Page 1 of 2 12 LastLast
Results 1 to 10 of 16

Thread: Anyone installed a spindle at an angle?

  1. #1
    Join Date
    Aug 2005
    Location
    N/A (right now), Valencia Spain
    Posts
    39

    Default Anyone installed a spindle at an angle?

    Many CAM programs that offer 5-axis milling strategies can make ball end milling toolpaths that hold the ball end cutter at an angle to the surface, i.e. not perpendicular.<br><br>This is because the very end of a ball end cutter doesn't really cut (!), it just spins, because the cutting edge reduces as you move from the sides to the end.<br><br>The result is that cutting wavey surfaces takes an age - between the need to go slowly because the end of the ball end cutter doesn't really cut and the need to do finish paths at several different angles to minimize peaks and ridges.<br><br>But it's clear that even with a 3-axis machine, if we could present a ball end cutter at e.g. 15 degrees off vertical, then we could cut much more quickly.<br><br>I've attached a photo of the spindle with a triangle showing what I'm thinking off - simply an attachment plate between the ShopBot and the spindle so that the spindle is held at an angle.<br><br>I'm convinced that doing this and combining it with using a relatively large ball end cutter would allow for signicant time saving if planning to cut large wavey surfaces, perhaps like the final photo, which is not my work, but the type of thing I believe could be done on the ShopBot.<br><br>Has anyone installed a spindle at an angle, like I'm suggesting?<br>If so I'd like to hear about the degree of improvement in cutting speeds with ball end cutters.<img src="http://www.talkshopbot.com/forum/attachment.php?attachmentid=33609&amp;stc=1" attachmentid="33609" alt="" id="vbattach_33609" class="previewthumb"><img src="http://www.talkshopbot.com/forum/attachment.php?attachmentid=33610&amp;stc=1" attachmentid="33610" alt="" id="vbattach_33610" class="previewthumb"><img src="http://www.talkshopbot.com/forum/attachment.php?attachmentid=33611&amp;stc=1" attachmentid="33611" alt="" id="vbattach_33611" class="previewthumb"><img src="http://www.talkshopbot.com/forum/attachment.php?attachmentid=33612&amp;stc=1" attachmentid="33612" alt="" id="vbattach_33612" class="previewthumb">
    Attached Images Attached Images

  2. #2
    Join Date
    Dec 2005
    Location
    Pro Signs, Coal CIty IL
    Posts
    303

    Default

    I might be wrong, but it seems like the ball end already cuts from the edge as it moves across the surface. The exception might be plunge cuts. I'd be interested in how this discusion goes though, as I can't say for sure if it would make a difference or not.

  3. #3
    Join Date
    Mar 2013
    Location
    Memphis TN
    Posts
    795

    Default

    You'd also have the complication of hitting the work with the shank if the angle of the end mill conflicts with the work. Perhaps there could be some value in this approach but each case would have to be evaluated manually for conflicts. That could severely limit the usability of such a setup. Besides, as pro70z28 pointed out, the cutting is done by the leading edge of the end mill, not the center.

    What might actually work better than tilting the spindle would be to tilt the work. Less trouble and the system would handle conflicts.
    ShopBot Details:
    PRS Alpha 96x60x12
    4hp Spindle
    12" indexer
    Aspire
    Rhino

  4. #4
    Join Date
    May 2014
    Location
    MA
    Posts
    510

    Default

    The hardware would be reasonably easy to do, the software side would be more difficult. You wouldn't be able to toolpath this in any Vectric products because they don't do multi axis. Fusion 360 could pull it off.

    If you're going to go that far you might consider just converting it to 5 axis:

    http://www.5-axis.com/

    There's another company that makes a similar kit, I can't think of the name at the moment.

    ShopBot controls do support more axes. You'd need to get some more drivers though.

    Perhaps a ShopBot 2 axis head from the 5 axis machine could be retro'd on....

  5. #5
    Join Date
    Aug 2005
    Location
    N/A (right now), Valencia Spain
    Posts
    39

    Default

    Quote Originally Posted by pro70z28 View Post
    I might be wrong, but it seems like the ball end already cuts from the edge as it moves across the surface. The exception might be plunge cuts. I'd be interested in how this discusion goes though, as I can't say for sure if it would make a difference or not.

    Thanks for the reply pro70z28. I'm convinced ball end cutters don't really cut at the very end of the tip - the cutting edges shrink to nothing and moreover that point doesn't even 'move' as such, it just spins.

    I'm also convinced it would make a difference in certain circumstances.

  6. #6
    Join Date
    Aug 2005
    Location
    N/A (right now), Valencia Spain
    Posts
    39

    Default

    Thanks too for your reply coryatjohn. There will, as you say, be the complication of hitting the work with the shank - but I'm thinking of maybe e.g. 15 degrees and will have the possibility to simulate the entire process in CAM software (SprutCAM). That woldn't be a problem on e.g. the wavey chess board I posted an image of.

  7. #7
    Join Date
    Aug 2005
    Location
    N/A (right now), Valencia Spain
    Posts
    39

    Default

    Thank Eric for your feedback too. As I mention in my reply above, I've got good CAm simulation software.

    But I'm going to look into it a bit more - there may be restrictions on the direction of cut because it will be preferable (quite important) to 'drag' the tip (the bit that dosn't cut) 'behind' the tilted spindle and not 'push' it in front, which would aggravate the problem your tring to avoid.

  8. #8
    Join Date
    May 2014
    Location
    MA
    Posts
    510

    Default

    I think it might be worth going back to your original assumption for a minute:

    "I'm convinced ball end cutters don't really cut at the very end of the tip"

    By that logic V carve bits would never work...

    The idea with rastering or offsetting with a ballnose is that you're balancing time vs detail. If you do a .05% stepover you will have a far longer carve, but way more detail (And less sanding if it's wood) If you do a huge stepover you'll have far less carving time, but more sanding.

    I think this is going to lead you down a fruitless and expensive path. Think of all of the people out there carving signs, most of them don't nee multi axis machines to get the carving done that they want.

    You should perhaps look into some different bits, perhaps ones that have a ball on the end (like an actual spehere, not a "ballnose") that can help you reach into places you can't with a regular ballnose. Or a flat bottomed ballnose bit. I've used those before were I had to mill big flat pockets with rounded edges. They save a ton of time in that situation.

    If you really do think that being able to tilt the bit at a different angle will solve your problem (and it might, I'll be honest I haven't tried it). Why not do a test by tilting the workpiece? That way you don't have to modify your machine at all, you'll just need to get your head around the software. You could use Fusion for free to test this out.

  9. #9
    Join Date
    Aug 2005
    Location
    N/A (right now), Valencia Spain
    Posts
    39

    Default

    Hi Eric - Stepover as you say is important in the type of curved surfaces I'm interested in beginning to do bigger than I have so far done, and I'm talking about using ball end cutters that are actual (hemi)spheres - it's the fact you can tilt a hemisphere and it will still cut in the same place (but with a part of the cutter that is able to cut better) that makes this tilted strategy possible. Here's what one tooling expert says about it : https://www.harveyperformance.com/in...trategy-guide/
    I've attached a couple of photos of a scale model I made - it took an age! Both sides done and about a foot diameter. I'd like to make it full size in hardwood. Another thing is I don't want to be sanding to such an extent the finished item has a surface that's not very close to what it should be by design, I mean it's a 'mathematical' surface and the finished item should as a minimum be able to be inspected and look like its got no flats it shouldn't have.
    Attached Images Attached Images

  10. #10
    Join Date
    Mar 2013
    Location
    Memphis TN
    Posts
    795

    Default

    Maybe I'm a freako here but I really enjoy doing the final, detailed sanding of a nice piece I'm working on. It puts a bit of humanity in an otherwise mechanical work. The amount of effort required to finish off something like that little flower is minimal. Why not just hand sand it?
    ShopBot Details:
    PRS Alpha 96x60x12
    4hp Spindle
    12" indexer
    Aspire
    Rhino

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •