With this tool you can precisely dispense very small dots of solder paste. Although this solder paste dispenser is cheap and uncomplicated, it works better for small SMD parts than many automatic dispensers. It is used in aerospace and medical electronics companies.

There are many solder paste dispensers on the market, often motor controlled or pneumatically. But can you use them for very small solder dots such as for 0201 SMD resistors? It is important that you are able to dispense the smallest amount of solder paste, else it will easy lead to solder bridges. The problem with SMD soldering is always the excess of tin. That’s why I invented this hand-tool solder paste dispenser.

Disper precision SMD micro-dot solder paste dispenser
Disper precision SMD micro-dot solder paste dispenser

Dispenser
Dispenser

FOR SALE

Manual solder paste syringe dispenser. Included are also two blue plastic tapered tips and two syringes.

You can buy it on my shop HERE at Tindie

With the sale, I can partly finance my hobby: inventing and publishing it. The further development of my Maxun One solar bike is expensive, many parts are unique and are manufactured by companies to my specifications.

For sale: Disper SMD micro-dot solder paste syringe dispenser
For sale: Disper SMD micro-dot solder paste syringe dispenser

Extra type T4 Chip Quik solder paste
Option: extra type T4 Chip Quik solder paste

You can also buy the extra solder paste option, where one syringe is filled with 4 grams high quality TS391AX10 (type T4) soldering paste from Chip Quik. Then you can get started right away without having to buy additional solder paste elsewhere. To give an impression of how much you can do with 4 grams: Not more than 3mm length of the solder paste in the syringe is needed for these three boards:

Just 3mm of solder paste was needed for these three boards
Just 3mm of solder paste was needed for these three boards

Prefered Chipquick solder paste

I tested four different Sn63/Pb37 solder pastes from Chipquick with the bended tapered dispensing tip 22G:

This one works fine:

  • TS391AX10 type 4 in syringe 35g: 

These don't work well:

  • TS391AX50 type 4 in jar 50g: it sticks badly to the PCB and is therefore difficult to apply.
  • SMD4300AX10T5 type 5 in syringe 35g: when heated, the tin spreads out over the PCB and causes short circuits.
  • SMD4300AX250T5 type 5 in jar 250g: same problem as SMD4300AX10T5 but slightly better.

Watch out for bad solder paste

  • If the syringe was filled with paste a few days ago, you should squirt out the first part, without using it, as this may be unreliable.
  • Solder paste is a critical product, if it has been stored too long or used too quickly after being refrigerated, it will no longer work properly. You can then mess up an entire PCB. If you are not sure if the paste is still good, first make a test PCB with a few SMD components.

Discrete 741 operational amplifier in DIL8

Here is a challenge to take on with the solder paste dispenser. Using the solder paste dispenser to make a 741 operational amplifier in DIL8 with discrete transistors.

Discrete 741 opamp in DIL8
Discrete 741 opamp in DIL8

Examples

I've used the syringe dispenser for assembling the Arduino SAMD21 board SAM 15x15: The SMD package 0402 is easy to do, see R1 and R2:

Manual assembling 0402 SMD parts
Manual assembling 0402 SMD parts

In de video below, I'm soldering 0603.

Replacement parts

You can buy the parts yourself here:

Syringe 1ml

https://www.ebay.nl/itm/5-100pcs-plastic-nutrient-Lab-hydroponics-measuring-disposable-sampler-syringes/391364467826?hash=item5b1f23dc72:g:56kAAOSw5r1cTstg

Stainless steel compression spring

  • Length 20mm
  • Wire diameter 0.6mm
  • Outer diameter 6mm

https://www.aliexpress.com/item/33054999325.html?spm=a2g0s.9042311.0.0.3a504c4dqBO379

Bended TT tapered dispensing tips

  • 22G Blue

https://nl.aliexpress.com/item/32981478726.html

F.A.Q .

  • How many pads are you able to tin with one filling?
    With 10mm of solder paste in the syringe you can already cover hundreds of SMD pads.
  • How can I clean the dispenser tip?
    Immerse the tips in acetone to clean them.
  • Can the solder stay in needle or clean each time? 
    You can leave it in the needle, but you should always squirt out and discard the first portion of tin before you start.

How to fill the dispenser with solder paste

Normally the solder paste is packed in a thick syringe. Take the thin dispensing syringe and remove the plunger. Then spray a little paste into the thin syringe, 15 mm is usually sufficient. Then insert the plunger and push the pasta all the way down.

Bent needle tips

There are all kinds of needles for sale that are suitable for the syringe:

Steel tapered bends needle
Steel tapered bends needle

Steel needles have a high resistance to the solder paste because they are thin over the entire length. Therefore, I use bend plastic tapered dispensing tips:

Plastic tapered bends needle
Plastic tapered bends needle

Needle diameter vs color

Needle colors are standardized according to Birmingham gauge.
Note that sometimes other colors are used, for example on AliExpress.
I recommend to use 22 - 27 Gauge tips for solder paste dispensing.

Gauge  Diameter [mm]  Color
22 0.41 blue
25 0.26 orange (sometimes red)
27 0.21 medium grey

I recommend to use only solder paste T4 for dispensing. 
The needle inner diameter should be larger than seven solder ball diameters. 

Particle size 20-38 [μm]

  • Gauge 22 
  • Gauge 25 
  • Gauge 27 

Information

At the website of Nordson, you can find a lot of interesting information about solder paste dispensing:

Dispenser assembly

Mounting the syringe with spring requires some practice, be careful not to force the holder:

Sealing the dispense tip airtight

I used a piece of faucet rubber with a drilled hole for sealing:

Faucet rubber
Faucet rubber for sealing

Sealing a needle with tap rubber
Sealing a needle with tap rubber

Nanoliter / microliter pipette for laboratories

The micro-dot solder paste dispenser can also be used as a pipette to handle very small volumes of liquids in laboratories. For use for solder paste, it must be possible to accurately dose a volume from 10nL to 100nL.

Nanoliter / microliter pipette for laboratories
Nanoliter / microliter pipette for laboratories

Can we do 0201, 01005 and ball grid arrays manually?

With the dispenser we can handle SMD components with a package 0402 and larger easily. I was curious if even smaller components such as the 0201 could still be done with the dispenser. I have made a try, it was difficult but, in the end, it worked, I’m hopeful. But 0201 parts are hardly used anyway.

It is more important whether ball grid arrays can be done, then an expensive stencil may not be necessary anymore. I found out that the plastic bended tapered tip is too large for 0201 and BGA and the viscosity of the solder paste must be just right. I don't have time to investigate this further, but there may be people who see this as a challenge…

See my try here for the tiny 0201:

DIY soldering 0201 with a solder paste syringe dispenser
DIY soldering 0201 with a solder paste syringe dispenser

Ball grid array solder paste dispensing

On this image and video, you can see how solder paste dispensing is used for ball-grid arrays:

Ball grid array solder paste dispensing
Ball grid array solder paste dispensing

Low viscosity solder paste for the dispenser

The viscosity of solderpase is very critical to be able to apply micro-dots with a dispenser. We need low viscosity paste, this also sticks better to the PCB. Common solder paste that works fine for stencils doesn't work with a dispenser, it is too syrupy:

Solder paste for stencils don't work with a dispenser
Solder paste for stencils don't work with a dispenser

The TS391AX10 soldering paste from Chip Quik is specially made for dispensing by a syringe. It is a thermally stable solder paste No-Clean Sn63 / Pb37 Type-4 in a 35g Syringe:

Chip Quik solder paste T4 for syringe TS391AX10
Chip Quik solder paste T4 for syringe TS391AX10

You can buy it at Mouser, Digikey and Amazon.

Solder paste info

  • Solder paste is thixotropic, to lower the viscosity, it may be needed to stir the paste.
  • The paste must be at room temperature before use.
  • Note that the volume of the soldered joint is about half that of the solder paste applied.
  • There are special solder pastes for dispensing and stenciling.
  • Chip Quik: shelf life refrigerated 3-8C (37-46F) > 6 months, unrefrigerated > 2 months.
  • Chip Quik: allow 4 hours for solder paste to reach an operating temperature of 20-25C (68-77F) before use.

Solder pastes are classified based on the particle size, from type1 (160 µm) to type8 (11 µm), see Wikipedia.

Here you can see the solder paste with the solder ball particles very well here:

Solder paste with solder ball particles
Solder paste with solder ball particles

Precisely dispense the smallest amount of solder paste

The main thing that goes wrong with soldering surface-mounted devices is the excess of solder. On this extremely small PCB from an iPod touch, which contains 0201 size SMD, you can see how little solder paste is used:

iPod touch micro PCB with 0201 size SMD
iPod touch micro PCB with 0201 size SMD

Real size
Real size

After the components have been placed, you can solder the board as you like, with a reflow oven or hot air. I use the Atten AT858D to solder SMD parts, it is important that you can control both the temperature and the airflow.

Solder paste dispenser step 1Solder paste dispenser step 2SolderedSoldered

Solder flux storage

Nail polish jars are useful for storing solder flux for daily use. The brush is resistant to all kinds of chemicals.

Filling a nailpolish jar with solder flux for daily use
Filling a nailpolish jar with solder flux for daily use

Small raised SMD work table

With small parts such as SMD you have to sit with your eyes close to the work. To be able to do this comfortably, I made a small raised work table of wood:

Raised work table for SMD
Raised work table for SMD

Double lens loupe for SMD

I use a loupe with 10x magnification. But keep in mind: the loupe must have a double lens to see the small SMD components well. Unfortunately, almost all loupes use just one lens.

Monocular jewelers 10x magnifying loupe with double lens
Monocular jewelers 10x magnifying loupe with double lens

High temperature grease for Hakko soldering irons

To prevent seizing of the nozzle screw, apply high temperature grease to the thread:

Faucet grease for lubricating soldering iron

You can use Hakko 800-026 Anti Seize Lubricant or just any high temperature fauset grease.

Tweezers

Small SMD parts such as the 0402 require tweezers with a curved pointed tip:

Weitus WTS-817 curved pointed tip tweezers
Weitus WTS-817 curved pointed tip tweezers

More about the dispenser on the web

See HERE a a post from LarryD

Do you have any comments about the website? Please let me know.