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And since the technology is changing rapidly, it depends on what capabilities were available when Bunker and Blue Ridge bought their printers. Not only does 3D printer manufacturer matter, so does the date of purchase.

3D printers are not created equal and the rapid change of printer capabilities means that newer printers, newer even by a just a few months, are more likely to outperform older printers. But after a vendor invests big bucks in a certain printer, the vendor needs to generate sufficient revenue for a period of time to pay off that printer before being able to buy a newer printer based on newer technology. It may take a few years of revenue to pay off a commercial grade 3D printer. In that time, one or even two new generations of technology may become available. Thus, 3D printers quickly become obsolete, often before they are paid off.

For a vendor, it's like buying a 1908 Ford Model T and two years later Ford releases a 2022 Mustang. And a brand new competitor just bought the 2022 Mustang and your Model T has another year of revenue generation before being paid off. A vendor could get stuck with expensive, commercial grade 3D printers that aren't competitive after just a few months. Leasing 3D printers rather than buying might provide a solution to that problem but leasing 3D printers is not common.

Here's how typical resin printers work now, and why some can print 1/700 scale Oerlikons and some can't.

Generally, when resin 3D printers finish creating a layer, the tray holding the resin, called a "resin tank" moves to peel the tank away from the model. The model is then raised slightly to create space to print the next layer. This action is done differently by different 3D printers. That peeling action puts a lot of force on models during printing. If the peeling force is strong, layers can get warped and fine features like gun barrels and hand rungs can get broken during printing. So printers that use more peeling force are less likely to be able to print small, fragile features. The way designers can help compensate for strong peeling forces is to use more supports to strengthen fragile features. Conversely, printers that put less force on models are more likely to be able to print models with fine, fragile features.

For example, I use two different kinds of resin 3D printers. Each has its strengths and weaknesses. Both types use a laser to cure liquid gray resin in a tray called a "resin tank". The resin tanks have a clear, elastic layer on the bottom. The laser is positioned below the tank. A series of motorized mirrors guide the light through the bottom of the resin tank upwards into the liquid resin where the light's energy cures a layer. The laser traces the layer curing the resin as it goes. Layer tracing "smears" the light across the layer making for very smooth surfaces (no pixelation). The process to trace an entire layer is generally very slow. Laser tracing is actually an older technology.

Newer 3D printers don't use a laser. They have a micro-LED screen like the screen on your cell phone to "flash" the entire layer at once. This is a much faster process than laser layer tracing. The smaller the size of the LED pixels in the layer, the smoother the surface. Over the last year or so, manufacturers have been releasing 8K printers with very small pixel sizes. The disadvantage of this type of printing, besides it producing surfaces that are slightly less smooth than those with lasers, is that the size of the build space is limited to the size of the LED screen. Until very recently, these printers had very small build spaces, often about 2 inches by 2 inches. Very few models can fit in a space that small. Newer LED printers have much larger screens.

Of the two types of laser printers we have, they peel differently. The older type, the two Formlabs Form 2 printers we have (2015 technology), move the tank in one direction, to the side, when peeling. Our Form 2s put enormous stress on models when printing. Their print quality is superb with very, very smooth surfaces. But they can't print small scale Oerlikon barrels, Bofors barrels or fine handrungs on 1/350 scale turrets, for excample, without warping them. To prevent warping, more supports are required. But the supports quickly smother smaller models and details making the models unusable by the modeler. The typical modeler can't remove the supports without damaging the model.

The other type of printer we have is the successor to the Form 2, the Form 3 (2019 technology). The Form 3 peels in two directions, not just one, to the side and down, as if you were peeling a Band Aid bandage off of your skin. The Form 3 puts a lot less stress on models and therefore can print smaller features that our Form 2s can't. Our Form 3 can print Spandau machineguns, for example. Our Form 2s can't print Spandaus. Our Form 2s break the cooling jackets during layer peeling and warp the model.

But because the Form 3 also peels in the downward direction, not just to the side, our Form 3 tends to pull on new, soft layers in a way that closes off small openings like 1/700 scale portholes. So we use our Form 2s to print objects with small openings like porthole-festooned superstructures and we use our Form 3 to print more solid objects like turrets and directors and fragile models like Spandau machineguns.

None of our machines can print 1/700 scale Oerlikons or Bofors barrels, sights or shoulder harnesses. They can't print them in 1/350 scale either. Although the laser can easily form those features, our Formlabs printers put too much stress on the models during peeling and break those features during printing.

A B9 Core 550, for example, uses an LED screen and uses very low-force peeling technology so it can print small features like handrungs and radar antennas. But at $14,000 per printer, we won't be buying one. We can't afford it.

But other more affordable LED screen printers are being released, now, and are becoming within budgetary reach. So, the next machines we will acquire will be LED screen types optimized for very small models, those that can print small barrels and handrungs. We hope to make that purchase in late 2023 or early 2024, depending on 2023 earned revenue.

Thanks to all who buy our models!