Printable View
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?
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.
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?
try Google search."epoxy granite"
Larry
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 :)
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
Yes please continue- that's a very good info..
I'm interested in all kinds of solutions.
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
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
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 :(
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.
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 :)
What about polymers is so benificial over portland as a bonding agent?
I read a couple of technical papers and it seems one disadvantage of regular portland cement is that it uses the water in the mix as the curing agent so voids are left within the cured mass. In addition portland concrete shrinks during curing and may continue to shrink for a long time such as many months.Quote:
Originally Posted by pminmo
While I'm still building m/c no.1, I'm thinking about m/c no.2 and no.3.
No.3 will have a 8ft x 4ft capability, so I'm thinking of making the frame from bricks bonded together with epoxy(possibly epoxy/sand). On top would be pre-cast concrete slabs, with a surface of epoxy to form the top reference plane. Along the sides would be posts of H cross section, with the support for the rails bonded to them.
Thoughts anyone ?
John
Found Polymer Products The Epoxy Experts Store on Ebay maybe they can help you?
Schrupphobel
Glad to see other member are researching E/G What we need to know is the mix ratio of epoxy to filler by weight.
Episs price looks realy good.Maybee you could E mail them again and ask how much epoxy is encluded,then we can calculate the mix ratio.You would'nt want to ship 400lbs of sand.Buy the epoxy and source the filler locally.By the way you are in Latvia.I use lots of birch ply from your country.
Here is some info if anyone wants to calculate volume.
1 gallon of material,1/4"thick is 6.4sqft
1gal of epoxy=10lbs.
1gallon of granite=24lbs
1cuft epoxy=7.2gal
1cuft granite=166lbs
Mark good stuff on particle sizing.Ihave only used graded fillers in the 20 to 200micron size.The idea is to use different particle sizes to fill in the spaces between the larger sizes.To get the 15% epoxy ratio I imange you would need fine gravel and graded fines to reduce the resin demand.Another trick is to add milled glass fiber 1/32"which increases the bond strength.Over 60% fill the mix is getting beyond pouring consistancy.I might add E/G for machines is subject to vibratory compaction which is "you gotta shake the hell outa it".
Pimo&geof
Why epoxy over portland as a bonding agent ? It is more expensive, must be better.Just kidding.Simply put epoxy is a superior"glue"which does not shrink and is fullly cured and stable in one week.Portland can take years to settle.
Water+steel=IO2=rust.good luck getting your portland out of your mill upright.
Greybeard
Great minds think alike.I am working on the same idea.For the table I will use W-13 wide flange I beams for the perimenter of the table.The beams are 4"x4".Filling the interior with 4" of E/G would be too expencive.I working on a sandwitch.Two E/G surfaces with a honeycomb core[niacore]Honeycombs used in boat engine rooms reduce sound transmission which also means they absorb vibration.Here is a link you will like.www.precisionepoxy.com.Your final unfilled epoxy pour will level to .005.now you have a perfect surface to mount the linear guides and reference to gantry squaring.
Hey Guys found the link which answers many questions.Try Google
machine design polymer castings.
If you guys still have intrest,
tomorrow I will post an epoxy 101
Larry
Granite chip sweeper
Larry, we may be onto something here :)
Our home made machines are growing in size, it takes ridiculous amount of time to weld these silly structures...
The alternative should be:
1. pourable, non toxic
2. low cost
3. zero shrinkage
4. self leveling
5. low cost... :)
The idea is to use concrete-like solution for frames, tables, etc.
How thick can we go with this "polymer-concrete" type of products?
Do we need reinforcements?
I'd like to be able to "pour" my frame- let's say 2"x4" slabs of zero shrinkage concrete-type-of-stuff. I would just use regular Home Depot cement but that stuff shrinks..
I think the self leveling feature is also important- imagine router tables with 8' - 16' of work area... Such a pain to level those linear rails!
My solution- just pour a 4" x 4" slabs and fasten the rails.
Yes, some of these compounds have incredible properties (vs cast iron) but we're trying to solve some very "basic" problems here. :)
For the "larger" size tables, would there be a good case forbuilding it straight onto the floor ?
You may well need a fence around it to keep the kids and the pets from investigating this noisy "animal" tearing up and down, but if you've already got a concrete floor flex in the x axis shouldn't be a problem.
You could even park the car over it ?
John
Folks,
The former Light Machines Corp. (Manchester, NH, USA), now owned by Intelitek, has been using Polymer Concrete for the frames of their top-line ProLight PLM and Benchman milling machines for nearly 20 years now. At one time (in the mid 1990's the bases were being made by ITW Philadelphia Castings. In fact there were pictures of the PLM molds and castings in the ITW catalog. I'm not sure if ITW is still making the bases for Intelitek, and I suspect possibly not, as I have noticed some minor changes in the newer PLM castings, and an absence of the PLM pictures on the current ITW website (although this may be for "trade-secrecy" reasons).
At one time I had seen an intentionally fractured sample bar (2"x2"-ish tensile or flexure test?) of the "zanite" type material used in the PLM bases. As I recall, some of the quartz or granite aggregate was similar in size and shape to "fish tank gravel" like BB-size (.18-.25" / 5-6mm). Anyhow - when professionally engineered/applied, polymer concrete can be an outstanding material. And with a bit of research and experimentation, I'll bet that us DIY folks could yield very good results. Good Luck! :)