Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
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
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Have you tried finding data for high speed machining?You have a router spindle and it won't be too happy at low rpm,not to mention developing only a fraction of it's power.You may have to adjust your cutting preferences for a lighter cut depth and more passes.If machining metal is going to be your main activity, a mill might be a better choice.One other factor might be the height of your gantry beam-simple leverage means that a high gantry and it's attendant big Z axis travel will permit more chatter than a lower setup.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
Have you tried finding data for high speed machining?You have a router spindle and it won't be too happy at low rpm,not to mention developing only a fraction of it's power.You may have to adjust your cutting preferences for a lighter cut depth and more passes.If machining metal is going to be your main activity, a mill might be a better choice.One other factor might be the height of your gantry beam-simple leverage means that a high gantry and it's attendant big Z axis travel will permit more chatter than a lower setup.
I mainly cut wood but like the hability to do some works on aluminium, simple stuff.
For HSM i found this: https://makeitfrommetal.com/cutting-...bbyists-guide/
The good is the fact he use same kind of machine and spindle, have to test the results, still he work with low DOCs which is expected.
My Z axis is definitely big and i still need to put the machine on a firm base to eliminate the vibration.
I also found a good datasheet that match my spindle: http://dbsrrwqxc6ai9.cloudfront.net/...-ER20-220V.pdf
It have some more information but still lacks of a torque graph. If minimum is 6000RPM and seller told me 9000 can i assume that 9000RPM is torque max peak?
After search on aliexpress i also found slower spindles which look better for metal, and reach 1500-12000rpm can it be a good balance between wood and aluminium?
https://www.aliexpress.com/item/32996693858.html and https://www.aliexpress.com/item/32546317403.html
EDIT: Found torque graph in description GDK85-12Z/2.2, but it show 3KW instead of 2.2?
https://ae01.alicdn.com/kf/HTB1eI0HP...0q6zEwXXa9.jpg
EDIT2: Found datasheet for GDK80-12Z/2.2 http://www.pdjinc.com/GDK80-12Z_2_2_manual.pdf It have torque graph on bottom
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
The obvious first step is to try a job with the alternative cutting parameters you found.The large Z axis travel will still allow a bit more movement than a lower amount of travel as the amount of play in the bearings is magnified by the distance from the rails and then you have the same large amount of potential movement at the bottom of the Z axis travel again because of the distance from the gantry beam.Finally,are you absolutely certain that the clamping arrangements for you spindle are completely free from flexing?Switching to a slower spindle won't eliminate any juddering from having the play inherent in the rails present.Have you tried placing a dial gauge against the collet nut and flexing the nose of the spindle sideways in the X and Y directions?
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
The obvious first step is to try a job with the alternative cutting parameters you found.The large Z axis travel will still allow a bit more movement than a lower amount of travel as the amount of play in the bearings is magnified by the distance from the rails and then you have the same large amount of potential movement at the bottom of the Z axis travel again because of the distance from the gantry beam.Finally,are you absolutely certain that the clamping arrangements for you spindle are completely free from flexing?Switching to a slower spindle won't eliminate any juddering from having the play inherent in the rails present.Have you tried placing a dial gauge against the collet nut and flexing the nose of the spindle sideways in the X and Y directions?
Will have a look at it tomorrow, thank you for pointing out.
I have photos of the machine on thingyverse, but website is now bad and doesn't show all photos i posted.
https://www.thingiverse.com/thing:3819149
https://www.thingiverse.com/thing:3849307
Quote:
Originally Posted by
tnorbi90
Hello!
First of all: forget HSS tools for machining metals. Use carbide tools, for a 8mm endmill (z=2..3) you should use about 10-12000 rpm at minimum (around 300m/min Vc, most carbide mills requires it on aluminium), with your routing machine use hsm toolpath with 8mm cut depth and 0.4mm cut width with about 1200-1400mm/min feedrate. For plunge use spiral toolpath with 2-3 degrees plunge, with about 450-500mm/min feedrate. Hope this will help!
I know HSS not the ideal for metal, but is that bad with aluminium? Right now i have Carbides but they are TiAIN coated and i guess that not good with aluminium? But i have TiCN bits on the way.
"at minimum (around 300m/min)" -- If run slower will it hurt the bit? for Example 200mm/m?
"8mm cut depth and 0.4mm cut width" -- I guess they are reversed? You mean 0.4mm cut depth (DOC) and 8mm cut width (Pocket)?
For the first slot i'm using adaptive toolpath with spiral plunge, 16mm slot
Second slot (width = bit diameter = 8mm) The plunge is made in a zig-zag pattern, should i take a smaller bit and use same strategy above?
https://i.imgur.com/WFhqzu9.jpg
Thank you for sharing the parameters, will test them latter.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
I followed the links to the thingiverse pages.You seem to have a good deal of experience with 3D printing and some very good machine accessories are there.One thing that stood out was the side plates of the gantry-they look a bit thing for resisting flex as the spindle moves across the gantry.Maybe bolting a piece of 40mmX40mmX5mm angle to the sides would reduce any tendency to flex.
For cutting strategy,it may be best to machine slightly oversize and then to run a light finishing cut as long as you are able to securely hold the parts in place.Maybe cut the holes first and then use bolts through those holes to hold the parts while you machine the outer surface.It definitely looks like a machine for HSM strategies rather than milling in a conventional sense.Coolant might also be a good thing to use but things do get messy.Which is why machining centres are enclosed and flood the cutting zone with coolant.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
One thing that stood out was the side plates of the gantry-they look a bit thing for resisting flex as the spindle moves across the gantry.Maybe bolting a piece of 40mmX40mmX5mm angle to the sides would reduce any tendency to flex.
You mean a L Shape 90 Degree bracket? something like that: https://ae01.alicdn.com/kf/HTB1g10qK...pq6yssXXak.jpg or https://www.aliexpress.com/item/32887666132.html
Quote:
Originally Posted by
routalot
For cutting strategy,it may be best to machine slightly oversize and then to run a light finishing cut as long as you are able to securely hold the parts in place.
You mean slightly undersize instead? Example: Slot is 8mm width, so use a inferior bit diameter than 8mm?
Quote:
Originally Posted by
routalot
Maybe cut the holes first and then use bolts through those holes to hold the parts while you machine the outer surface.It definitely looks like a machine for HSM strategies rather than milling in a conventional sense.Coolant might also be a good thing to use but things do get messy.Which is why machining centres are enclosed and flood the cutting zone with coolant.
My stock have space to do that is a 250mm bar and i will use only +/-200 of it. Still my 3d printed holders already do the job, securing the parts.
As coolant i use WD40 and also have another brand that cooldown the part at same time, it contain some sort of freezer. But i'm never sure what frequency i should spray, the way i'm doing it i think a can will not last long. The machine have oil support but as i have a wood wasteboard removing it everytime is a bit of pain and the wasteboard is planned, without it Z can have 6mm variance across bed point to point. Also it's not high pressure, just a regular flow compared with the water cooling on spindle in terms of flow
I also have took better photos of the machine:
https://i.imgur.com/xBjGJK6.jpg
https://i.imgur.com/pD7IwYF.jpg
https://i.imgur.com/WV8iSRx.jpg
https://i.imgur.com/TeSYr7y.jpg
https://i.imgur.com/oltUmMr.jpg
https://i.imgur.com/2E8baOc.jpg
https://i.imgur.com/LQAP81g.jpg
https://i.imgur.com/XN4THMe.jpg
Thanks for your input
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
The additional images are helpful.The sort of angle section I would recommend would be something like this https://www.monarchmetal.com/wp-cont...tock-angle.jpg and I would put it on the side plate of the gantry with the long edge running from bottom to top.There is no such thing as a machine that is too stiff.
When I describe machining oversize it means leaving additional material for a finishing pass and inside a slot that would leave the slot narrow because there would be material still to be removed.For the slot I might try using a 6mm tool.
You have the first machine I have seen with heat sinks on the steppers-interesting idea.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
The additional images are helpful.The sort of angle section I would recommend would be something like this
https://www.monarchmetal.com/wp-cont...tock-angle.jpg and I would put it on the side plate of the gantry with the long edge running from bottom to top.There is no such thing as a machine that is too stiff.
Placement like that on the back: ?
https://i.imgur.com/KMCSUf7.jpg
Do you know any online store that sell that kind of angle stuff inside Europe?
Quote:
Originally Posted by
routalot
When I describe machining oversize it means leaving additional material for a finishing pass and inside a slot that would leave the slot narrow because there would be material still to be removed.For the slot I might try using a 6mm tool.
Got it
Quote:
Originally Posted by
routalot
You have the first machine I have seen with heat sinks on the steppers-interesting idea.
Yes it come without them, but steppers get really hot after a while, to the point i can touch for more than 1s. And i don't like it. So i order and placed that heatsinks, look good and really do the difference. I also thought in put dedicated WC block on them, but it would add extra complexity and tubes. Think is good with passives
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
That is exactly the principle I am advocating.I am visualising pieces of that type fixed vertically on the end plates of the gantry and I would think steel would be a good choice.Maybe I am fortunate in having a business that sells all sorts of useful steel just a few minutes drive away,I can't imagine it would be particularly inexpensive to buy online as the freight cost might be significant.You might find pieces of storage rack or bench legs in a junkyard for very little money if you are willing to compromise on size and perhaps clean it.
Have you tried pushing the spindle nose to measure the deflection?I suspect you would help the spindle rigidity if you used the 3D printer to make an additional clamp for the spindle to be located near the top of the body.It shouldn't see forces of the same level as the metal clamp you already have and has to help minimise juddering at the tool.
Re: Chinese 2.2kw 24000rpm Spindle minimum RPM and aluminium mill
Quote:
Originally Posted by
routalot
That is exactly the principle I am advocating.I am visualising pieces of that type fixed vertically on the end plates of the gantry and I would think steel would be a good choice.Maybe I am fortunate in having a business that sells all sorts of useful steel just a few minutes drive away,I can't imagine it would be particularly inexpensive to buy online as the freight cost might be significant.You might find pieces of storage rack or bench legs in a junkyard for very little money if you are willing to compromise on size and perhaps clean it.
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.
Quote:
Originally Posted by
routalot
Have you tried pushing the spindle nose to measure the deflection?I suspect you would help the spindle rigidity if you used the 3D printer to make an additional clamp for the spindle to be located near the top of the body.It shouldn't see forces of the same level as the metal clamp you already have and has to help minimise juddering at the tool.
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
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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