Now I am feeling ten feet tall and bullet proof. The previous two real prints were tools that helped me make other things on my projects. On the smaller one the print time was only about 7 minutes. On the bigger clamp jig the time was around 40 minutes. Both came out as good as I was expecting.
Okay now it’s time to try some serious 3D printing. For my first serious print I want to see how well the stock ABS blue filament and stock settings on the printer handle finer details. I chose to try a print of the KM-20 cartridge shells made by Maszczyk. I dl the .igs file from their website, bring it into Solidworks and convert it to a .stl file. I then load that into the XYZPrinting Pro software for slicing and transmission to the printer. I chose to only do one half of the complete shell to keep the print time down. The estimated time is 1hr 30 minutes. It takes 1hr and 40 minutes.
The printer never balks. There’s a strange dragging sound sometimes when the extruder makes a long x axis run, but no obvious indication in the print that there is any resistance. I mark that down as something to investigate further.
So how does it do? Well see for yourself. I’ve put the printout in blue next to the original in black. Pretty good for stock settings. Not an exact copy, but I didn’t expect that.
The first thing I notice is that the original black half seems slightly smaller. ABS used in injection molding is notorious for shrinkage, 3D printing doesn’t seem as bad. I tried to mate the original with the 3D printed one and they do not fit together. Next I’ll try printing another half shell and see if it will fit the first one.
Then I notice the finish. The original has a nice textured feel and look on the back. The 3D printed one has the classic 3D printed look as each layer is built one upon another. I have some smoothing material that I will try and report on in a few days. I bought it a long time ago when I first got the FF Creator Pro, but never used it.
On the back of the original there is a round dimple that provides a very thin cover over the center screw hole from the back. The 3D printed version tries, but just can’t handle that dimple without support. The print was started with the back laying on the print bed. Truth be told I’m not sure how I could add support. It’s just so thin, maybe around .1 mm, definitely not more than .2 mm. The printer does handle the rounded top edge bottom very well. That’s called a slight overhang in 3d printer terms.
Now we turn the half shells over to compare the internal features. Again we see the classic telltale 3D printer finish in the center post and the inside sides of the half shell. This can be minimized by lowering the printer layer resolution, but it increases the print time significantly. I printed at the stock .3 mm layer resolution. The lip and groves seemed to print well, until you get towards the bottom of the half shell. Then we begin to see a strange split developing in an otherwise solid lip feature. We see the same issue in the horizontal bar running across at the bottom of the half shell. It’s pronounced enough that I can get my fingernail between the two halves. That I do not think is a printer issue. I believe that is a result of an error in converting from .igs to .stl in the 3D model.
Over all the print seems to turn out well. Definitely will need to fine tune the original .stl file to eliminate the splits in the lip and horizontal bar. The next thing would be to fine tune the layer height to improve the finish and accuracy of the print. Smoothing the print using acetone is also an option. The apparent size difference between the black original and the blue printed half shell is going to be harder to deal with. I think the filament used is a major factor there, with maybe a slight scaling down of the .stl file. But it’s a very slight scale amount.
More to come.