B9 Bonanza!

[finescalerr]

Pretty stunning, given how early in the game it is. -- Russ

[Hauk]

Pretty stunning, given how early in the game it is. -- Russ

indeed! And more so when you consider the price of $4.595,-

[Bexley]

Actually, it's only about $3500, if you assemble it yourself. Plus $100 for shipping. ($5500 for pre-assembled, I think.)

[Ray Dunakin]

Impressive!

[Chuck Doan]

Very encouraging.

[Hauk]

Actually, it's only about $3500, if you assemble it yourself. Plus $100 for shipping. ($5500 for pre-assembled, I think.)

Wow, Even better!

Could you tell us a little bit more about the skills needed to assembly the machine?

[Bexley]

It's pretty straightforward. The trickiest bit was getting the springs onto the sweeper. Otherwise, it's all nuts and bolts, one step at a time. You do have to install a PCB/Arduino, but it just bolts on, and all of the components that plug into it already have conectors attached. If you can handle Ikea furniture, you can assemble a B9.

[Bexley]

Though, I should qualify that by noting I may have made an assembly error. The projector is on a sliding plate, and the XY resolution is set by moving the projector up and down. The plate has a device with a fine adjustment knob, and a spring loaded pin. The back of the machine has three holes in it, corresponding to each of the XY resolution settings (70, 50, and 30 micron). To calibrate the projector, you select the resolution in the software, then move the projector into the correct position by inserting the spring pin through the plate and into the hole that corresponds to the setting you chose. Then you project a grid onto the bottom of the vat (the container that holds the resin). You take a printout of the grid, and with a combination of the projector zoom and the fine adjustment knob, you align the projected grid with the printout.

However, in the 50 micron position, even lowering the projector as far as I can with the fine adjustment knob, and zooming all the way out, I could not get the grid small enough to align. I ended up removing the spring pin entirely (which really just acts as a quick reference point for roughly where the projector should be) and lowering the projector about another two inches in order to get the image to align. It doesn't seem to be affecting the printing at all, but after asking about this on the B9 forums, the guy who made it said there's no way it should be that far off. Though, others also reported having the same problem, but not quite as drastic as mine. In some cases, replacing the fine adjustment knob (which is a plastic knob on the end of a socket head screw) with a longer bolt gives the amount of range needed, but I would require a 3.5 inch bolt for this to work. When I get home, I need to post images of the projector setup, so the problem can be diagnosed. I am also going to run through the assembly steps for that part again, to make sure I didn't mess anything up.

[finescalerr]

Nothing is ever straightforward, is it? -- Russ

[Bexley]

New images coming. The difference between the first print and second print is night and day. I am exceedingly pleased with the crispness of the detail. And this time, I'll have measurements to go along with the images. And a puzzle!

[Bexley]

The lack of crispness was determined to be caused by light bleed. To lower the amount of bleed, I doubled the amount of additional pigment that I added to the resin I used in the first print. It's much better, but I'm going to try adding even more pigment to see if I can really crisp it up. (After a point, adding more pigment doesn't make any difference, and too much will prevent light penetration into the resin, causing undercuring and possibly print failure.) I also dropped the exposure time a hair.




Small machine guns, designed to modify HO scale cars for a vehicle combat miniatures game. Printed on sprues for molding.
The flash supressor/venting holes are .6mm in diameter. The stroke width of the letters in the copyright is .3mm wide. The stroke
width of the circle around the "C" of the copyright symbol is .15mm. Each gun is 13.7mm long.




Size reference.



The hammer on the left was from the most recent print, the one on the right is from the first print.

And the puzzle: on the support/sprue blocks, the layer lines are clearly visible. However, those parts were actually at an angle. The guns themselves were aligned to be vertical, and the blocks with the text were at a 20 degree angle to the Z axis. So what I can't figure out is, why the lines are parallel to the blocks and not at a 20 degree angle. (And further, why they aren't visible at all on the actual gun parts, but very visible on the sprue blocks. Not that I'm complaining about that, as I don't care if they're visible on the blocks, so long as they're not visible on the actual parts.

Also, in the first image, the guns on the right appear a bit squished. That seems to be due to the camera angle, as they look fine side by side here on my desk.

[Bexley]

Also, it should be noted that the text is a little soft on purpose. Since these are intended to be molded, I filleted all the corners on anything I didn't actually need to be crisp, to lessen the wear from demolding.

[Bexley]

Also also: I have yet to try the highest resolution available. I've been using 50 micron xy and 25 z. The z in theory can be as little as 5 microns, though the layers are so thin it's hard to control light bleed. 25 seems to be the best, as higher resolutions in the z axis don't result in considerable gains, but increase the printing time a lot. For xy , there are three settings- 30 micron, 50 micron, and 70 micron. The trade off is that the xy is adjusted by moving the projector closer or further away, which alters the size of the print area. Increasing xy resolution decreases how much you can print at once. The 30 micron area is only 32.4mm x 57.6mm, so I'd like to get the leave of detail I want at 50 if possible, since I do want to be able to print larger models.

[finescalerr]

Unless I'm mistaken then, the resolution of the parts you've printed makes them about equal to HO scale molded styrene. If so, this is extremely promising and pretty darned impressive. -- Russ

[Bexley]

Hard to say. Those guns are nominally HO scale, but they're pretty oversized and cartoony, so that they read well on the tabletop for gaming. The barrels are probably twice as thick as a man's arm at scale. If anybody has any "true" HO scale 3d files, I'd be happy to give 'em a test print. Nothing too large, though, as I'd rather avoid 20 hour prints for the time being. Most of what I have right now is 32mm figure scale or larger.