Why is paste T4 and not T5?

[michael]

It seems most solder paste manufacturers produce paste in three particle sizes, namely T3, T4, and T5. T5 is the smallest size, and is easy to buy from vendors.

Because the Voltera nozzles get blocked and are unusable sometimes, wouldn’t it be better to use the smallest particle size?

The Voltera store only sells T4 paste, but I’m wondering if a T5 paste would lead to less nozzle blockage. If the reason for choosing T4 is due to the higher price of T5, just think of the savings in terms of throwing away blocked nozzles.

Do I need to rephrase the question, or is it clear enough?

[mewertow]

Hey @michael,

The main reason we don’t stock T5/T6 paste is that our solder paste manufacturer doesn’t have our standard SnBiAg0.4 available in that particle size, though they are working on it.

However, the T4 particle size is well within the acceptable range for using the standard black nozzle - if you’re running into clogging, it’s almost likely due to one of the reasons below:

1. Expired paste: As paste ages, the active ingredients in the flux slowly remove oxide from the solder particles - which will cause them to fuse together. Check the expiry date on your cartridge.
2. Storage conditions: If the paste isn’t refrigerated, the process above will happen much faster, meaning that your paste will expire much earlier.
3. Print Height Too Low: If your print height is too low, you might accidentally be corking the flow, which will cause separation of flux and solder particles, hence clogging. Keep the print height at 0.14mm.
4. Other paste issue: If you’re getting clogging out of a completely new cartridge (less than 2 weeks old), it might be something else - in that case, we can replace the cartridge and nozzles. Just send an email to support@voltera.io with the lot number of your paste.

• Matt

[Mark]

I’ve got to say that I have never been able to refrigerate the paste (with attached nozzle) and then get it to print properly. I have used different batches of paste, always store them in the fridge and paste height is fine but I have always had to either clean the nozzle or put a new one on. But my method of pasting may be different to others and maybe not as Voltera intended as I tend to have at least days and sometimes weeks between prints. I use the printer for prototyping one off’s generally and there can be quite a few gaps whilst I design a new board.
Paste in the tube has been fine once I clear the nozzle so it seems to be a nozzle issue for me. Once I put on a clean or new nozzle, it prints fantastically.

[jazozaya]

Super late reply - but for others that are browsing.

If it’s been several days or weeks since you last used your solder paste, and you are certain the nozzle is not clogged but you are not getting good paste flow, then you should purge your nozzle before using it. We’ve put together an article here