[veteq]

In the rar attachment the thread, hope you like it..

[veteq]

sorry..cant upload page 2 and 3.....strange...
you have to go and be a member off cncecke and use the search function for:

mineralguss (is EG)

[osiervt]

Alright, Im going to give this a go. I learned, more than once, that if I go really cheap on a tool I am never happy with it and end up replacing it wasting the money on the cheap tool. The table saw was my most recent experiance with that. So now that I have commited myself to makeing a CNC router/mill I might as well make it right the first time. That being said, my company is under a paycut/freeze so I'm being some what of a cheap bastard right now.
After reading this thread I am sold on using the 635 epoxy and Zeeospheres, however I am going to try to find agregates locally to save on shipping. I know I can get pool filter sand here and I believe I can get crushed Granite on the cheap. I know many posts at the start of this massive thread said to stay away from sharp fillers to aviod the stress risers, but I believe some one had sucess with them on here so will give it a go I think.
I will get the zeeospheres and epoxy on order tomorrow (Monday) and will make a few test pieces to prove to my self I can do it. I have a good idea of my design I just have to wait for my wife to give up the desktop so I can play in Sketchup Once I have a mockup in sketchup and have made a few samples I will post back here.

[brunog]

Romanlini,
You can actually buy the machine base from Thomas Zeitz.

Best regards

Bruno

[brunog]

osiervt,
You can get all the aggregates needed from Agsco including zeospheres in USA.

Best regards

Bruno

[oxford]

Anyone know what the cost per pound is of Zeospheres?

I have had no luck with getting a response from two companies I requested info from.

[osiervt]

osiervt,
You can get all the aggregates needed from Agsco including zeospheres in USA.

Best regards

Bruno

I copied all the supplier information into a word doc as I went through. Agsco had two locations, one in NJ one IL. Being in TX I would assume shipping on hundreds of pounds of rock would kill me... BUT, I guess you know what they say about assumptions. I will call them and get a qoute tomorrow.

Oxford - A previous post said G-800 Zeeospheres go for $ 1.44/lb for a 25-lb. plastic pail. G-200 can be expected to be twice as much. I have not called yet, and I dont know how old the post I wrote that down from was. I will be calling around tomorrow I will let you know what I find.

I'm going to log my build over here http://www.cnczone.com/forums/showth...603#post803603 How ever any samples and tests I do I will cross post here to add to this thread while trying to keep it clean of my actual build.

[RomanLini]

Thanks you Veteg and Brunog for the info on that very nice machine made by Thomas Zietz.

His webpage uses frames and won't allow direct links to the page with the machine, but the machine is called FS2MG and there is a photo of his bolt together mold, interesting to see that the entire machine base looks to be molded in one pour;



To get to the photos of the FS2MG on his web page you navigate;
(top menu) Maschinen -> (then left column) Neu im programm

There are a couple more photos there of inside his mold which are pretty interesting.

[veteq]

Its a nice machine... and the complete base is only 2300 euro`s or something.
The mould you see has vibration motors, it is cast in one pour.
Only there are seperating plates between the base and top, so it is one big mould with 2 compartments. You cann see the vertical plates in the jpeg.

On the cncecke forum there are a lot discusions about there proces, from the first prototype till this one.

[ckelloug]

Hi osievrt,

Welcome aboard. Zeeospheres can be obtained from the Cary Company in Chicago and Ribelin in Texas among other places. See www.ribelin.com

Ribelin Zeeosphere pricing just received from my rep there is:

G800- 50# bags
1 bag- $5.95#
5 bags- $1.69#
10 bags- $1.08#

G200- 50# bags
1 bag- $6.10#
5 bags- $1.88#
10 bags- $1.30#

FOB shipping warehouse.

There is nothing magical about the Agsco aggregates. This thread has featured them because Agsco publishes their size distributions online with no hassle and they ship anywhere in the US which allows anyone to duplicate exactly what has been done on this thread if they wish. The exact form of the optimal size distribution is a function of the size distributions of your aggregates so it's easier to discuss if we talk about the same aggregates.

If you have size distributions for what you want to use, I'd be happy to run them through the packing model I've developed over the last few years from de Larrard's book. If you can make E/G samples 7&1/2 x 1/2 x3/8 inch or in a sheet I can cut to those dimensions, I would be glad to run them on my materials test machine for you when I get back free of charge. I offer this to anyone on the thread that wants to check the specs of their material.

If you have engineering calculations of the stresses in your part, you can determine the strength and modulus required to meet them. If you don't, it's probably not important to go to the nth degree in optimizing your E/G material. You can count on 2,000,000 psi for flexural modulus (similar to yellow pine) and 4000 psi for flexural strength for a pretty vanilla mixture. Even equal parts by solids volume (since the densities are different) will get you 3,700,000 psi modulus although the mixture will be more prone to segregation under vibration than one on the optimal distribution.

All of theory posted here is mainly to get the modulus up to that of commercial equivalents at 5,500,000 psi. You have to pick your aggregates carefully to go from 25% epoxy by volume to about 8-11% to do it.

My current reference design from the model's output (by solid volume) is:

0.312 Agsco #6 Al2O3
0.206 Agsco #4 Quartz
0.101 Agsco #2 Quartz
0.183, Agsco #2-0 Quartz
0.111, G800 Zeeospheres
0.087, G200 Zeeospheres

Theoretical Packing Density=0.897
Theoretical Modulus ~4,200,000psi.

I don't have measured values for the properties yet as I haven't had a chance to make it, but I have pretty good confidence in the packing model and absolute confidence in the packing density to modulus calculation from the Hashin-Shtrikman equation.

I wish you the best of luck and success in your endeavor. A lot of us on this thread have invested a lot of time and effort in getting where we are now and I think I can speak for most of the regulars here saying that we would be glad to help if you have questions. Most importantly, enjoy what you're doing on this build and don't forget to wear gloves and a respirator when handling that quantity of epoxy.

Regards All,

Cameron

[osiervt]

Cameron,

Thank you for that run down I will contact Ribelin tomorrow and get the Zeeospheres on the way that was one item I did not get around to today. I do want to play abit before I pour my build. I have fun learning stuff like this and experimenting. I may take you up on your offers here once I get a hang of it.

For those interested I contacted Agsco today and got the priceing on the quartz today and got the following:

PRODUCT PRICE PACKAGE QUANTITY

Aluminum oxide, brown, #6 $1.342/lb. 25-lb. box 25 lbs.
Quartz, #4 $0.50/lb. 25-lb. box 25 lbs.
Quartz, #2 $0.50/lb. 25-lb. box 25 lbs.
Quartz, #2/0 $0.61/lb. 25-lb. box 25 lbs.


AGSCO’s terms:

Payment: Cash, Credit Card or Net 30 days (with approved credit)
Freight: F.O.B., Wheeling, Illinois 60090
Pallets: $12.00 each

Shipping not to bad at all.

[ckelloug]

Howdy,

In examining osiervt's original design, I looked up the properties of MDF. I used the Caberwood datasheet from Norbord in Canada since they were the first manufacturer whose data I found.
See http://www.norbord.com/documents/Caberwood_MDF_08.pdf

The result was:

MDF Modulus=580,000 psi
MDF Strength=6500 psi

Compared to:
Unoptimized E/G mixture Modulus=2,000,000 psi
Unoptimized E/G mixture Strength=2000 psi

While an unoptimized E/G has less strength than MDF, it is almost four times as stiff as MDF and like MDF it is excellent at vibration damping. An optimized E/G with the right additives has the potential to be almost 10 times as stiff as MDF and of similar or slightly lesser strength. So, even a bad E/G is a step up from MDF for machine parts which is something that never occurred to me. Perhaps I shall have to stop worrying about optimal

Regards all,
Cameron

[brunog]

... but the machine is called FS2MG and there is a photo of his bolt together mold, interesting to see that the entire machine base looks to be molded in one pour...

Romanlini,
I allways like to see these photos,that's the avenue I want to go!

Thomasz has done a great job on the FS2MG, the design of the mold permitting to cast both machine base parts together insures proper part alignment pour after pour. It is a perfect example of integration of design with manufacturing constraints or as often call it "breaking your head to make things simple".

A good example to follow

Best regards to all

Bruno

[nebbiasound]

Hello, I'm new to this tread and I think very interesting, I make a small contribution if it helps.
I have found this document on the website of this Italian company, I think that is useful for design of a vibrating table.
http://www.italvibras.it/user/upload..._scelta_EN.pdf
Dario

[RomanLini]

...
My current reference design from the model's output (by solid volume) is:

0.312 Agsco #6 Al2O3
0.206 Agsco #4 Quartz
0.101 Agsco #2 Quartz
0.183, Agsco #2-0 Quartz
0.111, G800 Zeeospheres
0.087, G200 Zeeospheres

Theoretical Packing Density=0.897
Theoretical Modulus ~4,200,000psi.
...

If I was actually making an EG frame CNC machine I would consider a different approach, from the view of a design engineer rather than a materials engineer.

If you could make the EG;
1. lighter
2. easier to work with (less fussy)

you could simply use larger structural beams to solve for greater rigidity through overall design instead of relying totally on material properties which is harder to achieve and more expensive.

As a starting point, why not try a 4 part composite;
1. high strength epoxy
2. lightening agent; glass aerated microspheres, or maybe perlite, or aerated ceramic etc
3. strengh agent; maybe chopped fibreglass strands
4. rigidity agent; probably larger sized stone, maybe a lightweight but relatively strong volcanic stone, compression interlocked (not vibrated) as a large particle matrix with the other smaller agents filling the voids.

It's a deliberately lower-performance material than a high refined EG mix but the light weight and ease of use allow big payoffs in rigidity and strength through the use of larger total structural size for a similar (or lower) weight machine.

[brunog]

If I was actually making an EG frame CNC machine I would consider a different approach, from the view of a design engineer rather than a materials engineer.

If you could make the EG;
1. lighter
2. easier to work with (less fussy)

you could simply use larger structural beams to solve for greater rigidity through overall design instead of relying totally on material properties which is harder to achieve and more expensive.

As a starting point, why not try a 4 part composite;
1. high strength epoxy
2. lightening agent; glass aerated microspheres, or maybe perlite, or aerated ceramic etc
3. strengh agent; maybe chopped fibreglass strands
4. rigidity agent; probably larger sized stone, maybe a lightweight but relatively strong volcanic stone, compression interlocked (not vibrated) as a large particle matrix with the other smaller agents filling the voids.

It's a deliberately lower-performance material than a high refined EG mix but the light weight and ease of use allow big payoffs in rigidity and strength through the use of larger total structural size for a similar (or lower) weight machine.

Romanlini,
I do not consider making EG very fussy. There are different ways of making EG, in the german forum for instance, members have used of the shelf Epoxy without degassing agents or any chemical additives and a few sizes of rocks and used Fuller's formula to get a decent (not necessarily optimum) and usable product. It all depends on what purpose you want to use EG: as a filler in weldments or in existing cast iron machine bases or to produce a complete machine base the constraints are different, the processes and the physical characteristics of EG will be different in all three cases.
It is a known fact that the strength of Eg is a strong as the weakest component you put in it. If you make a weak EG you must reinforce it with more steel or more structural components and that just might be more complicated as an overall project.
EG is only part of the solution, all the support plates embeded in the EG also play a certain roll that will affect the structural rigidity of the machine.
As for what concerns weight, EG has a density very close to aluminium. There is no reason why voids can be carefully placed in the design of a machine base to make it lighter, we even mentionned adding pieces of styrofoam to lighten the overall weight of EG bases. However no one(of us DIYers) has gone so far because of the added difficulties of mold making.

I totally disagree that EG should be taken on a design engineering only bases nor a materials engineering bases only. I believe that each case must be taken individually, I don't believe there is one way only of producing EG machine bases because all of us wish to build machines of different purposes. Every case must be looked at in a global (design, materials, process) way which also brings us to the other different ressources that each of us have. I believe that a DIYer that has only a few hand tools can make a decent EG machine base with a decent design and proper planning without too much fuss
There are many participants in this thread and we do not have the same goals, we do not all necesarily make an optimimum EG, however whenever the the information will be posted on this thread, I will certainly take a look at it and decide if it's the way I want to go or not.
The only thing I regret about this thread is that none of us seem to have the time to truly experiment with EG in the way that other existing forums around the world have with, in some cases, limited ressources. But eventually we will get there too.

Best regards all

Bruno

[veteq]

Bruno, you have hit the nail right on there...!!!

If we want to make a FULL EG machine, there are 2 ways:
Use the "Ultra Optimum mix" that is developed here, this is the best there is and needs hours off reading/studying and a lot experimenting (offcourse you cann wait till all of this is done and open source..).

Or for a working solution, use at least the Fuller curve with right choosen of the shelf epoxy (like the nice German machines uses)

BUT THE MOST IMPORTANT THING IS:

YOU ALWAYS NEED A VIBRATION TABLE, WITH VERTICAL AMPLITUDE OFF 0,25mm
AND 2 to 4 G ACCELERATION.

This is the bottleneck for DIY, because you need to buy a table with 2 motors, 1 drive and good isolation rubbers (at least 1000 dollar total)

[rowbare]

RomanLini,

I think that the mix Cameron mentioned, at close to 80% of the the strength and modulus of the commercial mixes, is already quite workable for building a machine. The specified materials aren't exotic and it should be possible to source them pretty much anywhere. It also seeks to minimise the amount of epoxy needed.

By increasing the total volume needed, your proposal would increase the amount of epoxy required which would increase cost. One might argue that what you are proposing is essentially where we are compared to the commercial mixes.

bob

[RomanLini]

Bruno- I do think a "proper" EG mix is fussy. Needing to stock many different grades of materials and use in exact proportions, including specific degassing or vibrating processes are what I would call fussy.

Rowbare- I wasn't trying to trivialise the amount of great work people have put into developing the material and its mix/process. But how many of us NEED the "real deal" in EG? Maybe a beam with 1/2 the flexural modulus but double the beam thickness will be a better result on our homemade machine. It's just as easy to cast something thicker (actually easier in some ways) provided weight is managed, hence the "light weight EG" focus.

I like the idea of a larger thicker machine with a lighter weight material with "voids" whether those voids come from styrofoam beads or perlite or glass microspheres or rice crispies. Rigidity should be higher from a voided matrix then the same weight of material in a solid block and that's the point I was trying to make that it might be worthwhile exploring ideas in machine construction and the EG optimised for that exact design.

I've worked with cold cast plastics on and off for a lot of years, much of it experimental, and one thing I know from my small amount of experience is that a good design in terms of shape and structure always beats a slightly better material. There are people making good functioning machines from bits of glued-together MDF, and my point was that a lightweight EG machine of a properly synergised design could be extremely effective without being limited to a traditional EG mix and heavy vibrating process (which is a definite stumbling block for many DIY builds - as Veteg points out).

[veteq]

Romani, of course all views on the proces are appriciated, no way we cant discuss everything overhere.

Another problem that occurs is that when the material isn`t vibrated enough, is the brittle structure. Strenght or stiffnes aint the 2 only parameters...

A brittle stucture makes it possible to a point that the inserts will breakout when torque is applied on the screws for the rails etc. or dig loads by milling or acceleration.
Degassing brings nothing, vibration is really a must.

Offcourse it al depends on the machine that is build, there are nice mdf machines too, but none will mill steal or aluminum properly.