Machine Upgrade Considerations

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Dan O
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Machine Upgrade Considerations

Post by Dan O »

I'm beginning to think about upgrading my CNC. I don't have any real issues with the Shapeoko. It does what is expected. Specifically though, I'd like to speed up the 3d finishing process. So my question is - will a higher HP spindle/router motor and more rigid machine frame decrease the finishing cycle time? Of course the roughing time will decrease, which is good, but will the extra mass of a more rigid machine and spindle offset any potential increase in speed? Currently, I finish with a .125 Tapered Ball Nose at 80 to 100 IPM with good results. Maybe I could go faster, but, depending on the detail of the carve, it's moving pretty quickly already. Your opinions/observations/ experiences are welcomed.

Dan

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Leo
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Re: Machine Upgrade Considerations

Post by Leo »

I never owned a Shapeko - so I don't "really" know for sure, but my guess would be YES - depending on what you upgrade to.

For me, I had a Larken 24 x 24 machine. It had a perske ER16 air cooled spindle.
It was a nice little machine with NEMA 24 steppers.

I upgraded to a 1300 x 1300 x 254 mm machine --- 51" x 51" x 10"
It has a ER20 4 hp spindle with NEMA34 steppers.
It has a 10" FULL rotary w/NEMA34 with rotary axis drives in control - no axis swapping.
I bought direct from China and did all the import stuff.
It's a big upgrade.
The machine is a lot faster and a lot more powerful.
My machine cost $7,000 including all costs; Machine, Rotary, Import costs, Shipping costs and all install costs in 2015

AVID CNC
SHOPBOT
CAMMASTER
Lots of options available

What sort of performance all depends on what you upgrade to.
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Adrian
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Re: Machine Upgrade Considerations

Post by Adrian »

My gut instinct is that there is a sweet spot of mass for 3D work that might mean a machine that is the bees knees for cabinet work might be outperformed by a smaller, seemingly less capable of machine.

I've only ever owned two machines and they are a very long way apart in capabilities though. I also do next to nothing in terms of 3D these days so it's just my opinion based on a loose grasp of the physics involved.

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Tex_Lawrence
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Re: Machine Upgrade Considerations

Post by Tex_Lawrence »

I do a bit of 3D cutting mostly objects the size of 6" x 6" (some smaller.)

Roughing is done with either a 1/8" or 1/4" endmill, depending on the size of the part.

I generally use two tapered endmills; 1/16" & 1/32". What I'm getting with that is a small step-over distance where the finishing bit is helping to cover up the start bit marks. I usually only have to clean up small fuzzies and perhaps smooth some detail. My feeds are between 35 and 70 ipm. Works well for me.

I've tried to speed it up, but the fine details always suffer from speed (depending on type of wood.)

I suppose the point I'm making is that my machine is never really loaded or near capacity. The finish on the part is where the limit is.
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Leo
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Re: Machine Upgrade Considerations

Post by Leo »

DEPENDING on the shape and size of the 3D work, I can run 125 - 350 IPM on 3D work. I actually do a fair amout of 3D work.

I also have a client with a 4 x 8 x 12 machine.
I do all his programming.
His machine is the same as mine but longer.
I also bought his machine and imported it for him in 2017.

He makes 3D items up to 60" x 18" x 2". I run his 3D at 250 - 350 IPM.
On the 3D roughing passes I run about 250 IPM and hog away material really fast.
He used a 1/2 carbide ball mill for all the cutting.
Time for a 60" 3D Whale is about 60 minutes.
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FabLab Wageningen
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Re: Machine Upgrade Considerations

Post by FabLab Wageningen »

Leo wrote:
Thu Dec 29, 2022 6:16 pm
He used a 1/2 carbide ball mill for all the cutting.
Uh, a half-inch mill ? As in 12.7 mil. ? That's EVIL. I'm blown away.

Marcel.

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Re: Machine Upgrade Considerations

Post by litzluth »

I routinely use a 3/8, 7/16, and 1/2 ball mill for 3D roughing/finishing on guitar necks. I have to be very careful with the Z travel speeds.
I have a Laguna IQ with the 3 hp water cooled spindle. Seems to handle it fine, although the neck heel carves require longer mills (up to 5") so I can definitely tell which direction the mill was moving into the wood!
Laguna sometimes has an end of year sale and you can buy the IQ for less than 6K. Pretty darn good deal at that price.

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FabLab Wageningen
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Re: Machine Upgrade Considerations

Post by FabLab Wageningen »

ah, that explains,

You run a real, serious spindle. We have a glorified 1 HP DeWalt. Max diameter size 8mm or 5/16". But we're still happy we at least have a CNC :D

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Re: Machine Upgrade Considerations

Post by 4DThinker »

The speed of cuts on most machines is self limited by acceleration/deceleration between nodes. On deeply contoured 3D cuts with toolpaths set to 200ipm I can watch my control software (linuxCNC) to see the bit speed rarely exceeds 30ipm. There are smoothing variables in G-code than can quicken curve cuts but they sacrifice accuracy which may matter more in 3D model cutting. Cutting the same 3D surface map on a 25x25 Probotix CNC and a 5' x 10' Multicam CNC the time taken was within a few minutes out of a 2 hour cut. The reason was mostly due to the Multicam's quick safe travel between toolpaths.
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Dan O
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Re: Machine Upgrade Considerations

Post by Dan O »

Thanks everyone for your insights. As expected, rigidity and HP are considerations. But 3D finishing doesn't generally require a lot of HP. The accel/decel issue is what I was wondering about. I watched a You Tube video of a machine using a 5/8 cutter running 600 ipm is solid Oak. (pretty impressive) except the machine came to a dead stop while stepping over to take the next cut. I think it would take a long time to carve a 3D model like that. 4DThinker, thanks for that info. I didn't know that the motion control software should also be considered.

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Re: Machine Upgrade Considerations

Post by Leo »

Dan O wrote:
Fri Dec 30, 2022 2:28 pm
4DThinker, thanks for that info. I didn't know that the motion control software should also be considered.
That is what I was referring to when I said it depends on the size and shape of the 3D model.

True that there is not a lot of horsepower for a 3D finishing cut, but if you really want to speed up the whole picture the roughing cutting is where the HP comes in handy. Also the roughing stepover can leave significant material for the finishing cut. So much so that the finishing cut will be removing some significant material and plunging into area that the roughing did not cut into.

There are ultimately many ways to do what is desired with different settings, tooling, methods, cutting strategies to get the job done.

On control software, I am currently using Mach3. While there is nothing wrong with Mach3 I am at my end with getting acel and decel and look ahead, and lots of other settings. BTDT as they say. Don't read that wrong - Mach3 is great. I have a couple of other hardware issues that I want to fix in addition to Mach3. I am looking for more - so I bought Centroid Acorn hardware and software to upgrade my machine. I am hoping that is improves my 3D machining performance. If it does, I will also upgrade my clients machine.
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Leo
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Re: Machine Upgrade Considerations

Post by Leo »

FabLab Wageningen wrote:
Thu Dec 29, 2022 8:18 pm
Leo wrote:
Thu Dec 29, 2022 6:16 pm
He used a 1/2 carbide ball mill for all the cutting.
Uh, a half-inch mill ? As in 12.7 mil. ? That's EVIL. I'm blown away.

Marcel.
Marcel, yes 1/2 ball mill. NEMA 34 steppers to push it around and a 4 HP watercooled spindle help a lot.

I have cut steep at 4-5000 RPM on my machine.
Light cuts, but it did it.
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FabLab Wageningen
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Re: Machine Upgrade Considerations

Post by FabLab Wageningen »

Respect

Certainly since you did a lot yourself and succeeded. I realise now that the only way I ever can become Master Of The Universe and fullfill my Evil Plans is to operate NEMA 43's. And that will not happen in a loooong time. So I now retract gracefully for the moment, biding my time. Tomorrow I still have to buy New Years Eve dinner.

Happy New Year to you all !

Marcel.

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Leo
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Re: Machine Upgrade Considerations

Post by Leo »

Marcel,

I had to save up for years.

Even at that I could not afford what I was drooling over which is why I went the Chinese rout.
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Re: Machine Upgrade Considerations

Post by Tailmaker »

Keep in mind, that many (but not all) 3d-cuts do not really need a time-consuming roughing operation.
Since the stepover for good surface quality may be small, the spindle is often capable to easily cut using full flute length.
That said, the flute must be obviously long enough to cut the deepest point of the part from the top.
Also, that works well, e.g. for dish shaped or dish surrounded models that start gradually from the surface.
If you have models that start at full depth in the very first row of the finish cut, you may need at least a narrowly roughed slot (using an appropriate vector boundary) to get the finish started. Or the bit will try to do the first row at full depth and full bit width which is not good...
Alternatively, for free standing models you may start the finish cut in air outside the actual material.
I use that method all the time when I can. Besides the time saving, it also distributes the bit wear over the length of the flute.
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