"Hoffman+" XL Side Bar for Frames in a Bee Barn Langstroth+ Style Hive — (inspired by Jim @ Vinofarm)

I redesigned the Bee Barn XL frame concept by Jim at Vinofarm and optimized it for 3D printing on consumer-grade 3D printers like the Prusa MK3.  The new frame design requires negligible "human time" to manufacture, very little time to assemble, and can be made from easy-to-source materials.

I printed these in recycled Prusa PLA at 0.3mm layer heights, 50% infill, 6 perimeters, and 6 solid layers on top and bottom (probably overkill).  You must only use supports on the build plate only, as there are internal geometries that will fill up if you use supports everywhere.  These were quickly cleaned up with a little bit of sandpaper, then assembled.  Half of a grooved bottom bar (recycled from a frame you are updating or purchased new) is epoxied into the cavity between the upper part and the bottom part of the side bars (making sure that the registration pin in the side block fits into the receiving cavity on the other half).  Then, the side bars are attached and epoxied to the grooved top bar and an entire bottom bar.  I sourced my components from Betterbee (where I also sourced my Lyson 8/9 hive and other components):

https://www.betterbee.com/frames/gtbp-grooved-top-bars.asp

https://www.betterbee.com/frames/gbbp.asp

I currently recommend these frame components from Betterbee because they fit the design well and are for sale in 100-count on their own.  I could not find bottom bars or top bars by themselves for sale by Dadant or Mann Lake. 

I plan on doing some further iterations after I've had a chance to review the concept and the early prototypes with Jim.  His excellent work can be found here: 

Youtube:

https://www.youtube.com/c/VinoFarm

Instagram:

https://www.instagram.com/vinofarm

One of the top comments on a recent video was very insightful for me (the gist of which was basically "don't try to mold the entire thing in one piece").  I have some Betterbee grooved top bars and bottom bars.  I've recapitulated Jim's sidebar design in Fusion360 (CAD software that I prefer), with an eye towards manufacturing it in plastic via 3D printing.  I must admit, my knowledge of injection molding is limited to small machines (that wouldn't be capable of making these frames in their entirety — bottom and top bars integral).  However, I do know some basic realities of injection molding: the molds are crazy expensive and they require years of experience to design and optimize.  The larger the object, the more costs rise — and not in a linear fashion.  

One realization that I've made while recapitulating Jim's design in CAD is from the "add-on" scene in the Youtube video on the subject of making the frames/asking for help with injection molding: there are two versions of the XL frame (and for good reason, apparently — the air gap).  With two versions of the frame, you would need two mold pairs (they are two designs, after all). 

So why not "just" injection mold the side bars?  Why not "just" 3D print the side bars?  That would make things a bit easier since the part would be so much smaller and more manageable for manufacturing & shipping.  Assembly would consist of simply adhering the side bars to a stock top bar and bottom bar, possibly with something like (my favorite) thickened epoxy, available in either pumpable liquid format or in tubes designed to be mixed and dispensed in one step (e.g. Six10 epoxy from West System).  This would be slightly more expensive than wood glue and staples, but would form an amazing and long-lasting bond and would save a LOT of “human time” — the real cost of the frame manufacture, I think.  The design I'm presenting here will save time and money, I think.  Jim's Bee Barn is an inspiration to every aging person out there who doesn't want to destroy their back for this hobby.

  
My riff on Jim's XL frame sidebars has integral gussets and blocks, with "Version A" and "Version B" so as to eliminate that air gap issue.  Here I am presenting only Version “B” but will add Version “A” with some improvements in the near future.

In the end, I think we could get this design down to three total parts for the side bars: one upper part, two versions of the lower part, with half a bottom bar inside each assembly for a stiffener (ONE CUT with whatever saw one has on hand, even a hand saw would do).  Even using a purchased grooved bottom bar (cut in half) for a stiffener would end up costing very little per side bar (at least for the stiffener) — and if that saves the majority of Bee Barn builders from having to come up with some alternative, then that's a win in my book.  It reduces the complexity of the design and reduces the overall part count, I think, and certainly saves a ton of time on the table saw and in the assembly process.  It allows for rapid iteration and improvement on the design by leaning into the 3D printing process, a process that the honey bees themselves are fans of as well.  It allows for local manufacture (at home, even) by using commercially-available and reliable consumer-grade 3D printers like the ones from Prusa Research.  Printing the frame parts in readily-available plastic filaments like recycled PLAis both eco-friendly and enjoyable, while giving added longevity to the parts over a material like untreated pine.  3D printing also allows for manufacture of designs that would be impossible to produce with injection molding (interior geometries, e.g.)  3D printing allows for rapid prototyping and improvement of designs and for adding features, for example the integral gussets could be printed as “corner starter strips” so the bees draw it out fully as comb. 

https://www.prusa3d.com/product/prusament-pla-recycled-2kg/

I did some rough calculations from prices and shipping quotes pulled off the Betterbee website.  Roughly speaking, if you get their plastic frames with foundation built-in (heavy wax), for a deep and a medium you are paying about $8.30 (landed at my zip code) per pair of frames.  This could be considered a rough stand-in for this XL frame if it were to be injection molded, covered in heavy wax, and shipped to the customer 100 at a time.  This is probably a high estimate, but it comes with benefits for the end user: (no assembly, no tools needed to use the design).  Injection molding costs are all shouldered by the manufacturer, of course.
 

Making these out of wood requires hours/days of manufacture and assembly (human time), wood stock, staples, and wood glue.  Tools required are staple gun, table saw, dado blades, etc.  The biggest costs here are the tools and the cost of your time; this is a dangerous process, but the costs of utilizing this method will depend on local cost of labor time and shipping to the final destination.

In contrast, this 3D printed design costs about a minute in assembly time (not included time waiting for the epoxy to cure), needs a 3D printer (or access to one) running for approximately 12 hours (machine time for four pieces, two side bars total) to manufacture, relatively exotic adhesives like thickened epoxy, and about $15.95 in material cost. This accounts for the landed cost of the recycled PLA filament used to make the parts, heavy wax deep + medium plastic foundation (black, Betterbee), landed cost of the top bar (Betterbee), bottom bar, a bottom bar cut in half to be used as a stiffener, and epoxy used to bind the wood parts to the plastic ones.  This process is safe and distributed.  
 

There is power in this sort of democratic design process — like the wisdom of the hive mind: 

EDIT 8/23/2023

IMPORTANT NOTE:

It has come to my attention that West Systems and other epoxies are not rated for “indirect food contact”.  As I stated, my original intention was to prove that these frames could be 3D printed and assembled without fancy equipment while retaining the ability to do a pullup from the frame (~230# human being).  Printing these frames at such a high infill % and assembling with epoxy is Overkill with a capital “O” — I am working on a version which is much simpler and can be assembled easily and cheaply with stainless steel hardware from McMaster Carr, similar to my hybrid AŽ frames: https://www.printables.com/model/561864-az-frame-for-a-hybrid-az-hive-that-uses-standard-l