what is the best extruder and hotend for repstrap

what is the best extruder and hotend for repstrap if you dont have any repreped parts ? i have access lathe and drill press etc.

Most Repstrappers build this type of pusher [www.thingiverse.com]

Edited 1 time(s). Last edit at 03/11/2012 09:41PM by Sublime.

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any more suggestions ?

If you want to buy a hotend I would recommend a J-head or Makergear

Edited 1 time(s). Last edit at 03/11/2012 09:42PM by Sublime.

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There seems to be dead volume inside the heater block. Wouldn't this be a problem when switching feeds since some of the old feed will linger in the dead volume?

I like this one-piece j-head hot end design by Reifsnyderb. I'm currently using the push-fit design by Adrian that I got from CdnReprap but I notice that the aluminum heater block tends to get loose when it's hot. So, I wonder if the actual nozzle temperature is lower than the reading from the thermistor on the block. This one-piece design would avoid that problem. On the other hand, as Nophead pointed out, brass is not as good thermal conductor as aluminum. So, that might lead to a larger temperature gradient from one side of the nozzle to the other.

what is best hot end for wade? i have lathe so please give design which is better on lathe

karandex Wrote:
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> what is best hot end for wade? i have lathe so
> please give design which is better on lathe


What is your metric to define "best" and what are the limitations
to exclude designs from the comparison?
Some prefer hot-ends that they can also get pre-fabricated,
some people fine it easier to work with fire cement, others with
Kapton tape. Some have access to CNC mills, others don't.
....

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can somebody figure out how to make makergear hot end, it seems its the best

finally
hot end compare

makerbot nozzle vs adrians nozzle vs mendel-parts v6 or c5 vs makergear vs j head nozzle

can you lathe offset ? because of j heads nozzle is machined offset. i was thinking adding two resistors by making it symmetric

Buy one.
They are commercially made.
All the details of the design are described on their webside.
The Nozzles are separate and replacable parts.
Cartridge-heater.
No thermistor but some other thermo-sensitive part I've forgotten.

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according to me
1 )the problem with adrian design is the threaded ptfe part slips or breaks , right?
2)how is new makerbot hot end ?
3)i think its about releasing plastic at tip of hot end without any bend and melting , am i getting concept right ? so makerbot should be great

i am thinking of making hot end similar to mendel-parts v5 but i read that is causing the problem. bot mill also uses it.

4)next have anyone tried the mixshop Assembly, looks straight forward.

5) why people use peek, isnt makerbot design better then peek designs

Hello,

While I don't have a 3d printer, I have been in contact with quite a few owners and I can tell you what I do know. See below.

karandex Wrote:
-------------------------------------------------------
> according to me
> 1 )the problem with adrian design is the threaded
> ptfe part slips or breaks , right?

At the root, of the PTFE thread, the PTFE is quite thin and will easily break. If you really want to make this design, I would recommend that you do not thread the PTFE and the ID of the nozzle. Without the threads, the force of the PEEK block will keep everything together and the PTFE will be thicker and less prone to breaking. I have made two like this, for a customer, and it has been working for months without any leaks.

> 2)how is new makerbot hot end ?

It's all stainless steel (except for the PTFE liner), so it is quite solid. I don't recall anybody reporting any serious problems other than the heater resistors falling apart in the Mk5. The Mk6 should fix this. It is large and quite heavy in comparison to other designs.

> 3)i think its about releasing plastic at tip of
> hot end without any bend and melting , am i
> getting concept right ? so makerbot should be
> great

I think you are getting the concept right. The extruder just forces melted plastic out of the tip.

> i am thinking of making hot end similar to
> mendel-parts v5 but i read that is causing the
> problem. bot mill also uses it.

I don't know.

> 4)next have anyone tried the mixshop Assembly,
> looks straight forward.

I don't know.

> 5) why people use peek, isnt makerbot design
> better then peek designs

I am not sure what "better" means. The Makerbot design is quite solid. But, it is big, expensive, and heavy. PEEK acts as an insulator and is light. So, by using PEEK, the extruder can be much smaller, cheaper, and lighter.

The Makerbot design also won't melt it overheats for some reason. (i.e. the thermistor or thermocouple fails) Though, you would have to replace the liner.

Regards,

Brian

Quote
karandex
1 )the problem with adrian design is the threaded ptfe part slips or breaks , right?

Adrian has redesigned the hot end for the geared extruder multiple times already. The latest couple of designs use a thermal insulation made of PEEK with PTFE lining inside which doesn't suffer the same problem. Please check this wiki. I've been using the push-fit version for more than a couple of months already. One issue I've found with the push fit design is that the aluminum heating block loosens from the brass nozzle when hot since the thermal expansion coefficient of aluminum is larger than brass. Perhaps is should be assembled while hot or another metal like copper should be used for a heating block.

what is better sleeve design or push fit, also is it required to use slot or flatten the drill for pushfit ?

The push-fit design uses a PTFE sleeve inside the PEEK insulator. The slot is needed so that you can push the nozzle into the heating block.

the slot drill is used to make push fit design , is it required to have.

what if i use the main adreian design which is threaded but without thread , as i find it hard to find peek

Hello,

Are you referring to the "Geared Extruder Nozzle" without the m7x1 threads on the OD of the PTFE and the ID of the brass nozzle? It will work. Make sure that the PTFE and nozzle have a very close sliding fit. The force of the m3 rods, on the PEEK block, will keep the whole thing together. It will also be more reliable than the threaded version.

Regards,

Brian



karandex Wrote:
-------------------------------------------------------
> what if i use the main adreian design which is
> threaded but without thread , as i find it hard
> to find peek

>Are you referring to the "Geared Extruder Nozzle" without the m7x1 threads on the OD of the PTFE and the ID of the brass nozzle?

yes i am thinking of same one (first). the problem is i cant get peek, so what is alternative to peek to hold parts ? one guy tried wood and melted the extruder with heat from screws!

If you're in the USA, you can order PEEK rods in small quantities from McMaster and use it instead of a PEEK block. Nophead has a Plumbstruder design that only uses a little PEEK that might work for you.

PM Sent.

I have some PEEK and I offered a blank block, for the Geared Extruder Nozzle, for slightly over my cost.

Regards,

Brian


karandex Wrote:
-------------------------------------------------------
> >Are you referring to the "Geared Extruder Nozzle"
> without the m7x1 threads on the OD of the PTFE and
> the ID of the brass nozzle?
>
> yes i am thinking of same one (first). the problem
> is i cant get peek, so what is alternative to peek
> to hold parts ? one guy tried wood and melted the
> extruder with heat from screws!