3D Printed Metal Engine Parts

[GreenTwin]

Someone here mentioned 3D printing a metal engine block in aluminum (it looks like gray iron to me).

That makes me wonder if that may be the future of the hobby; ie: some very large company that ownes multiple 3D metal printers could perhaps produce a lot of very nice model engine kits.

For now, the mass-produced CNC kits seem to be the least expensive, especially when produced in countries with low labor rates and little or non EPA-type regulations.

Our US government is discussing upcoming regulations that seem to require that the air inside a foundry be many orders of magnitude cleaner than standard outside air. The commercial casting magazines are saying this will end all foundry work in the US if it is implemented.

For the backyard casting folks, there is a lot that can be done with bound sand, but the ultimate small casting work I have seen is lost-PLA investment casting in gray iron.
The lost-PLA investment method is the only method I know that could approach or match a 3D printed metal engine part.

The good news is that lost-PLA does work extremely well with gray iron.

I have not seen anyone in a hobby setting successfully use the lost-foam method with gray iron.

I see greensand or Petrobond (tm) as sort of Level 1; bound sand as Level 2, and lost-PLA investment castings as Level 3.
Lost wax investment I see as Level 4.

Bound sand molds seem to be a good mid-level method that can produce some pretty intricate castings, without the trouble of burning out PLA or wax, and without the trouble of making ceramic shells.

Anyone familiar with the 3D printed metal model engine parts?
I would like to learn more about that process.

.

 

[GreenTwin]

I found this site.
I have not had time to read it yet.
(not my photo)

3D printing is absolutely changing the model engine hobby drastically and permanently, I think.

Whether 3D printing has changed the model engine hobby for the better is a topic of debate, but I think 3D printing and 3D modeling has really helped the hobby immensely.
I do know some old-school folks who prefer hand-made wood patterns, but even an old-school guy like myself uses 3D modeling and 3D printed patterns routinely.

The number of V8 engine blocks and other engine types that have been 3D printed in plastic, that can be found online now is astounding.

This hobby, and technology in general, is changing rapidly.

https://3dprintingindustry.com/news...ng-service-for-3d-printed-metal-parts-142735/

 

[Jasonb]

The lost-PLA investment method is the only method I know that could approach or match a 3D printed metal engine part.

What about printed waxes and investment casting, surely better than trying to burn out PLA and risking ash left in those intricate cavities

With PLA or even resin printing you will have two issues if you want to try and replicate that cast engine block
1. Supports PLA and resin need supports, not so hard to remove from the outside but how are you going to get into all tose passages and cavitie sto remove the internal ones.
2 Surface finish, Resin will be OK but most PLA prints will need the surface refining and on a complex part like that very hard to do.

On the otherhand printed metal parts do not use supports when they are printed and the layers can be a sgood as resin prints and really need no further work to the surface, maybe a bead blast to get the outside looking nice.

As for foam and cast iron. You don't see it much in the home foundry as most home foundries can't melt iron

 

[GreenTwin]

I thought 3D printed wax was going to be the next big thing, but after much hoopla from someone trying it, they ran into so many problems that they abandoned it.
3D printed wax would most likely have lines in it if it did work.

Resin prints seem promising as far as lost-resin casting, but I have not read much if anything about someone actually doing that.

The internal support could be an issue.
My Prusa XL seems to be able to print complex curved shapes (the dog) without any supports, so I think 3D printers and software are improving in that respect.

As far as lost-PLA, the only surface finish that would need to be smoothed would be the external surfaces, unless one is concerned about lines showing on internal parts of the casting.
The lost-PLA example I saw did use some filler on the surface, which I think was paint, and it appeared to burner out cleanly.

I think the more intricate the lost-PLA 3D print, the more potential for incomplete burnout there will be.


.

 

[Jasonb]

Is that just one guy with problems printing in Wax?

Take a look at this companies website, the majority of what they produce is from 3D printed waxes, though they mostly just show the CAD models this page shows an example of some castings. Plenty of detail, no real layer lines etc

https://www.crofittings.co.uk/miscellaneous-items-2/

I have seen Adam's products in the flesh and would certainly say they are far better than many of the lost PLA efforts I have seen on the net and in person. If you want to see the quaility of the waxes then have a look through this long thread of his ot just the first post which shows some of the waxes in blue wax, casting from that wax on page 3

https://modeleng.proboards.com/thread/10339/scale-fittings-locos?page=1

Your dog is hardly a complex or detailed item so self supporting it is when you get to the more details stuff that the supports are needed. I have had resin prints done of 50 or so of my CAD designs and they needed a lot of supports but not simple parts. Recently had another of my CAD files printed using MFJ (Multi Jet Fusion), again no visible layer lines and does not use supports so would be good to cast from

External surfaces are indeed what matter but what if those surfaces have detail on them? Far harder to smooth out close to detail or on internal corners that are commonly seen on the OUTSIDE of castings not just hidden away. That power disc of yours would obliterate any raised detail and simply not get into tight corners

Here is a good example of what I'm talking about, 3D printed metal (SLM in steel) Digger Bucket that one of the guys over on MEM has just had dome. You see the inside of the bucket as well as the outside so all surfaces would need to be of an acceptable level of finish including those between the teeth and the plates at the top

 

[GreenTwin]

Is that just one guy with problems printing in Wax?

Yes, I have only heard of one hobby casting person try the 3D printing wax, and he basically said it has a lot of problems, but I don't know the specifics. And this was about 4 years ago, so things may have developed since then.

That is one impressive digger bucket right there !

I will follow your links and read those.

.
Edit:
I am not sure how he 3D printed that manifold in wax.
Wouldn't you need supports for wax too ?
I will have to check into the wax printing; seems like it has progressed a lot.

Edit02:
Wow, 57 pages in the thread at that link !
I will get back with you guys next month when I get finished reading all of that.

Looks like the 3D printed wax patterns are especially useful for small intricate parts, and parts with text on them.

I would be concerned about the cost of large 3D printed wax patterns, and of course 3D printed wax patterns are not reusable like a 3D printed PLA pattern would be.
If you use the lost-PLA method, then of course those patterns are not reusable either.

.

 

[Jasonb]

That thread was started back in 2015, I expect it has got even better since then.

 

[GreenTwin]

The mother of all threads for sure.

.

 

[creast]

It's all horses for courses really.
For large parts I generally sand cast using either wooden or PLA patterns.
For small, intricate or impossible to cast in sand I use the lost PLA method and yes it is a lengthy process with pattern production, investing and burnout cycles but it is worth it from a hobbyist standpoint.
I always try to avoid supports on FDM printing as they invariably cause surface issues and so often I will print in two or more pieces to avoid them. This often allows internal cavities to be support free too as per attached photo of one half of my recent cylinder.
The parts are then glued together as a whole before the investment process.
I have recently purchased a resin printer with a view to using the wax type resin designed for lost wax casting which I add is very expensive and trickier to print with than standard resins. This printing method give a much finer finish to the parts but so far I am struggling with warping and shrinkage particularly on large flat areas. Printing figurines and jewelry has been fine but most of my engineering parts have been less than successful. However I am still learning.
If the requirement is for many copies of complex parts with good finish you cannot beat making a wax injection mould to quickly replicate parts for investment casting as per the norm in industry.
Before I retired, we had several parts which were printed directly in metal using direct metal laser sintering using titanium or cobalt alloys. The process is very costly at present but allows complex parts to be produced directly from difficult to machine materials or impossible to machine by conventional methods.
As for lost foam, I have yet to try this but Kelly Colfield produces some incredible automotive parts which match any commercially produced castings.
Thanks for the links Jason. Very impressive work there!

 

[lohring]

This is a part I had printed in stainless steel.

Lohring Miller

 

[ddmckee54]

I haven't tried either of these ideas, but.....

Printable waxes will also need supports for most overhangs. If you have a printer equipped with 2 extruders then one of those could be the printable wax and the other could be a water soluble material used just for supports. Telling the printer which material to use for the model and which to use for the supports is done in the slicing software. When done printing the model the support material can literally be rinsed away.

I believe that printable waxes can be vapor smoothed using isopropyl alcohol, similar to vapor smoothing ABS using acetone. Vapor smoothing leaves a glass-like finish when done properly. Vapor smoothing may, or may not, work for interior sections, i.e. inside a manifold or pipe.

 

[GreenTwin]

I always try to avoid supports on FDM printing as they invariably cause surface issues and so often I will print in two or more pieces to avoid them. This often allows internal cavities to be support free too as per attached photo of one half of my recent cylinder.
The parts are then glued together as a whole before the investment process.

This is a great idea, I think.
.

 

[GreenTwin]

As for lost foam, I have yet to try this but Kelly Colfield produces some incredible automotive parts which match any commercially produced castings.

The hobby style lost-foam process uses hardware store foam, which is not the same as the expanded bead foam (I don't think they are the same).

I have a few photos of xrays of high quality commercial aluminum castings, and they are indeed flawless inside and out.
Too bad this method is not readily availble to the hobby community, because it really tells the full story.
I have seen hobby sectioned castings, and you can check things like inclusions, gassing, wall thickness uniformity, etc.

.

 

[GreenTwin]

I looked at a commercial lost foam casting process, and it appears that there is fairly large funnel-shaped sprue at the top, and once that piece flairs/burns, then there is no gassing out the sprue after that.




Looking at Kelly's video at 9:46, it seems like a similar thing is happening, ie: his funnel-shaped sprue gives out a large flame as it vaporizes, and after that it seems like he gets a clean pour without back-gassing out the sprue.
So I think that is the secret to getting the quality that he does.
And I recall him saying he poured at a significantly higher pour temperature then would normally be used, ie: much higher than 1,350 F.

 

[GreenTwin]

The large cylinder looks really nice, but there are some horizontal lines visible inside the bore, and for a motorcycle cylinder, you could not afford to have a cold shunt.
I would like to the the cyinder sectioned.

Kelly has definitely taken the hobby lost foam process to a whole new level; there is no doubt of that.

 

[GreenTwin]

An interesting die-cast racing cylinder video (not lost foam, but never the less quite interesting).

 

[GreenTwin]

I just found this channel.
Most interesting.
I wonder if he tempers to T6 ?

















https://www.youtube.com/watch?v=oaXXVJdU6Vg

 

[TSutrina]

Someone here mentioned 3D printing a metal engine block in aluminum (it looks like gray iron to me).

That makes me wonder if that may be the future of the hobby; ie: some very large company that ownes multiple 3D metal printers could perhaps produce a lot of very nice model engine kits.

For now, the mass-produced CNC kits seem to be the least expensive, especially when produced in countries with low labor rates and little or non EPA-type regulations.

Our US government is discussing upcoming regulations that seem to require that the air inside a foundry be many orders of magnitude cleaner than standard outside air. The commercial casting magazines are saying this will end all foundry work in the US if it is implemented.

For the backyard casting folks, there is a lot that can be done with bound sand, but the ultimate small casting work I have seen is lost-PLA investment casting in gray iron.
The lost-PLA investment method is the only method I know that could approach or match a 3D printed metal engine part.

The good news is that lost-PLA does work extremely well with gray iron.

I have not seen anyone in a hobby setting successfully use the lost-foam method with gray iron.

I see greensand or Petrobond (tm) as sort of Level 1; bound sand as Level 2, and lost-PLA investment castings as Level 3.
Lost wax investment I see as Level 4.

Bound sand molds seem to be a good mid-level method that can produce some pretty intricate castings, without the trouble of burning out PLA or wax, and without the trouble of making ceramic shells.

Anyone familiar with the 3D printed metal model engine parts?
I would like to learn more about that process.

.

One thing I know is that Aluminum oxidizes almost instantly. Oxidized aluminum is gray. So what your seeing is Aluminum oxide. You can not solder aluminum without either a flux that removes the oxide chemically and places a shield, liquid to prevent oxidation or melting a metal alloy and mechanically scraping of the oxide because the aluminum belief is soft.
Printing aluminum thus can only be done in an atmosphere without Oxygen or any other gas that an react with aluminum and create a hard compound. This can be liquid flux that but this will create the problem of cooling the metal or creating a vapor that is corrosive typically.
The next possible approach is to heat the old metal near the melting point of aluminum and the new aluminum added pushes the oxide aside. This is typically happens when aluminum welding with a gash shield. Some pot metal would be a better choice.

 

[jirvin_4505]

Is that just one guy with problems printing in Wax?

Take a look at this companies website, the majority of what they produce is from 3D printed waxes, though they mostly just show the CAD models this page shows an example of some castings. Plenty of detail, no real layer lines etc

https://www.crofittings.co.uk/miscellaneous-items-2/

I have seen Adam's products in the flesh and would certainly say they are far better than many of the lost PLA efforts I have seen on the net and in person. If you want to see the quaility of the waxes then have a look through this long thread of his ot just the first post which shows some of the waxes in blue wax, casting from that wax on page 3

https://modeleng.proboards.com/thread/10339/scale-fittings-locos?page=1

Your dog is hardly a complex or detailed item so self supporting it is when you get to the more details stuff that the supports are needed. I have had resin prints done of 50 or so of my CAD designs and they needed a lot of supports but not simple parts. Recently had another of my CAD files printed using MFJ (Multi Jet Fusion), again no visible layer lines and does not use supports so would be good to cast from

External surfaces are indeed what matter but what if those surfaces have detail on them? Far harder to smooth out close to detail or on internal corners that are commonly seen on the OUTSIDE of castings not just hidden away. That power disc of yours would obliterate any raised detail and simply not get into tight corners

Here is a good example of what I'm talking about, 3D printed metal (SLM in steel) Digger Bucket that one of the guys over on MEM has just had dome. You see the inside of the bucket as well as the outside so all surfaces would need to be of an acceptable level of finish including those between the teeth and the plates at the top

View attachment 156243

Wow what an inspiational post. Probably got through 56 of the 57 pages

At the trade guilde we are playing with resin printers. Early efforts at printing wax models have been successful. After seeing the magnificent examples in the 57page thread my mate modelled up a globe valve with minature writing on the side that we hope will be a part of his ME beam engine build (it certainly changing the modelling landscape)

Obsessed with casting fine detail I recently did a jewerly casting workshop. I was the odd one out - 5 young mums and me the obvious old man

Example of process…


Cheers jeff

 

[Jasonb]

keep us posted of how the valve turns out.

This may be of interest if he wants some pipe elbows and flanges to go with it

https://www.modelenginemaker.com/index.php/topic,11630.0.html

The resin printers certainly seem to be changing the plastic model world, now you don't buy an injection moulded kit or aftermarket PU resin parts. You just buy the file and print out the it yourself be that a figure (historic or fantasy), body shell, turret, etc and you can make them in whatever scale you want.