Electronic devices are getting compact these days, and PCBs work as the brains of every electronic device. More compact PCBs pack more performance, and electronic devices are becoming more powerful with every new generation. With many things happening on the positive side, manufacturing and assembling PCBs are getting complex. Things like stencils help assemble the PCB, so everyone in this field needs to know how to order PCB stencils.
Here we will discuss how to order PCB stencils and everything you need to know.
What is a PCB Stencil?
When we need to attach PCB components to the PCB, a solder application is necessary. When manufacturing PCBs on a large scale, it is not efficient to use a soldering iron to solder every joint. So, a PCB stencil makes things easier when it comes to applying the soldering paste on the PCB.
It is a stainless steel sheet that has laser-cut openings precisely made according to the solder pads of the PCB. Solder paste is applied to the stencil and then flattened out, which deposits solder paste specifically on the solder pads on a PCB board.
The components can be placed next, so heating the whole thing melts the solder paste, and the components are soldered on the PCB. So, we can say that the purpose of the PCB stencil is to apply the solder paste adequately and accurately onto a PCB. This way, every solder pad on the PCB gets a perfect electrical connection and strength.
What are the qualities you need to consider when ordering a PCB stencil?
The first thing that you need to know for how to order PCB stencil is the set of qualities of a stencil. Each of these qualities has practical applications for a PCB. So, here are the qualities that you need to know when ordering a PCB.
The thickness of the steel sheet is the first thing to consider when you order a PCB stencil. The thickness of the steel sheet is essential to be perfect because the right amount of solder paste can only be deposited on the PCB if the stainless steel sheet is not perfectly thick.
Too thick steel sheets with deeper cuttings will leave more solder paste than needed.
Too thin steel sheets with not-so-deep cuttings will leave solder paste that will not be enough according to the soldering pads.
Leaving less soldering paste than needed will not bring the best mechanical strength with weaker joints. Similarly, having too much solder paste could be solder bridging. In either case, the functionality of the stencil will not be efficient if the thickness of this sheet is not perfect.
Sized of the opening
The next thing to consider is the size of the opening. It also needs to be perfect according to the PCB solder pads. Using the wrong sized openings on the stainless steel stencil means that there will be less or more solder paste applied on the PCB pads.
A general rule for the size of openings is to be two-thirds less than the area of the solder pads. It will ensure that the perfect amount of solder paste is applied to the PCB pads. Keep in mind that the openings being too small may get less paste on the pads because some solder paste will be left attached to the walls of the stainless steel sheet.
Considering the material of the PCB stencil is next because stencils are made with different materials. The material of the stencil also affects the ability to apply solder paste to the PCB pads. In most cases, stainless steel is used for making stencils. So, most of the time, you will use stainless steel as the material for making your stencil.
The last thing you need to consider is the alignment of the stencil because the stencil and PCB need to be perfectly aligned. Most stencils have multiple openings where the solder paste needs to be deposited. So, with the wrong alignment, the solder paste will not correctly apply to all the PCB solder pads.
In this way, the PCB will not work as required. That is why there are fiducial marks on both the stencil and PCB. When looking for how to order PCB stencil, you must plan where to get these marks on the PCB and the stencil for the perfect alignment.
How to order PCB stencil? The complete process
How to order PCB stencil is similar to online shopping with a few differences. So, here we will trace all the steps you need to consider in this process.
Designing the PCB stencil
The first thing you will do when ordering the PCB stencil is to design the stencil. If you order the PCB and stencil at the same time from the same place, then there will not be much to do.
For such cases, most manufacturer websites have built-in options that let you get the stencil according to the PCB schematic and PCB design. If you already have your PCB and only need to get the stencil, then you will need to design the stencil separately according to the PCB's requirements.
Selecting your stencil manufacturer
Now that you are done with the design, you must start choosing the stencil manufacturer. There are different options available online for manufacturing your stencil. So, whenever you are looking to manufacture your stencil, make sure to get the following qualities:
Usage of the correct material
Latest laser-cutting technology
Timely delivery without any delays
You can get your PCB stencil manufactured without any other issues when you find a manufacturer with all these qualities.
Uploading the stencil file
Go to the stencil manufacturer's website and upload your stencil design file. If you get the PCB and stencil manufactured simultaneously, you will only need to upload the Gerber file of the PCB, and the manufacturer will provide you with the perfect stencil. When uploading your file, you will come across different specifications, including:
Select each of these, and then you will be done with uploading the stencil file.
Proceeding with the order
You only need to proceed with your order when you are done specifying all the technicalities. Simply add the shipping details and proceed with the payment. Checkout, and you will be done with your order. Now all you have to do is wait for the delivery of your PCB stencil.
What are the benefits of ordering a PCB stencil?
PCB stencils come with many practical benefits for the PCB manufacturing process. Below are some benefits you can entail after knowing how to order PCB stencil.
Even application of solder paste
The first benefit of getting a PCB stencil is even application of the solder paste on all solder pads. Every SMD pad on a PCB needs an adequate amount of solder paste to ensure the perfect connection of every component and every pin. This way, the solder deposits on every pad are perfect when the paste melts.
It makes the PCB assembly process easy because there are fewer chances of creating errors in applying soldering paste. Thus, there are no solder bridges and weak soldering joints as well.
A quick application of solder paste
The next benefit of using a PCB stencil is how quickly it gets things done. These days, PCBs have hundreds and thousands of soldering points where an adequate amount of solder paste is required.
Applying the solder paste individually can be very time taking. At the same time, the stencil makes this job quick, and apple solder paste on a large area covers more solder pads in one go. Consider applying solder paste on a whole batch of PCBs, and you will see how quick it makes the application of solder paste is.
One of the biggest benefits of PCB stencil is the pinpoint accuracy of applying solder paste. The processor and micro-chips have very small solder points, many of which are a few millimeters. With the manual application of solder paste, accuracy is not achievable, while things are pretty efficient with PCB stencil.
PCB stencil only allows the right amount of solder paste to get on the PCB pads, so there is pinpoint accuracy all over the PCB. Additionally, the stencil ensures that every solder pad on the PCB gets the correct shape application of solder paste.
PCB is one of the most important inventions for mankind, and we cannot expect the future of our generations without PCB. With things becoming advanced with every iteration, the manufacturing process keeps getting complex.
While some things make PCB manufacturing and assembly easier, one of them is PCB stencil. A PCB stencil makes things easier on many levels, especially in the assembly process. The PCB stencil eases everything for us, whether it is applying solder paste correctly in terms of shape, volume, or location. Ordering it is pretty simple, and having a PCB stencil for your PCB can ease many things. We hope you know how to order PCB stencils and all their practical benefits.