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Aluminium cutting... questions never end :( GURU please help.

Discussion in 'CNC Mills/Routers' started by DavidCNC2017, Feb 13, 2017.

  1. DavidCNC2017

    DavidCNC2017 Journeyman
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    The question is about cutting aluminium.
    I was already trying different aluminium (6061, extruded) different end mills ( some expensive 1 flute upcut end mills from Amana Tools, some cheap 2 flute end mills from ebay....) .
    What can I say...
    Yes, C-beam machine cuts aluminium. But I can not get an acceptable cut.
    What I mean for acceptable? well, some typical metal shining, absolutely smooth and even , like polished cut, which I saw many times on big milling machines. The cuts, coming from big milling machines, looks like mirror, they do not need any sander or file or something like that.
    My machine is C beam, spindel is Bosch PR20EVSK Colt Palm.

    ..... and yesterday I saw this. Please look at this video



    The guys cut the aluminium plate like butter. Dry or wet, both acceptable quality.

    They point out the end mill model, they write about cutting parameters (feed rate, spindel speed and so on).

    So, now the questions for GURU.

    1.) I can buy this end mill from ONSRUD. If I set that feed rate and spindel speed, can I run my Cbeam machine, or it will just collapse :) , because this guys use 2.2 kW spindel, and my Bosch is just 0.85 kW max.
    2.) I can even upgrade to their 2.2 kW spindle, to have all the parameters of their machine the same.
    BUT, is C- beam rigid enough for 2.2 kW spindel.

    Please help with some suggestion and answer my questions, because I am very disappointed with that.

    Thank You so much for any advise and help in advance.
    Regards
    David
    P.S. ..and sorry for my English

    P.P.S. and finally. Yes, I know, that there are many online and offline calculators to choose the appropriate cutting parameters. But please, can anyone tell me: just set this parameters on Your C-beam, use (or do not use) cutting fluid or or something else, buy this particular end mill, use that type of aluminium (extruded, 6061, 6063) and so on and so on and You will get the cut You are speaking about: shine as mirror, clean, smooth, without tool scratches, which will not need sand paper, file or any other post production steps
     
    #1 DavidCNC2017, Feb 13, 2017
    Last edited: Feb 13, 2017
  2. Kevon Ritter

    Kevon Ritter Veteran
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    To be honest, the edge on the first cut looks really bad. The mirror was there, but the waves are terrible. I was able to get a better finish on my hdpe based CNC shark (which I greatly despise and am replacing right now). My settings were much slower. My endmill was also dirt cheap. I want to say I was around 360mm/min with a 0.3mm DOC. The endmill was a 3mm O-Flute. RPM was around 22k. It took time due to the flex from the crappy Shark.

    I don't at all recommend those settings. I'm only saying what worked for the machine I was using. I hope to ramp it up to at least 1000mm/min with at least a 1mm DOC with a 1/4" 4 flute radiused edge.

    [​IMG]
     
  3. Kevon Ritter

    Kevon Ritter Veteran
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    By the way, I have the same router,
     
  4. DavidCNC2017

    DavidCNC2017 Journeyman
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    Hi Kevon,
    My settings on C beam was as follows
    RPM 13000
    DOC 0.38 mm
    feed rate about 700 mm/ min
    3mm O-Flute by Amana tools
    Plange rate: 70 mm/min

    Don't like the cut finish at all, and no shine mirror, just scratched matte surface

    I would consider it acceptable if I had not seen how aluminum cut looks coming out of big milling machines. It like real mirror :)
     
    #4 DavidCNC2017, Feb 13, 2017
    Last edited: Feb 13, 2017
  5. DavidCNC2017

    DavidCNC2017 Journeyman
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    I will appreciate any machinist , who will say, that I would not expect clean and shine cut of aluminum using cnc routers like C beam.
    At least I will not wast my money and time trying to experiment any more.
     
  6. Kevon Ritter

    Kevon Ritter Veteran
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    I forgot to mention that I occasionally sprayed "Ultra Lube" (from Home Depot) as a lubricant and routinely removed chips by vacuum. That picture above was also made with a conventional cut direction (NOT climb). From everything I've read and from my own experience. Chip removal IS one of the most, if not the most important part of finish quality in aluminum. If you don't clear the chips, they just sit there and are either recut or welded back to the cutter or aluminum. That's less cutting being done overall AND with a much worse cutting edge. You can see the difference in my before and after cut quality in the same picture I posted.
     
    Joe Santarsiero likes this.
  7. DavidCNC2017

    DavidCNC2017 Journeyman
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    Kevon, You speak about pictures, but I can not see any picture in Your post
    As for lubricant I also use Cutting fluid and also remove chips with vacuum. But my direction was climb, because I read somewhere, that for aluminum on cnc router climb is the best
     
    #7 DavidCNC2017, Feb 13, 2017
    Last edited: Feb 13, 2017
  8. Darathy

    Darathy Journeyman
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    You cant compare Big milling machine to a cnc router. CNC routers will never be as rigid as a Hass or a Tormach. The finish is mostly result from vibrations i am guessing and deflection which evry machine has even bits have deflection. Try mybe with a stub end mill shorter the better.

    Also use finishing pass with 3 flute end mill with high helix. In fusion 360(dont know how it is in your cam software) i usualy use contour with stock to leave 0.1mm and then another contour with no stock to leave which minimises deflection which couses bad finish.

    Today i made a clamp which made kinda best result i got so far with a O-Flute 1/8" mill with 800mm/s 0.25mm DOC at 19000RPM Roughing and 0.5 DOC finish:
    IMAG0514.jpg
    IMAG0515.jpg
    IMAG0516.jpg

    You can see marks where tabs were made , i'm not really sure why it made them .
     
  9. Kevon Ritter

    Kevon Ritter Veteran
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    Try a different device. I can see it on both my PC and phone. I posted it as a url image, not as an attachment.

    meh...just as easy for me to re-upload.
     

    Attached Files:

  10. Rick 2.0

    Rick 2.0 OpenBuilds Team
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    You posted an image url from a site that you have to be logged into to see the images (which is why you can see it and we can't). Direct image posting is always the best choice.
     
  11. Kevon Ritter

    Kevon Ritter Veteran
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    I didn't even think about that. Thanks for pointing that out.
     
  12. DavidCNC2017

    DavidCNC2017 Journeyman
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    Thank You all for Your replies.
    I clearly understand, that the C beam machine in comparison with some professional big milling machines is like a waving flag in terms of stability.
    But I thought by mistake, that the right understanding of the limitation of cnc router and make appropriate steps of overcoming this limitations could be a key for quality cutting.
    In another word, just imagine that You have Porsche Panamera and I have Fiat Cinquecento and we both drive our cars from Munich to Frankfurt (why Germany? because there are no speed limits on highway there) to attend football match of world cup final. You drive 300 km/h, I 100 km/h, You drive with more comfort then I and are more fresh at the end of journey and etc. BUT ! We both will reach our destination and our goal , never mind that I will spent 3 times more, will more tired and etc. We result ( why we are driving to Frankfurt) will be the same for both of us.
    Unfortunately, seems this do not work in the world of cnc machines. If You have Tormach You will cut 3mm DOC, 2000mm/min , 2" 4 flute end mill and will finish the part in 10 minutes. I, with my C beam , taking into account all its limits, will choose much more small DOC, much more lower feer rate, 1 flute end mill 1/8" and make the same part 55 minutes.
    BUT! Even taking into account C beam machine limitations I will never reach You quality on Tormach. ( I think even Tormach has it's limits).
    I think You guys understand what I mean and what I would like to understand for myself: that even concerning all limitations of small cnc C beam machine and choosing all appropriate parameters, I can not get the result of big machine and the best possible quality will be that on the pictures above.

    Thank You for Your time
    David
     
  13. DavidCNC2017

    DavidCNC2017 Journeyman
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    I use Aspire. I can do that, to leave some material for final cut, change an end mill for 3 or 4 flute one and make final profile or pocket cut with it. I will try it and see if it helps. Thank You for Your suggestion.
     
    Joe Santarsiero likes this.

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