Basic Hermes ordered.

Discussion in 'Tool heads & ToolChanger' started by Jai Stanley, Nov 29, 2019.

  1. Jai Stanley

    Jai Stanley Well-Known Member

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    I got some Chinesium knock-off BMG extruders. They were a lot better, though go for the 'quality' ones like triangle labs. I wanted something to work in the interim, and NOT be Titans.

    I'm currently 'developing' direct drive extruders using parts from them. I've got a few issues with my design, but they're working fine. I've just got other priorities atm due to christmas, new family and promising an old printer to a friend (one issue is the motor sticking out, loosing a tiny bit of build volume, I think I can over-come this by using pancake motors - I wasn;t sure before but think I've sussed out why, I had a mis-alignment in the filament path I've since fixed).

    I'm willing to wager: if you buy the bits, you'll want to use it with something. Cheapo, reasonable quality, and ultimately re-useable knock offs might do the job. My design uses all the bits from the V6 bowden tool heads for just this reason; i'll release it as soon as I'm happy with the performance...

    HTH

    Jai
     
  2. Jai Stanley

    Jai Stanley Well-Known Member

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    Hi.. I'm more than willing to print you parts and post them at a more than reasonable price. Caveat is: you need to become an active member of the forum and contribute. :)
     
  3. yngndrw

    yngndrw Well-Known Member

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    Thank you, I appreciate the offer. I'll probably order the base bits like Paul Meyer and see where the platform goes before building it though as like a number of you I'm short on time right now.

    Not sure how much I can contribute but I do have some experience with a Titan Bowden setup (500mm tube on a Prusa i2) and I have to say I'm surprised that there is so much dislike for it as I can't say I've had any issues with it on PLA. (All of my quality issues come from the i2 frame which is about as rigid as a piece of wet string) I do wonder the issue is your expectation against what the motion system is capable of as opposed to relative to other setups?

    There have been a couple of comments about ringing / overshoot with the direct drive Hemera on this motion platform. Does anybody know which part(s) is/are contributing to this? If it's belt stretch, it looks like a slightly wider belt could be fitted quite easily which would be a little more rigid. It also looks like the Hemera could do with being raised slightly so that the center of mass is in-line with the gantry linear rail. (Just under the single ball on the mount) With the current design, it looks like the motor is a little too low. I'm just going off of the pictures, but that stood out to me when I looked at them.
     
  4. Jai Stanley

    Jai Stanley Well-Known Member

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    All I mean by contribute is share your experiences and get the dialogue going. The more people post on the forum, the more fixes/solutions/ideas will come to the surface....

    My issue with the bowden setup was about expextations vs reality I suppose: but my expectations of bowden systems in general I think. Even my genuine BMG extruder didn't give me the control I wanted whilst in bowden configuration. I am a little hard on the Titan's (I'm always guilty of speaking my mind, that's for sure). They just did my head in. I had a Tiatn aero on a previous machine, and although I did have some issues with bearings I was able to just leave the bolt that goes through the gear shaft off and the stiff aluminium did the rest. It didn't set the world alight but it was a perfectly capable extruder/hot end. In bowden configuration, in the toolchanger it was definitely the weakest link.

    As for ringing/overshoot: it's really not a huge problem. Remember E3D have given the base firware basically at 'flat out' settings. You're seeing artifacts from throwing a CNC machined, stout assembly around. I suspect its a combination of belt stretch, the mass of the system and the spring of the rotational inertia of the motors and their effective spring rate due to the magnetic flux. Not much we can do about physics! When fitting the Hemera, the mass goes up (in the config I have mine, they';re NOT light!). All I've done to mine is lower the jerk by 20% and I am getting the best results I've got from any FDM printer I've owned or used. There is a tiny bit of ringing but substantially less than I've seen on many machines. If I were to be fussy, I'd drop that jerk, acceleration and print speed a little more. Perhaps in slicer settings for ultra quality you could set lower values for that particular print.

    I have a benchy here printed in Spoolworks MG94 Natural ABS that is utterly stunning. I would say 98% perfect at a layer height of 0.2mm and extrusion width of 0.4mm (a 'standard' benchy then) and I have to keep looking at it because it's so flipping lovely. The Hemera really is an EXCELLENT extruder and the motion system is just lovely.

    Perhaps if I hadn't got an engineer boner I would have continued to make my own machine, and bolted the E3D toolchanger head to it; but I just really liked the idea of both a shecksy motion system, and a common platform to allow us to share ideas/improvements. It was a bit expensive: but I held off spending on machines the whole time I was waiting so you could say I 'saved' up for it. Still very happy.
     
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  5. Jai Stanley

    Jai Stanley Well-Known Member

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    Here's some crappy phone camera pics of the benchy using a Hemera in an insulated enclosure.

    Print speed 45mm/s, Max Inst. Speed Changes (Jerk?) at X600 Y600, Acceleration at X5000 Y5000, extrusion width 0.4mm, Extrusion multiplier 0.9, Retraction 1mm at 20mm/s, Cooling fan 15%, chamber temperature (measured at toolhead) 50degC, Nozzle temp (nozzle X) 250, bed temp 100 deg C (thick-ish PEI glued to glass bed), first layer extrusion multiplier at 0.89, first layer height EXACTLY 0.2mm (that took a while to get the config offset perfect)...

    I have since dropped the temperature a little and upped the fan to 20% (I'm still very surprised by the layer adhesion, ABS isn't a strong material and de-laminates easily, but this is a tough little benchy!). I REALLY like the MG94 ABS, it flows like silky love juice from the nozzle (eww). I think E3D are running their stock out and wont be getting more (complete guess but I got these four spools from Amazon for £12 a roll!). Shame. I much prefer ABS to PETG and PLA for pretty prints. Better temperature resistance too.

    [​IMG]

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    [​IMG]
     
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  6. Adriaan Greyling

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    Has anyone got the positions for their hemera tools using the upgrade? I've literally just finished putting mine together and have some alignment issues with the locking pin
     
  7. Paul Meyer

    Paul Meyer Well-Known Member

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    Has anybody tried the Hemera Bowden? Any way to make it fit (either in the current bowden mount position, or shifting the mount elsewhere on the case?)

    I just ordered with 2 v6 heads, a Hemera Direct, and a Hemera Bowden, no titan's. I'll start improvising once it's all here, and plan to buy some official Hemera TC tools once they are available.
     
  8. Jai Stanley

    Jai Stanley Well-Known Member

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    I only have one on position T2. Note: I had to put 0.6mm washers under the printed support extension (four, one under each bolt) to space it up slightly:

    Line from config.g:

    G10 P2 X21 Y44 Z-5.7

    Edit: also note, I'm using physical endstops. That shifts everything, so I'm not sure it's much use now I think about it!
     
    #88 Jai Stanley, Dec 27, 2019
    Last edited: Dec 27, 2019
  9. Adriaan Greyling

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    Thanks! I noticed that some of my tools were "drooping forward slightly, also did the washer thing in the end
     
  10. Jai Stanley

    Jai Stanley Well-Known Member

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    I've also realised I only furnished you with the nozzle offset. Sorry: I must've been half asleep last night!

    This was the main reason I was a bit 'meh' about the hemera on the TC. It's a lovely extruder, but feels janky ATM. We shall have to see what E3D come up with in the long term. I've had to pause my own, so I'm back to one really useful tool, a crappy Bowden volcano and two prototype designs that I've updated in cad to solve issues, but not really using. Once I get some chores done I'll get back to it.
     
  11. yngndrw

    yngndrw Well-Known Member

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    The offset would be more useful if you also provide the offset to a standard bowden tool in the same tool holder, then the difference can be calculated and applied to any machine. (+/- a little bit)

    Those results do look amazing. I think for myself I will order a bowden tool, a new motor for my existing Titan extruder and a blank tool plate to put a Hemera on once the design progresses slightly. To be quite honest, I'm not interested in the tool changing half as much as I'm interested in the general motion platform.

    It is a really interesting concept though, you could quite easily make a pick and place tool reusing the same motion platform and electronics - The different applications are really exciting.

    With regards to the Hemera, I always thought the motor they chose was a bit too large. For my own design (Which I also canned when this TC platform was announced as the design was very similar but without the TC) I had a direct drive Titan Aero with a thin pancake motor and that was all I was going to run. Sadly with the Hemera you can't easily change the motor but hopefully they will make a light-weight version at some point - I do wonder if the Hemera motor's face place can be transplanted onto a thinner motor. It would be interesting to see one with a really thin stepper motor and an encoder so that field oriented control could be used to drive the stepper and overcome the lack of torque. I think that would be the best of both worlds and result in a really light setup.

    Time to order some parts and then cry at my bank balance!

    Edit: Ordered. A full Hemera, a thin motor and a spare tool plate ended up in my basket - Couldn't resist.
     
    #91 yngndrw, Dec 28, 2019
    Last edited: Dec 28, 2019
  12. Jai Stanley

    Jai Stanley Well-Known Member

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    I think you're going to have to lathe off the end of the stator output shaft to fit the hemera drive gear.. I have a friend with a lathe; when he gets back from his Christmas escapades I might have a go.
     
  13. yngndrw

    yngndrw Well-Known Member

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    Fortunately E3D have provided most of the specs of the output gear (22T MOD 0.25) so I was thinking of just getting a new gear and boring it out to the right size. I think the standard shaft length will be fine but it's easy enough to cut down if needed. My biggest concern is the output shaft bearing which I couldn't find any information on, but with any luck they will be the same. (I'm hoping E3D have sourced them from the same manufacturer and they have the same internals.) Sadly I don't have a lathe myself (I have parts from an Emco 120P, that's a whole different project!) but I have a feeling it might be possible without. Worth investigating either way!

    Good luck with your attempt, do you have an E3D Slimline motor to try it with or would you be using a different motor?
     
  14. Andy Cohen

    Andy Cohen Well-Known Member

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    The toolchanger has been shipping for months now. Unfortunately though E3d sold it with Bowdens which are not optimal for what most of us will want.
    The Hemera is a direct drive replacement which goes on the tool and not where the Titans are mounted.
     
  15. Paul Meyer

    Paul Meyer Well-Known Member

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    I think the above was a reply to my post where I'm actually exploring both a bowden and direct hemera configuration. Until the Hemera gets much lighter, I like the idea of a bowden (I've had good luck with them on my ultimaker2) for fast moves with a very light toolhead where the extruder hysteresis isn't fatal, and a direct drive for flex materials and fine detail. Basically I want to explore both.

    However, I don't want to buy titans, as I've had bad luck with single gear drive extruders (original ultimaker extruder) and like bondtech style (upgraded ultimaker and both my Prusa Mk3s).

    So: I'm exploring direct drive Hemera (sounds like the plan is to release in the next two weeks), and also curious if I can jury-rig a bowden-style Hemera to replace the titan for the standard v6-tool.

    Ordered my motion-system/toolchanger last week with parts for a direct drive Hemera/v6-tool, and parts for a bowden Hemera with v6-tool. I have no clue if the bowden Hemera has any chance of fitting, but I figured the only way to find out was to grab one and give it a try.

    Paul
     
  16. yngndrw

    yngndrw Well-Known Member

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    Sorry I should have probably been more clear but yes that comment was regarding bowden Hemera configurations. Unlike Paul I haven't had any specific issues with Titan extruders (At least with PLA), but even without that reason to drive the change for a bowden setup I would still rather purchase and install a set of bowden Hemeras as opposed to a set of bowden Titans.

    If you're starting with nothing, you'd end up buying 4x Titan extruders for the initial bowden configuration and then having to buy a load of Hemeras for the direct drive upgrade and you're left with a number of unused Titans. If Hemeras are used from the start, they can be upgraded to direct drive without as much wastage.
     
  17. Andy Cohen

    Andy Cohen Well-Known Member

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    There is a Toolchanger specific issue with Bowdens which if your do not have the Toolchanger yet you do not see. Bowdens cannot do tiny tool paths and with the Toolchanger you will need to do quite a bit of tiny tool paths. What are tiny tool paths? When there's a change from one material to another, the shape at the transition can make for a very very tiny amount of material for that tool at the start of the transition. Bowdens put out BLOBS when they try to do these. There's other negatives such as at the start and end of the tool paths which when there's only 1 tool can be easily controlled, but when you are going from tool to tool the pressure in the long Bowden tube never gets the chance to equalize as it does when it is always in use. When you do a lot of tool changing the whole game changes.
    Then there's the issue of loading and unloading filament.
    Then there's the issues related to the Titans of which I have many more then one.
     
  18. Paul Meyer

    Paul Meyer Well-Known Member

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    Makes sense. I've got a prusa MMU2 and have done multi-material there (not extremely reliable, but enough to get the feel for what you are talking about). Clearly it will be model dependent, but for multi-material prints with multiple switches per layer and fine details per head, I could see it would be an issue. I do plan to get the direct drive tools (hemera for now) for fine details and flex filament.

    I'm still interested in trying out a bowden to compare the achievable accelerations which is why I'm interesting in mounting a Hemera as a bowden driver. I've had pretty good luck with fine details on my ultimaker, although that was with 3mm filament which may help a bit. If it doesn't work I'll just lower my accelerations and go with all Hemera's. I'll be watching the nifty style as well, although I'll need to see more experiences there before I trust the mechanical complexity of that approach.
     
  19. twam

    twam Member

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    Received my Hermera a few days ago and I'm trying to install it on the 4th slot. However it looks like one of the motor screws of the frame is in the way for the dock adapter. I thing it should have same clearout where the blue is pointing to. Maybe the red on is a little bit offset? Did anyone already tried to use the 4th slot for this?

    Screenshot 2020-01-12 at 17.13.04.png
     
  20. Killercds

    Killercds Member

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    Fits fine for me, maybe check the dimensional accuracy of your part?

    8D371FB8-A06F-456B-A19C-9DA2C5375CC9.jpeg
     

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