# Probotic CNC Machine



## klw

Great forum and long overdue!

I have a question about the Probotic line of CNC Machines. Anyone have one, and would you recommend it?

I've just started to look at CNC machines and it seems to have some pretty good specs…

Not looking for a big discussion on "what's better" as this one (FireBall Meteor) is in the price range and size I am kind interested in, but is it any good?

All info will be appreciated and welcomed.

Keith


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## FatherHooligan

Back when I was a lot more into cycling and really knew all the different component manufacturers I'd look at what a given bike was made up of as well as the brand of the particular bike…so often if it was not a top of the line bike brand it may have had particularily good components so that particular bike ( or model of bike) may have been better than the brand name suggested. I'm wondering if it is the same with cnc machines? Could you have really good well-known parts in a particular unit that would make it a strong competitor with 'name-brand' machines?


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## Underdog

Keith, I'm sorry I don't know anything about the machine. My experience is limited to the KOMO VR510 and my little CarveWright.

But I'll give a bump to this thread anyway…


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## oldnovice

My experience is limited to Shopbot, which I own, Legacy, which was my second choice, and the CAMaster Stinger, my third choice, and I have never heard anything about Robotic CNC.

I researched CNC machines for nearly two years before I bought the Shopbot … but it was a tough choice between the top three finalists.


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## DS

Did you mean probotix?

http://probotix.com/

They look like a basic desktop hobby setup. Can't speak for their specific quality, only that for a hobbyist, it will probably be fine. For any level of production, you'll likely want more machine than those.

Support will be a big deal unless you are the guru of all things cnc.
My 2 cents


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## klw

Thanks, yes that is the one - should have stayed in spelling class…


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## dannelson

I would shy away from a machine that has a rapid move speed of 200 in per minute. I would guess that cut speed would be a quite a bit slower. Painfully slower, And cutting with a trim router would limit your depth and speed of your cuts. Just my opinion.


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## oldnovice

Since I am not in a production environment, just a hobbyist, I have my cutting speed typically set at 1.7"/sec, about 102"/minute, wile the actual maximum point to point positioning speed for X and Y is 1800"/minute.


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## DS

Most hardwood is cut at around 200ipm to 400ipm depending on the tooling, material thickness and machine capability.

Panel processing usually is done a bit faster between 400ipm and 800ipm. With high speed tooling, I've cut parts at 1100ipm, though the chip load window (variations in feed rate, spindle rpm and depth of pass) is really small and had to be dialed in for each specific material.

A typical rapid move is about 1200ipm. (Hans, 1800ipm is a pretty fast rapid move for any sized machine)

Keith, if I were in your shoes, I'd first determine what I will be doing with the machine and make sure it will be capable of those tasks. Worry about everything else second. Nothing is more annoying than spending a chunk of money and still not being able to meet your needs.


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## klw

DS, Thanks for that info.

Part (most) of my problem is I'm not sure what I will be doing! I rushed and bought a used "I Carver" thinking it was a "CNC" machine, but it's not really.

I would like to be able to design something and cut it out. I presently do some flat work and lathe work so looking to expand my abilities in my little hobby shop.

Knowing nothing about them is tough - don't even know what to ask about.

You say you cut anywhere from 200 to 1100 ipm, where as dannelson (above) said that 200 was too fast, and would make a slow cut. Hard to wrap my head around that sort of thing, so I just keep googling 

Thanks for your reply.


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## DS

Actually I read what dannelson wrote as saying he would shy away from a machine whose rapid traverse speed is only 200ipm. Rapid traverse means there is no interpolation. Each axis moves as fast as it can (does not guarantee a straight line)
When it is cutting, that machine would be a lot slower (less desirable)

Cut speed boils down to chip load. The chips carry off heat. Too many flutes, too slow a feed rate, or too fast rpm will all lower the chip load (smaller chips = less heat carried away from the cutter and burns on the wood can occur.)

The opposite condition, too few flutes, too fast feed rate, or too slow rpm can put too much much mechanical stress on the spindle and/or the cutter. Either way, the result is bad cuts and broken router bits.

If your machine can't cut very fast then you need to compensate by selecting tooling with fewer flutes and lower rpm's.


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## oldnovice

*Doug*, you wrote "1800ipm is a pretty fast rapid move for any sized machine." are the specifications for a point to point, not cutting move, for my machine as posted by Shopbot but I have never moved at that speed.


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## DS

Yes, Hans, I recognize that wasn't a cutting speed. As a rapid traverse speed, that is still the fastest I ever heard of - and I've worked on quite a few machines.


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## oldnovice

*Doug*, there is a relationship between the any X/Y/Z moves for cutting that is dependent on communications speed with the Shopbot as it is connected via USB to the CNC. 
I really don't like that but until Shopbot embeds a controller, or a PLC, on their machines that's the case and that is why I am interested in approach you are using for your CNC!


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## ssnvet

I think that on a 4' x 4' gantry router, 400 ipm would be plenty fast.

The thing to keep in mind when considering machine specs is that on smaller machines (i.e < 4' x 8') you're likely to never realize some of the theoretical max velocities, because you'll seldom (possibly never) see a straight run long enough to accelerate to that high of a velocity.

On the mid 80s vintage 5' x 10' stepper motor router we ran at work for years, 400 ipm seemed stinkin fast.

Now we run a servo motor machine that tops out at 900 ipm on the transits.

The cutting speeds DS referenced are consistent with our experience. But over time, we've learned to pay close attention to how hot the chips cast off of the cutter are. Hot is good, as that means that the heat is being transferred into the chips and away from the cutter.


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