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| NeoTech:
Well why is a good question. Mainly out of curiosity. And secondary because i exhausted ways of getting a 1-1.5t cnc machine into my shop by, just buying it. I live in sweden, the country were logistics basicly stop at the border. I can find good deals in uk, holland and germany easily. And i can have them shippe basicly to the border quite inexpensivly. (less than 2000 euro). But here we hit a snag. From the swedish border and home to me, its about an 8 hour trip. For a like say a tormach with the more commong shipping companies that would run me an additional 4000-4500 euro. And ontop of that they will want taxes for the import and such. A ok machine can be found for about 7500-10.000 euros no problem. But when adding the shipping, im in a price range where buying a new one starts to be more affordable. So i started researching alternative routes, and i knew i read the epoxy granite thread a while back, and i knew i have seen concrete machines in production facilites i have visited before. So it seemed to be a valid route of doing things. In the end i will have spent about 4500 euro on this, for that price i can even afford to make mistakes. I have a small shop with a manual Aciera F3 and a small lathe, so i will be able to produce alot of the parts myself. Only thing im a bit worried about is howto level everything properly. |
| RotarySMP:
There is Silimix 282 from Euroquarz.de or Sikadur 43 from Sika. I contacted Euroquarz. The have no distribution network, but are happy to ship. Unfortunately shipping sand is very expensive. Sikadur is sold as a system with the epoxy. It was used by Alpenheli.at for his gantry. He informed me it was about €7/kg back then when e made it. I am still trying to source a fuller curve graded mix locally. Have you talked to local companies. The highest grades of concrete used in bridges (or at least in bridge repairs) also seem to use fuller curve graded aggregate. I think the 2x theoretical improvement in rigidity gained by added all that steel would be much cheaper and more easily gained by simply increasing the profile depth of your E/G castings. One of the huge advantages of E/G is that it is a casting method which is not sensitive to changes in thickness or very thick sections (as cast iron is). Especially your base is not that thick relative to machine size. It would be very easy to add a few more cm in depth, maybe with some hotwire foam cut inserts to form ribs reducing the total E/G consumed, and thus acheive your stiffness goals. With the steel ribbed construction, you have to build the frame twice needing two very different methods to ensure alignment. Once in steel, then again the mould for the E/G. With some changes in profile depth you save a whole set of construction steps with no loss of performance. The most active forum for practical E/G builders I found is CNCECKE.de (german language). Mineralguß is the german term for E/G. Nucky seems to have built the first one, and went on to make a business of E/G gantry mills. There are lots of other practicle examples of builds on there, including some which continued to post the performance of their machines in use. |
| NeoTech:
Thanks, will see if i can find a local dealer for those aggregates or if a car trip would be needed. ;D I joined cncecke.de - but it does not work well through translate.google.com - and every other thread i clicked on didnt have any post the last 365 days. so couldnt actually find the nucky thread. And overall it seems the germans have the upperhand on us in this subject. All the really working machines on the tube is from germany as well. =) And ridigity, actually i agree with you - but... (there is a but).. Epoxy is like 30x more expensive than steel, i can have inexpensive 240mc steel cut from 2mm sheet, and welded onto bar stock with a jig alot cheaper than it would be adding more volume to the casting. That said - a ribbed construction isnt something i had considered yet. And maybe i can reduce the amount of aggregate that way - because 7 euro kg, i need about 160 litres of the stuff as is ( no idea what one litre of E/G would weigh in at ) |
| NeoTech:
Damn, i actually found Sika-43 in sweden.. *emailing companies* :clap: |
| RotarySMP:
Epoxy is more expensive than steel is not a very good argument :) Granite should be nearly free (obviously not if we have to have 25Kg bags of it shipped from Switzeland, but there must be some way of getting correctly graded aggregate locally, especially in Sweden and Austria. They countries are made of Granite aren't they? You only need 8-9% epoxy. So it's maybe 16L for your current design, or say 20L of epoxy, if you bulk up your castings a bit. If you can get the aggregate cheaply locally, those extra four liters are not going to cost more than a fraction of what the steel, plus cutting, blus assembly, plus straightening that the steel will need. Sikadur43 is 2.0 kg/l according to the datasheet. If you can still get it for €7 /kg you are looking at €2240 for the casting. Euroquarz said that shipping 50kg of Silimix 282 to Vienna would be €170, and 20L of Expoy can be had over Ebay for under €300. Mark |
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