The process of designing the layout of a PCB or a Printed Circuit Board is one of the toughest jobs to do in this present market. Mistakes are bound to happen in any human, even in the easiest of jobs. Therefore, it only makes sense that errors will occur while the designing of the Printed Circuit Board layout is being done. A Printed Circuit Board contains multiple types of minute components, each of which is very crucial for the proper functioning of the Printed Circuit Board as a whole. The required purpose of the board will only be properly fulfilled if there is no fault with the Printed Circuit Boards, that is, with the manufacturing process of the board.
With such a huge number of crucial components, anyone can easily understand how even the slightest of mistakes can cause massive damage and sabotage the entire operation of the circuit board. You may be working hard days after days to put together a circuit board, and it can be a complete failure due to one silly mistake. In any such case, the person or persons who have manufactured that particular Printed Circuit Board will face the blame. Even the thickness of the board can go wrong, and the copper traces present in the circuit board can also be easily misaligned. In order to make sure that the Printed Circuit Board is perfectly alright, the designing and manufacturing process of the circuit board should be absolutely errorless.
In most cases, the soldering faults, misalignments, designing faults and manufacturing, also known as Design for Manufacturing or DFM is the reason for the failure of the Printed Circuit Board. If you want your Printed Circuit Board to be free from errors, at first you have to identify them. After that, you should also be aware of the ways in which you can easily avoid these problems. When a Printed Circuit Board is free from the general types of errors, the chance that the Printed Circuit Board will work properly increases dramatically. In such cases, you need to make sure that the manufacturing process and designing are mainly as required.
Common Mistakes That Are Present On A Printing Circuit Board
Given below are the top 10 types of mistakes found most commonly on the Printed Circuit Boards, and how to avoid them. These are the mistakes that you need to rectify to make sure that the Printed Circuit Board serves its purpose properly, has a long durable life, and provides output for the highest possible level for the longest time.
1. Adequate Edge Clearance Should Be Kept
The most common type of mistake that is found in most Printed Circuit Boards is that these boards do not have an adequate amount of edge clearance space. Mainly, the Printed Circuit Boards have a proper coating with metals such as Copper. Usually, this layer of copper is well protected by a layer of another material. When the Printed Circuit Board is manufactured, there is a very high chance that the portion near the edges in the circuit board will get cut off. This cutting off can also include the portion of the protective material. When this part gets scraped off, the copper present beneath this layer will get direct exposure to air and moisture. As a result, this part will get easily corroded. Therefore, the corrosion can easily destroy the functionality of the circuit. In extreme cases, even short circuits can occur, resulting in mishaps.
This mistake is very common, and it is also very easy to fix it as well. To make sure that this doesn?t happen, you have to leave adequate space between the copper part and the Printed Circuit Board edges. It is recommended that a minimum of 0.01 inches should be left out for the outer layers. Similarly, a minimum of 0.015 inches should be left for the inner layers of the board. The best way to make sure that this space limit is automatically maintained is by designing the Printed Circuit Board with such specifications mentioned in the layout of the circuit board.
2. Acid Traps Should Always Be Checked
The acid traps are one of the dangerous things to avoid while the manufacturing and designing of any Printed Circuit Boards. To simply put, when the circuit boards are put up with right angles, or angles pertaining to 90 degrees, it has a chance to accumulate the acid. When such a thing happens, the accumulated acid is strong enough to create problems such as corrosion and etching issues. Hence, to avoid this problem, the Printed Circuit Boards should avoid being designed with 90 degrees angles. The best replacement of the 90 degrees angles is the 45 degrees angles.
In most cases, it happens that the designers of the Printed Circuit Boards overlook the design, or fail to check all the aspects in a thorough manner. In such cases, the 90 degrees angles can cause the above-mentioned problems. These right angles are sometimes created unintentionally when two traces are joined in the circuit board. If not checked, such angles remain to accumulate the acid and degrade the functionality and durability of the Printed Circuit Board. Hence, it is very important to check the design of the circuit board to avoid right angles and remove any acid traps before the manufacturing process.
3. VIA Should Not Be Kept In Pad
It has been seen often that the space in the Printed Circuit Board is very limited. For this purpose, the VIAs are sometimes kept in pads. This is mainly done as the VIAs, when kept in pads, are very much beneficial to the Printed Circuit Board as the thermal management is much more properly done. This can also help in space management, as the different bypass capacitors can be kept much closer than before. If the components of the Printed Circuit Board are hand soldered, this is a pretty good choice.
However, the soldering process will consist of automated designs, and this is where it gets tricky. If the VIAs are kept in the pads, the solder is drawn away from the pads. This will result in the improper soldering of the components, resulting in decreasing the work efficiency of the Printed Circuit Board. Therefore, VIAs should not be kept inside pads unless and until there is no other option. The buried VIAs, blind VIAs, and the micro Vias are good options. If an extra expenditure is not a concern, then plugging and plating the VIA should be done, followed by the soldering process.
4. Avoid Over-Complicated Designs
Another mistake in the Printed Circuit Boards that is very commonly found in the implementation of designs that are way too much complicated. When the number of components to fit are much more than usual in the circuit board, then such type of mistakes are very commonly found. The most common type of complicated designs is when the assembly contains the SMT on both of the sides. This should be avoided as much as possible. For the through-hole components, the same thing follows.
The cost goes higher with this as the Printed Circuit Board will be required to run more and more with the pick and place machine, making the process complicated. Hence, the layout of the Printed Circuit Board should be done without complicating the design too much.
5. Send The Complete Pick And Place Files
The Pick and Place files can capture your interest. In this file, the required information regarding the position of the various components is respectively present. This is the file that has to be sent to the manufacturer of the Printed Circuit Board, and the designs of the layout have to be included as a must. However, the data should be verified at first before sending, and crosscheck where the required information is completely sent.
It is obviously a headache for the manufacturer of the Printed Circuit Board where the components are present, but the information regarding how to place them is not present. To make sure that you cover every required information, check these before sending-
? Component Description
? Component Part Number
? Component Reference Designator
? Manufacturer Part Number
? Mid-Point X (mm)
? Mid-Point Y (mm)
? Orientation Angle
? PCB Layer Side
6. The Layers Should Be Verified
The designing of the Printed Circuit Board will be generated sooner or later. Hence, the finalizing of the design of the circuit board should only be done after the board layers are said to be correct.
Use the free third part Gerber viewer to see and verify if the layers of the circuit board are matching up. When you get to know that the matchup of the layers is not proper, you can adjust the requirements accordingly and accurately.
7. A Single Tool Size Should Be Used
When multiple tool sizes are used, the total expenditure goes up by a very high margin. Therefore, it is always advisable to use a single tool size. When multiple tool sizes are used, the holes made are of different sizes. Hence, it can create a lot of problems in the future.
If the size of the hole is different, different toolsets are also required, which is both unnecessary and time-consuming. Therefore, the holes and the VIAs should be made with the same tool such that the holes are of matching sizes. When there are no different sizes, the cost gets curtailed.
8. Pads Should Not Be Put In Silkscreen
The manufacturer of the Printed Circuit Board can get extremely annoyed if this general rule is not followed. One should strictly avoid putting the pads into the silkscreen. The solder mask and the silkscreen should be separated by a minimum distance of 0.003 inches. If not, the chances are high that the pan will contain the silkscreen.
When such a situation occurs, the process of soldering becomes automatically difficult. Hence, the Printed Circuit Board layout should always be rechecked, and silkscreen should not contain pads.
9. Pads Should Contain Solder Mask In Between
The Printed Circuit Boards are often completely damaged by the internal short circuits. This happens when the solder bridges are formed well. If the pads do not contain a solder mask between them, then the chances of solder bridges forming is very high.
Hence, it is quite important to know about the solder mask application, especially when the circuit boards with larger size and design is involved.
10. Size & Shape Component Footprints Should Be Correct
Another of the major things that many people overlook during the manufacturing and designing of the Printed Circuit Board is whether or not the Printed Circuit Board designed pads will be actually able to accommodate the components. The BoM or the Bill of Materials should always contain the mention of the components in question.
It is to be clearly seen if the required components will be able to fit or not. The fit should be proper. There should not be any cramping, and the location near the edges should be avoided as well. Every minute detail should be checked from top to bottom. In many cases, it has been seen that the component footprints are sized very inaccurately. In such cases, the soldering of the components is not done properly. In very bad cases, the assemblies can even see the components breaking. Therefore, the IPC standards should be maintained while designing the Printed Circuit Board. The layouts of the Printed Circuit Boards should be always checked up, and every minute detail should be considered.
When a manufacturing approach is taken for the design and manufacturing of the Printed Circuit Board, the designs can be mostly free from any kinds of risks. In most cases, if you need a proper Printed Circuit Board, the companies and industries should always be your target. With proper designing, the assembly is very well done. With multiple components to choose from, it is highly probable that there will be at least some kind of errors. Therefore, follow the steps given above to identify and know how to avoid the Printed Circuit Board mistakes.