am interested in building a cnc router that can route hard materials such as stone & steel as well as softer materials such as wood, plastic, aluminum, etc. Can you give me some feedback and guidance? Can one of the OpenBuilds routers do this? I would appreciate any help you can give me. Thanks, Jeff
No one machine will cover masonry, ferrous, non ferrous, wood, and plastic unless you are really spending a crap ton of money. You need a wet environment for masonry. Ferrous metals run at very low rpm and high torque (think 5k rpm). Non-ferrous wants at least double that to be efficient. Both can take advantage of mist or high pressure air for cooling and chip evacuation. Wood can't be anywhere near moisture and normally feature 24k rpm spindles. You also need a vacuum for dust extraction. Plastics usually fall under non-ferrous. Composites also need a wet environment, preferably a submerged bath.
Hi Kevon Thanks for your reply. I need some clarification about your response. Keep in mind, I am truly a novice when it comes to the subject of cnc routers. Anyway, I am assuming stone falls under the category of masonry as it pertains to your definition, correct? Wouldn’t masonry and ferrous materials require similar routing capabilities because of their hardness? I know routing stone would require water cooling, but why couldn’t a water cooling system be turned off when routing steel and a lubricant system of some sort be used for steel? I also don’t understand that if a cnc router has the capability to route hard materials why softer materials couldn’t be routed? Do all the motors for routers only come with one speed?Can’t the speed and / or rpm’s be adjusted for whatever the material need is? Same with the router bits. Thanks, Jeff
Size is the first issue. Hard milling requires rigidity. Making a machine rigid becomes exponentially more expensive as size increases. I don't foresee anyone being satisfied with working within a 12" x 12" space for wood. The second issue is the work environment, pretty much what I mentioned before. - You can't mix dry goods and wet environments. - Wood requires dust extraction. Metals require chip clearing. They may sound similar, but they are not. - Wood does not need active cooling, but ferrous metals do. Non-ferrous and plastics can get away with just good air blast. - Ferrous metals produce a lot of rust if you aren't using proper cutting oils. Don't even think about switching back and forth. You would be better off building two different machines.
If you have a way to keep your main spoilboard dry and submerge the stone in a cool "bath" you can cut stone. It will be slow. You may fail many times until you figure it out. There have also been people that have posted videos of their LEAD 1010 cutting steel. Again, you have to carefully figure out how to do it and you will have to baby sit it. So, if this is for a business, you will not be real productive. If it is for a hobby, there is nothing wrong with trying. I have endmills for cutting stone. I plan to build a water tight tray for the coolant that will mount to my spoilboard. It will have a vise inside for holding the stone. I just don't know when I will get around to building it yet. As Kevin said, a smaller more rigid machine may be a better option and I have considered building one just for stone and steel. As for non-ferrous metals, woods, and plastics my current CNC loves to cut those.
If you're just doing stone and steel, a welded, epoxied, heavy-duty machine is the way to go. The problem would still be the spindle- steel requires torque and more precise speed control than many other materials, usually in the 4000-12,000rpm range. It's quite difficult to find reasonably-priced spindles with these characteristics, you'd probably end up needing to buy a spindle cartridge and figure out how to gear a motor or servo drive to get it in the right speed range. A 10,000rpm-continuous rated (12,000 peak) BT30 spindle cartridge is about $1100. I have one, that I haven't put on my mill yet. How well would it cut stone? I'm not sure, I think stone prefers much higher speeds with very small cutting edges, more like grinding. Dual spindles? Sure. But then you have to protect the expensive high-precision spindle from abrasive dust and rust. Machine design is a rabbit hole. Multi-purpose machines largely don't exist because a) everything has wildly different cutting conditions and parameters, as previously explained, and b) workflow around machines varies depending on the product, you can't set up a shop adequately to deal with such variability and changeover would be slow. Multipurpose machines are basically the worst compromise between several different extremes, and so do several things badly instead of one thing really well. A good multipurpose machine would be one that does a few things that have similar-enough setups that you can deal with the adjustment process. Plastics and composites, for example. You'd need to build a waterproof machine for the composites, but otherwise it'd be pretty similar to plastics. It could probably do non-ferrous too, depending on the spindle, and the change-out between all of them would be pretty minor. Basically, you need to do a lot of machine design research to understand why machines are built as they are, or actually try and build one and learn the hard way, whichever is your learning style.
Thanks to all for this great feedback. I would have never thought that there are so many variables regarding cnc routers and their capabilities from one material to the next. Sounds like this could get more expensive then I would be willing to invest at this time. I was hoping for a more equitable solution for what I would like to do with a cnc. I will definitely have to give this more thought and in all likelihood limit my goals. So glad I became a member and a forum user. I would have made very poor choices based upon what I thought was capable. Most suppliers of cnc’s would never give this kind of advice. Thanks to all. I will update you as I go along and sure I will need more advice and input from all of you and really appreciate this. Jeff
