Mesopotamia was considered the "cradle of civilisation"
Mesopotamia was considered the "cradle of civilisation"
Human beings have been melting metals and fashioning objects out of them for thousands of years, the earliest known example of casting discovered predates 3D printing by over 5,000 years. It is a copper frog from around 3200 BC created in Mesopotamia around 600 years before the first known pyramid in Egypt was constructed.
Mesopotamians, in what is now thought of as the ‘cradle of civilization’, began to melt down metals, pour them into moulds, wait for it to set before presenting the complex metal shape as a gift or using it to barter with, human beings had only ever forged metals. In fact, there’s roughly the same amount of time between the first forged metal tools (9000 BC), the first casting (3200 BC) and Chuck Hull’s first 3D print (1983), give or take a millennia…
Traditional Casting Techniques have been in use for millennia
Traditional Casting Techniques have been in use for millennia
The effect that the Mesopotamian amphibian and the techniques developed in the region that is now (roughly) modern day Iraq has had on civilization is unparalleled in manufacturing terms. Casting is used to make everything from precious jewellery to functional parts on aircraft. But from that first fire of Chuck’s laser to cure a resin 3D printing has been heralded as a replacement for traditional methods like casting and milling. During those hype-fuelled years of 2013 and 2014 it was even said that additive manufacturing was the first truly new way of making things since that frog was cast, Henry Ford and his mass-manufacturing production line may beg to differ.
As it has come to pass additive manufacturing is nothing like a replacement for traditional manufacturing in fact, if anything, it has reignited some traditional techniques and democratized access to the ability to cast. Desktop stereolithography machinery with wax-based resins, in particular, has given lone-jewellers a leaping off platform in order to create beautiful pieces of work that once may have been out of reach. According to Frank Cooper, Senior Lecturer & Technical Manager at Jewellery Industry Innovation Centre, that additive step is far from the most important factor when it comes to jewellery manufacture.
“There isn’t a machine, 3D printer or robot that can produce a beautiful piece of finished jeweller,” says Frank “The technology simply makes life a little easier for the jeweller but it still requires those hard won and learned artisan craft skills to transform the technological output into a finished piece of contemporary jewellery”
Going it alone
Despite the fact that we can now 3D print a pattern for casting the majority of casting is still produced in specialised foundries and factories that use industrial scale processes to professionally and repeatedly make parts. There is however, one man, who is bringing the process of metalworking back to the home, or the garage at least.
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Jeshua Lacock is an engineer, designer inventor, and maker, his videos on homemade casting using 3D printed parts printed on a desktop FDM machine in PLA have gone viral. He uses the 3D prints to explore techniques like that of lost wax casting and most recently sand casting using nothing but a PLA plastic part to act as a void which the molten metal fills. The results are quite extraordinary. We spoke to Joshua about his love of mixing new and ancient ways of making.
***PLEASE NOTE JESHUA’S TECHNIQUES ARE EXTREMELY DANGEROUS, TCT DOES NOT RECOMMEND THAT YOU TRY THIS AT HOME***
Q. Casting has been around for millennia but in the past 100 or so years it seems like it has increasingly become the reserve of foundries and industrial enterprises, do you think the ability to make patterns using a cheap desktop 3D printer could bring casting back to the makers?
A. Not in masses, but to some extent I do think so. I started casting metal with my late father when I was around 12-years-old. We built a charcoal fired furnace from scratch based on a Lindsay Publications reprint of an 1880’s foundry manual. This was long before the rise of the Internet, so the information we had was rather limited.
The problem we always struggled with was that we could only make a cast of something that we had a pattern for. We didn’t have a 3D printer, CNC machine or even a lathe, so we were mostly limited to casting copies of other parts. For instance, the cast in the image (from 1989) was made using a water gun as the pattern.
Metal gun cast from a toy water pistol
Metal gun cast from a toy water pistol
That said, I don’t think casting metal is for everyone. It takes a special kind of interest, willingness and patience to learn how to set-up a foundry and to safely use it. Its far more hands on, requires a great deal more work and is much more potentially dangerous than just printing something. It always requires far more available space to dedicate than a desktop machine. In other words – it’s something you really have to want to do.
Q. How long have you had the idea of being able to cast in metals using 3D printing? Did it stem from a frustration with getting parts made yourself, like the part you made for the CNC machine?
A. It was before I ordered my first 3D printer, which was an Ultimaker kit almost exactly four years ago, it was the primary reason I ordered the kit. I had experience with the lost wax method and I thought that PLA should burn practically as clean as wax does. My first attempt nearly came out perfect with the exception of one defect that was due to ash left in the mould. On the following attempts I used compressed air and/or a vacuum to clean out the meld first. The parts had extremely tight tolerances and fit perfectly without any machining.
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The part was 3D Printed in PLA
The part was 3D Printed in PLA
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Kid's play
Printed part in a mix of 50% playground sand, 50% plaster of Paris and water.
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Fiery furnace
The set moulds in a furnace
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Rolling Rock sprues
The melds still quite hot set in dry sand with aluminium cans used as spree extensions that provide more head pressure.
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Pouring the molten metal
After melting a crucible full of aluminium (with some added copper), skimming the dross, it is time to pour.
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It fits!
“I made the plastic part perfectly fit the extrusion, then printed it again at 102%. The extra 2% is precisely how much the aluminium shrunk as it cooled.” Explained Lacock.
Q. You have had several processes with the latest being your 3D Printed Lost Shell Sand Casting Technique, can you talk us through the discovery and trial and error process you went through?
A. The number one complaint I have received with all the interest in the lost PLA process was that it looked like it was too much work and too time consuming. I have had a lot of success with the Lost Foam method, where molten metal replaces Expanded Polystyrene (EPS) foam without having to burn out the foam before hand. The method works with both sand and investment casting methods.
I knew a solid plastic print would not burn out as readily as a foam pattern, so I thought that if a mould cavity was mostly a void (creating a fill density roughly similar to foam - or ideally even less dense), and giving the metal a large enough volume to fill, it should vaporize the relatively thin shell of plastic and work about the same as the Lost Foam process.
That indeed turned out to be the case. Well mostly the case. It seems whatever plastic doesn't immediately vaporize is more buoyant so it just floats to the top. That’s good news for the process too - since a slight infill can still be used with it. Most geometry will happily print with say 10-15% infill - not nearly as many will happily print with 0% infill.
Q. You can tell from the sand-casting video you shared online that there was a genuine excitement when you first took the bearded yell part out, do you think that thrill of making is something we're beginning to see more of and do you think 3D printing has played a big role in that?
Incredibly fine details
The Bearded Yell printed in PLA with 10% infill and placed directly into green sand, with molten metal poured directly into the 3D print. This was the result without any finishing applied.
A. We were unusually excited about the success because, while our first attempt showed promise, it didn’t turn out well enough to share. That said, breaking open the mould is always one of the most exciting aspects of metal casting, and when your hard work pays off I think it can be extremely rewarding.
I do think 3D printers are encouraging more people to make things, and while it can be a great deal less involved than casting something, I still think the results can be quite rewarding. Even if you print someone else’s design - I think people feel entitlement.
Q. Do you think we will start to see thermoplastic filaments, like we do with resin materials that can help make this process more accurate?
Not really - at least short of metal printers becoming affordable to consumers, which, I think is definitely coming in the future.
As it is now, with the Lost PLA method, I don’t think its really possible to cast more accurate parts. With the Lost Shell method, I think the accuracy is more of a function of the sand’s limitation versus the thermoplastic.
Q. What has the response been to your video, have people been in touch asking you to make specific parts?
A. People have been very receptive to the videos for the most part. I have had enough interest in the process to start a new venture that will be offering the service at Metalprinted.com
