesn’t have any issues during production.
Multi-layer boards allow you to create more complex circuit layouts than would otherwise be possible with a single-layer PCB. But, when it comes down to it, most manufacturers prefer single-layer boards because they don’t cost much more and will typically get you faster turnaround times than multi-layer boards.
If you’re trying to decide between single-layer and multi-layer, here are a few things to keep in mind:
Multi-layer boards require additional fabrication steps. Though multi-layer boards do indeed allow for more routing options than their single-layer counterparts, they also require additional fabrication steps which increase the manufacturing costs. This means that unless you need those extra layers, it’s probably best to stick with a single-layer board.
The single-layer printed circuit boards can fit more components. This may seem like an obvious point, but when designing your layout, remember that multi-layer boards have smaller component pads and traces than their single-layer counterparts. Each layer adds another set of traces and pads. So, if you’re looking to fit more components onto your board, you should consider sticking with a single-layer PCB.
In other words, both multi-layer and single-layer PCBs have their pros and cons. So, if you aren’t sure whether or not you should use one over another, or if you simply want to play it safe, go ahead and choose a single layer board instead.

Printed Circuit Board Routing Practices after Auto Routing
Printed Circuit Board Routing Practices after Auto Routing

Avoid Over-Relying On Auto-Routing

Though auto-routing is a great help, you cannot over-rely on it. Besides, you have to select the right software for this purpose. There are lots of free software available on the internet which might or might not work well in this case, so choose carefully. You should have practice to route traces with any software that we will discuss further. Besides, there are different parameters of auto-routing that should be precise, however, they vary from project to project or between different modules on a single printed circuit board.

Top 5 Tips for Manually Routing A Circuit Board

There are different things to consider while manual routing on PCB, such as:
1. Keep your route sizes as consistent as possible: Having a fixed grid is highly beneficial when it comes to routing. You should lay out your design in a way that allows you to connect pin-to-pin with no more than 5 percent variation from expected routes. It ensures an optimal layout before starting any manual routing work.
2. Use proper start and endpoint selection: Starting a route at a pad or component lead not only wastes time but also affects a board’s signal integrity. To avoid these issues, always use endpoints or pins for start/endpoints whenever possible.
3. Avoid using vias for signal layers: Vias are used for connecting two different copper layers on a PCB, not for connecting two pads on one layer. If you need to connect two pins on one layer, consider using micro-vias instead of traditional vias.
4. Don’t overlap traces: Overlapping traces can cause different kinds of problems, such as ground loops and impedance mismatches. So, make sure you leave enough room between each trace for easy soldering and troubleshooting later on.
5. Focus on long-term flexibility: Once you have routed your board, think about how you might want to change it down the road. For example, will you ever want to add another connector? How about changing around some components? You may find that adding the solder mask artwork into your design software now will prevent you from lots of headaches later on.
Your ability to change the designs without having to reroute everything from scratch makes a huge difference in future productivity and costs. The best way to learn new skills is by doing new things, so don’t be afraid to take chances and be innovative.
You can develop the best PCB by focusing on different techniques and design parameters for which you can also read our other posts.
Would like to know more about PCB routing practices after autorouting or PC Board assembly? Email us at sales@pnconline.com

Design Elements Influencing SMT Assembly

Design Elements Influencing SMT Assembly

Smart devices should perform well to satisfy consumers who want high-density devices. The Surface mount technology or SMT helps develop high-end electronics. The process of SMT involves soldering which goes through different problems due to PCB pads, reflow technology, stencil design, quality of the soldering paste, and different technical parameters.
SMT manufacturing involves many challenges and different design elements influence it. The supplier needs Gerber files and design data for the placement of components. Gerber files help configure different SMT manufacturing machines and develop stencils for placing the solder paste on the circuit board. The manufacturer and designer should discuss the design parameters and elements for precise SMT manufacturing.
So, different elements affect the quality of SMT that we will discuss below.

Making Bill of Materials (BOM)

SMT has various features and BOM is one of them. The flow of soldering has close contact with the bill of materials. You have to consider the below factors to create a high-quality SMT.
• Components packaging should be compatible with mounting requirements.
• The component figure should be according to the SMT requirements to get the desired shape with precise dimensions.
• The PC BOARD pad soldering should be compatible with the reflow technology to prevent its oxidation and the same applies to the solderable ends of the elements. If these two factors get polluted, it would result in defective solderings, such as solder beads or pseudo soldering. The same is true regarding the humidity sensor and PCB administration.

Design Elements Influencing SMT Assembly
Design Elements Influencing SMT Assembly

PCB Pad Design

PCB design highly influences the manufacturing of SMT in terms of quality. According to HP research, 80% of SMT manufacturing defects occur due to the poor design of a PCB. So, the designer should focus on essential factors, including the folder mask, layout of components, type of the substrate substance, thermal pad design, assembly techniques, component packages, the position of vias, optical positioning, and the transmission boundary.
If the PCB pad design is poor, it would result in deflected soldering even if the mounting position is fine. Like, tombstoning or disposition of components can happen. You can avoid these issues by considering the key aspects while designing the SMT pad, such as the distance between the pads, residual size of the pads, width and symmetry regarding pads, and avoiding through-hole vias.

Printing of Solder Paste

The paste of solder should have a compatible printing technology, or it will affect soldering. A poor printing of solder paste results in a deflected PCB that you have to revise. During the printing of solder paste, you should consider three essential elements, such as solder paste, scraper, and stencil

Quality of The Solder Paste

Solder paste is an integral part of reflow soldering, and it’s a combination of alloy and flux. Precise soldering joints depend on the powder of alloy, whereas the flux removes oxidation from the surface to ensure high-end soldering. Even, the paste of solder having 50 percent of solder of alloy can be enough if it has high quality. Two key factors of soldering paste, including storage and application, determine its quality. Make sure to store the solder paste at appropriate temperatures ranging from 0 to 10 degrees.

PCB Stencil

The pad of the PCB should have evenly applied solder paste through a stencil, which is a major factor in Printed Circuit Board printing. Moreover, the eminence of the stencil affects the printing eminence. The stencil is designed through different techniques, including laser cutting, and chemical corrosion. You can design stencils by considering certain characteristics, such as:
• The thickness of the steel sheet
• Aperture design
• Mark points
• Anti-solder ball processing
• Direction of printing
• Type of scraper in terms of shape and material

Printing Parameters

You have to consider essential parameters of printing for precise results, such as frequency, scraper speed, scraper pressure, stencils down release speed, and its cleaning mode.
Both pressure and speed of scraper should be well-balanced, like not so low or so high. If these values are not balanced, it would result in defective printing, thus influencing the manufacturing.

Right Equipment

There should be accurate equipment to have high-level printing of the soldering paste. A small space and high-density PCB should follow the right printing rules for a stable process.

Understanding PCB Support

The printing of the soldering paste depends on the PCB support, as its lack can result in an uneven soldering paste. So, it is important to have uniform PCB support to keep the PCB and stencil close enough.

Components Mounting

The mounting of the PCB parts or components depends on different elements, including the right pressure for mounting, the quality of the components, and their precise location. Components should be according to the BOM, and mounted on the PCB at the right place, following the right dimensions. At the same time, the mounter should be precise in this case to ensure a stable mounting of the components onto the PCB pads.
The mounting angle should be correct, besides, the mounting pressure should be suitable, like not too high or low. You can evaluate mounting through different elements, such as the thickness of the board, components’ package, mounted z-axis, and nozzle’s pressure.

Quality of Reflow Soldering

The temperature curves of the reflow soldering should be well-set to have high-quality soldering of areas to be welded. An increased temperature can affect the PCBA due to heat occurring at a fast rate. It would cause PCB deformation, damaging the components. Besides, the soldering paste has a solvent that gets volatile, splashing out the metal composites as tin’s plating balls. Engineers apply nitrogen reflow soldering to get rid of oxidation, enhancing the quality of soldering.
Moreover, make sure that the reflow soldering is compatible with the PCB substrate, size, material, weight, and thickness. Besides, it should be according to the reflow oven’s structure, and the temperature zone’s length should also be considered.
SMT assembly is easy to optimize by having the best PCB design and software to analyze it. The right design software helps you to set assembly standards without missing any factor.

Additional Information

The solder paste is applied to the pads through a machine by holding the stencil tightly on the PCB. Then components are placed according to the footprints with the help of optic technology. The engineers inspect the placement of the components through an optic machine to make sure it’s free from flaws, and this should be done before reflow soldering. Sometimes the x-ray technology is used for inspection which is essential before PCB testing. Such inspection helps detect poor solder joints, as well as short circuits that happen during the reflow soldering.
The placement machines are unable to hold a PCB if the PCB edge is crowded with components, and this can influence SMT manufacturing. You also have to consider the tooling strips for miniature PCBs. The tooling strips should be at least 6 mm to help a machine have a proper grip during the PCB assembly. You can also give the V-score on the tooling strips to separate the parts easily in the later stage.
Keeping the SMT components in one direction can also reduce the flaws and helps have placement the components in one go. So, the selection of the components and their placement affects the SMT assembly, making it smooth or horrible.

Frequently Asked Questions

What is PCB?
PCB is an abbreviation of Printed Circuit Board. It is used in electrical devices to provide them with signals or currents to operate. Printed circuit boards are used in different industries, including networking, electronics industry, gadgets, aerospace, and much more.

What is SMT in PCB?

SMT stands for Surface mount technology, and it helps develop high-end electrical devices.

What is Soldering in PCB?
Soldering is a manufacturing technique in PCB where two metals are connected through another material’s fusion. It should be precise because poor soldering results in a device malfunction.

What Are Important Characteristics Of A Stencil Design In PCB?
Stencil design depends on certain characteristics, such as the thickness of the steel sheet, aperture design, mark points, anti-solder ball processing, the direction of printing, and the type of the scraper in terms of shape and material.

Final Thoughts

Smart devices should perform well to satisfy consumers who want high-density devices. The Surface mount technology or SMT helps develop high-end electronics. The process of SMT involves soldering which goes through different problems due to PCB pads, reflow technology, stencil design, quality of the soldering paste, and different technical parameters.
SMT manufacturing involves many challenges and different design elements influence it. PCB design highly influences the manufacturing of SMT in terms of quality. According to HP research, 80% of SMT manufacturing defects occur due to the poor design of a PCB.
The PCB designer should focus on essential factors, including the folder mask, layout of components, type of the substrate substance, thermal pad design, assembly techniques, component packages, and the position of vias, optical positioning, and the transmission boundary.
Like to know more about the Design Elements or PC Board Fabrication? Write us at sales@pnconline.com

PCB Design

DFM Issues in PCB Design

You need a well-designed PCB for the effective functioning of the device, and you can have it by focusing on the DFM or Design for Manufacturing. Different requirements are there in terms of PCB design, management, and fabrication that you have to follow. At the same time, you should consider the timeline to have a circuit board within your budget.

PCB and DFM Issues

Having well-executed CAD tools is easy, but these tools cause certain DFM issues which need lots of effort to solve. Sometimes a PCB is correct in terms of electrical requirements, but it is hard to manufacture because you don’t focus on the design layout. The layout issues stay hidden, making it hard for you to assemble a PCB, besides the testing also becomes difficult.
However, you can overcome the DFM problems if you understand the entire process of manufacturing. Now, we will discuss a few DFM issues, including tolerances, acid traps, SMD issues like open vias and uneven connections, a wrong opening of the solder mask, and the violation of standards.
Once you know these problems, it becomes easier for you to resolve them and have an easy fabrication that involves less time to review the design. So, let’s discuss the DFM issues one by one and find their solutions to have the best device.

Connection Issues On The SMD Pads

The connections on the SMD pads often become uneven as components are so small and hard to handle. These connections should be even to avoid the tombstoning while soldering reflow. Likewise, this rule also applies to the BGA pads for precise soldering. In other words, you should place a compatible pad according to the footprints of the components, so the size of the pad matters a lot. Generally, the pad sizes are standard for common components.
The designer can easily check the pad sizes without exporting the Gerber files, like through a 3D, as the manufacturer won’t do this for you. Manufacturers only see the Gerber files to compare the sizes of the components’ in the BOQ.
You also need testing after PCB fabrication to make sure that the connection is even and it involves deep inspection like an X-ray. So, the designer should inspect the footprints to see if they are according to the lead size of the component.

A Wrong Solder Mask Opening

The term solder mask or solder aperture is an opening that helps the solder stay intact on the SMD pads while soldering, be it the wave or hand soldering. A solder ball develops on the pad while soldering which can collapse if it’s too large, moving around at high temperatures. Designers leave a small opening in the solder mask to keep the solder ball intact while soldering, even if the ball is too large. This technique also works in the BGA where a solder dam develops when the mask hinders the pad from circuit board’s via.
You can eliminate this issue by creating the footprints of the components having a proper solder mask opening which often crosses the pad edges about 4 to 5 mils. When the solder aperture is very large, it is not able to block the flow of a solder ball while wave soldering.

Open Via Issues In The SMD Pad

The designer should not give via-in-pad in the PCB. When you place a through-hole via very near to the soldering area, it causes the solder to move through a circuit board’s back. When via is attached to the internal layer’s large plane, it will cause the heat dissipation into that plane. So, it results in tombstoning during pcb assembly.
Though the via-in-pad has a great role in the HDI PCB having BGAs with a fine pitch, it should be avoided in smart circuit boards. You should insert plated-over vias for small boards to avoid the heat dissipation that occurs during soldering and also makes via the connection for thermal relief.

PCB Design
DFM Issues in PCB Design

Understanding the Acid Traps

Printed circuit boards consist of various copper images. Engineers remove extra copper from the laminate with the help of chemicals that sometimes get trapped in a PCB with narrow corners, and this is called an acid trap. This process results in rough copper, damaging the PCB.

There is a way to avoid the acid traps by using low-viscosity chemicals. Acid traps also happen when the routing is done at 90 degrees, so beware of the solution that a PCB manufacturer uses, in this case, to see if it is causing acid traps. The best practice is to route the traces at 45 degrees to avoid the acid traps.

Design Tolerances

PCB design depends on precise parameters and tolerances and you have to maintain them. If you don’t use specific design requirements, the routing tools will create any tolerance. You should keep traces at some distance from other traces, from pads, and from the copper pours. The clearances help in etching and leave a space for manufacturing clearances.
These tolerances are also essential in high voltage layouts. According to the IPC 2221 standards, the difference between conductive elements determines the minimum clearance between the conductor and a trace. The purpose is to avoid the unintended ESD or, conductive filamentation in the case of adjacent conductors, and electrochemical corrosion.

IPC Standards and Their Violation

There are unlimited IPC standards that you have to follow for a reliable PCB. Such standards are regarding tolerances, the annular ring size of the via as per aspect ratio, teardrops on vias and pads, land patterns, sizes of micro vias, trace width as per current, and high temperatures.
Some manufacturers check the Gerber files and testing rules to see if you have violated any standards. Generally, the IPC standards are not mandatory, unlike high-end industries, but following them makes a Printed Circuit Board more reliable.

Accessing The DFM Issues Through PCB Design Software

The above DFM issues are the common ones in PCB manufacturing, but there are several other issues. If you manage all the design rules, you and your manufacturer would end up with a reliable PCB. You need the right software to create a rules-based PCB, avoiding the DFM issues.

Frequently Asked Questions

What Is DFM In A PCB?
DFM is Design for Manufacturing which means you have to have a special layout design for a PCB to be manufactured correctly. You will have to face many issues if there is no DFM.
How to Check the DFM Issues?
There are certain PCB testing tools to check the data set, finding issues that can delay the manufacturing. Many online platforms also offer DFM testing tools.
What is SMD in a PCB Design?
SMD stands for Surface Mount Device, and SMD components are parts being soldered to the PCB by using the surface mount technique. There are several types of SMD components having different forms.
What is BGA in a PCB Design?
BGA means a ball grid array, and it’s a surface mount technique for integrated circuits. It helps mount devices permanently, like in microprocessors.
What are PCB Tolerances?
PCB design depends on precise parameters and tolerances, and you have to maintain them. If you don’t use the specific design requirements, the routing tools will create any tolerance. You should keep traces at some distance from other traces, from pads, and from the copper pours. The clearances help in etching and leave a space for manufacturing clearances.
What Are IPC Standards in PCB?
There are unlimited IPC standards that you have to follow for a reliable PCB. Such standards are regarding tolerances, the annular ring size of the via as per aspect ratio, teardrops on vias and pads, land patterns, sizes of micro vias, trace width as per current, and high temperatures.

Final Thoughts

Having well-executed CAD tools is easy, but these tools cause certain DFM issues which need lots of effort to solve. Sometimes a PCB is correct in terms of electrical requirements, but it is hard to manufacture because you don’t focus on the design layout. The layout issues stay hidden, making it hard for you to assemble a PCB, besides the testing also becomes difficult.
However, you can overcome the DFM problems if you understand the entire process of manufacturing. Now, we will discuss a few DFM issues, including tolerances, acid traps, SMD issues like open vias and uneven connections, a wrong opening of the solder mask, and the violation of standards.
There are several DFM issues, and if you manage all the design rules, you and your manufacturer would end up with a reliable PCB. You need the right software to create a rules-based PCB, avoiding the DFM issues.
Contact us at sales@pnconline.com to know more about DFM issues or pcb assembly services.

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