Solder paste and flux dispenser

[pvit]

I'm "reinventing" cheap motorised dispenser, easy to do for hobbyists, compact and precise enough with small doses.





Currently it's in WIP state, and it will be very helpful if you could review schematic & PCB. May be something should be fixed or improved.

Links:

• Github - firmware sources. Can be build for PC (in linux) with simulated hardware (convenient for fast interface prototyping).
• EasyEDA - schematic, pcb.
• Hackaday.io - here i post progress logs and different tips, until project in WIP state. When complete - create a manual on github.

PS. EasyEDA contains third iteration of hardware, while posted images have second iteration. There are some differences.

[001]

Great project!

It looks like some sci-fi movie weapon

[IanJ]

Hi,

Where did you get the small yellow blunt needle caps......been looking for something like these for ages!

Ian.

[pvit]

@IanJ, i describe all tech details in project logs:

https://hackaday.io/project/166699-solder-paste-and-flux-dispenser/log/168209-tip-needles-caps

2 heat shrink tubes + drop of silicone oil.

[chickenHeadKnob]

@IanJ, i describe all tech details in project logs:

https://hackaday.io/project/166699-solder-paste-and-flux-dispenser/log/168209-tip-needles-caps

2 heat shrink tubes + drop of silicone oil.

Useful and clever. will copy.

[tooki]

@IanJ, i describe all tech details in project logs:

https://hackaday.io/project/166699-solder-paste-and-flux-dispenser/log/168209-tip-needles-caps

2 heat shrink tubes + drop of silicone oil.

Very cool, but I’d probably keep away from silicone oil, since it gets everywhere and is hard to remove. You don’t want it getting on things you want to solder.

[pvit]

but I’d probably keep away from silicone oil, since it gets everywhere and is hard to remove. You don’t want it getting on things you want to solder.

It's only to fill micro-defects between needle and cap walls. And since cap sits tight enougth, quantity of oil is about zero - no volume to make outer parts dirty. But you may skip this step, it's for extra-safety only.

[pvit]

PCB v3:



- Added current monitor to autodetect retract size.
- Holes for SS wire pins, to lock plastic supports.
- Other polish.

Still WIP.

[pvit]

Firmware on bare metal:



Subpixel font smoothing, animated scroll and other cool things . I also started to write assembly manual. May be anyone wish to correct my spelling

Next step is to learn how to use 3d-printer, print plastic components and debug dispense algorithm. Goal is to avoid all cryptic settings and auto-tune retract level & dispense speed via motor current sensor.

[German_EE]

Cool, I want one!

[pvit]

About needle caps. I never seen before silicone heat shrink tubes https://atopelec.aliexpress.com/store/group/Silicone-Heat-Shrink-Tubing/118669_505069419.html. Those should be ideal for inner layer. I did not tied yet, but ordered. Will post result.

[pvit]

Tested silicone tubes for inner layer. Certaintly better than ordinary ones. Recommend instead of previous recipe.



Also, found PVC tube for dispencer's display. It looks more clear:

[MarkR42]

Great, but you really want a remote control e.g. foot switch.

Activating a button on the actual device is not convenient, if you're trying to simultaneously position it very accurately. This is why the compressed-air driven ones all have a foot switch.

But as I usually apply solder paste with one hand, my other hand is actually free to press a button or whatever, I will have any lights/ magnifier / board holders clamped so I don't need to hold those.

You just want it activated by anything *except* a button on the device.

NB: I really like the idea of a lead screw + small syringe, much more efficient than compressor+ dispensing machine + loads of tube flopping about all over the bench.

[pvit]

but you really want a remote control e.g. foot switch.

Current solution is to solder wires with pedal connector in parallel to button. If you see schematic, it contains required filters & protection units. I did not added connector on PCB, because it occupies a lot of place and is demanded not too often.

In other words, such request is known and solution exists. But i'm open to any suggestions how to improve.