What is PCB windowing

The wires on the PCB are covered with oil, which can prevent short circuit and damage to the device. The so-called window is to remove the paint layer on the wire, so that the wire can be exposed to tin.

How to design PCB window opening  PCB design how to set wiring window opening

As you can see in the picture above, it’s through the window. PCB window opening is not uncommon, and the most common one is probably the memory module. Those of you who have disassembled a computer know that the memory module has one gold finger, as shown in the picture below:

How to design PCB window opening PCB design how to set wiring window opening

The golden finger here means open the window, plug and play.

Window opening is also a very common function, that is, tin ironing increases the thickness of copper foil in the later stage, which is convenient for excessive current, which is common in the power board and motor control board.

Open Windows and bright copper in PCB design

In the design, we often meet customers’ requirements for opening Windows and brightening copper, but it is very difficult to communicate with them because the customers have little knowledge or we are not very clear about this process. In our design, often encounter customers need to add a shield cover, plate edge local bright copper, through the hole open resistance welding, IC heat sink back exposed copper, stolen tin pad and so on. According to the actual situation, let’s take a look at some pictures to explain.

1. Shielding cover

If the customer needs to add shielding cover, what we need to do is to add soldmask with a width of at least 1mm. We need to confirm with the customer whether we need to add steel mesh. When adding Soldmask, we need to lay the copper skin of the ground network in the area of adding Soldmask. The Soldmask plane must be covered, otherwise the substrate will be exposed (FR4, etc.). Other non – terrestrial networks should not cross the Soldmask. Add the Soldmask area to the PCB effect to reveal the yellow copper. Unadded areas will be covered by solder blocking.

How to design PCB window opening _PCB design how to set wiring window opening

2, welding window hole

In the design, we often hear the whole board plug hole or local plug hole, when adding holes, we pay attention to the plug hole company name is generally refuelled BGA, on the contrary, there is no BGA are welded window hole (our company specification). General company specifications exceed 12mil holes must be welded window holes.

How to design PCB window opening _PCB design how to set wiring window opening

3, IC heat dissipation pad

In general, on the back of IC heat dissipation pad add welding window (add the back soldmask larger than or equal to the surface pad) and hole, and on the back of the copper cover welding, so as to better put the surface heat through the hole to the back of the copper skin better out.

How to design PCB window opening _PCB design how to set wiring window opening

4. Stealing tin pads

In wave soldering, in order to solve the problem of connecting tin caused by the close spacing of pads, we will use tadpole shape of stolen tin pads. Notice the copper skin with the same size as the solder should be added.

How to design PCB window opening _PCB design how to set wiring window opening

How to realize the tin on PCB wiring window

The circuit needs to drive the 8-channel relay, when the multi-channel relay is closed when the current increases, in order to ensure the actual effect, in widening the current line at the same time, it is hoped to remove the welding resistance layer of the current line – green oil layer, after the board is made, you can add tin to the top, thickening the line, can pass more current.

The actual results are as follows:

How to design PCB window opening _PCB design how to set wiring window opening

The implementation method is as follows:

Just draw the line in the ToPlayer (or bottomLayer depending on which layer the preset line is in) layer, and then draw the line that coincides with it in the Topsolder (or bottom solder) layer.

PCB design how to set up the wiring window

CB design can set up wire wiring in TOP/BOTTOM SOLDER layer.

TOP/BOTTOM SOLDER green oil layer: Coat the TOP/BOTTOM layer with SOLDER green oil to prevent tin from coating the copper foil and maintain insulation.

Green oil window blocking can be set on the pad, through hole and non-electrical wiring of this layer.

1. By default, the pad will open a window in PCB design (OVERRIDE: 0.1016mm), that is, the pad exposes copper foil, expands 0.1016mm, and tin will be added during wave soldering. No design changes are recommended to ensure weldability;

2. By default, the hole will open a window in PCB design (OVERRIDE: 0.1016mm), that is, the hole will expose copper foil, expand 0.1016mm, and tin will be added during wave soldering. If the design is to prevent tin from coming onto the hole and copper from coming out, you must check the PENTING option in the additional attribute of the hole in SOLDER MASK to close the hole.

3, in addition, this layer can also be independently non-electrical wiring, welding resistance green oil corresponding window opening. If it is on the copper foil wire, it is used to enhance the current capacity of the wire, and tin processing is added when welding; If it is on the non-copper foil wire, it is generally designed for logo and special character screen printing, and the character screen printing layer can be omitted.