Questions about extruders

Hey guys,
I have started purchasing Mendel parts from forums users and it is getting to the part where I need to purchase motors and an extruder. What are the different types of extruder's out there and which does everyone recommend? I think the original bom calls for three (3) stepper motors, but some extruder's require an additional stepper motor? (wades?)

I would rather start with the better one instead of building a sub par extruder and then need to upgrade to a better extruder later on. Any help or info would be great, thanks a lot.

-Steve.

Right now the current "Hot" extruders are "Wades" and "Adrians"....

But I've also seen people say that their MK2 is the more reliable..

so i guess its all a matter of opinion....

EDIT: oh and yes you will need another stepper motor...

Edited 1 time(s). Last edit at 05/20/2010 01:26PM by Mdbaughman2.

Yo Mdbaughman2

What exactly do you mean when you talk about the MK2 extruder being more reliable? Are you referring to the extruder which is part of the Mendel 'official' build docs?

Cheers

So what are the pluses of using a stepper motor extruder like wades? as opposed to using the type that the original mendel BOM calls for?

If I used wades would I need a stepper controller (total of 4 for project) in addition to the basic extruder controller?

Hey Steve, my extruder gives you about 3 times more torque and resolution than the standard Mendel extruder (which also requires a stepper). Also, you don't have to machine the stepper shafts, and the pinch wheel is really easy to make. Finally, the springs are a lot easier to adjust, and more reliable than the fixed version. In my expeience, it's way more reliable than my old Mk2, which has been running for almost 2 years now, although each part on it has been replaced multiple times.

Disadavtage is that you loose some Z height. I think Adians is better in that respect.

Wade

Thank you for the response Wade. It looks like I will be going for an extruder of your design, as I plan to make some reprap parts first to try and get a little of my money back (i think that is everyone's original plan?), so z height isn't that big of a deal at the moment.

Ok so now that I have decided on an extruder, I need to decide on thermal barriers and nozzles? If I bought a Wades extruder kit, what would i need to slap it on my reprap and make it work? Thanks guys.

The thermal barrier needs to be non-conductive and be good up to around 300 degrees Celsius. It isn't that hard to buy and machine the nozzle and thermal barrier yourself if you have a lathe. Other wise I would recommend [ultimachine.com] if you can wait the 2 weeks for them to get the new ones instock or [store.makerbot.com] if you need them now. Ultimachine's nozzle is significantly cheaper, of a lower mass, and designed for the Mendel (vs. Makerbot). As for [www.makergear.com] I am pretty sure you need to pay $45 to get a nozzle from them, which is part of the super pack(comes with a bunch of goodies).

reifsnyderb sells a lot of different nozzles and thermal barriers

[forums.reprap.org]

He also sells on ebay and [www.reprapstores.com]

Ok a little change of topic. I ended up deciding to go with the basic extruder for now and print a Wade style one later. So I bought a thermal barrier and barrel. I have also purchased a basic laser cut mendel RP set from techzone, that hasn't arrived just yet. I was looking around at the parts sheet (http://objects.reprap.org/mediawiki/images/d/dd/Printed-parts-glossary.PNG) and didn't see the pinch wheel bracket on there. Do I have to purchase that from someone else? I am getting a bit confused now. Is the pinch wheel extruder the basic mendel extruder?

yes the most recent pinch wheel for the mendel is pinch-wheel-bracket-NEMA17_604-bearing_1off.par

instructions:
[objects.reprap.org]

and i sell that part for $15 PM me if you're interested:

I would strongly recommend not to use any PEEK or PTFE parts in your heated part of the extruder. I use a stainless steel / aluminum combination in my printers:

www.3dp-tools.com

I think you get Wade's extruder with RP parts from techzone. Check the following website: [reprap.org].

3dptools Wrote:
-------------------------------------------------------
> I would strongly recommend not to use any PEEK or
> PTFE parts in your heated part of the extruder. I
> use a stainless steel / aluminum combination in my
> printers:
>
> www.3dp-tools.com


Can't agree with that one - I've printed 3 Darwins and 2 Mendels using just simple PTFE and brass hot ends. They work fine as long as you treat them well. Nophead build a hot end using both PTFE and PEEK that I hear has lasted for quite a few Mendel prints. Here's his setup:

[hydraraptor.blogspot.com]

Wade

I am going to attempt to use a barrel I got from reifsnyderb. It looks exactly like the one Nophead is using except there is no nozzle at the end of the brass barrel, its built into the brass. But the upper portion has an insert in it with a retaining ring. And today actually, I will be building the extruder when I get home and trying to heat it up. I have already glued the barrel assembly to the pinch wheel block. Electronics are about 90% completed as well, just need to wire up the extruder and mount some opto sensors and flags.

Ok i made another noob mistake. Didn't get a gear or research how to put a gear on the extruder motor shaft. Where can I get a gear (make it?), instructions for how to notch the motor shaft?

EDIT1: I found the instructions for building a jig with a dremmel to put splines on the motor and use a brass insert. Are there any US suppliers? Would a local store have this part? I would like to get this done soon and not wait a week for a thimble sized part to arrive.

EDIT2: Ok I continued my research and found that makerbot (where I bought the stepper motor [store.makerbot.com]) also sells a drive gear [store.makerbot.com] , which I would think should fit the motor they sell. Would this work? The drive gear is "meant" for their mk5 plasturder but looks like it would fit the Mendel extruder. Anyone have ideas or experience?

The nichrome wire must be wrapped so that it doesn't touch another piece of nichrome wire? I wired it up and when I turn on the power to the electronics (no thermostat tho) the wire becomes red hot and stays that way. The host software is also not even running yet. Is that normal or does that mean i did it wrong? I think I might have the nichrome pieces touching in places.

I seriously underestimated the time and materials needed for this project and am getting frustrated because I thought I would be done by now. My fault though. Thank you for the help guys.

Edited 2 time(s). Last edit at 06/10/2010 01:08AM by steveo290.

Edit: Sorry i don't know what i was talking about there, the Makerbot gear won't fit in a Pinch wheel extruder (mendel).

i'm trying to run wade's extruder with a kysan DC motor which should work by altering it's RPM but i'm yet to experiment, it could be too slow?

Edited 1 time(s). Last edit at 06/10/2010 04:48AM by mlagana.

also i can sell the four parts for wades extruder, i just need to go buy some resin and i'll weigh to see how much it will cost but i already made a mould of it successfully you can see the result here:



edit: i can provide grub screws and tap tension lines for the drive gear and make it so it fits any bore size you specify, and the drive gear will be made of a harder resin than the rest of it.

but you will have to cut the groove into a shoulder bolt yourself:

[reprap.org]

Edited 2 time(s). Last edit at 06/10/2010 12:00PM by mlagana.

Well right now I would just prefer to get a gear sleeve that I can pin to a flat spot on the motor shaft and use the bracket I have. Then move to a wade or adrian extruder after I can print.

Unless someone has a full geared extruder set they can sell me now for a good price, ebay has 5 days left for the only full set.

this one will work:

[sdp-si.com]

Ok thanks mlagana I will buy one of those.

the next problem you might run into if you're using gen3 electronics and replicator as a host is that you need to change your extruder firmware to run a nema17 because it's programmed for a makerbot which uses a DC motor. i can't work out how to do so so which is why i'm trying a DC on wades.

Well I am using gen 3 electronics with reprap host software, is there still going to be a problem? Also, any thoughts on my question about nichrome wire wrapping? Is it supposed to glow red hot right off the bat with no software hooked up? or is it because i havent hooked up the thermostist yet? Thanks.

It should never glow red hot if it attached to the heater barrel. It will if it has nothing to take the heat away.

---

[www.hydraraptor.blogspot.com]

i can only assume the reprap host software/firmware is set to drive a nema17 for the extruder

Quote
mlagana
i can only assume the reprap host software/firmware is set to drive a nema17 for the extruder

YES, this is in fact the case.

---

Bob Morrison
Wörth am Rhein, Germany
"Luke, use the source!"
BLOG - PHOTOS - Thingiverse

Awesome, thanks for the clarification. I think I will try to hook up my extruder motor this weekend and see if I can get that working.