Wednesday, June 06, 2007


Very fine RepRap nozzles

I am visiting Jens Kaufmann at Heriot Watt University to give a RepRap talk to his group. He has come up with a really neat way to make very fine nozzles for RepRap.

Stick a standard nozzle with an 0.5mm hole on the end of a piece of silicone tube. Then flow copper sulphate solution through it and connect it up to copper-plate itself from a lump of Cu in the top bath (see the pic). The copper will plate on the inside of the hole closing it up. The thing has beautiful negative feedback, in that - if an area starts to close up too fast - the plating rate drops just at that location.

You can tell how the diameter is reducing by watching the flow out of the end slowing down. A few experiments would quickly establish how far up the side of the receiving vessel the level would rise in 30 seconds (owe) for a given diameter. Just time it, and turn off the electricity when you get there...

For best results it needs a constant-current source so you get a precise plating rate. You stuff the silicone tube right into the nozzle to prevent the threads being plated too.


nice! i recently was successful making 0.2mm nozzles. (if thats what you call 15 nozzles and 8 broken drill bits)

very rad technique anyway.
and I will supply you with a cheap plating circuit and the recipe for the plating solution.
Now if it was only possible to use electroplating to grow larger, non-symmetrical metal parts :)
That is indeed brilliant!
Very fine indeed.

Vik :v)
Soi Sentinel said...
> Now if it was only possible to use electroplating
> to grow larger, non-symmetrical metal parts :)

Why not?
Plate it indiscriminately, then cut off what you didn't want to add. Use wax or oil as a final application to prevent the part from growing any more in that place.

Plate for a moment, cut for a moment, plate for a moment, cut for a moment. Would probably be best to have the solution added and subtracted by a syringe so you don't have to keep moving the structure up and down.

Possibly 3 "heads", 4 counting the plating system.
One to machine off the excess. One to apply wax to prevent the thing from growing on the bottom, or in, side, (the current applicator head should be fine,) also to act as filler for the next head. One to apply solder to give a base to plate against to allow for overhangs.

I see no reason it should be a hurdle.
You need to wash off the millings, or, should they make contact with the metal, they'll grow.

Since the printer would be working "blind", from what should be there, it'd cause surfaces to grow bumps, which would cause problems quickly, both in that it wouldn't stay smooth, and in that it'd eventually interfere with the wax applicator head.

Probably use a strong vaccum system to vaccum up the millings as they're cut, but it needs to leave as little dust as possible.

Otherwise, the whole surface would need to be swept between each plating stage. This might actually be easier to implement and maintain, with fewer fails.
I have visions of a machine electroplating onto already electroplated layers, using wax to guide the formation of the object as it grows, depositing the wax underwater...

Vik :v)
Pretty much what I meant.
Except use a syringe to raise and lower the solution a few inches so the working surface can be brought above water for the milling and coating/filling steps. Not as a replacement for the Z axis, but to keep from having to use the Z axis in both directions for every plating operation.

So, now you're applying wax, and milling, above the "water"s surface.
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