The objective of setting test points would be to test if the components around the circuit board satisfy the specifications and solderability. For instance, if you wish to check if the resistance around the circuit board fast PCB manufacturing is wrong, the simplest way is by using a multi meter to determine both sides. First got it. However, in mass production factories, there’s no way to make use of an electricity meter to gradually measure whether each resistance, capacitance, inductance, as well as IC circuits on every board are correct. So there’s the so-known as ICT (In -Circuit-Test) The emergence of automated testing machines, designed to use multiple probes to concurrently contact all of the parts around the board that should be measured. Usually, it takes only about one to two minutes to check every part from the general board. The greater parts The more it requires.
However, if these probes directly touch the electronic parts around the board or its solder ft, the cool thing is that some electronic parts is going to be crushed, and it’ll be counterproductive. Therefore, smart engineers invented “test points”, that are on the a double edged sword from the board. A set of small round dots are furthermore brought on the finish, and there’s no mask on top, so the test probe can touch these small dots rather of directly contacting the electronic parts to become measured. In the past when there have been traditional plug-ins (DIP) around the circuit board, the solder ft from the parts were indeed utilized as test points. The solder ft from the traditional parts were sufficiently strong to not hesitate of needle sticks, but there have been frequently probe contacts. Poor misjudgment occurs just because a thin film is created at first glance of general electronic parts after wave soldering or SMT. The impedance of the thin film is extremely high, which frequently leads to poor contact from the probe. .
Actually, the exam points after wave soldering can also get the issue of poor probe contact. Following the prevalence of SMT, the misjudgment of testing continues to be greatly improved, and the use of test points has additionally been given a lot of responsibility, because SMT parts are often very fragile and can’t withstand the direct contact pressure from the test probe. There is no need for that probe to directly touch the various components as well as their welding ft, which not just protects the various components from damage, but additionally not directly greatly increases the longevity of the exam.
Using the growth of science, how big the circuit board gets smaller sized and smaller sized. It’s already a little hard to squeeze a lot of electronic parts around the small circuit board. Therefore, the issue from the test point occupying the circuit board space is frequently within the design. Tug of war between your finish and also the manufacturing finish. The look of the exam point is generally round, since the probe can also be round, that is simpler to create, which is simpler to create the adjacent probes closer, so the needle density from the needle bed could be elevated. There are several natural limitations around the mechanism when utilizing a needle bed for circuit testing. For instance, the minimum diameter from the probe includes a certain limit, and also the needle with not big enough diameter is simple to interrupt and damage. The space between your needles can also be limited, because each needle must emerge from an opening, and also the back finish of every needle should be soldered having a flat cable. When the adjacent holes are extremely small, aside from the issue between your needle and also the needle. There’s the issue of contact short circuit, and also the interference from the flat cable is another serious problem.
There’s also other test techniques that wish to switch the original needle bed test, pcb online china for example AOI, X-RayFree Content, however it appears that every test cannot replace ICT 100%.