Soldering Techniques

We might have heard about soldering techniques used by manufacturers to place/solder components on a bare PCB. For an experienced guy, these techniques are familiar but for a fresher these all look like hard stuff which add to the additional burden of learning. The two most terminologies you hear from manufacturing industry are wave soldering and re-flow soldering. If PCB is not so complex and if you are getting your PCB s soldered at your local manufacturing locations you may not be hearing more about re-flow soldering. Let us look at the major differences between these two techniques.

Wave soldering:

Wave soldering is used to solder both through hole and SMD also. But this technique may not be suitable for most of the SMD components. Even in this era of surface mount technology, there are many applications which demand through hole components. So, wave soldering is a popularly used technique.

Reflow soldering:

Reflow soldering is mainly used for surface mount components. Even the through hole component soldering can be done with this technology. In this soldering technique, a solder paste is added to the PCB to glue the components upon which is the PCB is exposed to a controlled temperature environment. Check the datasheets before selecting the component and check your manufacturing facilities in parallel to give a manufacturing guideline for maximum reflow temperature to be used. Reflow machines can be of infrared type or conventional type.

What are the latest technologies?

Now-a-days embedded market is growing faster enabling the technology to be used at every step. SMT reflow machines are having lots of inventions incorporated and are coming up with latest technologies. some of the important observations are:

• Graphical view of the temperature using a display attached 
• Touch based screens for control activities
• Minute temperature adjustment 
• Complete process level data logging
• Advanced cooling strategies
• Efficient flux distribution techniques
• Tracking the PCB from insertion to completion
• Power consumption reduction in latest machines
• Alarms for security
• Remote control

What are the advantages of latest innovations?

• Less maintenance costs
• Exceptional thermal performance
• Labour reduction
• Automation
• Quick turnout and hence high throughput
• Controlled environment
• Less chance of failures
• Report generation at every step

Understanding Oscilloscope Specifications - Part 2

Oscilloscopes can be said like heart of electronics testing especially protocol and high speed signals testing. Now a days oscilloscopes come with integrated test benches which help analyze high speed signals like USB, SATA, etc. These inbuilt test benches analyze signal specifications to the minute level and give a complete test report as a package. As a tester, this adds lot of flexibility and helps built confidence on the design. For a tester using oscilloscope initial challenge lies in understanding  specifications of it and selecting a right one for his application. 

Types of oscilloscopes:

The modern oscilloscopes come in various form factors which can be as big as bench-top to as well as wearable type and  middle level as hand-held type/pocket type. Hand held, pocket and wearable types are a very good addition to the field application engineers. That heavy packing, fright charges for a field engineer are no more a burden. The only disadvantage with these portable scopes is that their bandwidth is very less. So, the extent of debugging that can be done by the field engineer with these scopes is very limited. Even with such limitation, it is worth having one with you. Some people always have an eye on the pricing and cost wise they are nothing to worry as most of them are available in the range of $100 to $300. There are oscilloscopes especially designed for debugging phones during development.

Range of bandwidths:

Based on the domain you work on the oscilloscope varies. If you are working on a very low end digital signals and buses like SPI, I2C, SMBUS and UART, you don't need a very high end oscilloscope. The bandwidth requirement for such applications is very less and a 100 MHz bandwidth scope like TDS2014C works very much in such cases. If you are working on high end RF to high end digital signal signals, high bandwidth scopes are a necessity and be careful in choosing bandwidth of scope based on highest frequency to be measured. If you want to measure a frequency of 2.5 GHz, you must have a scope of bandwidth of at least 7.5 GHz. Today oscilloscopes are available up to 100 GHz. 

Waveform Generation:

One of the feature of oscilloscope is you have a output port which outputs fixed frequency signal. Hence, an oscilloscope can also be used in case you need a reference frequency for testing.