Verry nice Build Verry cool
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Verry nice Build Verry cool
Gesendet von iPad mit Tapatalk
Progress.. Frame is filled with epoxi concrette.. Next step is filling bridge, and then also filling back side of table with approx 20mm of epoxi, to prevent vibration of table.
My father was very kind to help me with filling frame.. For anybody else planning to do the same thing - leave yourself big holes, as this stuff is very dense and hard to pour.
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Progress.. Bottom surface of table is now finished - covered with epoxi granite. I made first cuts today with filled base and covered table, and surface finish looks great. It looks almost like polished. Next step is filling bridge with epoxi.
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Cable carrier holder.. Milled on my machine yesterday.. I am happy with finish I get on this machine.
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Beautiful work. Clean job.
Thank you
Pneumatic cilinder holder is now in place..
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What is that cylinder for?
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It will serve as counter balance for weight on Z axis. There will be additionall servo motor and additional NT30 milling head mounted on Z axis, which will drastically increase driven weight on Z axis to more than 35KG. Such weight would cause harm to Z ballscrew in no time. This is why most of VMCs use pneumatic or hydraulic counter balance cilinder on Z axis.
Nothing more to say but WOW rigid from the looks of it, professionally built, add a watercooled brushless spindle motor then I think you can operate it 24/7, 365 days a year, a workforce of 3 shifts hehe, great build...
Thanks. This 3.2KW ac motor can also work as long as you want, it doesnt get hot. I choosed air cooled due to less potencional problems. For larger tools there will be servo driven NT30 milling head.
Update.. NT30 milling head is now in working state.. Milling with 50mm face mill went very good today, surface finish is also very good..
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Some of the cables are already taken care of..
I am curious, what components does your milling head consist of and where would one source these type components from in the US?
Good question. Sadly I dont have answers. This milling head was removed from very big older milling machine. It was meant to be used as some kind of backup head, for some additional operations. It was never actually used, so It has zero operating hours. It is some German made head. I dont have any data about which bearings are in it. I made gearing for max 5000 Rpm, this is what I think it should handle without any problems. But it is a drawback that it isnt ATC. I dont know for US, but If you need milling head, I would suggest you to buy Chinese BT40 ATC milling head. They can be ordered with three different types of bearings - cheapest is for 6000rpm, then you can choose bearings for 8000 and 10 000rpm. Cheapest option is as low as 650USD. Best bearings will come for arround 950USD. One of my friends ordered it, and it is really well made. It has runout of less than 0.005mm. You just install pneumatic cilinder and you have ATC solution for bargain.
Video of machining part for rotating ballnut for bigger machine:
https://www.youtube.com/watch?v=dG3jCYBq26U&t=32s
I also tried milling stainless steel 304, and it went fine. I will post video soon.
That's fantastic work! Really awesome!
What kind of acceleration settings did you use in the video?
For my own build I still haven't made a final decision between gas struts or a pneumatic cylinder. Please tell me more about your pneumatic cylinder setup. What kinds of pressures are you running in your cylinder, what is the inner diameter of the cylinder, and how big of a reservoir are you using? Have you experienced any leaking anywhere so that you would periodically need to top up the pressure? I'm thinking of using a cheap pneumatic cylinder from ebay, but I'm not sure if it will leak.
Once again, what you've done is fantastic!
Thank you.
Acceleration is 1500mm/s*s Can go almost as high as you want with those mitsu servo motors, but it hurts even watching gantry at some high acc rates
About cylinder.. I made research as well. I called company which produces gas struts, and they advised me not to chose it for my application. They said it wont handle fast travel so many times.
There are pneumatic cylinders specially for this kind of applications, but I choosed ordinary one and had no problem till now.
I was also thinking about reservoir etc.. And decided that best option is, to buy one of those cheap 100USD 25L compressors. It already has pressure valve on it, you only need air preperation unit.
There is no chance you wont have even slightes leak.. And compressor handles this great. It will power on maybe once per week, so it will last very long, and you dont have to worry about pressure in sistem.
Problem with gas struts is also that when it travels down, it will provide much higher force than on top, while air cilinder doesnt make any practical pressure change in sistem when travels down, due to very small displacement compared to air reservoir.
I needed cylinder fast, so I bought festo here in my conutry, which was a bit expensive, if I had time, Id also buy cheap Chinese one. I just ordered whole bunch of different dimensions, and price for piston diameter 40mm, travell 250mm is about 5USD.
So if those will last more than year, it is already good
Another bennefit using air cylinder is, you can adjust force with pressure regulator.
Inner piston diameter for my cilinder is 60mm. But I am using it in opposite direction - it lifts when it travels up. So you have to calculate surface of piston - piston rod. Then you can calculate pressure nedded. In my case it is 300kPa.
You can go with bigger cylinder, assemble Z axis, and unscrew ballscrew nut, and then just apply pressure so long, that it lifts Z axis. Then you lower it a bit, to have a bit of weight pushing down, to eliminate any ballscrew backlash,
Thanks for the info!
I'm thinking about using two small Inner Diameter air cylinders at a max pressure of 80 - 90 PSI. That way I would only need a very small reservoir. I was thinking about a small fire extinguisher bottle or small propane tank mounted to the back of my Z plate. Something very small. The higher the working pressure, the smaller it can be. I don't really care if the top of the stroke force is off by 25lbs from the bottom of the stroke force.
I just don't know if the cheap EBay pneumatic cylinders will leak at those pressures. They say they will take the pressure, but will they leak, I don't know.
Gas struts would be the easiest, but they all have damping . Hard to even see a damping spec on an inexpensive gas strut, they usually don't mention it.
Really awesome machine you have made!