Noob questions, The Machine

[fredk]

...
fred - whether or not a 3d printed part is water tight is largely down to the way it's printed.

So I'm learning. From what I've read, if I want stronger parts with better inter layer adhesion, I want to go to a larger nozzle. The supposed advantages are that the previously laid down layer retains more head, it will bond better as the new layer is laid down. It also speeds printing considerably. For aquarium parts I think I should actually consider the E3D volcano. As a start, I will get the largest nozzle my head supports.

For water tightness, is that all down to inter layer bonding?

Anything that isn't watertight can be painted with varnish, or any of the propriatary 3d print smoothing compounds around.

I don't think varnish will hold up long term in salt water. I'd have to talk to the smoothing compound manufacturers to see what might leach into water and how well those compounds hold up. It is definitely an option.

pet-g has much better layer bonding than abs, prints on an unenclosed machine and isn't much more expensive than abs. It also has a lot less shrinkage, which helps reduce micro gaps in the structure.

If I can print water tight from the get go, its almost 'holy grail' product for my application. If plain pet-g turns out to be too flexible, I can always go for a carbon fiber reinforced product.

Bonding would be the one issue. The only product available to bond to other plastics like PVC or acrylic it Weldon 40, a rather expensive two part bonding agent. If it works and this is the only down side, I can live with that.


The fumes from abs are not as much of the problem as it's shrinkage and all the acetone you end up breathing in.
Yes people use it, I suspect many of them do so beacuse they haven't bothered to look seriously at the alternatives. The materials advances in 3d printing filaments in the last few years is just astonishing.

Another material you might want to look at is ninjatek's Armadillo. It's a rigid supertough material, that apparently prints easily. Handling it you'd think you were holding some kind of hardened nylon. I believe they said it was polyurethane.
Pretty impressive stuff.
I haven't tried it yet - but had along talk to the ninjatek guys and handled a few prints. The only thing that impressed me more this year materials wise, was a fibreglass composite from an italian company (maybe spanish). That was as light and strong as traditional fibreglass and printed - again - on an unenclosed machine.

Then you have innofil's new Pro 1 - easily the best material I've printed with for ease of use.
Lots of different applications depending on how hot and how fast you print it. Also food contact safe.

Great info, thanks. I'm at the "you don't know what you don't know stage, so its hard for me to even know where to look for info on new plastics.

Edit: Regardless of the material I work with, I plan to enclose the machine. I've spent enough time around injection mold machines (very large ones) to understand how finicky plastic can be. Since I'm concerned with long term structural integrity, I want to manage the print environment as much as possible.

[Todd-67]

So I'm learning. From what I've read, if I want stronger parts with better inter layer adhesion, I want to go to a larger nozzle. The supposed advantages are that the previously laid down layer retains more head, it will bond better as the new layer is laid down. It also speeds printing considerably. For aquarium parts I think I should actually consider the E3D volcano. As a start, I will get the largest nozzle my head supports.

It really depends on what your accuracy requirements are. A larger nozzle will print faster but I am not sure it has the advantages that you are citing. A normal .4mm nozzle can be setup to produce those exact same results. Extrusion width, your multiplier, and extrusion temps are you friends. These parameters are in your slicer.

For water tightness, is that all down to inter layer bonding?

I don't think varnish will hold up long term in salt water. I'd have to talk to the smoothing compound manufacturers to see what might leach into water and how well those compounds hold up. It is definitely an option.

If I can print water tight from the get go, its almost 'holy grail' product for my application. If plain pet-g turns out to be too flexible, I can always go for a carbon fiber reinforced product.

Bonding would be the one issue. The only product available to bond to other plastics like PVC or acrylic it Weldon 40, a rather expensive two part bonding agent. If it works and this is the only down side, I can live with that.

Water tightness is going to rely pretty heavy on your shell/perimeter settings. Lots of perimeter/top/bottom layers. You and I both know that coating anything in a saltwater environment is something to proceed with extreme caution.

The fumes from abs are not as much of the problem as it's shrinkage and all the acetone you end up breathing in.
Yes people use it, I suspect many of them do so beacuse they haven't bothered to look seriously at the alternatives. The materials advances in 3d printing filaments in the last few years is just astonishing.

You don't breath in acetone during printing. It's a solvent that dissolves ABS. You use acetone as a method of smoothing, creating slurry, or cleaning the bed with Kapton tape. What you are smelling during printing is the styrene. ABS = Acrylonitrile Butadiene Styrene. Does it smell? The short answer is yes. The real answer is that when processed at the correct temps the toxicity of the fumes is minimal. ABS when burned as in a fire condition is very toxic which is why they have flame retardant grades for certain applications (molding option) but that is not what we are doing. Extrusion temps are below injection temps. If it were toxic when processing OSHA would be all over the injection molding industry as it and nylon are the most processed plastics on a large scale and they don't require breathing aspirators for the workers. Can it irritate some peoples noses? Certainly.

Like i stated before the application defines the application. Material selection is based application. The array of thermoplastics is pretty wide ranging and application specific. Check out the range of what is out there on matweb http://www.matweb.com/search/MaterialGroupSearch.aspx Each of these has a use as matweb just covers the most common for each category not the full range from Dow, Bayer, GE, etc.... Yes the printing industry has brought out a lot of filaments but they are based on existing polymers with a modifications to make them easier to print. I use a lot of the stuff that is out there. There are applications for all of it.

Edit: Regardless of the material I work with, I plan to enclose the machine. I've spent enough time around injection mold machines (very large ones) to understand how finicky plastic can be. Since I'm concerned with long term structural integrity, I want to manage the print environment as much as possible.

Controlling the environment as much as you can is a very wise approach.

[curious aardvark]

if you enclose it leave a door.

the trick to pla is cooling fast, so that;s one material that you don't want to print in an enclosed setup.

back to the cold smoking - thing - that I know a LOT about.

what sort of setup are you talking about ?

[fredk]

if you enclose it leave a door.

Well how exactly am I gonna get in there without a door? Like I'd ever do something that silly...

OK, I get your point. I need a way to print cold as well. I plan to make a stand out of 8020 quickframe. I'll work out a way to make the panels easily removable for access around the printer. I've learned the hard way that you should always make your equipment as accessible as possible.

the trick to pla is cooling fast, so that;s one material that you don't want to print in an enclosed setup.

back to the cold smoking - thing - that I know a LOT about.

what sort of setup are you talking about ?

I have a Green Mountain Grill tailgate smoker (live in an apartment). I built a cold smoker attachment using a section of stovepipe, There is nowhere underneath to pipe the smoke into the smoker so I want to make something that is going to both block a partially open lid and direct the smoke in and down/around the items I wish to smoke.

I could probably MacGyver something from existing materials, but a 3d printed manfold would be much more elegant.

[fredk]

OK, Printer ordered. Again. Hopefully the transaction goes through without all the drama this time...

From all the reading I've been doing, all the low cost large bed printer kits out there have issues with powering the heat bed. Either the bed is greatly under powered and has trouble getting up to temp in a reasonable amount of time, or you get a great heat up time, but the main board and/or PSU can't handle the power draw.

The Tevo's 370 x 250 mm bed heater draws 400 - 500 watts of power. The silicone heat beds of similar size start at 400w and go up from there.

Other builds have a smaller PSU and ~150w heatbed that will not get to the 100C+ needed for some materials.

I'm only guessing, but I suspect it is the $499 price point companies are trying to hit that has got them where they are now.

I don't understand the main board chain of supply, but I would imagine that there is a market for a board properly designed to handle 500-600w at 24v.

I'm going to try controlling the heat bed separately using 24v out from the PSU though an SSR or mechanical relay. I may actually just shell out the money for a real Omron SSR and be done with it. If the PSU lets out its magic smoke I can upgrade to a proper Meanwell 600w PSU.

The internets claim I don't need to spend this much money for a relay, but I don't know that any of this 'Internets' has the appropriate training to make this call.

Now, lets see if the shippers can beat Santa.