Re: powder packing density!!!

From: Toby Gill <>
Date: Fri Feb 20 2004 - 17:21:47 EET

Dear Jean-Marc Boechat,

In response to your email.
Perfect spheres may have a maximum packing density of 0.74 in a perfect=20

However, I did mention in the original mail that these are randomly jumbled =

particles in a container. This will affect the packing density and also=20
makes the experiments more useful for correlation with manufacturing=20
technologies. The article I read mentioned a series of experiments, which=20
are published in a scientific journal which confirm this.


Toby Gill

--On 20 February 2004 16:04 +0100 Jean-Marc Bo=E9chat=20
<> wrote:

> Hello list and Toby:
> I have a problem with your statement that it packs more densely than
> perfect spheres and you said it approaches 0.74. In fact if you calculate
> the max packing density of perfect spheres, having the same diameter, it
> is 0.74. So anything under this is not really interesting to me.
> Could you elaborate on your statement?
> I think if you want to improve the packing density the easiest way is to
> use bi-modal particle distribution.
> Just my 2 cents worth! :)
> J.-M. Bo=E9chat
> Toby Gill wrote:
>> Thought this may be of interest to some,
>> It has just been published that M& M sweets pack together more densely
>> then perfect spheres when randomly jumbled in a container.
>> It was also discovered that by stretching the M&M shape (so elliptical,
>> like an almond) in computer simulations, a packing density approaching
>> the packing fraction of 0.74 was achieved.
>> This seems to me to be important to anyone involved with producing
>> components from powders, be it by conventional methods or by rapid
>> manufacturing techniques. Does anyone have any comments/thoughts on this
>> development?
>> P.S. I have just finished a PhD based on SLS and am currently looking
>> for employment. Anyone who has any vacancies arising in the near future
>> please contact me at the email address above.
>> Regards
>> Toby Gill
> --
> Jean-Marc Bo=E9chat email:
> MIM Systems Ltd
> phone:+4126 430 08 08 fax: +4126 430 08 09 Swiss Branch office
> website:
> P.O. Box
> CH- 1723 Marly 2
> Switzerland "when things go wrong, don't go with
> them!"
> Please remove the nafof in my e-mail address before use!
> Disclaimer: "I speak for myself only, it's hard enough!"
Received on Mon Feb 23 16:26:09 2004

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