Bringing A Swap Meet 3D Printer Back From The Dead

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.

Multi Material 3D Printing Makes Soft Robot

When you zoom in on a fractal you find it is made of more fractals. Perhaps that helped inspire the Harvard 3D printers that have various arrays of mixing nozzles. In the video below you can see some of the interesting things you can do with an array of mixing nozzles. The coolest, we think, is a little multi-legged robot that uses vacuum to ambulate across the bench. The paper, however, is behind a paywall.

There are really two ideas here. Mixing nozzles are nothing new. Usually, you use them to mimic a printer with two hot ends. That is, you print one material at a time and purge the old filament out when switching to the new filament. This is often simpler than using two heads because with a two head arrangement, both the heads have to be at the same height, you must know the precise offset between the heads, and you generally lose some print space since the right head can’t cross the left head and vice versa. Add more heads, and you multiply those problems. We’ve also seen mixing nozzles provide different colors.

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High Detail 3D Printing With An Airbrush Nozzle

On a fused deposition modeling (FDM) 3D printer, the nozzle size dictates how small a detail you can print. Put simply, you can’t print features smaller than your nozzle for the same reason you’d have trouble signing a check with a paint roller. If the detail is smaller than the diameter of your tool, you’re just going to obliterate it. Those who’ve been around the block a few times with their desktop 3D printer may have seen this come up in practice when their slicer refused to print lines which were thinner than the installed nozzle (0.4mm on the vast majority of printers).

Smaller nozzles exist for those looking to improve their printer’s detail on small objects, but [René Jurack] wasn’t happy with just putting a finer nozzle on a stock E3D-style hotend. In his opinion it’s still a hotend and arrangement intended for 0.4mm printing, and doesn’t quite fully realize the potential of a smaller diameter nozzle. After some experimentation, he thinks he’s found the solution by using airbrush nozzles.

As [René] sees it, the hotend is too close to the subject being printed when using nozzles finer than 0.4mm. Since you’re working on tiny objects, the radiant heat from the body of the hotend being only a few millimeters away is enough to deform what you’re working on. But using the long and tapered airbrush nozzle, the hotend is kept at a greater distance from the print. In addition, it gives more room for the part cooling fan to hit the print with cool air, which is another critical aspect of high-detail FDM printing.

Of course, you can’t just stick an airbrush nozzle on your E3D and call it a day. As you might expect, they are tiny. So [René] designed an adapter that will let you take widely available airbrush nozzles and thread them into an M6 threaded hotend. He’s now selling the adapters, and judging by the pictures he posted, we have to say he might be onto something.

If you’re more about brute strength than finesse, you might be interested in outfitting your E3D with a ruby nozzle instead.

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ERRF 18: Slice Engineering Shows Off The Mosquito

With few exceptions, it seemed like every 3D printer at the first inaugural East Coast RepRap Festival (ERRF) was using a hotend built by E3D. There’s nothing inherently wrong with that; E3D makes solid open source products, and they deserve all the success they can get. But that being said, competition drives innovation, so we’re particularly interested anytime we see a new hotend that isn’t just an E3D V6 clone.

The Mosquito from Slice Enginerring is definitely no E3D clone. In fact, it doesn’t look much like any 3D printer hotend you’ve ever seen before. Tiny and spindly, the look of the hotend certainly invokes its namesake. But despite its fragile appearance, this hotend can ramp up to a monstrous 500 C, making it effectively a bolt-on upgrade for your existing machine that will allow you to print in exotic materials such as PEEK.

We spent a little time talking with Slice Engineering co-founder [Dan], and while there’s probably not much risk it’s going to dethrone E3D as the RepRap community’s favorite hotend, it might be worth considering if you’re thinking of putting together a high-performance printer.

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3D-Printer Gets Hot-Swappable Hot-Ends

3D printers can be hacked into a multitude of useful machines, simply by replacing the filament extruder with a new attachment such as a laser engraver or plotter.

However, [geggo] was fed up with re-wiring and mounting the printhead/tool every time he wanted to try something new, and set out to design a modular printhead system for next-level convenience. The result? A magnetic base-plate, allowing a 3D printer to become a laser engraver within a matter of seconds. This new base-plate mounts onto the existing ball bearings and provides a sturdy place for attachments to snap to – with room for two at once.

Using neodymium magnets to mount the printhead to the base-plate provides enough force to keep the attachment in place and compress 30 pogo pins, which make the electrical connections. These carry the lines which are common to all attachments (heater, thermistor and fan), as well as custom connections for certain attachments – for example the extruder stepper motors.  A Flexible Flat Cable (FFC) is used to connect the pogo pin PCB to the main controller.

So far, the list of tools available for fitting includes an MK8 extruder, a E3D v6 hotend (for Bowden extrusion), a laser, a micrometer dial indicator, and a pen plotter (used for writing a batch of wedding invitations!). There was even some success milling wood.

For some automated extruder switching action we’ve shown you in the past, check out the 3d-printer tool changer.

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3D Printer Tool Changer Gives You Access To Lots Of Extruders

The benefits of having a 3D printer with multiple extruders are numerous: you can print soluble support material for easy removal, print a combination of flexible and rigid filament, or simply print in different colors. Unfortunately, traditional multi-extruder setups have some serious drawbacks, even aside from the cost.

Usually, the extruders are all mounted next to each other on a single carriage. This increases the mass, which can cause print quality issues like shadowing. It also reduces the printable area, as each extruder needs to be able to reach the entire area. All of this means that the design becomes more and more impractical with each extruder you add, and that’s why it’s uncommon to see more than two extruders on a printer.

Over on Hackaday.io, [rolmie] has come up with a very practical (and affordable) solution to this problem. He has designed a tool changer that gives the printer the ability to switch out hot ends on the fly. The system is very similar to the tool changers we see on CNC machining centers: tools (the hotends) are stored on a rack, and a tool change in the G-code sends the carriage over to the rack to drop off the old hotend and pick up a new one.

The benefit of the design is that both the mass and volume of the carriage are kept to a minimum, while allowing you to use many different hot ends. Each hotend’s settings can be configured individually, and you can even use different models of hotend altogether (maybe one model works better for PLA, while another is better for ABS). The design is still in the prototyping stage and needs some refinement, but it’s a very promising proof of concept that seems like it could be implemented fairly easily into most 3D printer models.

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Mini Delta Gets A Hot End Upgrade

3D printers are now cheaper than ever and Monoprice is at the absolute forefront of that trend. However, some of their printers struggle with flexible filaments, which is no fun if you’ve discovered you have a taste for the material properties of Ninjaflex and its ilk. Fear not, however — the community once again has a solution, in the form of a hot end adapter for the Monoprice Mini Delta.

The Mini Delta is a fantastic low-cost entry into 3D printing but its hot end has a break in the Bowden between the extruder and nozzle. This can lead to flexible filaments not being properly guided through the hot end and a general failure to print. This adapter allows the fitting of the popular E3D V6 hot end, and is similar to modifications out there for other Monoprice printers.

Overall, 3D printing has long benefited from the efforts of the community to bring both incremental improvements and major leaps forward to the technology. We look forward to seeing more hacks on the Monoprice range!