Epoxy-Granite machine bases (was Polymer concrete frame?)

[walter]

Did anyone managed to build anything out of polymer concrete? I would be interested in your experiences and materials suitable for machine frames, tables, etc.

Here's a nice looking polymer/epoxy(?) machine table called X2 Mini Mill base

http://www.cnczone.com/modules.php?n...threadid=24879

Do machine manufacturers use reinforcements in their frames?

[Mcgyver]

its been discussed many times - search will find it, but i haven't seen a diy effort yet. I like the idea of a normalized fabrication filled with epoxy and stone as a machine superstructure... maybe one day will get to it, until then its hearsay, at least on my part. the worlds best tool manufactures do use it, hardinge for example or some of the extremely sensitive and precise optics equipment manufacturers, millionth of an inch stuff.

[walter]

Yeah, I've seen the threads...Not much in there. I think I'm gonna buy a bag and experiment a little

Do you think they use straight polymer concrete or the mix of many components, epoxy, etc?

[lgalla]

try Google search."epoxy granite"
Larry

[Episs]

I just noticed this material too and it has amaizing properties.
yesterday I spent all day searching in google info about this material and found these 2 companys which make polimer comosite castings for industrial machines

http://www.itwpolymercastings.com/
http://www.accurescasting.com/index.html

I send emails to both companys about their product prices and then will see if they will reply to induvidual (lot of companys work just with companys ignoring non company people )
I want to experiment too with this material

[lgalla]

Episs
Companys fabricating machine bases of epoxy granite are not in the business of selling the raw material.I did a lot of research on the subject and there is little to be found.Sand is basicly granite and probably a good filler.
Idon't remember exactly the figures,but epoxy granite has 10 times the damping factor of cast iron and 50 times the damping factor of steel.
THE COST??? 1gal. epoxy $80 Maybee 10 sq ft/gal/1/4 thick.Figure it out,its
gunna cost mega bucks even with sand fill at 50%.
This is just off the top of my head.If anyone wants more accurate figures I will look them up again.
Any how I figured out a slab of real granite is 1/2 the price of epoxy granite,maybe less.A 4X8'X4"epoxy granite table top could cost 5or6 grand or more.A black granite surface plate 4X8'X8"with stand is $2600 from an E-Bay store.If anyone is still interested I will try to answer any questions or re-research my findings.
Larry

[walter]

Yes please continue- that's a very good info..

I'm interested in all kinds of solutions.

[lgalla]

Walter thanks for showing some interest.Also check www.moglice.com.Interesting stuff.
Why epoxy granite?It takes 4 to 6 months to develop a machine tool of traditional cast iron.After casting,it has to age for 4 months to releive stress before being surfaced and then get heat stress relief.Cast epoxy/granite can be ready in one week with coolant lines and other inserts or ways moulded in.As I stated before Epoxy/granite is super $$$$,But a machine tool manfacturer can save tons of money from the time saving and have better properties than cast iron.As stated in geoligy reports granite was stress releived billions of years ago.
Also companys are filling weldments or machines made of steel tube to eleminate resonance.Since epoxy has 0 VOC or solvents,when filled it has ZERO shrinkage.If you poured raw epoxy on the floor it will self level to .005 or better.What a way to get an accurate table surface to measure and build your machine on.
I am in the composites business,Know little of CNC stuff,but have knowledge of fillers and micro packing.
BTW in my business polymer concrete is out of date Polyester resin mixed with rocks for garbage cans and parking lot thingies.
Never Never get the idea I'LL use polyester or fiberglass resin as a bonding agent.It just shrinks too much and is extremely brittle.
Walter thanks for expressing interest,all the research time seems worth it.
I am not discounting the hobbyist use of the materials as they cost so much,but will not recommend usage until I am sure of performance.
Wow thought this would be short as I am swamped with orders righ now And
don't have much time.I am guilty of going on and on.I have tons more info on the subject if you want to hear more.Let me know if your intrest is still there and I will try to post something {short}daily.Questions are welcomed,Hope I can answer.
Larry

[lgalla]

Hear I go again replying to my own post.I am not good at typing so lets give epoxy granite an easy name to type.Fourtwith epoxy granite shall be nameth
E/G
Larry
E/G sweeper

[Episs]

I received email form Accures castings and they have special 3 cu ft Filler kit for 360$ and 3 cu ft kit weighs approx. 435 lbs (epoxy included),
but my problem is how to cheaply shipp 435lbs to Europe contry Latvia I think shipping will cost several times more than this kit

[RotarySMP]

My local library has a german book on this construction. The jems of knowledge I took away was that you don't want just sand as a aggregate, you want a mix of aggregate sizes up to about 1/5 the thickness of the thinest feature, and that the epoxy content is quite low, far less than 50% (I think something like 15-20% from memory). At 50% you are using epoxy as the load bearing structure, which means you basically have a plastic machine frame.

The aim is that the aggreate is the load bearing structure, and the epoxy just locks the aggregate into a fixed alignment.

You do not need to pour the whole structure in one go, so for hobby work, I could imagine that a hybrid structure built up of polymer concrete features poured onto a cheap chinese granite surface plate or two would have a lot of potential.

[Episs]

How about other materials for example I just found in my local distributos homepage sutch SicaDur 42 (Rapid High Strength Pourable Epoxy Grout) www.sika.com
in datasheet USES section was:
Grouting of bearing plates, machine bases,
mechanical bridge joints, bridge bearings and rail
base plates (I like this one becose I have THK reils which need base ).

Flexural strength: 30 N/mm2 @ 20°C
Tensile strength: 20 N/mm2 @ 20°C
Modulus of 18 KN/mm2 @ 20°C
Elasticity: (static)
Density: 2.0 kg/litre

There was nothing mentioned about wibration damping characteristics .

This is wery intresting material SikaRail® KC330/340 Polyurethane Flexible Resin Based Grout

USES
SikaRail KC330/340 provides a flowing, vibration absorbing load bearing resilient grout for:
* Bedding and bonding rail base plates to:
steel bridge decks, concrete bridge and tunnel slab
tracks, concrete sleepers

ADVANTAGES
* Out performs cementitious, epoxy and polyester
grouts under dynamic loading.
* Excellent noise and vibration damping.

maby this is the right material to tray out ?
and in datasheet is also sayed that Additional detailed information such as load/deflection graphs, spring coefficients, resonance frequency, damping factor etc are available on request.

I start to think Do i realy need this 10x vibration damping (over cast Iron)?
I think that the main benefit of these special compozit concretes are that i can make any solid shape myself for mutch lower price