3D printed sand molds

[kd0afk]

I saw this on YouTube the other day and was wondering how feasible it would be to build one of these in the shop?
It's a long trough sand dispenser that lays down a thin layer of sand, I'm assuming it's coated or mixed with something, and a printer head cures that layers parts.
Has anyone tried building this printer at home?

 

[nfk]

Hi,
I built something similar about a year ago.
http://www.thingiverse.com/thing:27794
I was hoping on using Portland cement as substrate with water on the printer head but it did not work as expected.
The pieces where very fragile and not suitable for any use. Even removing them from the printer caused cracks and goofs.
I may experiment a bit with molding sand after the holidays.

Cheers,
Norberto

 

[kd0afk]

I just got an estimate on a mold for a tool post grinder I want to make. $1000 to 3d print the mold. If I make the form and send it to the foundry and they hand make the mold and cast it in iron; less than $100. How they justify charging ten times the amount for something a computer does for them.
Isn't technology and advances is manufacturing supposed to lower costs?

 

[bmac2]

But on the up side you could buy a 3D printer for under $1000 and still show your wife all the money you saved.Thm:

 

[kd0afk]

But on the up side you could buy a 3D printer for under $1000 and still show your wife all the money you saved.Thm:

I don't have a wife and building the system to print molds is not a project I want to tackle.

I estimate it takes them maybe 20 minutes of actual physical hands on effort, the machine does all the real work. They load up a model, create the sprue, gates and hit the start button.

If all technology and advancements had happened the way that CNC owners have dealt with advancements, a car would cost a million dollars and a toaster would require a small home loan to purchase.

 

[kd0afk]

I don't have a wife and building the system to print molds is not a project I want to tackle.

I estimate it takes them maybe 20 minutes of actual physical hands on effort, the machine does all the real work. They load up a model, create the sprue, gates and hit the start button.

If all technology and advancements had happened the way that CNC owners have dealt with advancements, a car would cost a million dollars and a toaster would require a small home loan to purchase.

 

[Cogsy]

Just a thought, but I know some larger companies run just like this for 'small' orders, but it may be because they are literally too busy. If you supply a form then the hands-on workers can just run it with their next pour and it's no big deal. If they have to get their designer guy to spend time on it, it's time he's not spending on their 'real' customers I guess. One off maybe it's not an issue but I expect they're trying to discourage small orders that take design time away from valuable jobs.

The next step from this is that they just stop accepting small orders at all as they really don't make much from them. I guess we can be glad some places will still help the little guys out.

 

[Wizard69]

Just a thought, but I know some larger companies run just like this for 'small' orders, but it may be because they are literally too busy. If you supply a form then the hands-on workers can just run it with their next pour and it's no big deal. If they have to get their designer guy to spend time on it, it's time he's not spending on their 'real' customers I guess. One off maybe it's not an issue but I expect they're trying to discourage small orders that take design time away from valuable jobs.

I think you hit the nail squarely on the head here. That and the 3D printing might be new to them. Foundries aren't always the most modern places to visit.

The next step from this is that they just stop accepting small orders at all as they really don't make much from them. I guess we can be glad some places will still help the little guys out.

I don't see job shop foundries ever completely disappearing but it is certainly harder to find them. The need for one offs and small runs will never go completely away. What I find more disturbing though is that many businesses these days done even want to bother with non business entities. If you don't have a business license they slam the door in your face.

 

[hanermo3]

You have seen why 3d printing is mostly crap, hype, fluff and useless.
Its really slow.
Materials are quite expensive.
Qty is pretty weak.

I can program a cnc mill in 20 minutes (or less) just like the 3d printer.
That has == 0 to do with cost of part.

There are actual, valid, uses for 3d printing.
And some new stuff may make them borderline useful for some stuff, way out in the future, maybe 5-8 years.
But generally, for most stuff, its just a toy.

Basic problem is accuracy/vs time, cost vs time, and current costs.
A 3d printer scales exponentially for accuracy, and base prices are high for anything useful.

Then, they are still inaccurate, not-finished, and materials are baseline weak and expensive.

Thus, a good 1 micron 3d printer (vs 0.1 mm) is 100x100x100 times slower = 1 million times.
There is no technical reason it cannot deposit the material in 1 micron layers, e.g. laser fuse it (in metal), and later polish the resulting sintered object.
There are many reasons it will be much slower and more expensive, and weaker, than cnc milling the same, where such milling is technically possible.

But e.g. a dust cap, bearing shield, encoder holder, etc etc may be fine in plastic, wont need high accuracy, and might be small and unique.
Excellent for 3d printing, one.

Its not likely to be a mass-production tool, ever, except in very, very unusual and narrow cases.
Medical implants come to mind.
Custom optics, maybe.

 

[hanermo3]

To continue re: 3D.
The tool might deposit, fuse, prepolish or roller-burnish the surface. = Harder, stronger, looks better.
It might run 10, or 50 nozzles, at once. Faster by 50x.
Sw might run variable-size nozzles, or multiple-size nozzles, to increase speeds by 100-500x.
Ie 1 mm resolution inside, and finish at 1 micron.

Still..
Where base naterials need strength, mechanical tools will be much simpler and faster and cost much less.
Where molds are appropriate, well (injection)(gravity)(centrifugal)(pressure) molding is really cheap.

There may still be a major busines case, eg. for relatively-expensive novelty items at zero-latency.
Ie high end future printer combines printer, laser, light-mill (finish) and colour printer.
=> Finished product, out in 20-60 minutes.
At 100$ / unit, vs 20$ unit 1-3 weeks from now.
Such a tool might be 100k per unit, and one available in every staples etc. or within 10 minutes commute.
Not mass-production, but mass-customisation.

Custom grips/molds/inserts for shoes, golf clubs, guns, motorbike stuff, sport equipment.
Etc.

Something you email to the printer, and by the time you are there, its done, polished, and has your name/decals/logos on it.
Where cost/material is not an issue.

 

[kd0afk]

I wonder if a person couldn't manually make a 3d printed sand mold? Create the model with sprue and gates etc., divide it into layers and have stencils cut. Deposit the sand by hand and use the stencils to expose the areas that need curing. It would be time consuming and take forever but if registration is maintained it my work. Not saying I'll ever do it this way but is it a feasible option?

 

[kd0afk]

You have seen why 3d printing is mostly crap, hype, fluff and useless.
Its really slow.
Materials are quite expensive.
Qty is pretty weak.

I can program a cnc mill in 20 minutes (or less) just like the 3d printer.
That has == 0 to do with cost of part.

There are actual, valid, uses for 3d printing.
And some new stuff may make them borderline useful for some stuff, way out in the future, maybe 5-8 years.
But generally, for most stuff, its just a toy.

Basic problem is accuracy/vs time, cost vs time, and current costs.
A 3d printer scales exponentially for accuracy, and base prices are high for anything useful.

Then, they are still inaccurate, not-finished, and materials are baseline weak and expensive.

Thus, a good 1 micron 3d printer (vs 0.1 mm) is 100x100x100 times slower = 1 million times.
There is no technical reason it cannot deposit the material in 1 micron layers, e.g. laser fuse it (in metal), and later polish the resulting sintered object.
There are many reasons it will be much slower and more expensive, and weaker, than cnc milling the same, where such milling is technically possible.

But e.g. a dust cap, bearing shield, encoder holder, etc etc may be fine in plastic, wont need high accuracy, and might be small and unique.
Excellent for 3d printing, one.

Its not likely to be a mass-production tool, ever, except in very, very unusual and narrow cases.
Medical implants come to mind.
Custom optics, maybe.

1. This process is highly accurate.
2. I think you're talking about standard 3d printing like with PVC or sintered metal. That is not what this is.
We're talking about printing a foundry mold from sand.

 

[Wizard69]

You have seen why 3d printing is mostly crap, hype, fluff and useless.

I think they are talking about a 3D printed sand mold. Though they could be talking about a 3D printed pattern that gets burned out of the mold. Either way it isn't fast. The real advantage, at least with a printed pattern is the ability to cast parts that would be nearly impossible to do otherwise.

Its really slow.

Extremely slow. Part of the process at work involves injection molding plastics. Cycles times are a few seconds when injection molding something and one cycle can produce dozens of somethings. I don't think people running 3D printers even realize how slow they are.

Materials are quite expensive.

Terribly expensive. Most of the resin coming into our plant is in 2000 pound Gaylord's. In the plastics industry that isn't even considered a bulk shipment. What people pay for their filament is shocking.

Qty is pretty weak.

I'm not sure you mean quality or quantity here but in either case you are right.

I can program a cnc mill in 20 minutes (or less) just like the 3d printer.
That has == 0 to do with cost of part.

This statement though I find to be puzzling. Back in my job shop days the customer paid for every thing! Setup work was often a huge portion of a products cost as was initial design work. These where separate charges but when the production runs where small it did impact part costs from the customers perspective.

There are actual, valid, uses for 3d printing.
And some new stuff may make them borderline useful for some stuff, way out in the future, maybe 5-8 years.
But generally, for most stuff, its just a toy.

If you are focused on fused plastic extruder type machines yes it is commonly a toy, but that doesn't mean it hasn't been applied to serious work.

As for other 3D printing technologies, laser based systems ware already in production use for jet engine and rocket parts.

Basic problem is accuracy/vs time, cost vs time, and current costs.
A 3d printer scales exponentially for accuracy, and base prices are high for anything useful.

Then, they are still inaccurate, not-finished, and materials are baseline weak and expensive.

We could say the same thing about cast iron. Seriously non of the things mentioned in the line above really mean anything. This especially if there is no other economical way to build the part.

Thus, a good 1 micron 3d printer (vs 0.1 mm) is 100x100x100 times slower = 1 million times.
There is no technical reason it cannot deposit the material in 1 micron layers, e.g. laser fuse it (in metal), and later polish the resulting sintered object.
There are many reasons it will be much slower and more expensive, and weaker, than cnc milling the same, where such milling is technically possible.

But e.g. a dust cap, bearing shield, encoder holder, etc etc may be fine in plastic, wont need high accuracy, and might be small and unique.
Excellent for 3d printing, one.

Its not likely to be a mass-production tool, ever, except in very, very unusual and narrow cases.
Medical implants come to mind.
Custom optics, maybe.

I guess it depends upon what you call mass production. I still haven't figure out the reprap world, some of the people in that world are strange and have an even stranger understanding of economics. On the other hand you have jet engines being produced with 3 D manufactured parts, maybe that isn't mass production. I just wouldn't dismiss any form of 3D printing completely.

This is sort of like the dawn of the Computer age when you had big business executives seriously asking why anybody would want their own computer. Now just about everybody carries a computer around with them in their pocket. While I never expect to see a 3D printer in every bodies pocket (cellar or garage) I do see the tech accelerating to the point where it becomes a common shop tool for anybody with a shop. This includes commercial as well as hobby shops. It just takes time for the technology to mature.

 

[Herbiev]

In Melbourne a man has just received a new condyle ( bone that joins the jaw to the skull) that was 3d printed in titanium. A really complicated structure almost impossible to make by conventional machining.

 

[hanermo3]

Both yes and no .. and we mostly agree, without going into semantics.

Complex, relatively costly, one-off (or few units in quantity) shapes with little mechanical requirements are great stuff for 3d printing.

And as we both said, both the costs and times are huge..
and make such production a non-starter for lots of use.

And very special stuff is good for 3d printing-
Like the medical implants, exotic nozzles re: rockets, both with Price No Object.
My point is that the work suitable for 3d printing is a tiny % of all work.

This percentage will never be high - with current methods.

E.g. DLP-type layering, and submicron scale materials might change this.
Fast laser-sintering and diffusion-immersion-baking cooking solids.
At the moment these are SciFi stuff.

In a machine shop, I struggle to see useful 3d printing.

On a remote farm (space, medical, island) - sure.
Again, Price No Object due to lack of alternatives.

There is no reason we could not 3d print cast iron, afaik.

Its just that I fail to see a *general* technical and economic reason for same, using a very slow and complex process, vs a very fast and cheap process.

I see things like routers/mills/drill-tap machines and lasers uniting, quickly.
Especially for sheet metal processing.
The laser cuts stuff and marks really fast, really cheap, and the drill/tap finishes any precision holes needed.
Great for 95%+ of basic sheet metal proccessing.
Potentially really, really, cheap.

Disclosure:
I may start to make such machines in the near future.

I do see the tech accelerating to the point where it becomes a common shop tool for anybody with a shop. This includes commercial as well as hobby shops. It just takes time for the technology to mature.

 

[kd0afk]

Both yes and no .. and we mostly agree, without going into semantics.

Complex, relatively costly, one-off (or few units in quantity) shapes with little mechanical requirements are great stuff for 3d printing.

And as we both said, both the costs and times are huge..
and make such production a non-starter for lots of use.

And very special stuff is good for 3d printing-
Like the medical implants, exotic nozzles re: rockets, both with Price No Object.
My point is that the work suitable for 3d printing is a tiny % of all work.

This percentage will never be high - with current methods.

E.g. DLP-type layering, and submicron scale materials might change this.
Fast laser-sintering and diffusion-immersion-baking cooking solids.
At the moment these are SciFi stuff.

In a machine shop, I struggle to see useful 3d printing.

On a remote farm (space, medical, island) - sure.
Again, Price No Object due to lack of alternatives.

There is no reason we could not 3d print cast iron, afaik.

Its just that I fail to see a *general* technical and economic reason for same, using a very slow and complex process, vs a very fast and cheap process.

I see things like routers/mills/drill-tap machines and lasers uniting, quickly.
Especially for sheet metal processing.
The laser cuts stuff and marks really fast, really cheap, and the drill/tap finishes any precision holes needed.
Great for 95%+ of basic sheet metal proccessing.
Potentially really, really, cheap.

Disclosure:
I may start to make such machines in the near future.

You are expending way too much effort expounding on something that's off topic and doing it uninformed. The topic is specifically about 3d sand mold printing.

 

[littlelocos]

Back on topic...

The foundry I use in York, PA, Cochrane Foundry actually receives large (on the order of several feet on a side) printed sand molds from Detroit via truck shipment. They cast the part and ship it back.

They are currently considering spending on the order of $500k-$600k for a used, 3D sand printer so the molds won't have to be shipped and so the other specialty work they do can be done more easily.

I've held some of the smaller molds. They are pretty impressive regarding smoothness and toughness (feel like a porous brick).

They are a small, job-shop foundry that do short runs and one-offs.

Todd.

Todd Snouffer
Littlelocos Model Engineering