Great work. Hotends can be very expensive as well. Also not all controll boards have an additional port for more heater and Thermistor, but there could be a workaround with power supply to the Hotend by the carriage. Having parking positions with only filament would give a lot of options. You could reduce more cost by only using one hotends and still have an automatic multimaterial printer. More like an Prusa MMU2 by selecting the Filament. This Parking position could include a Filament cutter. I think Its possible to get this mod under 80 bugs for 10 Filaments incl. all items. (not the development cost :/) Or having 1 Hotend for high temp Material, 1 for low temp Materials and still the option to swap between more than 2 Filaments. Or going full crasy with an additional Extruder changer. Then you have 2 Extruder, 2 Hotends and additional Filaments to choose from. But I think an Extruder changer doesnt make sence as soon as you have an good one. Have fun

I know this comment is several months late here, but what if you used a mechanism like a switchblade knife as part of the extruder side of things with a swinging "V" shaped pivot switch that activates the switchblade switch on the extruder side of the mount. this would keep the hotend attached more securely in a similar way to the voron attachments with sliding bars. this should also allow for easier hotend removal because you should, in theory, have less resistance as physical contact with the hotend could be removed with appropriate tolerances.

Why dont you sleve the plastic part, with metal sleves/tubes, for the dowel pins?

Amazing +like +sub

you can use electro magnets which would be stronger, more controllable, and cheaper than even neodymium magnets.

CONGRATULATIONS! This is the first video I see a toolchanger can work like this. This is completely like my idea, but even simpeler. However, to print fast we would need a better extruder. Also, the accuracy of the positions will have slack. To obtain an accuracy of 0.03 mm will be a challenge...

imho. not sure if the extruder motor and gear is worth it. Parts for a Mk3s type extruder clone is dirt cheap on ali, including the stepper. How ever the stroy is different with all that fancy stuff in a prusa next-extruder, the damn nozzle alone is more expasniv than a normal nema stepper/gear/e3d clone on ali...

I tried 3d printing and using a manual tool changer which had the fans and hotend assembly all mounted together, but removable from the gantry plate, and ran into a similar problem with the hotend wobbling because it was held up by plastic. I think thats a major design challenge: using any type of plastic for the assembly of a part that is directly tied to specific structural components that need to be exact to get quality prints. Might be best to CNC those

A lot of good advice in the video, I would however point out that in or before the first stage you should find out why you design a product. Who is it for, what problem can it solve etc, some kind of Design Thinking.

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Would be interesting to have a printer that can change not only filament color/type, but size as well! I can imagine that'd be a pain to get a slicer to account for, but would be cool to do highly detailed areas with 0.2 mm nozzles / 1.75 mm filament and then switch to a 1.2 mm nozzle / 2.85 mm filament to fill in larger areas.

11:20 whats going on with those belts 👀

This multi tool head design where only the hot ends change is brilliant for saving cost and weight. I wouldn't be surprised to see a manufacturer implement this design in a future product.

Get rid of the dowel pins altogether and replace it with 2 or 3 V-grooves to align the tool. Pin and sleeve junctions alignment errors will haunt you forever, V-Grooves are self aligning .

pretty damn slick bro!

The geometry of the flex is very important, avoid stress concentrations, spread the flex over larger areas/lengths

May i suggest looking at various space docking mechanics, and copying mainly the mechanical part of it. Using probe/drouge or guides to achieve better alignment and better tolerance. You can use different design for extruder to holder and extruder to hotend. Flat head scred driver is kind a probe/drough , use funnel to guide the screw head and push it inside the funnel tube for hard capture

Why add a spring when you can design the spring in the actual print

That's awesome ! I'm curious to see if you can make a same system with a lower entry price 3D printer

Without a doubt this is a great platform to build on - still. Solid aluminum extrusion frame, linear rails, etc... If you do not like some features on it you can look at some current designs for inspiration and update it. The bed is a problem - you can go to holding it on 3 sides or 4 easily. The printer knobs - simply remove the knob! Use an allen key to make any adjustments. Keep up the great work - I would like to see you come back with this printer completed sometime in the near future and have it kicking butt!!! Defined as making awesome looking parts that look consistent, are dimensionally accurate and are made reasonably fast. RatRig and Voron designs can inspire the heck out of you (and others that speak to you like Bambu, etc..), the answers are all there and it should not cost too much to do it. Cheers

You have done some great work here. If you look at what you are trying to accomplish you will see that there are some standard design approaches for something like this. The locating pins - they should be hardened. Also, they should have a bullet or taper to help guide the alignment. Also they both do not need to be round - one can be a diamond pin which makes mating forces even easier and gives up nothing to positional accuracy. Now that you have the hardened pins you can consider using bushings in your receiving block. With the magnet locking idea - perhaps this is a weakness since that is the only thing other than friction in the mounting pins that is holding your tool in place. The back plane where the magnets are located should be a milled flat surface - then when the tool comes in it has something very precise to set that dimension. If you want the parts to be mostly extruded you could get some milled flat steel and embed it into the design. To assist wit the clamping perhaps something done in the code to open and close clamps on the toolhead. With these ideas implemented any "wobble" or positional inaccuracies should be taken care of. Hope this was helpful. I am sure that what I commented on you may have already though of. Also, I did this in just a quick minute so there could be something I missed. However I have worked in manufacturing as a degreed mechanical engineer for a very long time (think decades) and over that time I have designed and built a bunch of machines - But I don't think that i ever invented anything, mostly I learned from others - over the years I have been around some amazing engineers that were simply brilliant. Your design is very inspiring, it inspired me to make this reply and really got me thinking. Great work. Keep up the great work. Cheers.

My experience with TPU is, if there is a small gap between the extruder gears and the bowden hose it works for loading the filament with continous flow, but as soon as you print with retractions it finds the gap and will move that way, but lets hope for the best.

Needs a springed metallic sheet under each hotend dock, touching nozzle tip directly and blocking plastic from oozing.

hotend changer

I feel like a significant cost that has been missed is the electronics. Each hotend is going to end up needing at least one heater, thermistor and fan. This doesn't tend to be an issue for 2 tools, especially if using a mains powered bed, most big control boards have enough spare ports for that much. But, for more tools that won't be enough and you'll effectively need to have a toolhead board per tool, adding ~$30/tool. On the bright side, that'll also allow for all sorts of additional reliability improvements like sensors to ensure that tools have successfully docked/undocked.

27:26 looks like the pin was hitting the arm on the extruder, the arm its all chewed up. hopefully you have something better by now

I have no need for multi coloured parts, I make parts to suit a job, & to work. Colour is immaterial. An amazingly well worked project. 👍

i would love to use this design on my own machine if im allowed. what a lovely design! good job

Tell Olof that if he comes up with something to help with your shared extruder tool changer, i am a customer.

Have you looked at blackbox printer's extruder? That design shares a one extruder also.

I guess many appreciate if didn't use background music

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I bought all of the kit to make one of these when they were a thing. I was waiting for the MK2 metal kit to get released for it but it didn't happen, and a printer held together with plastic bits isn't a great idea, so the kit is still sat unboxed in the garage. I had contemplated buying the MK1 metal kit but even at ~€150 that it's selling for, it's more than the printer is worth, and it'd make more sense to put that money towards a modern printer, because I'd still have to invest more time and money to finish it. They were the makings of a good printer in their time, but their time has been and gone.

How about 3d print a tool changer that can swap hot ends on both sides of the frame. That means we can have twice the current counts of extruder hotends of 5 to 10.

This project needs to be picked up and run with! This is awesome! Tool changers should absolutely be cheap and wide spread!

Was very interested to see this approach mentioned in Teaching Techs latest Video. I really like this concept to avoid a fair bit of the wasted hardware in most tool changer designs - and also the removal of the need to cut filaments to get them to correctly feed into the extruder. (As per the BigBrain3d Swapper3d). The additional cost and electronics involved in each nozzle having its own heater is balanced out by the benefit of being able to keep/preheat each hot end at an appropriate temperature to facilitate fast tool swaps. My biggest concern is whether the size and weight could be scaled down to a) allow really fast printing and b) allow room for at least 12 hot ends to be loaded - to really complex multi colour prints - such as ship models. To me the ultimate solution would have 2-4 fully independent print heads (with extruder motors) for parallel printing, with each print head able to colour swap using something like this engineers grow approach. Perhaps backed up by some type share across multiple printers, cheap AMS type multiplexer too for access to a larger library of filaments than it would be practical to have a dedicated hot end for each one. The solution would need to have a fair number of sensors in it, plus some type of auto calibration/alignment of the nozzle positions in 3 dimensions - perhaps with some sort of load cell arrangement in an alignment pin on the bed somewhere which could be checked at the start of each print, or maybe even after every tool change.

I want to make this, but what did you use for software to get it to work 😅

good thinking man! cudos!

I just seen on Teaching Tech that you are going to collaborate with him on your toolhead. I'm really looking forward to that content. I'm just saying, you might want to get a patent on this before it goes big. Even if your not into it for the money.

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Downside is filament tension lets say tpu and abs etc

Dude after perfecting the hotend changer make a laser etcher head lol

I guess I'll be spending more money on another project now LOL! Jokes aside, this is such an ingenious design, top to bottom! Every design choice was brilliant and I loved the used of PTFE as a centering spring! I've been thinking about this idea of 1 extruder motor for 5 hotends for a long time and never had the time to tackle it. I think you'll also be interested in Mihai Designs' " pitstop " project which has a similar approach! Cheers

Being a designer of my own toolchanger as well, its a very nice concept and idea of a toolchanger. Appreciate the effort put into this design. Wouldnt this design requires u to have 2 umbillical at all times? 1 on the carriage and 1 on the toolhead?

I was already building a printer with the same toolchanger design ("brackets" on the hotends, unlocking extruder), when I saw your video. You were faster😄 I'll be using a servo-unlocked extruder based on Orbiter V2 gears, with a few different hotends (1x custom long hotend and 2-3x CHC Pro), in a Voron Trident-like printer. The overall cost, except for the enclosure panels, is about $1000. By the way, when a hotend is released, nothing prevents the filament from extruding/retracting a bit due to its tension, while the hotend is still hot. Do you somehow lock the filament when the hotend is not used?

Do your hotend fans continue to run when they are separated from the effector?

I am building a custom printer based of the BLV design. I decided to go with the BLV because of the metal kit as i wanted to avoid any printed parts for the printer mechanics. I solved the bed issue by going with triple Z. Its still a work in progress and I am expecting to get it running by end of the year.

However, even hot ends are not cheap. The E3D Revo system, will run around $100 per hotend, depending on nozzles used, and even more if you add the new PZ probe. Those cheap clone E3D knockoffs do work, but are iffy, till you find a good source. I suspect that the final design will have to be made from metal CNC'ed parts.