solder

I dont know if anyone has tried this (maybe something for mendel), but its a good question:

Solder are alloys that have melting points between 90 and 450C, and is commonly found in almost every store that sells electronic parts. Since the extruder can be warmed up until 250C and the normal solder is somewhere between 180-190C, I dont think it would be very hard to have an extruder running on solder.

A possible use for the reprap could be this:
If you have several PCB's that need soldering a lot of parts, you can also build a (plastic) frame to put all the parts in, and the PCB on top. Then you just have to run the program and all the parts are soldered onto the PCB. Another thing you could do is using solder to make elektronic connections in the plastic parts.

What do you think? Possible or total waste of resources?

Edited 1 time(s). Last edit at 01/06/2009 09:47AM by Mr. Seeker.

>
> I dont think it would be very hard to have an extruder running on solder.
>

I tried that. Couple of problems. Solder tends to bind nicely with most metals when it cools. I had a copper extrusion barrel and the solder would melt up the pb/sn filament till it hit the melting point and bind right there so that I couldn't put any more into the barrel without applying a LOT of force.

As well, when it does melt in the barrel it has virtually no viscosity, unlike molten plastic, and tends to dribble out of the extrusion orifice at an alarming rate.

I'm not saying that it can't be done, but a solder extruding extruder is going to be a bit tricky to design. I'd tend to go for solder paste instead. It's much easier to handle.
You might want to look at this...

[www.youtube.com]#

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Hell, there are no rules here - we're trying to accomplish something.

Opportunity is missed by most people because it is dressed in overalls and looks like work.

Thomas A. Edison

Greetings all,

From what I've read about it, many solder alloys are eutectic, to get the lowest melting point possible. However, being eutectic apparently implies that the solidus and liquidus temperatures are the same; thus there is really no plastic behavior at all for eutectic alloys. For controlled extrusion, we want plastic behavior (e.g. betwwen solidus and liquidus), where the viscosity decreases *gradually* with temperature. Thus, a non-eutectic solder alloy might work significantly better than the (more common) eutectic ones. Unfortunately, I have only eutectic solder handy. FYI, I read about this looking for a better solder/brazing alloy to connect nichrome to copper. I've had only a little luck with this -- and more crisped nichrome than good joints. Apparently I need a higher percentage of silver, $$ :-(

Regarding solder/metal adherence. My limited experience with soldering aluminum is that only solders specifically forumulated for aluminum stick to it at all -- and those only marginally. So perhaps an aluminum "hot zone" might work for a solder extruder.

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Larry Pfeffer,

My blog about building repstrap Cerberus:
[repstrap-cerberus.blogspot.com]

Extruding solder most solder is going to be a pain since most solder is designed to stick to copper. And it is going to clog up the nozzel unless you blow it out with compressed air or something when you are done.


As far as connecting copper wire to nichrome wire goes, the solution that works best is a mechanical crimp, but I have also used a brass screw and nut before with the nichrome wire and copper wire wound around the screw. It takes up more space than a solder joint, but it will not loose connection.

If you're worried about dripping, why not use a chute at a 45 degree angle, not unlike a cement truck's? Dispense little bits at a time. If the chute was part of the 'hot zone', it could press up against the joint on a pcb to protect against a cold joint.

Why bother with a barrel at all? Just build a toolhead with a soldering pencil tip and a device to feed solder wire in at the top of the hot zone. To use position the tip where you want to deposit solder, power up the tip, wait x time to heat up the tip and any wire/pad you're touching and then feed the wire. The solder liquefies and runs down the pencil tip until surface tension pulls it into the connection. Or until the solder flows into a channel and cools to form a wire. By controlling the pencil temp, the solder feed rate and the head movement rate it should be possible to start from the lead, to say a resistor, connect to it and lay a line of solder (in a pre-made channel) until you can connect to the next lead, to say an LED. While this might not work for surface mount components I think it should work otherwise. While it would be more expensive and higher resistance than copper I don't think it would be prohibitive.

If that doesn't work, how about a high temp head which feeds a copper wire through the hot zone and then uses a bearing to press the hot wire into the thermoplastic surface. A pair of end cutter type jaws fit between the bearing and the heater end and snip wire off at the proper length/location. A different head can then place small heated copper washers at the end points and drill the holes out to create normal copper connection circuit boards. This sort of head would be more complicated as it would have to exert some significant force to embed the wire and would have to be aware of its' direction of travel, and there would be a second step to create the solder point, but the result would be cheap high quality circuit boards.

BDolge Wrote:
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> Why bother with a barrel at all? Just build a
> toolhead with a soldering pencil tip and a device
> to feed solder wire in at the top of the hot zone.
> To use position the tip where you want to deposit
> solder, power up the tip, wait x time to heat up
> the tip and any wire/pad you're touching and then
> feed the wire. The solder liquefies and runs down
> the pencil tip until surface tension pulls it into
> the connection. Or until the solder flows into a
> channel and cools to form a wire. By controlling
> the pencil temp, the solder feed rate and the head
> movement rate it should be possible to start from
> the lead, to say a resistor, connect to it and lay
> a line of solder (in a pre-made channel) until you
> can connect to the next lead, to say an LED.
> While this might not work for surface mount
> components I think it should work otherwise. While
> it would be more expensive and higher resistance
> than copper I don't think it would be
> prohibitive.

You mean a bit like this: [www.okaphone.nl]

And about the "copper problem", why not try nopheads "de-soldering extruder"? You dont know if that works better if you havent tried it yet I know it can drip very easely, most non-lead soldering materials are liquid at 200C (with going from solid to liquid in 2C, so very tight margin).


> If that doesn't work, how about a high temp head
> which feeds a copper wire through the hot zone and
> then uses a bearing to press the hot wire into the
> thermoplastic surface. A pair of end cutter type
> jaws fit between the bearing and the heater end
> and snip wire off at the proper length/location.
> A different head can then place small heated
> copper washers at the end points and drill the
> holes out to create normal copper connection
> circuit boards. This sort of head would be more
> complicated as it would have to exert some
> significant force to embed the wire and would have
> to be aware of its' direction of travel, and there
> would be a second step to create the solder point,
> but the result would be cheap high quality circuit
> boards.

Also a good idea that you can do. Push the begin of the wire against the extruder point, and let the extruder do the rest... The onliest drawback is that you cant do any 3d wiring.

I hope I can get my own reprap soon (waiting for bitsfrombytes to open shop).