OPAM Water-cooled Hot End Now on Indiegogo

[khitho1]

Hi Fellow Reprappers,

I have just launched my indiegogo campaign on All Metal Hot End (Water-cooled) as per:
http://igg.me/at/OPAM-hotend

In summary, the distinct features of my hot end design:
1) A truly One Piece All Metal (OPAM)design (where nozzle, heater block & heater cartridge is combined into one single piece of stainless steel) to remove any filament jams
2) Water-cooled for high temperature extrusion of up to 350°C
3) Jamless printing of ABS, PLA, PC-ABS & much more!
4) Compact design (Lightweight of 40 grams)

Please review/feedback and contribute if it interests you!
The indiegogo campaign have just been launched. If you are quick, you will be able to get the early bird perk.
Even if you can't contribute directly, I will appreciate it if you will inform your 3D printing buddies about this new design!
Thanks for your support!

[Tincho85]

Hello, nice design, but where is the thermistor? is it threaded?
I can't see it in any pictures.

[stonewater]

I like the idea, a lot really, but 50 hours of print time is not really enough to get me to invest in ANOTHER hot end..... show me 500 I would be interested. a couple of questions.... how do you determine if the coolant flow rate is correct for your heat settings? how long till the hot end temp stabilizes? it would take some time for the heat exchange cycle to stabilize in the system.

Tom C

[mvansomeren]

I can't see how this would work on a delta printer. It seems like the tubing for the water would cause too much resistance to the movement of the effector/hotend. Also, the water reservoir is fairly small. Wouldn't the temperture of the water slowly climb, causing it not to cool as effectively the longer you are printing?

[Nylocke]

I have a Kraken on mine and its water cooling tube are something like 6mm ID silicone tubing. It prints fine as is, though I do have the TL arms. Michael also uses the same setup.

I don't really think "coolant rate" matters, just as long as water is flowing and being exchanged. What seems more important is that you have a large enough reservoir that the average temp of the water doesn't rise too much above ambient, and that the heat sink stays pretty cool in addition. I thought the Kraken might have some special design to it but it seems like they just drilled 3 holes in it and called it good enough, so I can't see why this would be any more complicated.

[khitho1]

Hello, nice design, but where is the thermistor? is it threaded?
I can't see it in any pictures.

Hi Martin,

The thermistor is secured to the SS304 body using thermal paste (MUFFLER&TAILPIPE SEALER) as per attached pic, not threaded.

Thanks,

[khitho1]

I like the idea, a lot really, but 50 hours of print time is not really enough to get me to invest in ANOTHER hot end..... show me 500 I would be interested. a couple of questions.... how do you determine if the coolant flow rate is correct for your heat settings? how long till the hot end temp stabilizes? it would take some time for the heat exchange cycle to stabilize in the system.

Tom C

Hi Tom C,

Currently, the maximum reachable coolant flow rate is 200L/H.
At this value, the hot end will take 1min 50sec to stabilize at 230°C from room temperature.
As for heat exchange cycle stabilization, I have printed ABS for over 5hrs and the water reservoir raise from 30 - 45°C.
The water reservoir temperature stabilize and hold at 45°C due to natural air connection. (No additional electrical fan required.)
My recommended water reservoir capacity is at least 1000ml. (Of course, the more the merrier)
Thanks,

[khitho1]

I can't see how this would work on a delta printer. It seems like the tubing for the water would cause too much resistance to the movement of the effector/hotend. Also, the water reservoir is fairly small. Wouldn't the temperture of the water slowly climb, causing it not to cool as effectively the longer you are printing?

Hi

As mentioned in my campaign, I have yet to test the OPAM on bowden setup but that does not mean that it will not work with delta printers.
The water pump that is used is able to provide a maximum head of 1.5metres.
I have chosen flexible tubing from LEGRIS to minimize the movement resistance.
From my actual printing condition of 230° hotend temp & after 5 hours, a water reservoir of at least 1000ml will have its temperature rise and stabilize to 45°C due to natural air convection.
Thanks,

[Captain Starfish]

Hello, nice design, but where is the thermistor? is it threaded?
I can't see it in any pictures.

Hi Martin,

The thermistor is secured to the SS304 body using thermal paste (MUFFLER&TAILPIPE SEALER) as per attached pic, not threaded.

Thanks,

Pretty.

A couple questions though.

What steps are required to replace the thermistor when it eventually fails? Do we need to cut a mess of muffler putty/tape off the heater block and bog the new thermistor on again? The locking screw and washer setup used on my E3D v6 is so much better that I will never go back to a design that requires any kind of adhesive to hold a thermistor in place. It's a PITA, it's messy, and there's no need for that kind of dodginess any more.

Is 304 grade SS up to the task of a water housing? I've always thought 316 was pretty much the minimum grade to be used wet without significant corrosion (very happy to be wrong here, btw).

I occasionally need to print fast (0.6mm) or hi res (0.25mm) instead of my "go-to" of 0.4mm nozzle size. Does this mean I would now have to buy and swap between three complete heads, each time watching the water caught in the pipes etc go everywhere and generally making a mess? Not ideal, but I guess if you have customers who only ever use one nozzle size it won't be an issue.

How have you - and have you at all - polished the bore down to the nozzle orifice? Just run the drill bit down? Jammed in a polishing head and spun it around? Or done a longitudinal stroke polish?

[khitho1]

Hello, nice design, but where is the thermistor? is it threaded?
I can't see it in any pictures.

Hi Martin,

The thermistor is secured to the SS304 body using thermal paste (MUFFLER&TAILPIPE SEALER) as per attached pic, not threaded.

Thanks,

Pretty.

A couple questions though.

What steps are required to replace the thermistor when it eventually fails? Do we need to cut a mess of muffler putty/tape off the heater block and bog the new thermistor on again? The locking screw and washer setup used on my E3D v6 is so much better that I will never go back to a design that requires any kind of adhesive to hold a thermistor in place. It's a PITA, it's messy, and there's no need for that kind of dodginess any more.

Is 304 grade SS up to the task of a water housing? I've always thought 316 was pretty much the minimum grade to be used wet without significant corrosion (very happy to be wrong here, btw).

I occasionally need to print fast (0.6mm) or hi res (0.25mm) instead of my "go-to" of 0.4mm nozzle size. Does this mean I would now have to buy and swap between three complete heads, each time watching the water caught in the pipes etc go everywhere and generally making a mess? Not ideal, but I guess if you have customers who only ever use one nozzle size it won't be an issue.

How have you - and have you at all - polished the bore down to the nozzle orifice? Just run the drill bit down? Jammed in a polishing head and spun it around? Or done a longitudinal stroke polish?

Hi

Thanks for your feedback regarding the securing of thermistor. Will take that into consideration.

Regarding SS304, I have been testing it for the past 4 months (water as the coolant) and there is no sign of any rust at the wet portion.

My main intention is to simplify the design and eliminate jams which leads to an all in one piece structure. So yes, it is currently catered for 0.4mm nozzle size. (0.6 & 0.25mm will be considered in the future)

The bore is drilled and unpolished. Throughout my 50 hours of testing, there is not 1 single jam encountered which I believe is due to the sharp transition zone (4mm) and the one piece design which eliminate leaks.

[Captain Starfish]

Sweet, glad to hear you're thinking of these things.

For those that are getting jamming on a frequent basis something like this could be the go.

[khitho1]

To Mvansomeren,

Noted on point regarding OPAM's compatibility with delta printers / bowden extruders.
The video below that shows the OPAM Hotend printing with a bowden extruder.

[youtube]https://youtu.be/8Yju8kP3Aw0[/youtube]

I have modified Thing-o-matic's original design just to demonstrate the OPAM's capability with a bowden setup
Normally, I will not do this as Thing-o-matic's extruder moves only in the Z axis and do not benefit with bowden setup.
However, since I do not own a delta printer, this mod is the closest to show the OPAM's capability with a bowden setup.
Thanks,

To Captain Starfish,

Thanks for the encouragement. Much appreciated!

[bot]

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[Generic Default]

It looks cool and it would be nice to have in a heated chamber. The video review was pretty negative overall, but some of the problems could be fixed before the final production run finishes (if it does).

1) The video showed a cheap looking tip where the plastic comes out. I'm guessing the countersink was a machining mistake. If it were flat and smooth it would print much better.
2) The thermistor broke in the video. Strain relief is important!
3) The heater block should be aluminum or brass.
4) The printed mount part should be rigid and have chamfers on the holes. Any slop in it and the tip of the hotend would wobble during prints.

I don't think it's necessarily a bad design but there are manufacturing errors with it. It's not to late to change if it hasn't shipped yet!