3D printing - the end of the beginning?

bryan_machine · Aug 4, 2022

TeachMePlease said:
WHAT?

How many tools did you touch off to run your 3d printer?

Well, you do touch off the nozzle. But it's more the "part holding" and "tool clogging" issues - I've made quite a number of tangled rats nests of plastic which then let go of the bed and went plop onto the floor....

Strostkovy · Aug 4, 2022

bryan_machine said:
Strostkovy - I own a machine made by Z-corp (decades old, it sits in a corner) - said machine printed a "sand" flask, which was at least good enough for pouring aluminum castings. (It was used to make aluminum race engine parts - things like water impellers.)

The process, I think, was called Z-cast.

Note that what it printed was the mold (you had to apply shrink rules, etc.) So casting metal could be poured straight in. (I'm not 100% sure what they did for cores, the project was in the UK I just happened to invest in it.)

I don't know if it would work for zinc or not. (What's the actual alloy? Does it pour hotter than aluminum? Z-cast wasn't good enough for cast iron...)

This was all circa 2001 to 2005, so the market will have moved on.

So if you search around, there likely *IS* a machine/process/material that can 3D print a mold good enough for a decent casting - at least in aluminum.

But Die-casting is a different kind of tooling and a different alloy, right? Isn't it closer to injection molding plastic?

Zinc is much easier to cast than aluminum. The issue is that sand cast parts (and lost PLA or wax parts are easy enough to make with sand casting) is that the surface finish is terrible and the tolerances aren't great.

Die casting is very similar to injection molding in that the mold is typically tool steel with a mold release sprayed on and has tight dimensional tolerances and excellent surface finish. Metal is injected into the mold cavity at high pressure.The part cools in the mold and to my knowledge doesn't shrink, or shrinks very predictably.

Scottl · Aug 5, 2022

bryan_machine said:
Strostkovy - I own a machine made by Z-corp (decades old, it sits in a corner) - said machine printed a "sand" flask, which was at least good enough for pouring aluminum castings. (It was used to make aluminum race engine parts - things like water impellers.)

The process, I think, was called Z-cast.

Note that what it printed was the mold (you had to apply shrink rules, etc.) So casting metal could be poured straight in. (I'm not 100% sure what they did for cores, the project was in the UK I just happened to invest in it.)

I don't know if it would work for zinc or not. (What's the actual alloy? Does it pour hotter than aluminum? Z-cast wasn't good enough for cast iron...)

This was all circa 2001 to 2005, so the market will have moved on.

So if you search around, there likely *IS* a machine/process/material that can 3D print a mold good enough for a decent casting - at least in aluminum.

But Die-casting is a different kind of tooling and a different alloy, right? Isn't it closer to injection molding plastic?

Die casting needs not only precisely made smooth molds but also precision in the external dimensions so they can be used in multiple casting machines without excessive time consuming setup. IMO highly unlikely that printing will ever achieve that, at least not in any of our lifetimes.

If external dimensions are not tightly controlled you get excessive flashing, which requires additional steps to remove.

Scottl · Aug 5, 2022

3D printing certainly has its place but I can't see it ever totally replacing high volume methods such as injection molding and die casting. Where it excels is in one-offs or low volume specialty stuff. Currently a lot of custom fit medical parts and prosthetics are 3D printed.

As a case in point, while CNC has mostly replaced manual methods in manufacturing, manual machining still plays quite a role in repair jobs and other niches.

JST · Aug 5, 2022

Material cost, and time per part.... make a mold once, cycle it every 20-40 seconds, and you have blown away a basketball court full of 3D machines.

That may change. Probably will. But 3D printing is not the only way to run near net shape. And, it does not run "net shape", surface finishes are not "final" for many of the processes. Molding can be net shape; cut gate and use part....

3D prints commonly do not hold air or water unless done slowly. Molded parts do, one every 30 to 40 seconds, or faster.

Is it going to improve? Sure. Will it hit 40 seconds per part on a complex shape? Not for a while, if ever.

What is it good for? Very flexible manufacturing, short lead times on small volumes, very high value complex parts, etc, etc.

If you want 1000 per day, good luck as things are now.

bryan_machine · Aug 5, 2022

So there is one more use for 3D printing - I'll call it 'crafts and hobbies' - if the only tool you have is a hammer, you view all problems as topological variants of nails. If the only machine you can fit in your garage/bedroom/closet is a 3D printer, then you may well naturally view 3D printing as the natural solution to your projects - because it's the only solution at hand.

Just because what you have is a VMC, that doesn't mean "milled from billet" is the sensible way to make a part (though it is a Very Good Way to make many parts.) Same story for 3D printing - or anything else.

Shipp · Aug 11, 2022

bryan_machine said:
Well, you do touch off the nozzle. But it's more the "part holding" and "tool clogging" issues - I've made quite a number of tangled rats nests of plastic which then let go of the bed and went plop onto the floor....

Sure, but that's a mess, not a z crash that blew out your spindle bearings. And once you've got your material dialed, "cam" software is four clicks and export. Obviously the parts that come off can't compare to machined parts, but the fact some accountant can buy a printer and make usable complex parts in a weekend is mind-blowing compared to the learning curve for machining.

jscpm · Aug 31, 2022

There is just no common sense to think that 3D printing is some kind of blueprint for the future.

For example, let's compare apples to apples here. How does 3D printing compare to injection molding, the current process for making high volumes of complex-shaped parts in plastic? Well, from a cost, quality, quantity, reliability standpoint 3D printing is not now, or for the foreseeable future in any way capable of competing with injection molding.

Sure, 3D printers are used to make one off prototypes or models, but for manufacturing they are irrelevant.

As for using 3D printers to make parts in titanium for B1 bombers and stuff like that. That is only economically possible because there are only 45 B1 bombers in the entire world and the guvmint is happy spending $25,000 per part on them.

eKretz · Aug 31, 2022

Yes, currently the 3D printers aren't good for a whole lot other than prototyping or very small production. Some of them can be used competitively with machining on extremely complex parts, mostly the newer stuff that print metal parts from powder. Those can later be sintered or not. So their niche is currently low volume, prototyping to prove a design or things like making patterns for casting. They get better all the time though, just like most every other technology. They will probably get considerably faster eventually. I don't think they will ever replace all machining though. For instance, you can't use one to square up or trim a part to repair it, etc. At least not yet...

CPM2014 · Aug 31, 2022

I think there is an often overlooked aspect of 3D printing when having these sort of debates. The ability to manufacture otherwise impossibly machined/molded parts. An example in the marketplace today is OSS Firearm Suppressors. Another example is rocket engine components. I recently cut open a combustion chamber and nozzle from one of Firefly's rockets. It was very interesting to see how this technology is helping young engineers rethink how things should be designed. Another interesting thought exercise is to look at Matsuura's Lumex machines. It sinters a layer of metal and then immediately machines that layer for a complete and very high tolerance part.

I think to say this technology wont replace existing ways of doing things might be a bit naive. I have been on the resin printer wave since very early on and there has been a massive change in both available (engineering) resins, and the speed cost, and accuracy that they are printed. 3d printing is here to stay and WILL displace a percentage of manufacturing.

bryan_machine · Aug 31, 2022

sure, just like CNC displaced a lot of manual machining, and CNC machined from solid ("billet") displaced some amount of casting. and CNC pattern making has displaced a lot of manual pattern making.

CPM2014 · Sep 1, 2022

bryan_machine said:
sure, just like CNC displaced a lot of manual machining, and CNC machined from solid ("billet") displaced some amount of casting. and CNC pattern making has displaced a lot of manual pattern making.

Yes, Just as manual machines still have a place next to CNC machines, CNC machines will have a similar supporting roll.

Schjell · Sep 2, 2022

We get small parts printed in ti gr5 and Inconel 718.
Outstanding quality, no fuss with drawings and machinsts

, two week lead time and the price equals equivalent for machining when volume is low. We don't require tight tolerances though. That's the exact reason why we'll never invest in 5 axis machines & CAM. High volume, tight tolerance or large parts is still def. not cost effective for printing I think. But it's getting better and better fast!

3d printing is a designers dream. Complexity (aka coolness) is free, but material is expensive. Exact opposite of machining in other words.

Orange Vise · Sep 2, 2022

The nature of 3D metal printing makes it easy for machine manufacturers to lock down the consumables, and there's too much money to be made in the consumables for them to willingly drop the prices anytime soon.

mhajicek · Sep 6, 2022

Schjell said:
We get small parts printed in ti gr5 and Inconel 718.
Outstanding quality, no fuss with drawings and machinsts, two week lead time and the price equals equivalent for machining when volume is low. We don't require tight tolerances though. That's the exact reason why we'll never invest in 5 axis machines & CAM. High volume, tight tolerance or large parts is still def. not cost effective for printing I think. But it's getting better and better fast!

3d printing is a designers dream. Complexity (aka coolness) is free, but material is expensive. Exact opposite of machining in other words.

Who are you using for those parts?

Schjell · Sep 7, 2022

mhajicek said:
Who are you using for those parts?

Hi, we use Materialise. Some plastic, but most of it in Ti and Inconel. Upload part as Step file on website, get instant quote, options, and leadtime. Just brilliant for us so far.

Stirling · Sep 11, 2022

Shipp said:
Sure, but that's a mess, not a z crash that blew out your spindle bearings. And once you've got your material dialed, "cam" software is four clicks and export. Obviously the parts that come off can't compare to machined parts, but the fact some accountant can buy a printer and make usable complex parts in a weekend is mind-blowing compared to the learning curve for machining.

There is a looong list of settings and considerations to get quality 3D prints, even with simple fdm machinesx
Can I ooze out the shapes I want, yup, but my buddy with the same machine does it x2-4 tones faster with stunning quality and accuracy all while being stronger than mine every time.
I could only imagine how deep you could dive in to getting top quality parts from the lasers and sintered parts

Shipp · Sep 12, 2022

Stirling said:
There is a looong list of settings and considerations to get quality 3D prints, even with simple fdm machinesx
Can I ooze out the shapes I want, yup, but my buddy with the same machine does it x2-4 tones faster with stunning quality and accuracy all while being stronger than mine every time.
I could only imagine how deep you could dive in to getting top quality parts from the lasers and sintered parts

Of course, my benchy looks like someone heated it up and stepped on it a little. You can get into the weeds in anything, my point is simply that to start 3D printing at an acceptable level is cheaper, easier, and safer than to build a decent intro machine shop and the skills to go with it.

Stirling · Sep 13, 2022

Shipp said:
Of course, my benchy looks like someone heated it up and stepped on it a little. You can get into the weeds in anything, my point is simply that to start 3D printing at an acceptable level is cheaper, easier, and safer than to build a decent intro machine shop and the skills to go with it.

I would not disagree at all with that statement.
I don’t use mine too often. But when I do they are a great tool to have.
Knock out a quick in hand concept part, or more often I use them to make custom parts trays if I need to send parts to another shop for additional processing (plating and such)

3D printing - the end of the beginning?

Diamond

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Titanium

Diamond; Mod Squad

Cast Iron

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Aluminum

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