In 2023, is it suitable to use miners to mine or buy coins? In recent years, with the increasing popularity of blockchain technology and the rapid development of digital currency, more and more people have joined the team of mining and buying of coins. In 2023, for most people, choosing to use a miner to mine or buy coins will be a critical decision. Advantages and disadvantages of miners High power consumption, high cost, and high technical requirements are the salient features of miners' mining. But at the same time, miners also have a stable income from mining and have the advantage of controlling the speed of block verification. Here are a few viable Bitcoin miners and their profitability in 2023. Antminer S19 Pro is a miner produced by Bitmain , which is very popular in the market. It is equipped with 114 BM1398 ASIC chips , which can achieve a faster and more stable mining experience. It is estimated that the average daily income of this type of miner in 2023 will exceed 120
What is the effect of solder balls on SMT patches?
Solder balls are mainly caused by flying solder caused by rapid heating during the soldering process, and usually appear on the sides of chip components or between fine pitch pins. In addition to causing solder dislocation and edge collapse, solder balls are also related to solder paste viscosity, oxidation degree, solder particle thickness, and flux activity. Let's look at these factors' impact on SMT patches today!
1. Solder paste viscosity
For solder paste with a suitable viscosity effect, its adhesion will offset the effect of solvent emission during heating and prevent the solder paste from collapsing.
2. Degree of solder paste oxidation
After the solder paste is exposed to air, oxidation may occur on the surface of the solder paste particles. The oxide of solder paste is generally controlled at about 0.03%, and the maximum value does not exceed 0.15%. Experiments have shown that the occurrence rate of solder balls is proportional to the percentage of solder paste oxide.
3. Thickness of solder particles
Suppose a large amount of particles below 20 μm is contained. In that case, the uniformity of the solder particles is not uniform. These particles have a large relative area, are very susceptible to oxidation, and are most likely to form solder balls. In addition, these tiny particles are also easily washed away from the pads during the evaporation of the solvent, increasing the chance of solder balls. Generally, the number of particles under 25um should not exceed 5% of the total number of solder particles.
4. Solder paste absorbs moisture
This situation can be divided into two categories: before using the solder paste, take it out of the refrigerator and open the lid immediately, causing water vapor to condense; insufficient drying before reflow soldering, residual solvent during solder heating makes the solvent and water boil and splash, Solder particles are sprayed onto the printed board to form solder balls. Depending on these two different situations, we can take the following two different actions:
1) Do not open the lid immediately after removing the solder paste from the refrigerator. Instead, it is recommended to return to room temperature and open the lid after it is stable.
2) Adjust the reflow soldering temperature curve so that the solder paste is fully preheated before soldering.
5. Flux activity
Solder balls are also prone to occur when the flux activity is low. The activity of uncleaned solder is generally slightly lower than that of rosin and water-soluble solder pastes. Therefore, pay attention to the formation of solder balls when using.
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