There's only a vague resemblance between model and part. No way could you use that sprocket. Not only are the edges rough, it has voids. You could grind or machine down down rough edges, but voids make the process worthless even for making blanks.
That's about what you'd expect with MIG welding. Welding just isn't a good way to make smooth surfaces.
The low-end 3D printer people tend to obsess on the problems of building a 3-axis motion system (a completely solved problem in CNC machines) and gloss over the problems of what's happening at the weld point. The common extruder-type printers are trying to weld a hot thing to a cold thing, which never works very well. (In soldering, that creates cold solder joints. In welding, it creates bad welds.) Heating the bed plate helps a little, but once the thing being built is more than a few cm high, the build plate isn't accomplishing much. That's why most taller objects made with low-end 3D printers fail.
There's a plastic welding technique that's been in use since the 1950s that works reliably. (http://www.professionalplastics.com/WELDER). Not only is the welding rod heated, the target area is heated with hot air. This produces a solid, reliable weld.
I've suggested doing something similar for extruder-type 3D printers, using small lasers (2-5 watts) to preheat the target area just ahead of the extruder. So far nobody has done that.
Heating things with a laser is not quite as easy as you might think. Different materials will absorb different wavelengths of light at different rates. So for example a 1um laser might not heat white polyethylene enough while it would melt black ABS. Hot air has the advantage that it is always a consistent temperature regardless of the material.
Use a laser diode pulsed with pulse width modulation, at perhaps 1KHz, duty cycle < 80%. During the off period, view the hot area with two photodiodes behind different-wavelength IR filters. The ratio between the outputs gives you the temperature. Go closed loop on temperature.
Comments
It is extremely bad. See the actual paper, where they show one part and its CAD model.
http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=6678...
There's only a vague resemblance between model and part. No way could you use that sprocket. Not only are the edges rough, it has voids. You could grind or machine down down rough edges, but voids make the process worthless even for making blanks. That's about what you'd expect with MIG welding. Welding just isn't a good way to make smooth surfaces.
The low-end 3D printer people tend to obsess on the problems of building a 3-axis motion system (a completely solved problem in CNC machines) and gloss over the problems of what's happening at the weld point. The common extruder-type printers are trying to weld a hot thing to a cold thing, which never works very well. (In soldering, that creates cold solder joints. In welding, it creates bad welds.) Heating the bed plate helps a little, but once the thing being built is more than a few cm high, the build plate isn't accomplishing much. That's why most taller objects made with low-end 3D printers fail.
There's a plastic welding technique that's been in use since the 1950s that works reliably. (http://www.professionalplastics.com/WELDER). Not only is the welding rod heated, the target area is heated with hot air. This produces a solid, reliable weld. I've suggested doing something similar for extruder-type 3D printers, using small lasers (2-5 watts) to preheat the target area just ahead of the extruder. So far nobody has done that.
Heating things with a laser is not quite as easy as you might think. Different materials will absorb different wavelengths of light at different rates. So for example a 1um laser might not heat white polyethylene enough while it would melt black ABS. Hot air has the advantage that it is always a consistent temperature regardless of the material.
Use a laser diode pulsed with pulse width modulation, at perhaps 1KHz, duty cycle < 80%. During the off period, view the hot area with two photodiodes behind different-wavelength IR filters. The ratio between the outputs gives you the temperature. Go closed loop on temperature.