TG All metal Hot End - Call for help

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Liquid
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Re: TG All metal Hot End - Call for help

Post: #3161 Liquid
Sat Jun 01, 2013 11:18 am

That would leave the opening wider after the barrel. Wouldnt be good, but I think I know what you mean.

More like this

Image

Or at the very least like this

Image
Last edited by Liquid on Sat Jun 01, 2013 12:12 pm, edited 2 times in total.

AndrewRutter
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Re: TG All metal Hot End - Call for help

Post: #3162 AndrewRutter
Sat Jun 01, 2013 11:20 am

Just to add my 2 pence.

The Makerbot Mk7 (and its many derivatives), is spiritually at least based on:

http://www.hydraraptor.blogspot.com/200 ... ruder.html

Anyone who hasn't read all of Hydraraptors blog, go read it, its what got me first excited about 3D printing.

That said. The Mk7 (as published at least) doesn't work. It jams after about 40 minutes in my testing (although I am actually using parts from someone else, not MBI).
If you read that blog post and look closely at the design of the MK7 you should see what they left out. I'll let you guys figure out what I mean ;)

We have a hotend in testing (currently testing for the Pro, but I start working on integration for the existing machine next week) that is all metal, has been proven with 30+ hour prints, has interchangeable nozzles, retains the existing mounting system, but does require a new mounting block. Technically its groovemount compatible, but a new version of the winchester mounting clamps are required.

Please do not ask to buy these! Please do not ask me when they will be ready!
We are working on it as fast as we can. We will get parts out for beta testing as soon as we can.

TG, it looks like your version will not require any changes to the existing winchester, and either way there is a market for a more direct replacement for the groovemount/MG hotend (like the pico). And its very satisfying to build a new hotend design anyway, so please don't think that we'd want you to stop.

Also, I like the heater block clamping onto the nozzle, helps keep everything as short as possible. The shorter you can get the melt zone the better.
What ID is the barrel? And you probably want to try and get the wall thickness down at the necking point too.
And drilling a concentric bore that long through stainless is hard, you need things like a drill mounted in your tailstock so you can spin the drillbit as well as the part. Think about using an off the shelf barrel and working around that (believe me, its a ton easier).

jd_3d
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Re: TG All metal Hot End - Call for help

Post: #3163 jd_3d
Sat Jun 01, 2013 11:28 am

Coming from someone who currently has 12 Makergear hot ends, please put me down as interested! Has the internal shape of the nozzle changed on this new hot end, or does it use the same MG nozzles? That is the biggest limitation IMHO on the current nozzles in terms of usable life before service/replacement is needed.

AndrewRutter wrote:We have a hotend in testing (currently testing for the Pro, but I start working on integration for the existing machine next week) that is all metal, has been proven with 30+ hour prints, has interchangeable nozzles, retains the existing mounting system, but does require a new mounting block. Technically its groovemount compatible, but a new version of the winchester mounting clamps are required.

Liquid
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Re: TG All metal Hot End - Call for help

Post: #3164 Liquid
Sat Jun 01, 2013 11:38 am

Thanks Andrew.

Right now the id is 2mm in the cad files, but I havent finalized that yet. I used 2mm as a starting point and plan to revisit before actually making anything.

I always planned on it being usable to a wide range of users, so you hit the nail on the head there. As far as any competition from older or not yet developed manufacturers, doesnt faze me a bit.

You did pick up on the clamping portion of the nozzle/heater block, I believe this is where the magic will happen, but seeing as its untested, the only way to really know is to just build the damn thing :)

AndrewRutter
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Re: TG All metal Hot End - Call for help

Post: #3167 AndrewRutter
Sat Jun 01, 2013 12:15 pm

TheTechGuru wrote: 2mm in the cad files, but I havent finalized that yet. I used 2mm as a starting point and plan to revisit before actually making anything.

2mm should be just fine. Its the ID for just about anything using 1.75mm filament.
the only way to really know is to just build the damn thing :)


Very very true.

And just to repeat myself, look at the drawings in the link, then look again at your design. Then go and read all the posts Nophead wrote about extruder design and thermal transition zones and all that.
Then you'll see what I mean.

LaserGnomes
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Re: TG All metal Hot End - Call for help

Post: #3168 LaserGnomes
Sat Jun 01, 2013 12:16 pm

Yes more like that taper. I'm not sure why there are such obvious steps (assume it's a machining limitation) with existing designs, like the one Andrew posted. I noticed also that theirs has a taper OUTWARDS then back in just before the nozzle. Interesting... pressure zone? Beta and non-working as well so wouldn't put much stock in it.

-1 cent

Liquid
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Re: TG All metal Hot End - Call for help

Post: #3169 Liquid
Sat Jun 01, 2013 12:22 pm

And just to repeat myself, look at the drawings in the link, then look again at your design. Then go and read all the posts Nophead wrote about extruder design and thermal transition zones and all that.
Then you'll see what I mean.


10-4, actually started to read right after you posted. Been up for 48 hours so a little out of it, I will post back if anything stands out. Im guessing there is something in my design that has been tried but didnt fare too well lol.

Liquid
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Re: TG All metal Hot End - Call for help

Post: #3170 Liquid
Sat Jun 01, 2013 12:26 pm

I'm not sure why there are such obvious steps (assume it's a machining limitation) with existing designs


Any steps seen in my pics, are just from drill bit angles. Common bits have a 59-60 degree taper/angle, horizontal from the center of the bit.

I actually have a polishing technique in mind that I used a while back that should bring most of the inner diameters to a mirror finish. better tapers are now also on my list.

Liquid
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Joined: Sat Feb 16, 2013 12:46 pm

Re: TG All metal Hot End - Call for help

Post: #3171 Liquid
Sat Jun 01, 2013 12:28 pm

Andrew, thanks for the confirmation on the 2mm.

I suspect Im going to try a few id's but 2mm was def the one I wanted to start with. What prompted me to decide on that was LG saying hes had pla over 1.75mm and all my pla is under 1.75, right around 1.69-1.7 when averaged. Just want to use something that will work for a wide (within reason) range of potential users.

LaserGnomes
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Re: TG All metal Hot End - Call for help

Post: #3172 LaserGnomes
Sat Jun 01, 2013 12:29 pm

Yeah had assumed it was a bit depth consideration. Further treatments maybe required (as you mentioned) to reduce the steps effects for better drafting.

In reality.. it's going to get clogged anyway with material just sticking to the wall (mirror finish sounds nice though) so looking down the road for easy cleaning would be the next consideration. If the reverse fed wire can't get the material then maybe the quick swap nozzle will overcome that with ease of cleaning?


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