DIY Epoxy Tombstone for our Okuma Horizontal CNC Machine!
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- เผยแพร่เมื่อ 19 พ.ค. 2024
- Tombstones for horizontal CNC machines are typically made of cast iron and are a great option in terms of rigidity but milling cast iron is messy! After purchasing our first few tombstones, we decided to make our own out of epoxy and aluminum. If you listen to the Business of Machining Podcast with John Grimsmo and I, you know I'm a stickler for not taking on projects just because you can. Let's talk about why this project did make sense for us, how we made it, things we learned, and what we would do differently next time!
00:00 Don't Get Cute! Why This DIY Project IS Right for Us
00:54 Slab & 6-Sided, and Square Style Tombstones
01:46 CAD Design & Epoxy Granite
03:01 Our Advantages
03:53 Pool Noodle Insurance Policy
04:37 Tight & Tedious - Smaller Concrete Form or Fastener Removal
05:34 Indicating on the Okuma MB-4000H: Y-Axis Could Be Better
06:01 Securing Tombstone to Okuma Base - All Thread Not Enough!
06:47 Solution: Adding Precision Alignment Bores
07:04 Decking with a 5" Facemill
08:04 Would I Do It Again? Final Thoughts
5 Reasons to Use a Fixture Plate on Your CNC Machine: bit.ly/3sNA4uH
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Links for this video
Epoxy on Amazon:
www.amazon.com/gp/product/B08...
How to Build Epoxy Granite Machine Base by Adam Bender
• How to Build Epoxy Gra...
Building an Oil Fired Foundry Furnace - Part 5: How NOT to Cast Refractory by Keith Rucker
• Building an Oil Fired ...
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Reach us / CNC Info:
Speeds & Feeds: provencut.com
Fusion 360 (Purchase, Support, Training): dsi.fyi/3yu7Mt0
Online Fusion 360 Training: bit.ly/LearnFusion360
SMW Products: saundersmachineworks.com/
CNC Resources: www.nyccnc.com - วิทยาศาสตร์และเทคโนโลยี
I love the honesty you bring to the world, owning your failures and celebrating a well executed plan. Thank you
I have poured more concrete than I care to remember over the years, I think what I would have done is built a plywood funnel that would be attached to the top until you had it filled, would have made that so much easier than fighting it. Also an old sander works great as a vibrating tool.
I had no idea bout the epoxy granite though, learned something new today.
It's 4am, I don't own a CNC, but watched the whole thing. Enjoyed the vid.
LOL go to bed!
Correction you don't own a CNC YET... you start watching these channels, things will happen...
I have never bought a cast iron tombstone. I have never tried this cast epoxy granite. I will keep that in mind, if I build another one. The ways I have done it is welded steel or bolted together aluminum plates (The ones on the Mitsubishi now). But I have also done this. Just buy a large diameter aluminum bar. The one I did was 16" in diameter. Then face the ends and bolt it to the aluminum base plate. Then face flats on it when mounted in the machine. This was easy and less expensive the a commercially made cast iron one. One question. Don't your pallets have a bore in the middle to install a large pin to locate the tombstone/fixture? Most machines I have owned also have these side plates bolted to the pallets. Something I have never used because they always get in the way. I'm also surprised they only use four screws to hold the fixture to the pallet. One other thing that has also been very useful is to have a base plate with just t-slots (You may have seen this in some of my videos). This is very useful to hold large parts, or even making your fixtures. It gives you much more flexibility for clamping something to the pallet then just its tapped holes.
One thing I failed to mention/ask. Did you use high strength all thread to hold down your fixture. The plain all thread from say the hardware store isn’t strong enough. It will stretch when you tighten the nuts. The stuff you need is called B-7 or ASTMA 193 High Stress.
@@EdgePrecision Exactly my thoughts (except metric grades) when I heard all thread. You can never seem to reach fixture fixture level tension between two surfaces with anything under 8.8 grade bolts, as they will just stretch apart, almost regardless of tightening torque and diameter
@@EdgePrecision i can personally vouch for b7 rod. I run an old g&l manual mill and everything is held down with 3/4 theeaded rod. A milwaukee high torque impact set to full power can't damage the stuff.
I remember watching the video of you setting up the Tormach in your garage. Come a very long way from then!
in the future you can take a small rubber pad, and put it between a sawzaw with no blade and run it against the surfaces, this acts as a pretty good concrete agitator and may have made it much easier to infill the project.
This one worked, the next will work better and be made faster with the knowledge gained. That’s a win. 👊
Well great work i never expected you can make the tombstone out of epoxy nice learn something new 👍
Another awesome video guys.
Excelent. We gonna make a horizontal tombstone to use in our Okuma multus 4000. Its not a main job thing, but it will carry us over with more potential customers until we can expand into a solid mill as well!
Uhhh... did you mean MU-4000? A multus is a millturn or multitasking lathe.
Unless you're actually sticking a tombstone in the bastard you madlad. I could see it being feasible with c axis nonsense.
@@orangedream267 It will be custom made, just 1meter long, maybe 300mm X 300mm box shape, able to handle high density small parts using miteebite clamp on custom fixture plates for easy swap and low setup time. Pretty basic stuff now days.
As said, it will only be a odd job here and there, but we can expand the working envelope with just not letting the machine name dictate what you can do with it.
@@steinarne79 That's not the issue here... I'm trying to understand if you're sticking a tombstone inside a LATHE, or a 5 axis. Or maybe a different okuma that you're misnaming.
I was looking into this, about two weeks ago... Haha, thanks for the video.
Be keen to know if you see any differences in surface finish between your cast iron and DIY epoxy tomb stone (vibration absorption properties). Thank you for sharing so much info on the process + prices, etc.
Another option is UHPC (ultra high performance concrete). It's flowing really nicely and is self-venting, without shaking or putting it under vacuum. It's also really strong, I'm planning on making a machine base out of that stuff (as many others did before me). Just can't use concrete with anything aluminium while it's wet, it will influence the curing process negatively.
alu will rust in concrete you need to smear it with epoxy or do some metalic coating. UHPC also shrinks so you must use a shrinkage reducer like ECLIPSE FLOOR, it will help long term with micro cracking, its a must. I initially wanted to cast in UHPC E80, but for my build 500kg the price was the same between UHPC and EG. I decided on EG in the end due to longevity of the cast. I have a vacuum pump and a vibration training device on hand so no additional cost there either.
A recip saw with no blade, with the nose pushed on the form, works to vibrate pretty good. Do not vibrate more than is needed to remove voids to avoid aggregate stratification.
I've never thought to use a recip saw as a vibrator. Thanks for the idea.
@@AnunnakiAaron They do sell silicone attachments for that use :P
@@MikrySoft yeaaaahhhh
Excellent!
A lot of people don’t realize that a concrete form tube is only design for pressure from the inside what you really need to use is a piece of PVC green sewer pipe
The outside also does not have the same coating as the inside, so the paper on the outside absorbs moisture faster
Interesting process.
I really dislike aluminum tombstones. I worked with them for about a year and as I got the machine and coolant up to temp I had to chase the growth of the aluminum up the Y axis. The machine had HP coolant but no chiller which made it worse.
I'm really curious to know if that tombstone will hold up or if the thermal cycles of the aluminum will eventually separate it from the epoxy.
Looks stupendous, keep it up.
Graniton or epoxy granite has been used for machine beds for many years. I think Titans have a Swiss surface grinder with a Graniton base.
Qué lindo proyecto. Muy bueno quedó!
You can rent or buy a concrete vibrator and or you can buy a vibrator or make your own using a ball bearing in a raceway using air !! They are pretty cool.
Did you by any chance have to return one of those epoxy kits due to a leak? I just snagged the same exact kit from an Amazon auction site for cheap and I am near your shop.
Did you have to drill and ream. For dowel pins to make sure the plates would not move.
Next time have a look at durfill uhpc. It is awesome stuff
Did you bake the sand beforehand?
Water is terrible with epoxy causes bubbles.
What’s the red all over the tombstone?
I have a question ;-)
There are threaded holes all around the tombstone which are drilled before the assembly and the epoxy filling.
You surfaced all sides afterwards to get them true, isn't there the possibility that these holes are also off some thousands?
i think they are just for holding your mounting plates, does it matter if they are off?
a threaded fastner is generally not precise enough for any precise positioning, that's done by dowels, pins, etc, so being a bit off here shouldn't matter any.
@@Echo51 thanks a lot for your answer
maybe besides saving money the most important value that you got out of this project is that you learned something yourself
I really don't like permanent aluminum fixturing, we use it all the time on short one time jobs but for something permanent like a tombstone I would have used something like 410 stainless.
Since most of you pallet is plates that are like your regular product line, maybe you can offer a tombstone kit for sale.
Can epoxy tombstones survive / cope with -26º C / -14⁰ F western temperatures?
Has someone tweaked your camera/encoder settings? You've got a lot of pretty bad de-interlacing artifacts on the facecam video at the beginning.
"Cast iron is miserable to machine" lol thats mostly what i cut both on a manual boring mill and a cnc mill. I actually prefer iron over steel in most cases but maybe I'm just weird.
I machine cast iron and steel regularly. I think knowing the differences on how the materials cut is really the main factor. The best comparison I have is the difference between trying to cut frozen butter and refrigerated butter. Different cutting tool geometries and feed speeds really make the difference.
@@mikezaq1 the dust is what usually makes people hate cast iron. On an open machine like my boring mill the dust floats quite awaits and covers everything and on a CNC it gets trapped in the coolant tank. The nice thing is you dont have to fight stringy chips, it doesn't stress relief nearly as much as aluminum or steel, and while you don't get a mirror finish it's pretty hard to get a crappy surface finish.
cosine error 6:00 ?
What if you'd fill the inside of the tombstone with a non-Newtonian liquid?
That would be interesting!
Just spray paint the sonatube to avoid cardboard saturation 🤷♂️
I’m surprised aluminum is strong enough and thermally stable enough for this given the precision you require.
It really isn't. But I guess these tombstones will work during John's learning curve with this horizontal mill, since he had to have 6 of them. In 3 years, he'll come back with some improvements.
Either way, Edge Precision's tombstone is an ideal version of what John wants. It's 4 welded slabs of steel. It even has an open top, and still holds itself well. That whole thing is pretty rigid.
0:15 I assume that's not blood?
Has anyone seen the new intern this morning?
Those are awfully thin walls on the EG. I would have left it monolithic without any holes in the middle. EG is not that heavy. Instead you could have added some piping to keep the thing thermally stable. Also the metal elements in the cast should not touch each other.
Geez you became grey and wise
The coolant something do with your eyes :(
I think it will be quicker and more efficient if you would just simply buy a big piece of aluminium for this project and make a solid aluminium fixture.