Geir Andersen over at LetsMakeRobots has designed and built this cool solder paste dispenser:
As I’m doing SMD prototypes I wanted to do reflow soldering instead of hand soldering and needed a solder paste dispenser.
The professional ones are not that expensive but you need an air compressor and I was trying to avoid that extra cost and noise. So I came up with this design.
It uses a PICAXE M14 microcontroller and ULN2003 Darlington driver to run the 28BYJ-48 stepper motor. As a stepper the 28BYJ-48 sucks with its gear ratio, but for this purpose it is cheap and has lot of torque. For my type of work and one-off prototypes it works great.
DIY solder paste dispenser - [Link]
by Juan Chong @ juanjchong.com:
In this post I’ll be going over how to cut out solder stencils for both ExpressPCB and EagleCAD designs on a laser cutter. I recently had a need to create some stencils from both of these programs and spent quite a bit of time at the Dallas Makerspace working with their laser cutter to get the settings just right. I’ll be cutting some designs that are mostly 0603/0805 package sizes, so don’t expect ultra-tight pitch stencils from this technique!
Cutting Mylar Solder Stencils from ExpressPCB and EagleCAD Files - [Link]
From a wide offer of solders from company Stannol, it´s easy to choose the most suitable type meeting your demands.
The solder matters, it is an undisputable fact confirmed daily in a development and production of electronics. Hand soldering of prototypes, automated machine soldering, soldering of small SMT components or on the in contrast soldering of big joints of massive connectors, rework, … all that wants a solder optimized for a given usage. As we know, features of a solder wire are determined by an alloy itself (PbSn xx, SnAg xx, …) but in a considerable extent also a flux used. A flux has a big influence mainly on a soldering process, spreading of solder (often even on partially oxidized surfaces), spitting at hand soldering, etc. That´s why despite of often similar specification (according to datasheets), it is still possible to see considerable differences among solders after all. Besides the most important parameters like composition of alloy and flux properties, some features (like spitting and solder spreading) can be really evaluated only at working with a given type.
Over 130-years experience of German company Stannol give a guarantee, that in their portfolio can be found a type suitable even for your work. In a Stannol catalogue can be found favourite “universal” types suitable for the most types of works in electronics and electrotechnics (for example HS10, HF32, Kristall 400) but also specialized types suitable even for soldering of poorly solderable surfaces.
The principle of Stannol products marking is in it, that they are marked by a flux type (HS10, HF32,…) and by an alloy used (Snxx, SnPb,…). A solder wire is available in many combinations flux / alloy , that´s why it is suitable look at their properties in detail and then to choose a suitable type. On stock we keep the most favorite types with fluxes HS10, HF32 or 2630, suitable for majority of joints.
● HS10 - no-clean flux containing halides, based on a natural resin (colophony). Outstanding properties regarding spreading and electrically safe residues. The flux is non-corrosive on non-ferrous materials. The most popular type for electronic industry.
● HF32 no-clean halide-free flux with an activated resin (colophony). Outstanding combination of high activity, good wetting properties and small amount of residues. Residues are transparent, hard, dry and non-corrosive. Very suitable even for SMT components, high reliability of joints. Special version HF32 SMD features even lower flux content and leaves minimum residues, that´s why it´s very suitable even for rework, manual adding of components to PCB and similar.
● 2630 - the most active no-clean flux containing halides. Usable even on places where HS10 is not sufficient. Ideal for surfaces with poor solderability as well as for soldering of bigger joints (thicker copper wires etc.).
Upon request, we´re able to provide you with another types from Stannol production, for example Kristall 400 – no-clean halide-free flux with synthetic resins, with transparent residues and good activity, able to provide excellent soldering results. In general, fluxes, which contain halides are more active and at soldering they feature better wetting. On the other side halide-free fluxes are more safe in respect of possible corrosion around a solder joint and modern fluxes already have very good wetting properties. Normally, neither halide fluxes marked as “no-clean” don´t cause corrosion around a solder joint but at certain circumstances (for example devices intended for very humid conditions) it may be necessary to wash soldered joints from flux residues.
Detailed information will provide you the attached table as well as Stannol catalogue, overview of Stannol soldering materials, overview of Stannol solder wires and overview of soldering fluxes standards.
For detailed information we recommend you to contact our sales agents, which will be pleased to help you at choosing the right type. It´s also possible to contact us on a well-known address firstname.lastname@example.org.
Find the right solder for you – [Link]
alexglow @ instructables.com writes:
Note: By “beginner’s guide”, I mean a guide written by a beginner. (I made it at TechShop SF, during my first weeks!) I have some technique tips to share, but for more in-depth questions, Google is your friend.
Solder paste allows you to populate a board with many tiny components, without straining your eyes and fingers. Using minuscule components saves space, and you can dramatically cut down the space between them when you don’t have to solder every connection by hand.
Beginner’s Guide to Solder Paste - [Link]
SMD solder paste stencils are used to accurately “print” a thin layer of solder paste onto a PCB on which the components are placed before reflow soldering. The “printing” is done in a method similar to screen printing, where the solder paste is squeegeed through a 4 mil thick, stainless steel stencil onto the PCB.
This is all well and good, but commercial stencils are expensive, and are massive overkill for prototype boards. Here is a method for producing a “good-enough” stencil using aluminium sheet via a method similar to PCB production via the UV photosensitive film method.
Home-made solder paste stencil - [Link]
The soldering assistant is a project idea I had to have my soldering supplies conveniently in one spot. The Solder spool holder is close to the work area to have a read supply of solder to feed directly from the spool. The soldering assistant also features and adjustable vise to hold your projects securely as you assemble them. Just behind the work area is a parts bin, to put your resistors, capacitors, IC’s tweezers or other supplies. Side “fins” make it possible to make custom add-ons that can just snap into place. The only part that isn’t printable through a 3d printer is the center threaded rod that moves the base, this is a 1/4″ threaded rod that can be purchased at any local hardware store. 2 hex nuts are also required, one that fits into the moving side of the platform, and one on the stationary side. This is an entry for the “Make it real Challenge” contest. If you like the design, please vote, Thanks.
Soldering Assistant - [Link]
redFrog Pick and Place machine – example of the pick and place process – [via]
This video demonstrates the process from solder paste application to picking and placing the SMD components to the final flowing of the solder. The picking and placing is done using the new redFrog pick and place machine.
redFrog Pick and Place machine - [Link]
Greg (@SiliconFarmer) did this great little write-up about solder fluxes. He offers:
The purpose of flux used in soldering is to remove oxidation from the copper and the devices being soldered. The ability of flux to react with and remove oxidation is called its “activity”. Highly active flux does a good job removing oxidation, but it can also corrode metal, such as the iron coating on soldering iron tips.
Water soluble fluxes have a high activity. They are even more corrosive when in contact with the high temperatures of a soldering tip, where it can damage the tip’s iron coating by corrosion. Water soluble flux is not recommended for hand soldering as it can significantly shorten the life of your soldering iron tip.
Water soluble flux is often used in wave soldering systems that are followed by an automated cleaning step.
No-clean fluxes have low activity. They are designed to boil away during soldering, leaving very little residue. Because it rapidly boils off of a hot soldering iron tip, no-clean flux may not have time to clean off a buildup of oxidation. Using no-clean solder requires using good soldering and cleaning techniques to prevent oxidation build up on the tip. If the tip becomes oxidized and won’t wet with no-clean solder, rosin flux can be used to clean the tip, then you can tin the tip with no-clean solder.
Solder Flux Choices for Hand Soldering – [Link]