Intro and looking for advice on printer selection

[mmmggg]

Hi all, I am very new to 3d cad design and even newer (as in never) to 3d printing. This site looks like a great resource for someone like me ... I hope to gain a lot of information from it and one day contribute back to it. For now though, I am looking for advice on the printers that I'm looking at. The first is the Creality CR10 kit. This thing gets very good reviews and is at a good pricepoint for me. I am concerned that I will regret the single nozzle / media restriction of this machine as I foresee wanting to print with HIPS or PVA supports. The other machine I'm looking at is the creator pro dual extruder. This one is actually outside of my budget but ... I could stretch the budget if it's worth it. My concerns with this printer is that the circuit boards are inside the cabinet which, when printing ABS will reach ~ 90 deg C. How hard are these temps on the life of the boards? Other than that, I like the look and features of this machine. I'm also looking at the Yite ET - K1 but can't find any reviews on this machine. Any advice you can provide would be much appreciated.

Thanks, Mike

[Trakyan]

I'll start with this, I don't hear many people who buy a single nozzle machine later complain that they regret that and feel limited. I do hear of a lot of people who buy dual extrusion printers and end up hardly using/completely removing the second extruder and nozzle. There are definitely cheap dual extrusions kits out there, though. I'd go for a 2 in 1 out solution rather than dual hotends.

Secondly, what sort of printing will you be doing? Organic models? Engineering parts? Organic models often benefit from support (though many people try to avoid it) and you can design most engineering parts so that they don't require support. As a matter of fact, I always design my parts to require no support. It saves printing time, material costs and post processing. Even with dis-solvable support it takes time (a fair bit of time, people often underestimate this) and can be a pain to remove it all.

Thirdly, that printer you linked to is a paper printer...?

[mmmggg]

Thanks Trakyan for the advice. I came to these same conclusions and will likely go for the CR-10. Apparently, when I wrote the word printer, the forum automatically created the link. Funny ... Talk about advertising efforts.

[curious aardvark]

well before you get a cr-10 have a look at the qidi: https://www.amazon.com/TECHNOLOGY-3D...idi+3d+printer

Basically a flashforge pro, just cheaper - and given the millions of hours these printers have printed abs all over the world - it's not an issue.
Well 3d printed abs has a lot of issues and I wouldn't personally bother with it - but mechanically there's no problem.

That said trakyan is right - dual extruders sound cool - but in reality they are a real pita.
What you actually want is either a machine with independant dual extruders - like the bnc3d sigma, OR a machine with two feeds into one printing nozzle. Which you could probably add to a cr-10 fairly easily.

[mmmggg]

Thanks C A. Ordering the CR-10 tonight and planning to get me feet wet on that. Who knows ... If I win the lottery, I'll upgrade to something really really cool.

[Don McLean]

I've been researching single / dual extruders and also multiple extruders using a single nozzle as I have decided to build my own FDM printer.

Keep in mind that this is based on my research, not my experience.

The multiple extruders with one hot end can waste alot of filament. I watched one YouTube review where the amount of wasted filament on the cleaning block that was created weighed more than the finished parts.

Personally I want to print some fairly intricate parts where designing the part so that it doesn't need support isn't an option, and I want excellent quality when bridging, so I really think whether or not to have a second nozzle for support material is a good idea really depends on the user and not everyone has the same needs.

That being said, in my research, I have found people who have two headed machines often end up removing one head and not using it, so I don't disagree with what aardvark has said.

Also I want to print with some Nylon that is reported to need temps up to 285 C. So the temp you can get at the hot end is important if you want to do that. I don't know what the best setup is, perhaps someone with some experience there can chime in.

[Don McLean]

like the bnc3d sigma.

That's very interesting. I'm guessing it uses two independent limit switches for homing on the gantry axis, to home each extruder, one to each side? Plus it has a proprietary calibration sequence built into the machine to get it to work right. I wonder if you could do this on a DIY machine?

Looks like they used very nice linear components for the X and Y but for some reason used unsupported 10mm linear rods for the Z axis.

So is the common problem with dual extruders one extruder leaking on the print or misalignment with one nozzle higher or lower than the other?

[Trakyan]

If you're wanting multi extrusion for different materials (i.e. soluble supports, flexibles, anything with differing extrusion temperatures. So nylon+PVA is a no go), single nozzle solutions are a bad idea. You'll end up cooking and burning the lower temp plastic in the nozzle. And yes, this method has the most wasteful purge blocks. Only really good for multi /color/ in my opinion, yes it can do multi /materials/ but it's iffy.

This leaves multi nozzle solutions, and if you're doing this you'll want a system that can lift or move the idle nozzle out of the way. Things like the CEL robox, ultimaker or best yet, the BCN3d sigma. These also waste much less filament and time when printing, and can print with different /materials/ quite happily. Lifting the idler nozzle (or better yet, parking it aside like the sigma) solves two problems. The first is oozing onto the print, the second is actually colliding with and knocking over or damaging the print because both nozzles aren't perfectly aligned. There is still the issue of lining up the hotends in X and Y (z can be done with a bed sensor).

And no, the BCN does not use a proprietary calibration sequence, they are an open source company, feel free to use their ideas, software, design etc. Yes, the z axis smooth rods are an odd choice, but I guess it experiences lower loads than X and Y and they decided to save some cost.

One thing to note about multi extrusion, is it takes much (much) longer to print an object than with single extrusion.

[curious aardvark]

So is the common problem with dual extruders one extruder leaking on the print or misalignment with one nozzle higher or lower than the other?

yes.

You basically have to build a wall around the print and for each layer and colour change it empties both nozzles before printing.

I reckon it takes 2-3 times longer than a single material print.

One reason I almost never bother.

Plus there's the whole two seperate but interlocking stl files to deal with :-)