[Hydropower]

What he said! ^

Skickat från min GT-I9300 via Tapatalk

[rowbare]

Congratulations on getting the mill done. A very nice job indeed!\

bob

[turpija]

If i would make it again, what would i reconsider is how to more efficiently enclose bottom part of machine where the ballscrew and linear guides are, on a image you can see an improvised plastic cover that certainly help but still some chips find it's way around
and offcourse, some sort of enclosure, but that's not machine upgrade, it's environment upgrade

and if you really want an accurate machine, go for better ballscrews, this works fairly well but as chinese cheap version, have a error in "step" accuracy, for 200mm movement i've measured almost 0,1mm difference ... nothing software can compensate but hey ... for the price i'm satisfied
and definitely, if you want to have really accurate setup of axis (to set them perpendicular to one another), there should be a way to finely tilt Z axis "forward" or "backward" (relative to looking in front of machine), as this is simply defined at how accurate you can machine bottom stands in according to top side where linear guides for Xaxis are mounted ... unless you want to add spacers between, which could be really difficult as it's not much room for hands and tools




and here's a video of machining mild steel, just testing it out, and some new endmill (4mm, 4 flute)

4mm DOC
0,2mm stepover
8mm/s feedrate
6600 rpm

pretty light cut and according to sound, there is plenty of room to go harder, but i'm happy with this

https://youtu.be/5T-Mj-l1HY4

[jefersonbmx]

Nice cut quality in stell.

It's ok to put a low rpm in this spindle?

Have you mensure the backlash of chinese ball screw? I buy screws from TBI Motion and Hiwin, in a local reseller here in Brazil. They can change the balls to remove the backlash. I like to use the 1610 from TBI to get a high feedrate without a high rpm motor steppers. I'm saving money to a new machine for me. Now, I only have a poor mini router that I use to mill aluminum parts to the routers that I sell. I need a best and fast machine to produce this parts.

Here you can se the parts that I mill to machines that I sell:

https://lh3.googleusercontent.com/-N...35584761_n.jpg
https://lh3.googleusercontent.com/-E...82181186_n.jpg

In proportion to US money, and how much cost cnc components in US, I will have about 8 to 9 thousand to invest in a new machine. I'm think in build a machine between a mini mill with EG base, and a Datron M8 with a smaller worksize and without the fancy stuff. I will not get the feedrate of a Datron with this budget, but maybe can achive 8000mm/min with easy servo motor from Leadshine. Have you guys see any machine with a moveable gantry in EG? The base and table of this Router that I have in mind will be with EG, but the gantry I don't know if will be stell beam or EG too.

[CaptainVee]

Dabit has built a machine with EG gantry, tried to find it here but could not.

Here is his long thread in Dutch:
? Bekijk onderwerp - Bouw epoxybeton/staal freesmachine

He used old servo motors and gets the kind of speeds you mention.

[RCaffin]

have a error in "step" accuracy, for 200mm movement i've measured almost 0,1mm difference ... nothing software can compensate but hey ... for the price i'm satisfied

Um ... I believe Mach3 can read in a compensation table for the errors in a ball screw pitch (or was that the ESS?). I have not tested that.

there should be a way to finely tilt Z axis "forward" or "backward" (relative to looking in front of machine),

There is a far easier way to correct for Z axis tilt on your machine. Basically, shim the upper or lower Y axis support rail, or even the Y-axis bearings off the big spindle plate. Much less mass to move around that way :-)
Yes, I have done this sort of thing myself to level up the mill table along the X axis. I first measured the error across the mill table with a probe (ie along the X axis), then figured what shim I would need - which was very close to being two layers of aluminium cooking foil. That foil went between the bearing carriages and the mill table. Worked very well too.
They talk about the benfits of 'big iron'. I think maybe that should be 'big iron and EG'?

Cheers
Roger

[Zekyx]

Very nice build, congratulations! Very inspiring for me to start "solidworking" Can you tell which epoxy you used, since we are from same country, to give me more insight in costs involved. Novapox, WEST, R&G or something else? Also, if you can give more details where you obtained stones, gravel.

Lastly, is it really 12% resin by volume, not weight? If that is true than this is relatively cheap.

Thanks

[turpija]

It's roughly 12% by weight, about 10kg of epoxy was used (or less, can't remember)

kompozit-kemija.hr elan-tech epoxy EC157 + W152XLR hardener, about 100kn per kg of total mix

gravel and sand is from pet-shop, it's clean, sorted by size and relatively cheap

[Zekyx]

Excellent, thank you for your quick reply! Resin price seems quite good (for international readers roughly 100 kn = 15 usd = 13 €)


PS
Why PVA is not often mentioned for mold release? It creates physical barrier with surface and it is much, much more reliable than waxing.

[jefersonbmx]

Why PVA is not often mentioned for mold release? It creates physical barrier with surface and it is much, much more reliable than waxing.

PVA is paper and wood glue?

[Zekyx]

Hi
No, it is standard mold release used in composite manufacturing, polyvinyl alcohol.

[RotarySMP]

You mean PVOH. PVA is polyvinyl acetate. Wood glue.

[rocketflier]

You mean PVOH. PVA is polyvinyl acetate. Wood glue.

No, it's called PVA, try searching on PVOH release.

[RotarySMP]

Fantastic machine, and very quick build. I would love to see more Videos of it at work.

[Zekyx]

Can you give some review of your SMS-303 controler, there is hardly any info from users:
3-axis stepper motor driver and step motor CNC controller.

Price seems good. Are you satisfied, what could be better, motor performance etc?

[eloid]

pouring, or actually, shoveling the epoxy mix


here you see the tools i've use to compact it between all those gaps ...


...done


here you can roughly see the size of stones, scale is in mm


and fast forward it to interesting part ...


you can see some mdf pieces stuck to aluminum, cause i didn't properly closed all the holes, and epoxy found it's way out ...
but still, it turned out pretty great

did a quick test and weight it, it turns out this bad boy is solid 42kg ... will make a stable base for sure

what epoxy system did you use what was the mix ratio of aggregates to resin

[pup]

Turija, so what' new?
Just few quetions: What is the length and width of the basement? Have you performed any FEA prior to casting EG? How do you plan to align the bed, the sides and the gantry? (I mean how do achieve the right angles between them?)