An Alternative to Groovemount

Discussion in 'E3D-v6 and Lite6' started by Rory, Apr 3, 2017.

  1. GeckoBox3D

    GeckoBox3D Well-Known Member

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    Thanks again Rory for sending one of these new hotends my way! I've not had much chance to test out the mounting options in a real way yet, but i'll offer some observations.

    it's a pretty solid mounting option. Once the screw threads have been tightened down it won't budge. It certainly solves the problems of the groovemount. It gives some nice new alternatives to mounting as well, you can use groove adaptors, and then tighten down the nut to keep it in place. I had one of these groovemount plates lying around, unfortunately it was slightly too thick to get under the threads, and the diameter of the heat sink under the thread is slightly larger (12.4mm) then a standard groovemount (12mm), but a bit of work with a file for 10 minutes got it in. Perfect for a bowden set up, and very rigid.
    [​IMG]

    An interesting option, is that most well tuned printers can actually print screw threads really easily. Using fusion360, I designed a block with an M14x1 thread. It screwed in first time with no problems. Perhaps not the best mounting option, as it actually poses the same problems as a groovemount (wear over time), but you can buy machine screw taps really cheaply these days, so perhaps designing your own metal mounting system may not be as hard as you think. Access to a pillar drill and a steady hand is all you'd need now, whereas before you'd need a CNC set up or a lathe to produce your own groovemount. Now just drill a 13mm hole in metal, and tap it M14. Once I get an M14 tap this is likely how i'll mount the hotend.

    Although as a quick and easy option, the printed thread works really well. Its tight and solid, and it won't be going anywhere. Tighten it in with a set screw on the side and this is a very viable option still.

    [​IMG]

    [​IMG]
    Next up is the screw holes. Pretty simple and works well, however it seems overly bulky to me. Its also weighs more. The nut is a pretty solid chunk of metal, I've not weighed it but I can certainly tell the difference in my hand. The screws can also only be used in the top of the nut, you can't use them from underneath as the heatsink is slightly too large. I think this is what annoys me the most about this mounting system.... How do you use it with a direct drive extruder? If you could use these 3xm3 holes to screw it directly into an extruder, then that could potentially be useful (or perhaps just use the original m14 screw?)
    [​IMG]

    Why not place the M3 mounting holes in the fins instead? Get rid of the top 16mm, and just screw into the fins directly, perhaps this is the best way to keep the groove mount as well. You could simply have a heatsink with a thread on both ends, one thread is used for the heatbreak, and the top is used to screw in the optional groovemount or m14 mount. Remove it for 3x m3 mounting holes. Heres a quick render of what that could look like:
    [​IMG]
    Perhaps the best in terms of versatility?
     
    #41 GeckoBox3D, May 4, 2017
    Last edited: May 4, 2017
  2. GeckoBox3D

    GeckoBox3D Well-Known Member

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    A bit more on that.... [​IMG]
     
    #42 GeckoBox3D, May 4, 2017
    Last edited: May 5, 2017
  3. Paul Winter

    Paul Winter Well-Known Member

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    I like the idea of a new mounting system, as someone who is just in the process of removing my hotend/nozzle etc to try and resolve some issues yet again, it's topical to say the least.
    However, I would not like to see a threaded mount, and I think you may be complicating it more than it needs to be. The current mount itself is good, with a lot of life left in it yet, and a huge user base. Where it wins, is the way you can drop the hotend out of a mount without having to rotate it - and without having to compromise your cable management and the integrity of the heater cables and fine thermistor wires.
    Where it loses, is the printed mount and it's clamp compressing down, becoming loose, or maybe even the clamping screws ripping out of the mount.

    What I would like to see is an insert or mounting ring that could be designed for, and embedded into a mount, similar to the way the Groovemount works now, and similar to the proposed new threaded mounting collar - but without the thread. The hotend only really needs to be secured in using one or two good quality, well sized grub-screws, as it should not be under any major loading, or there is something wrong. The grub-screws would come in through the sides of the collar.
    Heatinks would then be machined parallel up to the top of the hotend assembly.
    I note the concerns of better minds than mine regarding the downsides of turning hardened grub-screws into fairly soft aluminium, but to be honest, I would just go and buy another heatsink from E3D if I chewed the neck of the heatsink up too badly
    For existing owners of E3D V6 hotends and heatsinks, a pair of clamp around aluminium shells could be used to convert the hotend into a new-style hotend that would fit up into the collar.


    Benefits:
    • Easier to machine - no threading of the collar or every heatsink produced subsequently
    • Easier to maintain - no having to disconnect intractable and delicate wiring
    • Can be retrofitted to existing hotends - E3D sell a kit of parts
    A purchasable upgrade kit would consist of a new mounting collar, and a pair of clamp around aluminium shells.

    I think it's fairly inevitable that some redesign and reprint of the User's mount is going to be needed to retrofit the collar, whatever it's final design outcome, but that is the price of moving forward here.
     
  4. dc42

    dc42 Well-Known Member

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    Paul, the new heatsink mounting system that E3D has prototyped has a screw-on collar with three M3 tapped holes on top and a set screw in the side. You don't need to screw the heatsink into the print head when fitting or changing the hot end. You do one of two things:

    1. Use the set screw to clamp the collar on to the heatsink in the desired orientation, then attach the collar to your print head using three M3 screws.

    2. Use the collar as a nut to attach the heatsink to a plate. This is is ideal for delta printers. Your suggestion would have the same issue on a delta that groove mount does i.e. taking up too much valuable space on the effector.

    I really don't like the thought of the hot end being held in place just by grub screws - that would surely fail any serious risk assessment.
     
  5. Paul Winter

    Paul Winter Well-Known Member

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    My concern was sparked by one of the opening statements :)
     
  6. GeckoBox3D

    GeckoBox3D Well-Known Member

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    I agree with dc42... the hotend needs to be strong enough to deal with collisions and I wouldn't trust grubb screws... not to mention that if the head of the grubb screw strips it is almost impossible to remove without drilling it out.
     
  7. Rory

    Rory Member
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    Loving the design with the screw in head, would allow for a range of new options and keep the groovemount purists happy too. I'll look into this idea. Thanks!
     
  8. Rory

    Rory Member
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    Just so we're all on the same page, are you thinking of something a bit like a motor clamp but miniaturised? If so I think the idea could have legs, this kind of clamp has a ton of grip, doesn't mark either part and allows you to have the heatsink in any orientation you like. Downside is that it would be more difficult to machine, a threaded collar can be made on an autofed lathe, a milled part can't.

    [​IMG]
     
  9. Faeia

    Faeia Member

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    Not too sure if this idea would dramatically complicate production or increase cost, but have you ever considered something like a spring loaded collar with a ball bearing to do something like those kind of pneumatic hose kind of fitting? Idea just hit me after i found one of those QDC fittings i used with my pc watercooling loop sitting around and it felt plenty solid
     
  10. GeckoBox3D

    GeckoBox3D Well-Known Member

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    No worries, I hope the idea is of use to you!
    The more I think about it, the more the idea makes sense. It really gives a huge amount of flexibility in mounting options. It's quite common to see people hacking off parts of the heatsink these days especially on deltas to get everything into a nice form factor, but with this you don't have to. Without the groovemount, you make the heatsink 1/3rd smaller, and the entire unit measures around 45mm then... This makes it smaller then some of the smallest hotends out there (eg, the deltaprintr mini hotend is 58mm tall).
     
  11. Paul Winter

    Paul Winter Well-Known Member

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    Hi Rory
    Sorry not to get back to you earlier, but Elmoret actually came close to my vision of an ideal clamping collar that can stay permanently attached to the printer carriage mounting. He does mention three screws drilled down through the collar to hold it down to the carriage mount.


    I have drawn something similar, but with the mounting screws only occupying 180 degrees of the circumference, to allow the option to overhang the carriage mount.

    E3D V6 Collar Mount.jpg

    The problem with a threaded or true bayonet style mounting is that, due to the way the heater block is attached to the heatbreak and heatsink of the hotend, you don't know at which angle the whole thing is going to end up facing - a real problem if you have two hotends adjacent to each other. This also affect cable routing, temperature interdependencies, and maintenance.

    You would either have to rotate the whole collar on the mount (drill more holes/elongate the collar mounting holes, or make the collar rotationally adjustable some way), or not screw the heatsink right up into the thread. Which then means you need some way to fix it - probably with a screw....

    I am also finding that due to a dual extruder carriage, I need some vertical adjustment in either one or both hotends, and the smooth neck of a newstyle heatsink, or an existing V6 with shims to make it smooth would allow this.


    @GeckoBox3D - absolutely love the designwork and modelling!
     
    #51 Paul Winter, May 15, 2017
    Last edited: May 15, 2017
  12. GeckoBox3D

    GeckoBox3D Well-Known Member

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    Thanks Paul, glad you like the designs!

    if a clamp fitting is what you want, have you considered just using the existing groove mount with something else? A lot of clamp mounts already exist and a new one doesn't need to be made by E3D. For example, a quick bit of googling and I found some 12mm 2 part clamp mounts used on RC motors:

    [​IMG]
    These *should* be thin enough to attach around the inner groove. I found them on a popular chinese website, retailing around £5. If they don't fit your exact need, there are many iterations found in both 12 and 16mm diameters to fit either the larger or smaller grooves of the groovemount. To be honest though, the groovemount is just a variation of the clamp fitting, where the groove stops it coming loose and falling out.
     
  13. drmaestro

    drmaestro Member

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    Hi,

    I have received the new part today. Thank you very much for this opportunity.

    The new part is very robust if tightened. However, if it isn't tightened, and kept in place with only a setscrew, it tends to slightly bend in the direction of the setscrew. So, I think it would be better to have 2 setscrews, each one facing the other.

    I use Titan as extruder in a direct drive configuration. I think the new design is very good for a Bowden setup, as you only need to find a way to integrate the nut into the carriage. However, when you try to use it in a direct drive configuration, there is a problem caused by the groove mount insert of the Titan: You need to slide your hotend's groove mount into the Titan. As there is no groove mount on this prototype, you need some kind of adapter. I normally use a plastic groove mount adapter in my actual setup so I tried to come up with a similar solution:

    E3DExperimental2.jpg

    The nut is inserted inside this adapter which has 2 slots for the bolts. By using slots, you have some freedom to choose your orientation. However it isn't possible to make an adapter without partially cutting some pieces from the groove mount, as the center path for the bolts collides with the outer neck of the groove mount. As the groove mount has to be flush with Titan, the bolts have to be embedded inside the design, which is the case in my design. I haven't printed it yet, so I am not sure if it is possible to insert this adapter inside Titan without having any wobble but I'll give feedback when I do.

    I am not sure, but if I can find some small washers, they might be used to control the height of the hotend, by adding them on the down side of the adapter.

    Note: I also need to increase the thickness of the adapter to be able to support the motor.
     
  14. Paul Winter

    Paul Winter Well-Known Member

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    I had previously put together a post thanking you for the research into these clamps and all the other bits, and somehow managed to lose the lot when applying some text formatting. Now, with the dubious benefits of old age I can't remember what I tried to post.

    One of the reasons for wanting to move away from Groovemount (for myself, at least) is that in moving to a dual hotend/extruder bowden setup, I find that I now have the added complication of aligning the two nozzle tips in yet another dimension - height. I am relatively fortunate that there is some (accidental) tolerance in one of the Groovemount positions that allows me to move one of the hotends vertically to try and bring it's nozzle level with the adjacent nozzle (which cannot move).

    Tip position on the E3D V6 system is variable depending on how much you screw the heatbreak into the heater block before you wind the nozzle in, and subsequently how far you can screw the heatbreak into the heatsink, so you do need the option to slide at least one whole extruder vertically, at least a couple of millimetres above or below it's partner.

    As well as that issue, when I do get the nozzle tips aligned, I then start to get perimeters being dragged off by the inactive or non-printing nozzle, passing over already printed walls and surfaces.

    I'm not entirely sure I will stay with Dual hot-ends mainly for this reason among others, and I feel that there must be a better way of doing multi-extrusion (I have looked at 1 heater-block, multiple nozzle systems, Y-feed Bowden tubes into single extruders, and even systems that pre-splice different colour filaments before they reach the hot-end), but they all have problems.
    One system of interest is the one the Ultimaker 3 now uses of lifting the whole unused hotend up out of the way, while the other is printing.
    I came across a company manufacturing lift-up extruders that looked quite interesting.
    This type of system could be compromised, or unable to be implemented, with a very rigidly mounted hotend such as a screwed collar.

    I am looking with interest at Greg's work on the IDEX - but if I go this route I think I'll build in larger axis to cater for the twin X-carriages, wiper systems etc.
     
  15. elmoret

    elmoret Administrator

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    Not true, actually. Because the nozzle always bottoms out on the heatbreak, the length of the heatbreak/nozzle assembly is constant regardless of heater block position.
     
  16. GeckoBox3D

    GeckoBox3D Well-Known Member

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    I've always been of the opinion that the mounting option doesn't need to include an option for leveling two nozzles. I've actually designed my own system where the hotend is mounted on a small linear guide that allows 30mm~ of movement. I wont go into to too many details, but a motor is then used to lift the idle hot end when not in use.

    Interestingly, if you needed to level two hotends using my proposed system you could install it, figure out the offset using feeler gauges and then use shims between the heatsink and mount to get the perfect distance. Shims are ready available from decent suppliers, are very cheap and are quite simple to make yourself with foil and calipers.
     
    Paul Winter likes this.
  17. GeckoBox3D

    GeckoBox3D Well-Known Member

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    Is there any update on this hotend system? Would love to see more development on alternative mounting options
     
  18. n8bot

    n8bot New Member

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    I am also very interested in an alternative to the groove mount. I like the 3 screw top-mount, whether it has the threaded portion or not for "lightbulb" functionality. I need this! When can we buy them?

    I would need 4 at a minimum.
     
  19. Faeia

    Faeia Member

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    Thanks for sending one my way Rory! I am liking the new design better than the original groovemount for sure. Biggest plus point for me would be that the simple 3 screws to the collar makes it so much easier to mount and dismount from a delta effector, and the way that it is fitted on gives me so much more flexibility on effector design as it takes up a smaller footprint without the need for the mounting clamp. it feels much more secure as well. The only thing I would change if I could would be not using a grub screw as I never did like those as they can easily be overtightened by accident and risk stripping the threads and such. Id rather use a thumbscrew that i can tighten by hand and that would add to the ease of tool-less switching out the hotends when needed.
     
    Rory likes this.
  20. dc42

    dc42 Well-Known Member

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    Faeia, I agree with you about the need to take up less room on a delta effector. That's why we (Duet3D a.k.a. Think3DPrint3D + Escher Technologies) started discussions with E3D about this some time ago, and I am pleased to say they have been very responsive. Earlier this month, we ordered an initial batch of custom heatsinks from E3D to fit our PCB delta effector with built-in nozzle contact sensor (see https://duet3d.com/wiki/Smart_effector_and_carriage_adapters_for_delta_printer for more info). These are based on the design with a 12mm threaded area at the top. We will be using a nut and a fibre or plastic washer to attach the heatsink to the effector, so no need for the collar. We hope to have them available around mid July
     

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