Noob questions, The Machine

[fredk]

A bit of background. I learned to diy the old fashioned way. I grew up on a farm. The bug never left me and as I take on new projects I always run into something where, if only I could make this part a little different, things would work so much better.

3D printing has gotten silly inexpensive, so its high time I moved away from bailing twine and barbed wire and started working with this new fangled plastics stuff.

Printers are the new wild wild west and there are a mind numbing range of options out there, even when you narrow it down in price range.

Uses: I`m looking at a printer as a practical adjunct to my DIY habit. Some of the stuff I build will be immersed in salt water, so that narrows down materials requirements considerably. ABS and poly-carbonate are two materials I know will hold up in salt water. Another project I have in mind is a cold smoker manfold adapter for my smoker. Typically it should not be exposed to temperatures above 90F, so I probably have a wider range of materials I can use. We can probably up the tolerance to 120F to make up for those 'oops' moments.

If I was happy with the standard sized bed I think I would go for the all metal Wanhao i3 clone as it seems a good compromise between cost and quality and the company is legit. Unfortunately, one of the very first projects I want to take on will be around 12" x 8" x 10" in size. I could probably shorten the height a little, but the width is important. This size, if I want to print it in one piece, eliminates a lot of printers.

The Tevo Black Widow delivers on bed size (14.5" x 9"), the company appears to stand behind their products when things go wrong and the stock machine appears to be capable of quite good prints. That's also about as much as I want to spend on a machine right now. Actually it ticks quite a few boxes. The frame is well constructed and rigid and the kit fits together quite well. Assembly instructions are mostly good and there is a large community for support. It can usually print well right out of the box, though I'm told it is wise to check the hot end for finish before using it. The biggest downside seems to be component quality variability. They are quite willing to ship replacement parts though.

My question is around a large bed and how that might affect printing. ABS is probably the first material I'll use (salt water), so I plan to enclose the printer. Will I start to run into temperature uniformity issues on such a large bed? Are there down sides in general to such large prints?

Are there downsides to doing small prints on a large bed? One I can think of might be location accuracy. I know that in manufacturing, robots that work in xyz space need periodic re-teaches to correct for the inevitable drift that comes from tiny differences in movement over time. I don't know if that would be an issue with such a low volume fabricator though.

Do you guys who have been printing for a while find yourself running into limitations in what you print because of bed size? Other than the one project mentioned, I can`t think of anything else I would need to print in that size. In fact, I`ve not seen any Black Widow owners doing prints that require that bed size. OTOH, I wonder if, once you have a larger bed, useful projects will come to mind.

I`ve got a million other questions spinning in my head right now, but the above will do for a first post.

Fred.

Edit: One other obvious question. Is there any other printer in the $350 to $550 range I should consider?

[Roxy]

If you want to use a large print envelope... It is very helpful to have a heated bed and some flavor of Auto Bed Leveling mix. Some very big bed printers print on acrylic sheets (like the gCreate gMax 1.5+) I wouldn't even bother trying to print ABS on a 16" x 16" print without a heated bed. But it does PLA just fine. The PLA sticks so hard you need a razor blade scrapper to get it off the bed. (And in fact, that is part of the reason I'm going back to glass for a print surface. I can just unclip it, put it in the freezer, and my print comes off it!)

I`ve got a million other questions spinning in my head right now, but the above will do for a first post.
Edit: One other obvious question. Is there any other printer in the $350 to $550 range I should consider?

My vote would be to put together a RepRap printer kit and use it as a learning experience.

[fredk]

Thanks for the reply Roxy.

...
My vote would be to put together a RepRap printer kit and use it as a learning experience.

Well that really narrows it down then. Only a couple of hundred different companies to look at. Seriously though, every time I take another look it seems like I find 5 or 6 more companies offering printer kits. Tevo is one of a hand full Chinese companies offering Prusa i3 kits that is regularly mentioned and has good feedback. I`m one of those analytical types that likes to evaluate everything on offer before making a decision, but I think in this case that is not possible.

I will most definitely go with a heated bed and an enclosed print area.

[djprinter]

If you're printing large parts in ABS you'll want to heat your chamber (not just a heated build plate). This can be done inexpensively with a low-wattage hair dryer ($10-20) and a temperature controller ($40-60).

I suggest a temperature of 50c, this is warm enough to keep the ABS from warping but not so hot that it will fry your electronics.

[Todd-67]

If you're printing large parts in ABS you'll want to heat your chamber (not just a heated build plate). This can be done inexpensively with a low-wattage hair dryer ($10-20) and a temperature controller ($40-60).

I suggest a temperature of 50c, this is warm enough to keep the ABS from warping but not so hot that it will fry your electronics.

^^ This is good advice. Even without the heat chamber mod an enclosed chamber with a heated platform will reach 40-45C. One key thing you are eluding to are printing higher temp materials and a larger build volume. That means not only are you going to want the ability to enclose, and have a heated bed you are going to need an all metal hot end. That to me points at the Ultimaker 2+ Extendedd. If you can give up the large build chamber than a modified Flashforge or Qidi would fit the bill.

When printing with ABS hacking up a larger model and bonding the pieces together is what I typically do. Gel superglue works like a champ this way. The thing with large builds is they take a long time and it really sucks to get 10 or more hours and the material into it only to have it fail.

[fredk]

... That to me points at the Ultimaker 2+ Extendedd.

If someone were to drop one of those in my lap for $800 I wouldn't say no, but that's way above my budget. I missed out by a day on a used Flashforge Creator Pro for $550. At that price I would probably have given up on the larger bed for now.

When printing with ABS hacking up a larger model and bonding the pieces together is what I typically do. Gel superglue works like a champ this way. The thing with large builds is they take a long time and it really sucks to get 10 or more hours and the material into it only to have it fail.

I have no design experience, so I have no idea how slicing and gluing might affect structural integrity on a part.

I'm of half a mind to go back to the original plan and buy the base Tevo Tarantula kit for $330 CAD and play with that to really understand what my needs are. I would imagine there is quite a learning curve for 3d modeling and printer setup to get whats in my head to turn into a real usable part.

I normally like to buy once and, other than minor mods, be done with it. There is not much technical info on these low end printers, so even when I buy one with an 'all metal' head, it is not clear what that really means or if I can work with higher temperature parts. Everyone seems to have all metal hot ends these days, but I imagine that they are not all created equal.

Materials is a whole other can of worms. I've been looking into PETG for the last couple of days. It looks to hit all the marks with a bonus of no/little toxic fumes while printing. The one downside is for some things I would want to bond to PVC, ABS, or acrylic. There are lots of good bonding options for poly-carbonate and ABS, but only one for PETG.

Hmm, buy a cheap printer (that works) and loads of different materials? Or maybe a lottery ticket...

[Todd-67]

The inexpensive option is not a bad route to go when you are starting from scratch experince wise on not only printing but modeling as well.

Most printers do not have all metal hot ends. The have metal nozzles and a metal guide tubes but use a PTFE tube in them as a heat brake. That cant take the heat of nylon and PC. The upgrade is cheap though.

Slicing up a model for bonding back together is not hard. You use tounge and groove, rabbit joints and pins/holes. Think wood working. A quality superr glue combined with those methods is very strong.

[fredk]

...
Most printers do not have all metal hot ends...

I double checked and both Tevo's have clone E3Dv6 all metal hot ends. My impression was that a lot of the cheap kits had moved to this clone. I may be wrong though. I've seen multiple reviews now and the Tevo clone hotends do work

Thing is that the E3D genuine is rated to 300C, but the clones are only rated to 260C. I have no idea why that is. It could just be the thermistor, it could be... anything else...

Too many unanswered questions. Go cheap and learn really does seem like the best option.

[curious aardvark]

go for the black widow and do the sensible thing and just don't go anywhere near abs.

pet-g is damn near as cheap these days, much much easier to use, doesn't need a heated chamber and is resistant to just about all chemicals, also food contact safe so it won't kill your fish :-)
$25 a kg and cheaper: https://www.amazon.com/eSUN-filament...rds=esun+pet-g

Abs is way more hassle than it's worth. I mean way way way more hassle !

I'd also be inclined to try pla in the salt water setting - can't see any problems, also unlikely to poison your fish.
Bear in mind that abs filament often has additives to help the printing process and isn't considered food safe as it can leach chemicals.
Tropical Fish in tanks seem to spend their lives just looking for ways to die ;-)

If you don't have tropical fish - ignore all the fish references :-)

I spent 6 month fighting abs before I came to my senses. Haven't touched it in the 2.5 years since and never needed to.

There are a bunch of new abs beaters coming on the market as well.
I can thoroughly recommend innofil's new Pro 1
has to be the easiest filament to print I've yet tried. Costs more than pet-g - but you're pretty much guarenteed perfect prints every time.

As far as bed size goes. Mine are 9x6x6 inches and to be honest in 3 years I've yet to need anything bigger.
What i tend to find is that if I need to make a large thing I'll design a 3d printed part that attaches to a cheap existing 'thing' and do it that way.

As an example - my dad wanted some longer pegs to attach his pigeon decoys to.
So instead of printing long plastic pegs I simply made an adaptor that you inserted a cheap tent peg into and then slotted the existing pigeon stick in the top.
Gave a 10 inch extension for bugger all money and a lot less printing.

The thing to bear in mind is that 3d printing is slow. So what i do is look for stuff - often from a pound store that i can use with a 3d printed adaptor.

Another example. I have a tassimo coffee machine. So when making a pod holder for the kitchen. rather than printing it in one piece I made it in 3 quick to print pieces that were either joined together by bamboo skewers (1 pence each) or lengths of metal bbq skewers (12 for £1). That way I could make a much taller pod holder - and after a quick wipe with acetone, the stainless steel bbq rods look really good, for minimal printing and bugger all money.

Basically as long you are practical and used to making things - you probably won't ever need to print anything really big.

[Todd-67]

Curious Ardvark is expressing his opinion which he is entitled to, as am I, but I would take it as just that. I disagree with him more often than not.

ABS is not hard to print if you know what you are doing. A lot of people do it. The industrial high end companies like stratasys customers go through a lot of ABS. :-) I use it almost exclusively as it is very durable for snap fits and impact resistance if you have your settings correct and you can print other materials if you have a dual head machine for dissolvable supports. It also post processes well. Brittle ABS prints are results of improper extrusion/heat parameters and infill/shell settings.

In your initial posts you mentioned mentioned you wanted to print parts for use where heat is involved for your smoker and you also mentioned the use of Polycarbonite. Heat is best handled with a semi crystalline structure material as they don't creep and loose strength with heat at their glass transitional zone. That would be nylon. PC and ABS are amorphous and while way better than PLA at temps are not the material of choice because of degrading strength properties and creep. Both PC and Nylon require high temp metal hot ends. PLA is horrible in heat situations even though your temps that you listed are well below where it should be a problem the part probably will not last long.

Absolutely DO NOT use an item printed in PLA in a salt water tank. PLA degrades in a few ways. Moisture is the base then you have chemicals such as chlorine which is high in saltwater. Heat and bacteria are the other enemies which your tank requires to be sustained. I have salt water reef tanks as well. The constant flow of water in the tank with the dissolved abrasive salt will not be good. I know this because before HIPS came out I used PLA as a disolvable support structure for ABS prints. See the video below on how it's done. I have a unit very similar to this one.

https://www.youtube.com/watch?v=uWYn5wJ72zY

PLA is great for a lot of applications and it is easy for noobies. I print almost exclusively for prototype parts for consumer retail goods as I am a mechanical engineer so it just isn't for me most of the time. No one polymer is. There are so many different ones for a reason. The application dictates the tools.