X-truder, Dual Nozzle 3D Printer Head Assembly
Finally, a print head worth buying!
X-truder, Dual Nozzle 3D Printer Head Assembly
Finally, a print head worth buying!
What is it?
A high temperature, dual nozzle, single motor, compact, affordable, light weight, professional 3D print head. We've integrated all the best functionality, in a small package weighing about 16 ounces.
Why is it?
We wanted a print head capable of high temperatures and running materials such as ABS, PC, PVA, PLA, TPU, etc. Along the way, our wishlist grew to include dual hotends, nozzle retraction, simplified wiring, LED lighting, compact size, low cost, etc. We weren't interested in what was available in the marketplace, so we created it.
Who buys it?
A tinkerer, a hobbyist, a 3D printer enthusiast, a Maker. You want more from your existing printer. You know how easy it is to edit and upload firmware, and you can tune your slicer settings to get great prints. You're looking at our X-truder and can picture it adapted to your printer.
Who are we?
We're a 3 man team working together in an industry unrelated to 3D printing. We were designing and fabricating 3D printers in our spare time and then about a year ago, we pitched several ideas to our management as potential products. We were given a small R&D budget and spent months designing and fabricating complete printers, print heads, CoreXY mechanisms, and generally immersing ourselves in all things FFF/FDM. Early in 2014, the decision was made to launch a small print head stuffed with all we'd learned. We chose the names Praxis, Klix and X-Truder, in homage to our long history of using X's in names.
NOTE: The X-truder can only handle filaments ranging from 1.7mm to 1.85mm. We are not exploring 3mm filament compatibility at this time. We have settled on 0.4mm diameter nozzles which allows for good printing at layer heights from 0.2-0.4mm thick.
Klix Mounting Solution
With so many different printers out there, we wanted to provide a simple interface to mount the X-Truder. Our Klix idea provides an accurate magnetic mounting, with multiple hole patterns and ways to secure it to your printer. One Klix will be included with your pledge, and the Klix mating features are designed into the rear of the main housing. Klix will be available in pairs on our website soon, for those interested in accurately and securely mounting most anything. Below we are showing a Klix mount on a generic (not provided) printer framework, and is meant to help you visualize how it works and how you might adapt the X-Truder to your framework.
The below CAD drawing/exploded view includes our planned front bezel, which is held on with magnets to the front of the assembly. We are also providing a motor twist knob, which is handy for manually feeding filament and for visually verifying activity. Again, the rods/frame members are not included.
What's been achieved so far?
Since January and our decision to focus on the print head, we've built 4 prototypes and refined every system within the X-Truder. The Nema 11 drive system and filament pathway within the head are done. We've created a CNC based machining fixture to accurately cut sharp splines into the motor shaft. We've sorted the changes needed within Marlin firmware to control the stepper motor reversal and the servo actuation. The nozzle retraction's cam mechanism has been tested over 100,000 activations without issue and can return each nozzle to its printing position with great accuracy. We've identified the electrical connections necessary on RAMPs styled controllers and have eliminated servo jitters caused by the typical electrical noise running throughout 3D printers. We've tuned slicer settings and learned how to run PLA, the most challenging plastic for an all metal extruder. We've tested PC, ABS, HIPS, PVA, and PLA. In addition to the product development, we identified sources for each component, set up the websites, created e-commerce accounts and created our Kickstarter campaign (no small feat)
Below is a time-lapse video showing a 2 color calibration box running in PLA at 200C, with the idled extruder cooled to 170C, fan at 50%, a 60C hairsprayed glass bed, 0.4mm nozzle, 0.25mm layer height, and a print time of about 2.5 hours. Print speed is a modest 40mm/s and chosen to produce a nice part finish and not a limitation of our head design. Tool change time with warm up is about 40 seconds with these settings. Retract/Replace are both set at 1mm to limit ooze and path start blobs. A priming pillar is being used to purge the incoming extruder, and is one of the many nice features within the Kisslicer Pro software. part credit: (thingiverse: dob71)
Developing a hotend capable of extruding over a wide temperature range is very challenging. Using small cross-section stainless steel tube and an efficient copper heatsink, we've achieved the necessary short thermal transition zone. There's a high flow 40mm x 28mm fan inside the print head to cool the Nema 11 motor and the heatsinks. Finally, we settled on a 35mm long heat block/cartridge heater combination, capable of fast heating and ingesting filament at speeds of 10mm/s or more.
This video shows a 2 color thin walled test piece running in ABS at 260C, idled extruder cooled to 200C, fan at 50%, a 90C taped bed, 0.4mm nozzle, 0.3mm layer height, and a print time of about 10 minutes. Print speed is again held to 40mm/s, decreasing vibrations associated with the moving bed style of printer. Tool change times with warm up are about 45 seconds with these settings. Retract/Replace are both set at 1mm to limit ooze and path start blobs. In this example, there is minimal ooze, mainly in the warming up side and not in the idle side. part credit: (Praxis3D)
How well does it work?
We want to be up front about the X-Truder’s performance and share what we’ve learned. We've found that ABS, HIPS, and PC extrude very well and we can achieve great prints with a wide variety of slicer settings. We have limited testing with PVA as our roll of it degraded during the year spent outside its bag. We've also had difficulty when printing with dissimilar plastics like PC + ABS, as their adhesion to each other is poor and ABS is prone to warping without a heated chamber. In fact, most of our ABS tests use small parts for that reason.
As for PLA, it's a Good News/Bad News situation:
The Bad: PLA is prone to jamming when we don't use the fan at all times or use temps of 230C or more. Without cool air flowing over the heatsink, heat creeps up both the stainless tubing and the PLA itself, softening a long length that jams due to friction within the tubing. Our tubing has a bright drawn ID finish, but that’s not enough to combat a long PLA piston. We found that both the warm up and cool down periods need the fan to prevent a potential jam. In fact, we run the fan at 50% in all situations, as it also cools the Nema 11 motor.
The Good: PLA can run reliably with a few gcode additions. Most slicers allow for easy insertion of custom gcode and we're now using retract at the deselect tool moment, idle extruders are lowered to a non-oozing temperatures, M106 Fan On is used in the prefix, a priming pillar readies the incoming extruder, etc. We’re able to print reliably now.
Below is the last half of a vase running in PC at 275C, fan at 50%, a 90C hairsprayed glass bed, 0.4mm nozzle, 0.3mm layer height, and a print time of about 2 hours. Print speed was 75mm/s and chosen to keep the vase from shaking off of the bed. part credit: (thingiverse: fablabmaastricht)
How are the Rewards structured?
The Early Bird rewards have nearly zero profits for us, considering the BOM costs and the various fees involved with launching: $25 or 10% goes directly to Kickstarter/credit card processing fees and another $65 for fixed costs like packaging, shipping, labor, taxes and tool amortization.
Why is the minimum funding so high?
The X-Truder contains 9 tooled items, 2 PCBs, a ribbon cable, 2 all metal extruders, a ball bearing metal gear servo, a high torque stepper, a server class fan, and much more. We're operating on thin profits, with our break even at about 400 assemblies or $110,000 in sales. If we can't reach these numbers, which lowers our costs with volume purchasing, we won't launch the X-Truder.
What's left to do?
As a priority, we're committed to answering backer questions while we launch the X-Truder, plus some final tasks listed here in no particular order. We need to modify the CAD data for drafts and manufacturability, pull part numbers, finalize the drawings and put them under rev control. We will create detailed instructions for the installation of the X-Truder in a generic 3D printer, defining the electrical connections for RAMPs styled controllers, firmware changes needed, etc. We will be sharing our slicer settings and detail our troubleshooting thought process so everyone can tune their printers quickly. We will create instructions for calibrating the nozzles in XYZ, share our calibration prints, detail filament loading, etc. We need to design and source the packaging materials. We need to set up our assembly workspace.
Risks and challenges
The X-Truder was refined during 4 rounds of prototypes and about 8 months of printing. We are confident the design is ready for production. For our team, the sourcing and qualification of components is also a familiar process. Finally, our design is modular and should be easily assembled.
We made some early decisions to reduce risks. To simplify manufacturing and order fulfillment, we're only launching one product, without confusing options, configurations, etc. We decided against offering filament, T-shirts, etc., as it complicates packaging, inventory, etc. We're selecting as many local and domestic vendors as possible, so we can closely monitor deliveries. If there is early success with the campaign, we can release tooling and place orders for long lead time items. Lastly, the delivery dates are conservative, increasing the likelihood of delivering on time to each group of backers.
That said, our challenges lie mainly with vendor selection, vendor performance, and the unknowable. We also will be updating the campaign with our tips and tricks for successful printing. We're continually learning how to make this head work better, and as a community, we hope others share their settings and tuning tricks.
We're unable to source and test every material on the market, and we look forward to the collective sharing their settings and successes.
- (30 days)