26 July 2006Manufacturing / Production Technology, Hardware & Services
Soldering is based on the ability of different metals to dissolve or diffuse into each other and to cause an electrical connection at lowest resistance and mechanical fixing. Flux is used to dissolve metal-oxygen layers on the surface of the different metals being connected with each other due to the dissolving of the tin into them.
Soldering tips
A soldering tip has two major tasks. The first is to transfer thermal energy with as low a loss as possible, and secondly, to carry the solder on the joint in combination with flux. Due to physics, the tip turns out to be a wearing part. And these tasks have to be done in combination with achieving long lifetime and at lowest cost.
To achieve excellent thermal conductivity, a soldering tip consists of a copper core (silver would be better, but is much more expensive).
The wettability of copper with solder tin is extremely good, which means the solubility of copper in solder tin is extremely high, causing the tip to be quickly consumed. The tip must be wettable to properly carry the heat and the tin on the soldering joint. Iron is also wettable with tin, but the solubility is far less. Unfortunately iron has a very low thermal conductivity and hinders thermal flow. The thicker the iron layer, the lower the heat transfer from the tip towards the soldering joint. The thinner the iron layer, the shorter the lifetime due to the solubility of iron in tin. Using other materials that are not soluble in tin will cause a non-wettable tip and poor soldering results.
Heating tips to high temperatures
The aggressiveness of the solubility of iron into tin increases with rising temperature. So also, the mechanical resistance of the tip's iron layer is reduced. When soldering, the tip is somehow always touching some part of the component and is in contact with the aggressive tin. Now, with lead-free soldering, the content of the tin in the solder is increased by 35%. This results in a 35% more aggressive solder towards the iron layer, simply causing reduction in life.
Now, standard tips have an average iron layer of 200 μm depending on the geometrical form. Weller's new LF tips carry an optimised layer of twice as much iron. More iron would cause a lower heat transfer and hinder the soldering process. Influence of the temperature to the lifetime and iron layer can be seen in Figure 1.
Figure 1. The graph shows that the LT-LF soldering tips provide a cost reduction and that the main influence to tip lifetime is the soldering temperature
A general recommendation is to use a tip as large as possible, and if necessary, to improve the process by using a thinner solder-wire. For lead-free solder, the adjusted soldering temperature at the station should be in the range of 340-360°C, depending on the geometry of the tip. For further enhancement of tip lifetime 'Stop+Go' stands should be used.
Transparent rigid PCBs launched on PCBWay PCBWay
Manufacturing / Production Technology, Hardware & Services
[Sponsored] PCBWay is thrilled to announce a highly anticipated new service - transparent rigid PCBs – a combination of technology and aesthetics.
Read more...20 years of precision, progress and purpose – the Jemstech journey Jemstech
Editor's Choice Manufacturing / Production Technology, Hardware & Services
Twenty years ago, Jemstech began as a small, determined venture built on technical excellence and trust. Today, it stands among South Africa’s leading electronic manufacturing service providers.
Read more...An argument to redefine IPC class definitions for class 1, 2, & 3 electronics MyKay Tronics
Manufacturing / Production Technology, Hardware & Services
One of the most critical aspects of electronic assembly reliability is cleanliness. Contaminants left on a circuit board after the reflow process can lead to failures through mechanisms such as electrochemical migration or corrosion.
Read more...Large platform stencil printer Techmet
Manufacturing / Production Technology, Hardware & Services
GKG’s large platform stencil printer, the P-Primo, is designed to meet customer’s ultra-large printing requirements by supporting board dimensions up to 850 x 610 mm.
Read more...Press-fit component inspection MyKay Tronics
Manufacturing / Production Technology, Hardware & Services
In electronics manufacturing, optical inspection of press-fit components is crucial to ensure the quality, reliability, and performance of the final assembled product.
Read more...A new era in wire bond inspection Techmet
Editor's Choice Manufacturing / Production Technology, Hardware & Services
Viscom is developing a 3D wire bond inspection system that incorporates substantially improved sensors, a high image resolution, and fast image data processing.
Read more...Mycronic’s MYPro A40 pick-and-place solution MyKay Tronics
Manufacturing / Production Technology, Hardware & Services
Mycronic’s MYPro A40 pick-and-place solution, equipped with an MX7 high-speed mounthead technology, increases top placement speeds by 48% over the previous generation.
Read more...Why ergonomics matters in digital microscopy TANDM
Manufacturing / Production Technology, Hardware & Services
While magnification technology has kept pace with demand, the wellbeing of the people behind the microscopes has often been overlooked with technicians spending long hours in intense focus, leading to chronic strain, fatigue, and costly mistakes.
Read more...From ER to effortless: The 15-year journey of Seven Labs Technology Seven Labs Technology
Editor's Choice Manufacturing / Production Technology, Hardware & Services
What started as a business likened to an ‘ER’ for electronic components has today grown into a trusted partner delivering kitting services and full turnkey solutions – taking the effort out of electronics and helping customers truly ‘Move to Effortless.’
While every effort has been made to ensure the accuracy of the information contained herein, the publisher and its agents cannot be held responsible for any errors contained, or any loss incurred as a result. Articles published do not necessarily reflect the views of the publishers. The editor reserves the right to alter or cut copy. Articles submitted are deemed to have been cleared for publication. Advertisements and company contact details are published as provided by the advertiser. Technews Publishing (Pty) Ltd cannot be held responsible for the accuracy or veracity of supplied material.
printer friendly version