A shark hogging aluminum. Yeah right.

Discussion about the CNC Shark Pro Plus HD

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Rando
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A shark hogging aluminum. Yeah right.

Post by Rando »

Is there anybody still out there????..... Seems awfully quiet.
I've been having loads of fun :D

Lookie what I made! (download short video attachment)

2020-012-023 QuickIntro -- Take1.mp4
OOoohhhhh....coming soon! You too can HOG, not just cut Alu!
(2.68 MiB) Downloaded 28 times
If you're interested, drop me an email, address in the vid: thom at thomr dot com.

Web site, etc., are NOT up yet. Email is the thing.

Seriously...hogging at 0.86 cubic inches per minute.
1/4" 2FL 16.5K RPM @ 70IPM at 0.33" DOC, 15% stepover...in 6061 ALUMINUM.
Mirror finishes are now possible on a Shark!

Yes, I'm doing this on my modified Shark HD2 Pro+

Boy, the chips sure are a lot sharper now!

Rando.

Get the longer introduction video

--
Cutting parameters:
Wowser....this is for reals, people.
Wowser....this is for reals, people.
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

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Bob
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Re: A shark hogging aluminum. Yeah right.

Post by Bob »

Hello Thom,
Yup, still here.
Your video is intriguing. I'm not sure if I should run in terror, or get in close for a better look.
I definitely want a closer look. I have not done any aluminum milling. There are times when I would like to make aluminum parts for projects. I look forward to seeing more information about this.
I've been doing a lot of work with HDPE plastic, and like the versatility of this material.
Bob

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Kayvon
Posts: 454
Joined: Tue Oct 21, 2014 11:46 pm

Re: A shark hogging aluminum. Yeah right.

Post by Kayvon »

Thom! You're back! It's great to hear from you again.

That's an impressive upgrade. Would it work for the original Shark series? It's what Bob and I have.

I still frequent these forums, but my CNC machining time has been divided by a 3d printer and a laser cutter. It's the trifecta of creative home projects.

Rando
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Re: A shark hogging aluminum. Yeah right.

Post by Rando »

From what I can tell, if it has the same 20mm horizontal rails and 5.25" spacing, it should work perfectly. It eats 3/8" on each side, but it increases the Z-axis rail separation from that puny 3" to 5.5", for MUCH more rigidity. Better cleaner cuts, and zero fear in anything but something difficult like that in the video.

And, if it doesn't fit, it looks like it's very adaptable; I'm preparing a lower-height (stepover) one for a guy now.

The fun thing is that I'm not so much worried about anyone stealing the design. First, they'd have to come up with 3/8" thick, 3x4 uneven-leg aluminum angle. Then, they'd have to create and validate and test well over 300 toolpaths. It would be a nightmare if I hadn't written that GCODE-management tool a long time ago. Now for the 11 parts it's typically 1, maybe as many as 3 steps, even with 20+ individual feature toolpaths. With the PilotFish attachment I have, the chip blower, the mister, the spindle coolant are all controlled by the GCode. So, it can use the mister during the roughing, and then turn it off on the finish pass for that mirror-quality. It's pretty amazing to see.

Seriously, though I don't expect anyone will get where I've gone with it, if you compare a water-cooled spindle on an HD2 Pro+ like I have, versus that same machine with this upgrade, I'm seeing a full order-of-magnitude faster material removal anywhere from 9x to 14x. That means toolpaths that used to take an hour now take 10 minutes. It's astonishing the difference it's made.

Even cutting wood, it's just a lot more stable. There's no lunging and diving with fast acceleration anymore.

The other nice thing is that because it's only 2 ounces heavier, out of 9# for the assembly and 12+# for the spindle, the movement dynamics are essentially the same for acceleration and max speed, so no worries about somehow losing steps compared to the original setup.

The design goals were same weight, and at least 4x increase in stiffness. Since Young's Modulus for HDPE versus Alumunum is 1:28x, and the weight density is 1:4, I figured if I used the same weight, I could expect somewhere in the 7x range for stiffness. With clever design, some beastly billet-blocks as starting points, and LOTS of bolts, it's now a VERY rigid thing. In fact, it's now the rest of the machine that acts soft, and so I ended up reinforcing those too. Parts for those (secret?) upgrades are included in the kit.

Anyway, the design to completion took about 3 months, but that was mainly because I had to make 100% sure everything fit (I reused all the precision components from the original machine) before I disassembled the machine. After all, once it's torn down and the bearings removed, there's pretty much no putting it back together. But, it worked out great, with careful planning and alignment. Well, that and I now work in a metals-fabrication shop and have the ready advice of the resident machinist (the owner). I "work" here, but I'm not "employed" by them. That way they can't fire me. ;)

Anyway, I'm starting to make them, if people are interested. I'll contact NWA pretty soon to see if there's something they want to do. But, even if you're just working in wood or plastic, just having so much more rigidity, stepover height, accurate alignment, and easy access to the workings has made it a very different machine. Heck, just imagine: you'll be able to use a precision angle to align the spindle and movement to the bed, AND it will actually be that way before, during and after the cutting.

Cheers!
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

Kevink18
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Joined: Fri Nov 23, 2012 3:30 pm

Re: A shark hogging aluminum. Yeah right.

Post by Kevink18 »

I ordered one of these from Thom and cant wait to get it. I will post more when I receive it it is being built Right now. I believe I will be the first one he will produce after his original.

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Kayvon
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Re: A shark hogging aluminum. Yeah right.

Post by Kayvon »

That sounds fantastic. The lack of gantry stiffness has almost made me a little jealous of the Axiom CNC line. What a great upgrade.

I've never attempted any metal cutting. The baseline Shark has an MDF bed, prohibiting liquid lubrication/cooling. I'm also using a router, rather than a true spindle. It works well enough that I've never worried about upgrading it, though I do wish I could true it up a little better to be perfectly perpendicular to the workpiece.

I'm excited to see more adoption of your upgrades. I hope NextWave picks it up from you.

Rando
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Re: A shark hogging aluminum. Yeah right.

Post by Rando »

Kayvon wrote:
Thu Sep 10, 2020 10:44 am
That sounds fantastic. The lack of gantry stiffness has almost made me a little jealous of the Axiom CNC line. What a great upgrade.

I've never attempted any metal cutting. The baseline Shark has an MDF bed, prohibiting liquid lubrication/cooling. I'm also using a router, rather than a true spindle. It works well enough that I've never worried about upgrading it, though I do wish I could true it up a little better to be perfectly perpendicular to the workpiece.

I'm excited to see more adoption of your upgrades. I hope NextWave picks it up from you.
Interestingly, if you use a mister, there's almost never any liquid present off the workpiece at all.
In my case, I drive it with 40psi to the nozzle and about 2psi into the kool-mist container.
There are solenoid-actuated air valves; one going to the container, one going to the mister nozzle.
They are fired for 125 - 175ms, every 5-10 seconds. There's a manual "flood it!" button in case
I've programmed the cut too hard, but even then it's rare to see fluid. Also, since nearly all the
parts are in a vise, I just attach a shop-rag using some rare-earth magnet "tacks" from waktak.com.
That catches any mist. But, in normal use, maybe half an ounce of the liquid is used over an hour.

Kool-Mist 88 is incredibly cost-effective. It comes in a gallon container, for about $60, or about $0.50
per ounce. You use one ounce in a quart of water, so each ounce is now only $0.0156. So, for
each hour of misting, figure about 3/4 of a penny :D .

The thing to remember, since we're hobbyists, and don't have our CNCs in their own HVAC system
for the enclosure they're in, we can NOT run the misters full time. They create a nasty cloud of mist
throughout the shop that will get over everything. Instead, we want to go with the
hot-damn latest-and-greatest process, "Minimum Quantity Lubrication", MQL. Flood is very old-school,
and a lot of people machine aluminum completely dry. If you get the cutting parameters, especially
SFM, correct, it's amazing how the cutting tools stay sharp for an insanely long time, and you just
never see edge built-up (where the aluminum slowly welds itself, molecule by molecule, into the
carbide matrix, what with Carbide tools coming from a compressed and sintered powder). In those
cases, where the cutting parameters are proper, it is feasible to machine dry. But, the limit of small
delicate features gets worse due to warping and weakness, say with vertical walls on the order of 0.030"

But, I digress.

Aluminum can be done on the shark. As you learn more about doing it, you realize we never should
have started with a shark. But, we did, and with a little bit of thinking, it's possible to get there.
The key is to balance the material cutting forces with the machine capabilities. Getting the cutting
parameters for wood correct is like walking down a sidewalk. You can move one way or the other pretty
far, and still stay on the sidewalk. Aluminum, thought, is like skating on the sharp edge of a razor
blade. You can do it, but it takes some practice to get into the middle of the much-smaller sweet spot.
The cnccookbook.com site has a lot of really great material for doing this; they helped a lot.

Regards,

Rando
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

Rando
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Re: A shark hogging aluminum. Yeah right.

Post by Rando »

The second project I did after installing the gantry upgrade was to make mold positives for aluminum castings for an ornamental deck railing.
Ten years after installation, the condo-complex couldn't get the parts anymore, and they were starting to fail in the ocean spray.
So, I made these.

Yes, I know, you're saying "so bloody what?".

Well, the thing I noticed was that cutting through oak with a 2" long 1/4" end mill was quite literally no different than if I was using
a nice short stubby. No chatter at all, and I was cutting the full 0.375" long flute, with 30+% step over. Yeah, that's as much due to the sharpness of the
bit. But, with NO deflection in the head now, the surfaces came out completely smooth. The darker ones are oak sealed and coated
in polyurethane.
20200910_110929.jpg

What seemed interesting to me was that the results were not saw "dust". Nor even "chip" like I'm used to seeing. No, these were the
shape of rice grains, and upon closer inspection, you can see how the edge cut through nice and clean, nor ripping at all. Almost like
a hand-rolled cigar.
20200910_111335.jpg
Not having the head moving in strange ways made the job come out dimensionally accurate. Now, granted, a mold-positive for
an aluminum casting does NOT have to be very accurate. Plus and minus 0.020" was more than adequate; it was the surface
smoothness without sanding we were after.

Cheers!
=====================================================
ThomR.com Creative tools and photographic art
A proud member of the Pacific Northwest CNC Club (now on Facebook)

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