What Spindle and Bit for Garolite (G10)

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WillAdams
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Re: What Spindle and Bit for Garolite (G10)

Post by WillAdams » Mon Mar 31, 2014 11:05 am

End Mill size is a series of tradeoffs between:

- amount of material lost when cutting
- rigidity of the end mill
- durability (the small ones break, and require a better quality spindle w/ lower run-out)
- size of the smallest feature you can cut
- price

When starting out, just get a carbide 1/8" 2-flute straight or spiral up-cut end mill --- then as you find the limitations of that balanced against your needs, get end mills which address what you need to do.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
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rnelias
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Re: What Spindle and Bit for Garolite (G10)

Post by rnelias » Mon Mar 31, 2014 12:25 pm

WillAdams wrote:End Mill size is a series of tradeoffs between:

- amount of material lost when cutting
- rigidity of the end mill
- durability (the small ones break, and require a better quality spindle w/ lower run-out)
- size of the smallest feature you can cut
- price

When starting out, just get a carbide 1/8" 2-flute straight or spiral up-cut end mill --- then as you find the limitations of that balanced against your needs, get end mills which address what you need to do.
Thanks WillAdams for your advices ;)

As I'll use Shapeoko to learn with my mistakes, I was thinking about buying a range of diameters to make some tests. The problem is that It's hard to find these bits in my country and I'm making a list of parts to get on my next coming trip to USA, including the Shapeoko itselt :D (I'll probably change the stock spindle to a Dewalt Dw60).

Here's the bit I've chosen from the link you've posted before

http://www.soigeneris.com/precisebits_d ... tails.aspx

BTW, I saw there are 1/8" and 1/8" ZrN bits (almost twice the price). Do you know the difference?

I'm not planning to cut a bunch of plates. I'm just looking for some "freedom" in creating my own designs of multirotor frames and car chassis... well, it's a hobby BTW :P

WillAdams
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Re: What Spindle and Bit for Garolite (G10)

Post by WillAdams » Mon Mar 31, 2014 12:39 pm

Of course, ``strategizing so as to minimize shipping costs'' is a perfectly valid strategy.

Unfortunately, end mills have to be considered a consumable --- so you either need extras to start, or a source to purchase more from which can deliver w/in a reasonable timeframe.

ZrN (Zirconia Nitride) is a coating intended for cutting aluminum --- it is important to match the coating w/ the intended material --- using a coating which is not intended for the material you're cutting can be either a waste of money or a total detriment to the work.
Shapeoko 3XL #0006 w/Makita RT0701 Router w/0.125″ and ¼″ Elaire precision collets
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RobCee
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Re: What Spindle and Bit for Garolite (G10)

Post by RobCee » Mon Mar 31, 2014 2:53 pm

rnelias wrote:The problem is that It's hard to find these bits in my country
For things like the milling cutters, your best bet is getting some inexpensive ones from China in packs of 10. They are great for the learning stages, as you won't pay much for them. The simplest international source for these is your local eBay, the quality is probably not quite up there with the USA ones, but they are good enough.
ShapeOko2 #3400 - Chinese 800W AC Spindle - Stiffened X-Axis - TR10 Z-Axis - Inverted Z Motor - Hall Effect Limits - Drag Chains & Custom Brackets

rnelias
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Joined: Tue Jan 14, 2014 1:49 pm

Re: What Spindle and Bit for Garolite (G10)

Post by rnelias » Mon Mar 31, 2014 5:30 pm

Thanks RobCee and WillAdams,

I'll take a look in some cheap deals on eBay. Just for practicing...

As a contribution, I'll leave a link that I've found when trying to understand what's influence of the kind and number of flutes

http://wiki.imal.org/howto/cnc-milling- ... ting-tools

secretspy711
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Location: Colorado

Re: What Spindle and Bit for Garolite (G10)

Post by secretspy711 » Sun Jul 27, 2014 11:45 pm

There seems to be a lack of info for gutting G10 so I just thought I'd share my experiences so far.

I just finished cutting about 90 parts on a 12x24" sheet of .125" thick G10. Was using .0625" fishtail diamond-cut bits from drillman1 on ebay (uncoated). These are genunie Kyocera bits so supposedly they should be decent. Feed and speed settings: 20 ipm feed, 8 ipm plunge, DeWalt DW660 on 90%-100% throttle. Pass depth was .045" for a total of 3 passes with .010" of over-cut into particleboard. A brand new bit plows through it like nobody's business, but I actually went through 2 bits during this cut, after 1 broke. At first the spindle did not bog down at all. Then I noticed the spindle slowly bogging down more and more (though still nothing to be concerned about) as the work progressed, until I noticed that I had not heard for a couple of minutes -- at which point I looked over, and it had missed some X steps, messing up 2 parts and left another 3 completely uncut. I was able to pause it, manually crank up the Z axis, change the bit (with depth ring) and start cutting again.

I think the feed is pretty good, but I might try shallower passes next time. I know these aren't the same exact ones that Precisebits sells, but they are darn close and at $18 for a 10-pack, I definitely can't complain. But Precisebits say theirs are supposed to last 3000 linear inches. This entire job should've been about 1500 inches if you count all 3 passes. I'm not ready to blame the bits just yet until I experiment more with them.

This is slower than the recommended feed rate at Precisebits... I kind of cringe at the thought of increasing the speed, but sometimes this stuff is counter-intuitive. Increasing the speed would mean a higher chip load and maybe less dulling, MAYBE making the bit last longer???

EDIT:
ok it looks like the settings I was using were a bit off the mark. I'm not sure how many "flutes" you'd say those diamond-cut bits have, since they don't look like flutes at all, but you could just pick a number for the sake of this calculation. Let's call it 1 flute so that part drops out of the equation:

Precisebits recommendation for a .0625" bit:
ChipLoad = feed / (flutes x RPM) = 40 / (1 x 36000) = .0011

Since my spindle only goes up to 30k, I would need to use:
Feed = ChipLoad x Flutes x RPM = .0011 x 1 x 30000 = 33.3 ipm. I was using 20 ipm, and a 50% deeper pass than what PB recommends (.045" vs their .030"). Oops! No wonder the bit broke!
Shapeoko 2 #5510: 1200 x 500 mm, Makita RT0701

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