I recently purchased yet another 3D printer, but this time with an eye towards a specific project/product. After having run the old Stratasys FDM thousand series machines, I realized that in the past few years cheap consumer level machines had managed to reach parity (in most respects) with these hulking monsters that were $100,000 investments a little over 20 years ago. Hooray for progress (and patents expiring).
Around four years ago I decided to take a chance on a cheap machine to do some concept work with, intending to then actually produce on the Stratasys (can’t easily move a Stratasys around the house – it’s more of a garage implement). I wound up purchasing a refurbished Monoprice Maker Select V2. Despite a few issues (remedied by running a Raspberry Pi running OctoPrint), I was quite honestly impressed with how far hobbyist machines had progressed since the days of the early Makerbot offerings (Cupcake owners, I recall your cries of anguish). Once I realized the amazing level of detail these machines offered (over double the layer resolution of a Stratasys machine running at 0.007″), I then set about printing loads of very important items. [insert cry of NERRRRRRD here]
The high quality of the output and greatly improved software since I had first looked at open source 3D printing offerings led me to really appreciate the current state of hobbyist level 3D printing, and I find myself with fewer and fewer reasons to champion Stratasys machines over other alternatives (the ostracism of hobbyist users notwithstanding – their acquisition of Makerbot to court that market while also spiting 3DS with the purchase was an utterly expensive boondoggle, and the Makerbot name has almost entirely receded from awareness as a result).
While the Monoprice machine was a great teaser of capabilities, it has been challenging to keep running (though those challenges have proven to be excellent learning experiences and have forced me to become far more capable/knowledgeable as a result). More importantly, the Z-travel wasn’t quite sufficient for my needs after all. So after another round of google searches for “what are the cool kids using for 3D printers”, it appeared that the offerings from Creality were excellent bang-for-the-buck, and the Ender 5 model ticked all the boxes for my needs. This Teaching Tech video (an excellent channel that I highly recommend) sealed the deal, and I purchased one during a sale.
The machine as it exists out-of-the-box is excellent value as far as I’m concerned. But naturally I started to upgrade things that bugged me – I switched to Capricorn PTFE for the Bowden tube, added an insulating pad to the heated bed, replaced the stock control board, power supply, hotend, etc. etc. My fellow 3D printing hobbyists understand the aggravating-yet-rewarding cycle of endless upgrades in pursuit of making our machines just a little bit better than they were before. And then cursing ourselves for not leaving well enough alone when things go awry.
I think the Ender 5 construction design is excellent – the bed only moves in the Z-axis, which means that the tall sorts of prints I intended to build on the machine aren’t in danger of being shaken loose from rapid Y-axis moves as they might be on more popular machines such as the Ender 3, Prusa i3, and similarly designed platforms (known as ‘bedflingers’). Adding a glass bed and thus significantly increasing the moving mass only exacerbates the issue.
So, I’m a big fan of the Ender 5 bed mechanics… …in theory. In practice, the bed base is a cantilevered steel plate supported only from the rear, and flexes quite a bit as a result. I am far from the first to be dissatisfied with this, as ‘bed struts’ appear to be a popular item to add to the Ender 5 in order to increase rigidity. However, such bed struts are almost always printed items, and thus limited by the process and material itself. I’ve certainly printed various mechanical upgrades for my two machines, but they have consisted of things like mounts for end stop switches, end stop screws, and other such items of minimal structural requirement. Bed supports, on the other hand, I consider a wholly structural item, and I wanted to come up with something a bit more, well, structural.
Somehow, I latched onto carbon fiber tubing as being the optimal base material for this task. Likely due to me having a bunch of carbon fiber arrow shafts purchased from Wal-Mart years ago for use in RC plane construction. I quickly found that these arrow shafts have 8-32 threads on the tip end, so sticking a cap screw into the end offered a simple means of adjusting length. Moreover, a button head 8-32 socket head cap screw has a spherical diameter of 3/8″… Without attempting to elucidate my thought process further (because I don’t really know how I concocted it in the first place), here are the salient details:
1″ long 8-32 button head cap screw
Links are to the McMaster-Carr items. I added in a few other 8-32 pieces (hex nuts, etc.) when building, in addition to printing a pair of end braces that slip onto the front cutouts of the bed frame. Using a 3/8″ ball end mill, I made a small divot onto each of the shaft collars to accept the button head of an 8-32 machine screw. I turned down the shank diameter of the rivet nuts just enough on the lathe to slip into the arrow shaft tubing so they could be epoxied in place.
The divoted shaft collars get attached to the shaft bearings (left side of the picture) and the end braces (the gray right-angle looking parts on the right side of the picture) slip onto the stamped sheet metal bed frame. Unscrewing the screws from the end next to the shaft collars compresses the CF tubing and the nut can then be locked in place to set the overall length. The end result is a bed frame that is overwhelmingly stiffer than stock – the icing on the cake is using some silicone standoffs instead of the stiffer springs generally recommended as an upgrade. An STL of the end brace is here: