At this point, most readers will be familiar with fused deposition modeling (FDM) 3D printers, and how a plastic filament is pushed through a heater and deposited as liquid through a nozzle. Most of us also know that there are a huge variety of materials that can be FDM printed, but there’s one which perhaps evades us: you can’t load a spool of metal wire into your printer and print in metal, or at least you can’t yet. It’s something [Rotoforge] is working on, with a project to make a hot end that can melt metal. Their starting point is a ceramic diesel engine glow plug, from which they expect 1300 C (2372 F).
The video below the break deals with the process of converting the glow plug, which mostly means stripping off the metal parts which make it a glow plug, and then delicately EDM drilling a hole through its ceramic tip. The video is well worth a watch for the in-depth examination of how they evolved the means to do this.
Sadly they aren’t at the point of printing metal with this thing, but we think the current progress is impressive enough to have a good chance of working. Definitely one to watch.
Evaluating the performance of 3D printers and component upgrades is a more difficult than it may seem at first glance, and subjective observations can lead to incorrect conclusions. To objectively determine the maximum flow rates of different FDM 3D printer hotends, [MirageC] is developing a robust testing standard backed by more than just visual observations.
Defining the max flow rate threshold is not straightforward. A common method is to run a test print while slightly increasing the flow rate with each layer, and visually making a judgment on the last acceptable layer. It would be easy to miss errors, or unconsciously be inconsistent with observations over time. [MirageC] wanted to back up observations with measurements. To do this, he is measuring the true feed rate of the filament with an encoder wheel, and the backpressure of the filament on the extruder using a load cell. A Bowden tube helps to isolate the extruder from the vibration of the moving printhead.
After much testing, [MirageC] determined that the numerical threshold would be a specific deviation percentage between the desired and actual flow rate. At temperatures above 230°C, [MirageC] found that the last visually acceptable layer was consistently around 5.75% flow rate deviation for one specific PLA filament. It does not mean that 5.75% will be the magic number for all filaments and nozzle size, but it does provide a measurable parameter to back up visual observations.
In a world of questionable product reviews this dedication to objectivity is a breath of fresh air. If you are looking to upgrade your 3D printer’s hotend [MirageC]’s tests would be a good source of information.
Multicolor printing on FDM machines can be tricky to get working flawlessly, and purging hotends when changing colors can end up wasting a lot of filament and material. To solve this problem for the popular Prusa i3 and Ender 3 printers, [BigBrain3D] developed the Swapper3D, an automated system that swaps the entire hotend when the material is changed, eliminating the need for purging almost entirely. Video after the break.
The Swapper3D works very similarly to the tool-changing systems on CNC machines, and is just as satisfying to watch. A large circular carousel on the side of the machine holds up to 25 hotends, and in practice, a pair of robotic arms pop out the previous hotend, cut the filament, and load up the specified hotend from the carousel. This means you can have a separate hotend for each color or type of filament. Since most existing hotends also integrate the heating element, [BigBrain3D] created a special hotend assembly that can be robotically removed/inserted into the heater block.
The Swapper3D is designed to be used with existing filament changers like the Prusa MMU and the Mosaic Palette. Using these systems involves a lot of purging, to the point where you sometimes end up using more filament during purging than you need for the actual part. On one five-color demo print, the Swapper3D reduced the print time by 45% and the filament used by a massive 86%. It also helps to eliminate problems like stringing and color fading in multicolor prints. With those advantages, it looks like the Swapper3D might be a worthwhile upgrade if you do a lot of multi-color printing, even though it adds quite a bit of complexity to the printer.
Sometimes advances happen when someone realizes that a common sense approach isn’t the optimal one. Take radio. Success in radio requires bigger antennas and more power, right? But cell phones exist because someone realized you could cram more people on a frequency if you use less power and smaller antennas to limit the range of each base station. With FDM 3D printing, smaller nozzles were all the rage for a while because they offer the possibility of finer detail. However, these days if you want fine detail you should be using resin-based printers and larger nozzles offer faster print times and stronger parts. The Volcano hotend started this trend but there are other options now. [Stefan] over at CNC Kitchen decided to make his own high flow nozzle and he claims it is better than other options.
Don’t get too carried away with the DIY part. As you can see in the video below, he starts with a standard nozzle, so it is really a nozzle conversion or hack. The problem with high flow isn’t the hole in the nozzle. It is melting the plastic fast enough. The faster the plastic moves through the nozzle, the less time there is for it to melt.
My son, Patrick, has observed on more than one occasion that I do not like 3D printing. That may sound odd, because I built a printer back in 2012 and since then I’ve built a lot of printers and I currently have at least three in my lab. But Patrick correctly realized that I don’t actually enjoy printing things that I need. What I do enjoy is building, fixing and even more importantly improving the printers themselves. If you are reading Hackaday, you probably know how that is. This is the story of an upgrade gone bad, although the ending is happy enough. If you’ve ever thought about moving from a traditional hot end to an all-metal hot end, you might want to hear me out and maybe I can save you some trouble.
A few years ago, I picked up an Anet A8 for a really low price. As printers go, it is adequate. Not bad, but not amazing. But it is a fun printer because you really need to do some work on it to brace the acrylic frame and fix other shortcomings. I merrily improved the printer quite a bit over a relatively short period of time and I also bought a bunch of aluminum extrusion to rebuild the frame to the AM8 plans you can find on Thingiverse.
For all of us fascinated with 3D printing, it’s easy to forget that 3D printer jams are an extra dimension of frustration to handle. Not to mention that our systems don’t really lend themselves well to being easily disassembled for experiments. For anyone longing for a simpler tune-up experience, you’re in luck. [MihaiDesigns] is dawning on what looks to be a cleanly designed solution to nozzle-changing, servicing, and experimenting.
The video is only 39 seconds, but this design is packed with clever editions that come together with a satisfying click. First, the active part of the extruder is detachable, popping in-and-out with a simple lever mechanism that applies preload. For consistent attachment, it’s located with a kinematic coupling on the side with a magnet that helps align it. What’s neat about this design is that it cuts down on the hassle of wire harnesses; tools are set to share the same harness via an array of spring-loaded pogo pins. Finally, a quick-change extruder might be neat on its own, but [MihaiDesigns] is teasing us with an automatic tool change feature with a handy lever arm.
This is a story told over multiple sub-60-second videos, so be sure to check out their other recent videos for more context. And for the 3D printing enthusiasts who dig a bit further into [MihaiDesigns’] video log, you’ll be pleased to find more magnetic extruder inventions that you can build yourself.
The world of tool-changing 3D printers is simply brimming with excitement these days. If you’re curious to see other machines with kinematic couplings, have a peek at E3D’s toolchanger designs, Jubilee, and [Amy’s] Doot Changer.
At a recent swap meet, [digitalrice] found what appeared to be a like-new QIDI X-Plus 3D printer. It wasn’t clear what was wrong with it, but considering it retails for $900 USD, he figured the asking price of $150 was worth the gamble. As you might expect, the printer ended up being broken. But armed with experience and a supply of spare parts, he was able to get this orphaned machine back up and running.
The first and most obvious problem was that the printer’s Z axis didn’t work properly. When the printer tried to home the axis, one of the motors made a terrible noise and the coupler appeared to be spinning backwards. From his experience with other printers, [digitalrice] knew that the coupler can slip on the shaft, but that didn’t appear to be the case here. Removing the stepper motor and testing it in isolation from the rest of the machine, he was able to determine it needed replacing.
Improving the printer’s filament path.
Unfortunately, the spare steppers he had weren’t actually the right size. Rather than waiting around for the proper one to come in the mail, he took an angle grinder to the stepper’s shaft and cut off the 5 mm needed to make it fit, followed by a few passes with a file to smooth out any burrs. We’re not sure we’d recommend this method of adjustment under normal circumstances, but we can’t argue with the results.
The replaced Z motor got the printer moving, but [digitalrice] wasn’t out of the woods yet. At this point, he noticed that the hotend was hopelessly clogged. Again relying on his previous experience, he was able to disassemble the extruder assembly and free the blob of misshapen PLA, leading to test prints which looked very good.
But success was short lived. After swapping to a different filament, he found it had clogged again. While clearing this second jam, he realized that the printer’s hotend seemed to have a design flaw. The PTFE tube, which is used to guide the filament down into the hotend, didn’t extend far enough out. Right where the tube ended, the filament was getting soft and jamming up the works. With a spare piece of PTFE tube and some manual reshaping, he was able to fashion a new lining which would prevent the filament from softening in this key area; resulting in a more reliable hotend than the printer had originally.
It’s great to see this printer repaired to working condition, especially since it looks like [digitalrice] was able to fix a core design flaw. But a broken 3D printer can also serve as the base for a number of other interesting projects, should you find yourself in a similar situation. For example, replacing the extruder assembly with a digital microscope can yield some very impressive results.
