Machining parts for the extruder...anybody doing it?

Hello,

I am new here and have spent some time looking at the RepRap project. While looking at what parts are required, I was wondering how people procure the parts for the extruder as most people don't have a lathe. Is there somebody here that makes these parts?

Since I am very interested in the RepRap project, wouldn't mind having a RepRap, and have a machine shop, I am willing to make the extruder parts...if there is some interest. I already spec'd out most of the materials and figure I could make the parts kit (barrel, nozzle, bearings, feed screw, etc.) for some cash or some sort of trade. (i.e. Somebody sends me some RepRap parts I need and I send them the nozzle kit...at least until I can build my own RepRap.)

What does everyone think?

Regards,

Brian Reifsnyder

Personally, I redesigned the extruder so that it didn't need any machined parts. You need to repost your offer in the "For Sale" thread and possibly talk to Ian about making a trade. I think you are going to be able to make a deal.

Hello,

I just found your re-designed extruder and it looks like a good solution to the machining problem. However, not everybody has the tools and/or skills to braze, either. Personally, I am hung up on figuring out the electronics end of things; but, I'll muddle through it when the time comes.

I'll post my offer in the "For Sale" section, as you suggest. But, I figured that it would be a good idea to post in the general discussion as I don't have anything for sale yet and more people read general discussion forums. I want to gauge the interest in it first. If the reaction is positive, I'll make up about 8 or so kits and see what happens. (I figure 8 because I have to buy M6 threaded rod by the meter.) If the reaction is extremely positive, I'll tool up to make larger quantities faster.

Regards,

Brian

I think you're going to get a lot of interest.

Hang on reifsnyderb,

if all goes well we have some readymade heaterbarrels early next year
Than there's just the screw left to machine (that can be done with a drill and a file )

Until then you may want to take a look at bitsfrombytes.co.uk
There's an extruder kit you can built without any machining.

'sid

reifsnyderb Wrote:
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But, I figured that it would be a
> good idea to post in the general discussion as I
> don't have anything for sale yet and more people
> read general discussion forums. I want to gauge
> the interest in it first.

Brian, et al,

I've been pondering doing something similar, though tweaked to use imperial-unit threads (easier, lower cost in the US.) My interest is more in fostering a local reprapping community (in greater Boston) than for profit. I'm still prototyping, but will post details when/if my design is both stable and working reasonably well.

Sid:
What readymade heater barrels are you referring to?
Would you please post more info, if you can?

-- Larry

Interested but where are you, reifsnyderb? Is this a UK only thing or in the US too? I keep busting my damn heater barrel and PTFE assembly and having another source for them would be very nice.

Demented

Larry,

I was thinking about using imperial units, as well. However, for the sake of compatibility, I am going to keep with metric. But, as you know, metric could be considered "odd" imperial measurements.

Also, there is no tolerance listed on the web page for these parts. So, for the 16mm diameter PTFE holder a piece of 5/8" PTFE should work fine as 16mm is 0.630 and we would only be under by 0.005. This would be slightly under a +-0.1 mm tolerance by roughly 0.001. If we were to assume a tolerance of +-0.1 mm (+-0.004), then machining all of the parts would be quite easy anyhow.

In order to avoid having to thread metric, I am planning on obtaining M6 threaded brass rod as it is $17.69 per meter. So, for each meter, I have the threaded materials for 7 kits. That puts the materials cost, for the threaded rod, at $2.53 per kit.

Regards,

Brian

Hello,

I am in Pennsylvania, USA.

Regards,

Brian

Brian,

I *think* the extruder tip at rrrf.org is an acorn nut with 3/8"-16 (UNC) thread; if so the other parts I now see there probably match that. I'm planning to stick with that for the hot parts of my extruder, so I could mix/match. Something may be amiss at the rrrf.org store site; I'm getting errors on some items, like the extruder tip.

-- Larry

Larry,

3/8-16 is what I remember too...

Demented

Larry,

I had exactly the same trouble with machining parts, so I kindly asked a company (who's making soldering irons) to custom build one of there desoldering heaters to match...
And they did... almost that is, at the moment there's too little resistance for the heating element, and a type E thermocouple which should be a type K.

Nevertheless nopehead and Zach do have a prototype, oh well and me too
Hopefully Chris and Zach can test that thing soon (I'll have to wait for the thermocouple Kit from Zach which I ordered today)

And if it's reliable, and possible to control, not leaking ()
and so forth we will try to make the improvements necessary for a larger number of heaters, that'll take some time I guess, but if all goes well enough I guess two to three months (durability should also be tested ).

After that you'll surely find more informations on this topic.

And as a sneak preview... here's a photo of the prototype:


'sid

Sid,

Thanks much for the info and the sneak-preview photograph.

(When it can be revealed, please post the name of the company that prototyped this; the very least we can do is give them some publicity -- and business when our irons need replacment.)

-- Larry

Larry_Pfeffer Wrote:
-------------------------------------------------------
> Brian,
>
> I *think* the extruder tip at rrrf.org is an acorn
> nut with 3/8"-16 (UNC) thread; if so the other
> parts I now see there probably match that. I'm
> planning to stick with that for the hot parts of
> my extruder, so I could mix/match. Something may
> be amiss at the rrrf.org store site; I'm getting
> errors on some items, like the extruder tip.
>
> -- Larry

Larry,

I just checked and 3/8 - 16 is nowhere close to M6. M6 is closer to 1/4 - ?. I'd have to double-check; but, I think M6 is even smaller than a 1/4".

Regards,

Brian

sid Wrote:
-------------------------------------------------------
> Larry,
>
> I had exactly the same trouble with machining
> parts, so I kindly asked a company (who's making
> soldering irons) to custom build one of there
> desoldering heaters to match...

(snip)

>
> 'sid

Does this mean I shouldn't bother?

Regards,

Brian

reifsnyderb Wrote:
-------------------------------------------------------
>
> Does this mean I shouldn't bother?
>
No, it doesn't mean that. It simply means that sid is trying to solve the problem in a different way, just like I have.

reifsnyderb Wrote:
-------------------------------------------------------
>
> I just checked and 3/8 - 16 is nowhere close to
> M6. M6 is closer to 1/4 - ?. I'd have to
> double-check; but, I think M6 is even smaller than
> a 1/4".

Brian,

Yes, that's true. However the acorn-nut extruder tips at rrrf.org are 3/8"-16.
I'm not sure exactly why, but my guess is that 3/8" is easier for reprappers (without access to a lathe) to drill out without breaching the sidewall. So, I think that's the right place (for me, at least) to start.

-- Larry

Quote

Does this mean I shouldn't bother?

No no.. please go ahead Brian!
It's just that I thought, it'd be a benefit for unexperienced users to just connect some cables and not machine screws, wind nicr wire, play around with firecement and such.
Making things as easy as possible will help spread the idea I think.

For those who know how to do things there will always be a homemade version of heaters, and you'll speed the process

Larry, since it's a big company selling their products all over the world under different brands, I'd like to keep their mailboxes clean with questions about this, I'll let you know as soon as we have a massproduction

'sid

Larry_Pfeffer Wrote:
-------------------------------------------------------
>
> I'm not sure exactly why, but my guess is that
> 3/8" is easier for reprappers (without access to a
> lathe) to drill out without breaching the
> sidewall. So, I think that's the right place (for
> me, at least) to start.
>
I think that that is a good guess. As you saw on mine, I use 5/32" hard copper tube which has an ID of a touch over 3 mm to do the same thing. One thing that you have to keep in mind is that the extruder barrel on the Darwin extruder is threaded into the PTFE thermal break and, by and large, that connection has to resist the downward thrust of the filament being forced into the heated extruder barrel. At elevated temperatures PTFE gets a little soft, so you need the bigger diameter to provide enough thread contact area between brass and PTFE to resist that thrust.

> I just checked and 3/8 - 16 is nowhere close to M6. M6 is closer to
> 1/4 - ?. I'd have to double-check; but, I think M6 is even smaller
> than a 1/4".


According to this table: [www.aaronspushnuts.com] the nearest equivalent to M6 is 1/4-28. Looks like about 5% larger in diameter and about 10% finer pitch.

Very interesting!

It looks like the heater fits into a external sleeve that has tip to send more heat out to the tip.

Where does the filament enter?

sid Wrote:
-------------------------------------------------------
> Larry,
>
> I had exactly the same trouble with machining
> parts, so I kindly asked a company (who's making
> soldering irons) to custom build one of there
> desoldering heaters to match...
> And they did... almost that is, at the moment
> there's too little resistance for the heating
> element, and a type E thermocouple which should be
> a type K.
>
> Nevertheless nopehead and Zach do have a
> prototype, oh well and me too
> Hopefully Chris and Zach can test that thing soon
> (I'll have to wait for the thermocouple Kit from
> Zach which I ordered today)
>
> And if it's reliable, and possible to control, not
> leaking ()
> and so forth we will try to make the improvements
> necessary for a larger number of heaters, that'll
> take some time I guess, but if all goes well
> enough I guess two to three months (durability
> should also be tested ).
>
> After that you'll surely find more informations on
> this topic.
>
> And as a sneak preview... here's a photo of the
> prototype:
> [forums.reprap.org]
> body_attachment=1
>
> 'sid