How to design a casting machine?

I was wondering, what are the factors to consider or how to find the required technical specifications for the new machine?

For example, if we consider a design of horizontal centrifugal casting machine with orbitary dimensions, Let suppose I do not know the dimensions of the machine. How do I calculate

1. centrifugal force required?
2. Torque of the Motor?
3. Power required to rotate the rotating tube?

To calculate the Centrifugal force, $F_c=mv^2 / r$ or $F_c=M\omega^2r$. where, angular velocity, $\omega=2\pi N/60$.

Hence, in order to calculate the centrifugal force we need to have the Speed ($N$) of the rotating tube. But, how do we know that whether the assumed Speed is enough for the casting process? Using this $F_c$, torque and power can be calculated, $T=F_c*r$ and $P=2\pi NT/60$.

Assuming $N=200\text{ rpm}$, I have carried out some calculations which are as follows, $\omega=2\pi N/60=20.94\text{ rad/s} = 3.33\text{ rps}$.

Let, part to be cast is Aluminium and has $\phi_{out}=20\text{ cm}$, $\phi_{in}=10\text{ cm}$ and $L=50\text{ cm}$. Then, $V=3750\pi\text{ cm}^3$ and $m=31.83\text{ kg}$. Hence, from $F_c=M\omega^2r=173.13\text{ N}$ (considering inner radius of the cast part as the Minimum distance need to achieve which 5 cm).

Dimensions of rotating tube is assumed as $\phi_{out}=30\text{ cm}$ and $\phi_{in}=20\text{ cm}$ and $L=50\text{ cm}$. Torque required $T=173.13\cdot0.15=25.96\text{ Nm}$ (considering radius as the outer radius of the rotating tube that is 15 cm).

Power, $P=543.70\text{ W}$.

Are the steps I have performed are correct? If so, How do I know that assumed $N$ is the suitable value for the present machine or what is the usual Speed of the rotating tube in horizontal casting machine considered?

If not, how do I approach when there are several unknowns or dependencies present in the system, for example centrifugal force depends on angular velocity which in turn depended on speed of the rotating tube.

• A diagram would help? With which axis are you rotating the tube...? – Solar Mike Mar 29 '18 at 9:02
• The axis of the rotating tube is horizontal. I am not able to add diagrams because it is not showing any such options to do but it resembles the diagram of horitzontal centrifugal casting machine. @Solar Mike – Ranjith Mar 29 '18 at 10:53

2 Answers

Don't make a centrifugal machine for producing parts of your dimensions ; Length 50 cm : Use static casting or possibly extrusion for aluminum. Centrifugal casting is used to produce about 10 m lengths of iron, steel and stainless steel ( and concrete) , I never saw one for aluminum. Steel oil well casing couplings are short but they cast as a long tube which is cut to short lengths.

• I have used Aluminium as the reference for the calculations of mass. But, I really want to know the calculation behind the technical specifications. Here part to be casted is nothing but the output of the centrifugal casting machine which has just for reference. Since power requirements are done based on the Output. – Ranjith Mar 29 '18 at 11:51

Hello we are currently in the process of working on a True Horizontal Centrifugal casting machine at work as well.

So I am no expert but from my understanding the required value range of N can be calculated via the formula driven by optimal G-Factor values.

• Please provide the information in your post instead of an image. If the image goes away, then the information is lost. Also, it looks like this is from a google book search. Please provide the book where it is from. – hazzey Jan 7 '19 at 19:12