Ergonomic SMD Solder Paste Dispenser for 1ml and 3ml Syringe

For those of you who place solder paste on a PCB by hand using a solder paste syringe, this tool provides additional control and consistency to the application process.   

Parts Printed:

1. Syringe Holder [A]
2. Syringe Plunger [B]
3. Knob [C]
4. 1ml Syringe Adapters [D]

Other Materials Required:

• M3 50mm screw x 1.  (Available at your local hardware store on Amazon at, for example,  href=https://www.amazon.com/Bemaka-420PCS-Socket-Washers-Assortment/dp/B0CSZ2L3KW).
• M3 H10 threaded insert x 1. (Local hardware store or Amazon https://www.amazon.com/uxcell-knurled-Printing-Threaded-Embedment/dp/B0CB8LDRZK).
• 3cc Syringe with 14 G dispensing needle - Amazon at https://www.amazon.com/Refilling-Measuring-Liquids-Adhesives-Applicator/dp/B01N4B9282
• 1cc Syringe - Amazon at https://www.amazon.com/Syringe-Liquid-Plastic-Syringes-Non-Sterile/dp/B0BYJ7R7BC   
• Solder paste.   I use  Chip Quik SMD4300AX10 available at https://www.digikey.com/en/products/detail/chip-quik-inc/SMD4300AX10/2057274

Slicing and Printing:

• Use 0.2 mm layers with PETG filament.  
• Add modifier boxes at each end of the plunger to force 100% fill about 1cm down at both ends.
• Add supports on build plate only using auto-painted organic supports. (optional)  
• I used a glue stick to add just a tad more adhesion to the bed and to avoid using a brim. If you use a brim, it is a tad awkward to remove it from the knob but a little remnant at one end of the knob has no impact on the functionality.  

Assembly:

• If you used organic supports, there may be residual inside the holder [A] that needs to be removed.   You can pull it out with tweezers and push it from the other end using a long hex key or similar device.   
• Make sure all brimming is removed especially from the plunger [B].  The plunger should be easily inserted all the way into the holder. [photo]
• Use a soldering iron (I set mine at 200 C) to insert the threaded insert into the knob [C] so that it is flush on both sides.   It may be helpful to use the 50 mm screw as a holder and guide for the threaded insert as you melt it into place.

• Lay the syringe, filled with no more than 1.2 cc of solder paste, on to the holder [A].  The gradations of the syringe body should face up.  Prime the syringe with the dispensing needle in place so that there is no air in it. 

• Push it down and snap it into place.  Using pliers, gently squeeze the bottom two wings on the syringe plunger stem and twist to make sure the stem is grabbed by the left and right V-shaped guides at the end of the syringe holder [A]. 

• Insert the plunger [B] into the holder [A].  Gently pull up the syringe plunger stem while adjusting the plunger [B] so that the syringe stem seats into the plunger [B].     
• Cradle the knob in the holder slot  .
• Insert the 50 mm screw into the other end of the holder [A] and screw it through the knob and into the plunger [B] until it is secure and tight   .
• The assembled product should look like this: 

1ml Syringe Adapter Assembly:

• Simply insert the adapters [D] into the holder [A] as sleeves at both ends around the 1ml syringe that has been filled with no more than about 0.15 ml of solder paste, and then snap down the syringe into the cradle of the holder [A].  All other instructions are identical.

Instructions for Use:

Simply turn the knob just a tad in the ↟D direction to dispense the paste on a PCB copper pad or ↟R to retract the paste.    

Results will depend on the solder paste being used, solder paste age and viscosity.  I use Chip Quik SMD4300AX10.  Handle, seal and store the disperser loaded with paste according to the manufacturer's instructions.

Happy soldering! 

P.S.  For frequent solderers:
Take a look at https://www.printables.com/model/843353-solder-scroll-ergonomic-adjustable-solder-tool.   This tool, shown below, is a great counterpart for use with solder spools.  Really well designed, easy assembly and highly ergonomic.