A 3D printer unlike any other, fits inside a spool box? - Positron V3 intro & Design Story

hello everyone finally after more than a year of development this is the latest and greatest of the positron 3d printer series the positron version 3. this is an upside down compact super fast and portable 3d printer this video is split into two parts in the first part i will introduce the positron version 3 and all its features in the second part i will tell you the design story of the positron series and how everything got started from beginning to the present time and please stick around until the end of the video for an important announcement so let's see what the positron version 3 can do the entire printer fits inside a 1 kilogram filament spool box and can be easily carried around to wherever you want and when you are there from being packed fully inside the box to set up it only takes one minute now in my previous video i showed that positron version 1 had at least double the build volume of similar 3d printers well what if i told you that positron version 3 has almost 1.7 times the build volume compared to even positron version 1. thus with a build volume of 180 by 185 by 180 millimeters positron version 3 is easily one of the most compact 3d printer designs positron version 3 is also the lightest of the positron series weighing in at just 2.7 kilograms or the weight of a generic gaming laptop being so lightweight and portable some of you might think that this printer might be slow and not rigid but this is precisely the opposite positron version 3 is three times as fast compared to traditional cartesian 3d printers it can print at 250 millimeters per second travel at 400 millimeters per second and its acceleration is 1g or 9.8 meters per second squared it achieves all these impressive specs because of three high-level design decisions number one its upside down nature means that the center of mass is always down low so there isn't any need for frame to support the gantry and positron version 3 actually has the lowest center of gravity compared to its predecessors number two a all-new hotend design together with a bounding extruder makes the hotend extremely light so it can be moved around at high speeds number three a custom cable-driven cross-shaped h-spot gantry with cross-liner rails this design decouples the motor's mass from the x and y-axes thus reducing inertia speaking of the gantry instead of using belts positron version 3 kinematics uses these special synchromesh cables what's special about these cables is that it allows the drive plane to be switched at will unlike basically all other 3d printers the positron series all features a 90 degree hotend and as i will show later this has no effect on build quality and as a plus of this fifth generation design it actually allowed me to improve the efficiency of the hotend drastically so now it is basically on par with a e3d volcano in terms of flow rate one of the coolest features of the positron series is the transparent heated build plate which you can look through and see exactly how your first layer is being laid down there's also automatic bed leveling so there is no need to adjust screws each time the printer is folded and unfolded these two features together make sure that the first layer is laid down perfectly every time additionally the build plate is also magsafe so it can be easily removed or secured in place positron version 3 is running one of the best 3d printer firmware the clipper firmware the printer features a full color touchscreen and has wi-fi built-in it could connect to your home wi-fi or if you are out and about it broadcasts its own wifi signal so you can control upload and manage prints anywhere within the vicinity of the printer finally as usual positron version 3 has rgb built-in for printing in the dark as well as four status indicators that's basically all the high level feature of the positron version 3. and let's see its print quality if you have seen the previous video on positron version 1 you will see that printing upside down actually has no effect on printing quality and positron version 3 is the same as well the major difference is that positron version 3 now has dual cooling fans this produces better overhang and bridging performance at higher speeds just to illustrate the point i designed this 120 millimeter bridging test and positron version 3 handles it without any problems in terms of tolerance this printer managed to clear all the way down to 0.2 millimeters which is on par with other printers thus printing place models work flawlessly overhangs they work up to 70 degrees supports are printable and easily removable too both organic and geometric shapes work extremely well on this printer as a challenge i also printed this lattice torture test which also worked without any problems the positron series is designed for rapid prototyping in both pla and petg the build plate goes up to 90 degrees celsius and the hotend goes up to 250. it handles these filaments extremely well because it is printing upside down many of you could be worried about bad adhesion however bad adhesion is a non-issue because the bed uses borosilicate glass as its material when hot the intermolecular forces between the print and the glass makes the print adhere strongly to the bed and the prints automatically pop off the bed when the bed is cooled due to differences in thermal expansion as a final note on print quality i printed an all-in-one print quality test and this is the quality compared to my prusa i3 as you can see both printers can produce excellent results positron version 3 has now over 500 hours on record and it has been my daily printer as i have to frequently travel between cities to attend classes and even though there is a bunch of crucial printers in the university shop i still brought positron as it allowed me and my team to go through multiple iterations of design because it can print so fast and that is positron version 3 a compact fast and portable 3d printer it took over a year of work and three redesigns to get to this point and so the second part of the video is about the development history of the positron series and everything it took to get to this point but before that let me tell you about the sponsor of this video jlcpcb from whom you can get 5 high quality pcbs for just two dollars and now all three versions of positron uses pcbs from jlc pcb it is easy to create schematics and convert them into boards using their free online editor easy eda the pcbs generally gets to me in just 5 days so i can go through multiple revisions to fine tune the design check them out in the link at the description now here is the full design history of the positron series which you will see how design choices are made and evolve as you may have known i don't usually present the progress of my projects only the final result so please let me know in the comments if you like this segment so let's begin the initial idea for this product came from me just getting tired of cartesian 3d printer design don't get me wrong this design was great in 2011 and still good in 2018 when creality introduced the ender 3 but nowadays it seems like every printer is under 3 clone and overall lacks innovation so i want to create a printer that can print much faster and it is a lot more unique in design i started by doing research of a lot of core xy designs as well as winch driven mechanisms it is during this research that i had an idea to 3d print upside down because if you flip a core xy 3d printer upside down all the heavy moving mass is near the bottom and there is no longer a requirement for heavy frame and furthermore this drastically reduces on the vibrations of this printer as you can see in this video by cnc kitchen when the printhead is very high it induces more vibration into the 3d printer frame so i initially planned for just a traditional upside down printer with a core xy gantry however this is when i found this design by lobo cnc when he made an upside down 3d printer that is mounted onto a granite plate his design gave me a lot of inspiration and i started sketching for ideas during this process i made two major realizations number one the gantry does not need to be mounted perpendicularly with the base it could be mounted diagonally and this can reduce the overall footprint of the design and also if i can find a way to get rid of the belt twisting issue i can make a gantry that is a lot more compact and last a lot longer this is when i found something called the synchromesh cable which advertises as being able to change the drive plane at will i was initially skeptical about its usage but then i found a video of someone putting this on a 3d printer and it looks like it functions just fine these realizations together with several iterations of the drawing evolved into a compact small unfoldable 3d printer idea the next step is to determine the build volume of this printer for this i went through almost all my 3d printed models in the past two years and i realized 95 of them fit inside a 180 millimeter cube build volume then with some rough layout in cad i found that it is possible to fit the entire gantry into a 200 by 200 millimeter bounding square which is also conveniently the size of most filament spool boxes with that i wrote down a simple list of all the requirements overall the 3d printer consists of four major subsystems the hotend the extruder the kinematics for the x and y axis and the z-axis in the beginning i was not certain that the kinematics would work at all and be accurate so i tried to test it out first the initial model was very rough it is just some laser cut pieces of wood together with some 3d printed components and to my surprise the kinematics works just fine and it was reasonably accurate even with all the janky components the next step is to test out the 90 degree hotend because of how flat the machine needs to be there isn't enough space to fit a traditional hotend so the filament has to take a 90 degree turn my first revision was very rough it was just an aluminum block with drilled and press fit tube the other side is threaded for the nozzle and the two holes met in the center in the 90 degree angle this design is pretty bad because there is just too much space inside a block and this causes highly inconsistent extrusions after another two revisions i made a drastic change to the design of the hotend the change is the addition of a brass insert this change allows the ease of manufacturing as there is no more body main tab required and also this design allowed the use of traditional heat breaks and both the nozzle and the heat break can be sealed against the brass insert to create a constrained filament path this design was a lot more successful than the previous versions and it achieved a similar flow rate as an e3d v6 at 12 cubic millimeters per second with both the kinematics and the hotend design validated i went on to design the extruder back then i was fixated in the highest amount of torque in the smallest package so i went with a warm gear design and paired it with a nema 11 stepper motor this resulted in a small extruder with very high push forces however in hindsight using worm gears is a bad idea as i will explain later for the z-axis this is what i spend most of my time on because it has to be folded and compact it also have to be very rigid many designs were tried but i eventually settled on a warm gear driven belt design and the z-axis is detachable through some screws and the motion is coupled using a spider coupler and the warm gear was chosen mainly because that's what i already have on hand and i felt that would simplify things the next major task is to find a way to heat up a transparent heated build plate the build plate had to be transparent because otherwise it would be very difficult to see what the printer is doing and i want the printer to come with great user experience too initially i was looking at indium tin oxide glass which is a type of coating on glass that makes it electrically conductive the only problem was the price so i looked at another source of heated glass and that is a car's rear windshield fortunately i found a company that sells these heater strips as diy kits so i bought a few of those calculated the resistance of the strips and laid them out in a densely packed pattern on a piece of burl's lucky glass and the result was actually quite decent and from the thermal camera the temperature looked quite stable as well for bed leveling since this printer is going to get folded a lot and transported automatic bed leveling is basically a necessity for this design so i selected this ir probe it actually works pretty well on glass and it is one of the smallest and most low profile of bed sensors now with all these subsystems validated i basically delved into a cad for the next three weeks trying to integrate everything for the control board i basically have no choice but to buy the smallest control board that is available at the time which is the skr mini e3 even then with the design i had to remove a lot of headers and connectors as they are interfering with the internal geometry each step of the way i would try to 3d print the component and try to place them to see if they work together if not it is just a cycle of going back revising the design in the end i ended up with over 10 major revisions and i got to a point where the printer finally made its first print i was happy at the time as i got to anything to work at all but the quality is terrible so i went on to diagnose the issues and made more revisions to the design after more tests i got to a point where i feel confident to make the final prototype then it is time to start making modification to the board 3d printing various components and all the machining and sheet metal bending eventually after around 30 hours of assembly time the printer was finally complete and they generated some very good prints you can see the printing quality in the positron version 1 intro video after i posted the video it was way more successful than i thought even large 3d printer channels recognize my design which i am really grateful of and i started to film the positron version 1 build series almost immediately however when i was editing the footage and writing the script i realized that the design is still heavily flawed in many aspects even though it generated some very good results number one the amount of modifications that needed to be done to the main board made the assembly process extremely tedious second the warm gear turned out to be a really bad choice for both the z and the extruder at that time i didn't really know that linear advance which is a setting that compensates for the changing pressure inside the nozzle made the extruder make sudden rapid movements which makes the extruder to skip steps anytime the printer is printing faster than millimeters per second during corners the warm gear on the z-axis is not really any better as i realized that these cheap chinese horn gears produced quite a lot of z banding on the prince this resulted me in having to buy a 35 worm gear from mcmaster car worst of all after 300 hours of printing there is noticeable wear on the worm gears furthermore i couldn't really achieve all of the objectives i set out to do even though the printer does fit inside a filament spool box i needed to find the largest filament spool box available to do so the build volume turned out to be a lot smaller than 180 millimeters cubed together with the painfully small screen and the very flimsy build plate i decided against on making a build series or positron version one this is because i do not want to launch a inferior product i do not want anyone wasting their time building positron version one only for positron version 2 to come out a few months later that is much better so i began designing the version 2. my main objectives are pretty simple solve all the design problems of positron version 1 and make it much faster being able to complete a benchy in under 15 minutes and also to simplify production and assembly and here is the cat of the version 2. i will highlight all the major design changes number one i got rid of all the worm gears for extruder it is a belted design with a 3 to 1 gear reduction ratio driven by a pancake nema 17 motor this change made the rapid movement of the linear advance and retractions much smoother and faster for the z-axis i went with a lead screw driven design and a vertical coupler that is much easier to align and place the complexity of the z-axis is reduced dramatically as i ditched the dual linear rail design in favor of a single wide linear rail to solve the flimsy bed problem instead of having foldable arms that comes out to hold the bed i went with extrusions attached by thumb screws this gives the bed a lot more vertical rigidity and the kinematics is also changed in version 1 the motors are offset from the center of the printer and they took up quite a lot of space to be more space efficient i placed the motors at the two extremes of the printer and folded the gantry on top of itself this made it so that on each motor there is one drive pulley and one idler pulley another major change was the hot end instead of having a heating cartridge right next to the brass insert now the heater cartridge is inserted perpendicularly into the brass insert the main advantage of this design is that the most critical part of the filament path is the bend and that bend is now only two millimeters away from the heater cartridge this simple design change actually doubled the performance of the hotend compared to positron version one and now the flow rate is comparable to e3d volcano for the build plate i use jlc pcb service to make jumpers for all the heating strips and furthermore inside the pcb i also incorporated heaters to compensate for the edge losing more thermal energy compared to the center for the controls i found the clipper screen project and i also saw that the 3.5 inch tft can be used so i bought it and it has been working out great as it is just the right size for the printer so after another two months of designing and building the positron version 2 was born and it is a lot more capable than positron version 1. i originally hoped to print a benchy in under 15 minutes however with some tuning i was able to get it under 10 minutes from a pure functional standpoint pulsatron v2 was great it produced way more reliable prints than the positron version 1. it is also around 2.5 times faster now the last step before releasing the design is user testing which did not go so well long story short i think i became set on improving the performance and the build volume to the required size and i had to sacrifice many other aspects of the design the main problem is that now there is too many thumb screws and the z-axis leaf screw was extremely finicky to install and to take apart the design is just overall too complex this increased the assembly time to above 3 minutes which to me it was unacceptable also throughout the calculations i left a safety factor of 5 and this resulted in extremely rigid design however now the design no longer fits inside a normal filament spool box and i needed a rather large 3 kilogram spool box to hold the printer the weight now is also increased to 4.6 kilograms which is almost double of positron version 1 and it was noticeably heavy inside the backpack and indeed i got some very negative feedbacks from my fellow designers regarding the portability and the ease of use of the machine after user feedback i had to make a very difficult decision either to launch positron version 2 as it is which it has very good performance but bad usability or go back to the drawing board and make positron version 3. by this time i had spent more than 1 000 hours and thousands of dollars of material costs and looking back at the original specifications for my design i wondered if they are possible at all i was very close to start making positron version 2 intro video however this is when i saw a new 3d printer control board called the xkr picot this is by far the smallest commercial 3d printer control board i have ever seen and with its small size i realized that i can make things work potentially so i started again laying things out in cad and also looking back at the design decisions i made for version 1 and version 2 and i try to select the best aspects of both revisions and together incorporate them with some new features so i started the design for positron version 3. for this design i really want to come up with a solution that both looks aesthetically pleasing and functions well long story short again here are all the major changes i made to the positron version 3. the z-axis is now driven by a nema 14 motor with a 3-1 gear reduction with belts not only this gets rid of the z-banding problem it also solves the torque issue in the previous versions the power is transferred to the build plate by copper strips on the side this system works okay but because of the exposed copper strips it can happen that the bed can short out with a printer frame during removal in fact this happened to me on positron version 1 and burnt out the entire control board so for version 3 i found this magsafe connector and it has special magnets inside that can handle high temperatures and it is very convenient to insert and remove the build plate because there is no longer a need to run wires to the z-axis arms the z-axis arm can be machined out of a single piece of aluminum and it is simple and solid the next major change is the extruder now it is using a compact cylindrical nema 14 motor with bmg drive gears for 5 to 1 gear reduction the design is also very compact and gives plenty of torque because of all the weight savings on the tool head and the x-axis i was able to get away with pancake nema 17 motors while still maintaining a theoretical max acceleration of 12 000 millimeters per second squared and a travel speed of 500 millimeters per second there are also some miscellaneous changes such as because of the chip shortage raspberry pi's are hard to come by so i designed the computer compartment to be compatible with both raspberry pi 3 4 and the pi zero 2w it is also compatible theoretically with the orange pi h2 if you are willing to go through some hassle to make the screen work speaking of the screen it is now mounted by a front connector this gets rid of the finicky ribbon cable on positron version 1 and 2. with all the changes and revisions positron version 3 was finally able to achieve and exceed all my objectives positron version 3 now takes only 60 seconds to deploy and with its folded height of only 75 millimeters it fits inside almost all standard filament spool boxes i have its print quality is on par with some of the best machines on the market and overall i am glad that i decided to go with version 3 and after all of this talk i hope you will agree with me as well before i show you a printing montage of the positron 3d printers i would like to make an important announcement you might be wondering when is the positron build series coming and i promise that it is coming soon however due to personal reasons which i cannot disclose here i cannot manufacture positron 3d printers in the foreseeable future but this is where the good news is i will release the entirety of the design the cad the build of materials the production files the pcb design files the schematic the printer configuration as well as cura slicer configuration all to public under the creative commons license this means that anyone group or company may manufacture and sell this product as long as you credit krellin as the inventor somewhere visibly on your product basically i wish to break the cycle of copy and lack of innovation in the desktop fdm 3d printer space so this is why i am basically releasing this design for free this is my gift to the 3d printing community if you like what i do please consider subscribing to my channel and share this video i realized on this channel when i usually develop something it usually takes me several months to do so and only if the product works do i show the final results this often leave a huge gap in my upload schedule and i realized this is not the best way to keep all of you updated on what i'm thinking and doing so this is why i'm excited to announce that from now on i will be on patreon where you can support my channel and see frequent updates on behind the scenes stuff as well as the projects i am working on please consider becoming a member of my patreon i would gladly welcome any support as it enables me to continue to create awesome designs and release them for free and i guess that's all for the positron version 3 intro and the story of the positron series if you have any questions please ask away in the comment section and now for the montage uh [Music] um [Music] um [Music] [Music] you

Channel: K R A L Y N 3D

Views: 688,148

Keywords: upside down 3D printer, upsidedown 3D printer, inside-out 3D printer

Id: X_QLxTVtyng

Length: 33min 59sec (2039 seconds)

Published: Wed May 18 2022