Jeshua Lacock Presents Lost Shell Sand Casting for PLA 3D Printed Models

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Originally Posted by 3DTOPO

Or - you can buy one brand new for around $1k. Sealed in an enclosure and working with instructions.

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I have no idea where they are getting that 15kw rating from a device which runs on 110v single phase. That's simply not possible with any safe currents. You would need 140-150 amps to do so at that voltage.

http://www.mtixtl.com/15KWDualStatio...Q-SP-15AB.aspx


This one pulls 34a from the wall at 240v. That's 8kw, and they are calling it a 15kw unit also. Certainly a LOT more power than those 110v amazon units for around $1k are utilizing. Those ones don't even list an input current rating.

They would have to be using some massive capacitance to charge/discharge 15kw through that coil long enough to actually melt something, but these units claim they can run at 100% constantly... which means they aren't charging anything.

I was referring to building a *proper* 15kw furnace instead of one that is just "kind of" 15kw. The math just doesn't add up. If you have some insight as to how those things are magically taking at most 3500 watts of 110vac (you can run up to 30a on 110v if the wiring and outlets support it) and turning it into 15,000w (at any voltage) please fill me in. I am honestly curious.

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Originally Posted by awerby

What sorts of things are you making with that router? What materials does it cut?

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I mostly use it for carving out EPS foam and wood for patterns for metal casting.

It will also machine aluminum if I am not in too much of a hurry.

Let me know if you need anything big carved! ;)

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Originally Posted by Ama-fessional Molder

I have no idea where they are getting that 15kw rating from a device which runs on 110v single phase. That's simply not possible with any safe currents. You would need 140-150 amps to do so at that voltage.

http://www.mtixtl.com/15KWDualStatio...Q-SP-15AB.aspx


This one pulls 34a from the wall at 240v. That's 8kw, and they are calling it a 15kw unit also. Certainly a LOT more power than those 110v amazon units for around $1k are utilizing. Those ones don't even list an input current rating.

They would have to be using some massive capacitance to charge/discharge 15kw through that coil long enough to actually melt something, but these units claim they can run at 100% constantly... which means they aren't charging anything.

I was referring to building a *proper* 15kw furnace instead of one that is just "kind of" 15kw. The math just doesn't add up. If you have some insight as to how those things are magically taking at most 3500 watts of 110vac (you can run up to 30a on 110v if the wiring and outlets support it) and turning it into 15,000w (at any voltage) please fill me in. I am honestly curious.

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I believe they call it 15KW because that is how much power is in the work coil at resonance.

That said, mine will even pull 45 amps running at 240V - that is over 10KW.

I have no idea about the 110vac one you are talking about.

I am actually going to buy a 65KW unit. Well its 65KW on 3-phase and 48KW on 2-phase. I currently only have 2-phase here. That one will require a 125-amp breaker on 240v. For the money, it just can't be beat trying to build one IMHO.

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Originally Posted by 3DTOPO

I mostly use it for carving out EPS foam and wood for patterns for metal casting.

It will also machine aluminum if I am not in too much of a hurry.

Let me know if you need anything big carved! ;)

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Thanks, but I've already built a router a lot like yours, from automation actuators. I can cut wood with it, but I don't think it's rigid enough for aluminum. I use mills for that.

Have you got a link to that 65KW induction melter? If I did want to make an aluminum piece that big, it would make sense to carve it in foam and cast it, rather than attack a huge piece of billet.

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Originally Posted by 3DTOPO

I believe they call it 15KW because that is how much power is in the work coil at resonance.

That said, mine will even pull 45 amps running at 240V - that is over 10KW.

I have no idea about the 110vac one you are talking about.

I am actually going to buy a 65KW unit. Well its 65KW on 3-phase and 48KW on 2-phase. I currently only have 2-phase here. That one will require a 125-amp breaker on 240v. For the money, it just can't be beat trying to build one IMHO.

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Now that's some serious hardware.

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Originally Posted by awerby

Thanks, but I've already built a router a lot like yours, from automation actuators. I can cut wood with it, but I don't think it's rigid enough for aluminum. I use mills for that.
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Quite true. Casting large items still involves its own work as well though - more hands on than running a robot unless you are the big foundries that do use plenty of automation.

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Originally Posted by awerby

Have you got a link to that 65KW induction melter? If I did want to make an aluminum piece that big, it would make sense to carve it in foam and cast it, rather than attack a huge piece of billet.

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Below is a link to the company I have been dealing with through Alibaba.

I don't own a machine from them yet, so I don't have any experience with their hardware, but they have been very professional and helpful with all my questions. Their 65kw model is WZP-65 (they have other models the number is KW). The 25kw and up need 3-phase as standard.

https://yongdagp.en.alibaba.com/prod...836.186.ngNXj2

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Originally Posted by 3DTOPO

Quite true. Casting large items still involves its own work as well though - more hands on than running a robot unless you are the big foundries that do use plenty of automation.

[Yes, there's definitely a bit of work involved, at least until you've got the robots trained to do it.]



Below is a link to the company I have been dealing with through Alibaba.

I don't own a machine from them yet, so I don't have any experience with their hardware, but they have been very professional and helpful with all my questions. Their 65kw model is WZP-65 (they have other models the number is KW). The 25kw and up need 3-phase as standard.

https://yongdagp.en.alibaba.com/prod...836.186.ngNXj2

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[Thanks for that, and please let us know how it works out for you. The information on that site is rather strange, though. Since aluminum has a Specific Gravity of 2.8 and steel has a SG of 7.8 I don't see how a furnace that holds 10 kg of steel at max can also hold 10 kg of aluminum. Maybe that "hotrolled cannabis cobalt" is having an effect...]

Andrew Werby
Juxtamorph.com

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Originally Posted by awerby

[Thanks for that, and please let us know how it works out for you. The information on that site is rather strange, though. Since aluminum has a Specific Gravity of 2.8 and steel has a SG of 7.8 I don't see how a furnace that holds 10 kg of steel at max can also hold 10 kg of aluminum. Maybe that "hotrolled cannabis cobalt" is having an effect...]

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Induction generators will have different rated capacities based on the metal intended to be melted.

They sell the generator - its up to you to make the work coil and size the crucible, etc. - other than the one crucible and work coil it comes with which of course is a fixed size.

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Originally Posted by 3DTOPO

Induction generators will have different rated capacities based on the metal intended to be melted.

They sell the generator - its up to you to make the work coil and size the crucible, etc. - other than the one crucible and work coil it comes with which of course is a fixed size.

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So it's not about the size, but the energy required to melt that amount of metal? It seems odd, then, that the same rig that will melt 30 kg of copper will only melt 10 kg of aluminum, which is a lot easier to melt. Or am I missing something?

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Originally Posted by awerby

So it's not about the size, but the energy required to melt that amount of metal?

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Correct.

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Originally Posted by awerby

It seems odd, then, that the same rig that will melt 30 kg of copper will only melt 10 kg of aluminum, which is a lot easier to melt. Or am I missing something?

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It is because while steel melts at much higher temperatures; aluminum conducts electricity much better than steel. When you heat metal with induction, you can essentially think of the work piece as being shorted out to your main. So the additional resistivity of steel allows more heat for the same amount of energy. Ferrous materials have an additional advantage too, in that they are heated by magnet eddy forces up to the currie temperature.

So while it seems counterintuitive, induction generators actually heat ferrous materials easier.

That said, one can use a conducive crucible (eg high purity graphite) and that is heated directly by the EM field and can be used to heat things that are both non-conductive and non-ferrous (eg you could melt glass). But in an ideal induction furnace, you want the metal to adsorb the energy directly; not the crucible.

The more I learned about induction; the more surprises it has reveled!

;)