1. #1
    Hi

    Can anyone recommend a surfacing bit for aluminium? Its only for a hobby cnc with a kress spindle.

  2. #2
    Quote Originally Posted by dfox1787 View Post
    Hi

    Can anyone recommend a surfacing bit for aluminium? Its only for a hobby cnc with a kress spindle.
    I think there are many methods, tools and theories of what is "best". Personally I am using simple four flute, 6mm diameter bits at 18-22krpm and that works fine for me. The surface is very smooth and shiny. I can't use larger ones because I have ER11 spindle. I would not dare using any fly cutters with these high speed spindles.

  3. #3
    Quote Originally Posted by A_Camera View Post
    I think there are many methods, tools and theories of what is "best". Personally I am using simple four flute, 6mm diameter bits at 18-22krpm and that works fine for me. The surface is very smooth and shiny. I can't use larger ones because I have ER11 spindle. I would not dare using any fly cutters with these high speed spindles.
    Thank you. Thats the issue i am having. Very limited collet size. Ive used a standard endmill before but i seem to get tooling marks that have a slight texture to them. not sure if this is machine related or if its normal.

  4. #4
    Quote Originally Posted by dfox1787 View Post
    Thank you. Thats the issue i am having. Very limited collet size. Ive used a standard endmill before but i seem to get tooling marks that have a slight texture to them. not sure if this is machine related or if its normal.
    Close your eyes and feel the surface with the tip of your finger or the nail of your index finger. If you can feel the pattern then it is machine related and not good. Otherwise it is normal. There is always a visible pattern unless you polish the surface. Of course, you must use sharp tools.
    Last edited by A_Camera; 08-05-2018 at 08:44 PM.

  5. #5
    Don't use coated endmills on aluminium. You will tend to get build up on the tip and poor finish. I find these work well. Also make sure you have a good grade of aluminium for machining - it makes a world of difference.

    Russell

  6. #6
    tooling leaving ridges means your spindle is out of tram in one or more axis (ie it is not perfectly perpendicular to the X/Y axis)

    The smaller the bit, the less obvious this will be so one solution is to use smaller bits and smaller step overs but you will never get a really smooth surface unless you spend some time shimming your spindle into tram (or if your machine has adjustable tram then even better than shimming of course).

    As mentioned above you will always have visible swirls/marks but if the surface feels ridged then look to tramming as your solution. With good tram, it should be relatively easy to polish away the tooling marks with some light sanding.
    Last edited by Zeeflyboy; 09-05-2018 at 02:39 PM.

  7. Quote Originally Posted by dfox1787 View Post
    Hi

    Can anyone recommend a surfacing bit for aluminium? Its only for a hobby cnc with a kress spindle.
    Do you want flatness or finish ? to put a surface pattern I use a dremel wire brush, the lowest spindle speed and WD40 (otherwise it drags the ali and messes the finish). I use a pocketing cut at a fairly high feed rate and 0.2mm DOC. The dremel brush must be the genuine one like these DREMEL Multipack Accessories 443 3 x 3.2mm Carbon Steel Polishing Brush Pack 3. If you spin it too fast it splays out and is useless from then on.

    For a flat surface - yes the 6 or 8mm HSS uncoated cutter from ArcEuro, when they have them.
    Albert Einstein may have been a genius, but his brother Frank, was a monster

    Having just moved to Windows 10 (which is crap) My stress levels are through the roof !!!

  8. #8
    Quote Originally Posted by cropwell View Post
    Do you want flatness or finish ? to put a surface pattern I use a dremel wire brush, the lowest spindle speed and WD40 (otherwise it drags the ali and messes the finish). I use a pocketing cut at a fairly high feed rate and 0.2mm DOC. The dremel brush must be the genuine one like these DREMEL Multipack Accessories 443 3 x 3.2mm Carbon Steel Polishing Brush Pack 3. If you spin it too fast it splays out and is useless from then on.

    For a flat surface - yes the 6 or 8mm HSS uncoated cutter from ArcEuro, when they have them.
    Hi

    Its flatness I need. I'm going to run some tests this evening. Bare in mind my machine is a china cnc 3040 so not the greatest thing. I've got a quite a few endmills I'll upload some images so you can see.

    I'm only a hobbiest and still working on feeds speeds and general use of the machine. My time is very limited these days but I'm doing things in small drabs.



    Sent from my SM-N910F using Tapatalk

  9. #9
    Quote Originally Posted by dfox1787 View Post
    Hi

    Its flatness I need. I'm going to run some tests this evening. Bare in mind my machine is a china cnc 3040 so not the greatest thing. I've got a quite a few endmills I'll upload some images so you can see.

    I'm only a hobbiest and still working on feeds speeds and general use of the machine. My time is very limited these days but I'm doing things in small drabs.



    Sent from my SM-N910F using Tapatalk
    I wouldn't say the finish is bad it's more textured than rough but I can feel slight tooling marks. Maybe I'm being picky and expecting too much from my little machine.

    Sent from my SM-N910F using Tapatalk
    Last edited by dfox1787; 09-05-2018 at 08:32 PM.

  10. #10
    Quote Originally Posted by dfox1787 View Post
    I wouldn't say the finish is bad it's more textured than rough but I can feel slight tooling marks. Maybe I'm being picky and expecting too much from my little machine.

    Sent from my SM-N910F using Tapatalk
    Pic

    Sent from my SM-N910F using Tapatalk

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