Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
sn4k3
You are lucky, here is hard to find any kind of bussiness selling that parts, even rustly or junk. It's easier to find plain bars but L shapes.... But may be my fault as i live in a village and not much aware what exists on near-by cities. When i ask people they also don't know because its rare to find someone attach to this area or wordsmith. That's why i ask for online store, a click away to buy.
Tried just now, but i have grabed spindle with two hands instead of nozzle, is that ok? So i got 0.20mm difference and 0.30mm max
Do you think that amount of flexing might have been a factor in the finish of the part in the first post?It would certainly encourage me to use a high speed machining approach with light depth of cut or to add some stiffness.It would be best if you could identify which part is flexing the most and think of a way to improve the situation.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
Do you think that amount of flexing might have been a factor in the finish of the part in the first post?It would certainly encourage me to use a high speed machining approach with light depth of cut or to add some stiffness.It would be best if you could identify which part is flexing the most and think of a way to improve the situation.
The main factor is due machine not on a solid base, it still on a wheel platform and it shakes as printer move axis, need to prepare my bench to get it fixed and stable. Due it weight i can't put it on ground or else will be very hard to move again using man power.
I definitely can see what part most flex by crashing a bit against a alu stock, i seen it before when i tried to drill and machine steel but have to repeat and inspect the part that move. WIll test that latter.
Thank you for all support
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Ok i found the weak parts on the machine. I gently crash spindle into alu block.
The spindle looks like doesn't move or bent but...
The steel sheet table from machine start to bend and do a concave at it center, due no supports on center, the table is fixed only at corners with steel bars (Rectangle frame without middle support)
Also the two bottom linear guides along with granity structure also start to concave, the linears start to concave and whole granity get pull up as long spindle crash down
Bed does A)
Bottom rails and Y granaty does B)
Ref:
https://www.researchgate.net/profile...ex-surface.png
Under Machine:
https://i.imgur.com/7nxlsu8.jpg
https://i.imgur.com/bZQGRSW.jpg
Video:
https://www.youtube.com/watch?v=1JRppkMkMiI
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
I hope no damage has been done by this method of finding the flexible areas of the machine.Were you able to see if the spindle was flexing in it's clamp?It would suggest that light cuts at high speed will be a good wy to go until you determine a permanent solution.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
I hope no damage has been done by this method of finding the flexible areas of the machine.Were you able to see if the spindle was flexing in it's clamp?It would suggest that light cuts at high speed will be a good wy to go until you determine a permanent solution.
Motor stall under a high pressure threshold and prevent future damage if i keep going down, also as it flex a little there's no damage.
By my eye it seen that spindle didn't flex, as that's the smallest area on machine it's more robust than the base structure
The only way to fix is put horizontal steel bars under, supporting the bed and fixing the gap, but that seens impossible because granity pass there. Vertical bars however are possible, will not eliminate problem but will give more base, the problem is it need to be welded from bottom and the oil tank is weleded preventing the removal for manitence
Will start will light cuts at 0.4mm to see
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Or making a grid of steel under bed like that:
https://i.imgur.com/iL4kOO7.jpg
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Finally i could test the suggestions, it went fine, apart some notes...
1) DOC = 0.4mm, 1200-1400mm/min, 22000 RPM for 4mm bit and 14200RPM for 8mm bit. Ramps = 500mm/m, Plunge = 100mm/m
2) the unstable struct where machine is still a problem, but will fix soon. For now fixed with lower accelaration (200 - 300, was 800 before).
3) It took +/- 1h to finish two pieces, fully contourned from block.
4) Tried increase feedrate and it went ok
5) Used 8mm for big slot only, 4mm the rest
Result - Test 1: https://i.imgur.com/RQxKH7K.jpg
Test 2:
1) DOC = 0.5mm, 1200-1400mm/min, 19000 RPM for 6mm bit and 14200RPM for 8mm bit. Ramps = 500mm/m, Plunge = 150mm/m
2) Used 6mm instead of 4mm to decrease RPMs but it fail at 7.5mm hole, on plunge near first hole end, guess chip recut and alu weld to bit, lucky i was able to stop and pull the alu from bit, after test on countor bit still cuts ok
3) Use whole block instead of countour it, so only countour top and bottom to clean and spare time
4) Reduced machine time to 40m
Test 3:
1) Used 8mm bit for everything, except hole, 14200RPM, 1mm DOC, 1500mm/min. Ramps = 600mm/m, Plunge = 200mm/m
2) Used 7.5mm drill to peck
3) Everything went good, machine time reduced to 25m!
test 2 (top) and 3 (bottom - Wrong x offset):
https://i.imgur.com/3QP7rJl.jpg
In sum the bigger 8mm bit does the job better without overheat, plus no toolchanging, the ramp was used without finish pass, even countour was made in one pass.
My next test will increase DOC to 1.5mm but need more alu bars, waiting...
Cut: https://youtu.be/T27x0Xob-9k
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Its good to see progress being made.It may not seem like it now but you will be able to produce better parts in a sensible amount of time now you have learned more about the way to extract accuracy and performance from your machine and it will keep getting better.Sharp tools and avoiding flexing of the machine will be at the heart of the process.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
Its good to see progress being made.It may not seem like it now but you will be able to produce better parts in a sensible amount of time now you have learned more about the way to extract accuracy and performance from your machine and it will keep getting better.Sharp tools and avoiding flexing of the machine will be at the heart of the process.
I'm with these bits: https://www.aliexpress.com/item/32995535888.html
Don't like the fact they say Blue nano Coated, that says nothing about true coating for me but they work fine with this aluminium. I also wanted to mill 6061 but the price diference is big :( so i will stick with 6063 for my holders, price of one 6061 = 3 of 6063 (250x50x10mm)
About mist, apply by hand is a pain, my machine have the tubing, nozzle and motor for apply mist, but i want something more controlled, there are any system that i can connect the tube and trigger by hand? Somekind of a can where i can press something to release a amount of mist. As i have wood under i don't want to flood it with continous loop.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
sn4k3
Hello,
I'm having a little trouble setting correct settings (I'm new in this) for mill aluminium 6063-T5 on a RTM-80-2.2 (
https://www.aliexpress.com/item/32880152613.html) spindle. Calculator gives crazy feeds and i'm not sure to trust them.
The only sucessfull mill was using a 3.175mm 2 flute at 5000RPM and 150mm/m feed, then i boost to 200 and even 250mm/m without break the tool.
Now i want use a HSS 8mm 2F bit for a big pocket and i like to ask first before use it and ruin something. For example calculator gives 6310RPM at 1413.52mm/m for a DOC of 1mm and 8mm pocket.
After reading about these spindles i notice they are not good at low RPMs, some websites say 6000, people says 4000/6000/8000 and i ask the seller which told 9000 as minimum. Also i ask for power curve but none have such data... So with that high variance of RPMs min, what should i take? The seller recommendation?
Also does my previous cut at 5000RPM can wear spindle or damage it if i continue use such RPMs?
Heres a picture of my first sucessfull mill on Alu:
https://i.imgur.com/Wp02oEA.jpg
https://i.imgur.com/nrO9BuU.jpg
PS: My machine is a 9060 homemade all made of steel and linear guides
I looked through your posts, you have a water cooled spindle so the minimum speed is 6000 RPM=100Hz but for cutting aluminum you should not go below 7200 RPM=120Hz
Yes you can damage your spindle if you run it to slow, which you want to avoid doing, if you stall the spindle this will damage it also
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
mactec54
I looked through your posts, you have a water cooled spindle so the minimum speed is 6000 RPM=100Hz but for cutting aluminum you should not go below 7200 RPM=120Hz
Yes you can damage your spindle if you run it to slow, which you want to avoid doing, if you stall the spindle this will damage it also
Thank you for the info.
Seller told me the spindle is constant torque, so i can assume it start at 6000RPMs, hit the max value at 9000, keep torque up to xRPMs and then start to goes down?
7200RPMs seens ok to me as lower value, since my collet is ER20, for a 10mm bit calculator recommends about 10000 RPMs, still in a valid margin for the spindle.
What you can consider a good RPM value for 3mm bit? The recommended 24000RPMs produce heat and welds but leave a good finish while cut
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