Setting this discussion up to gather up and brainstorm ideas.
LIST OF EQUIPMENT AND MATERIALS UNDER CONSIDERATION:
Materials to be Used:
Some design considerations:
Everyone feel free to inject any comments. This is your chance to provide input on what features go into the DIYDrones CNC Machine!
Current Bed Size:
Currently we're thinking the bed size will be 18x24 inches.
Insights from bGatti:
Some observations I can offer from experience:
1. Inexpensive skate bearing are not well sealed, and will likely stick if exposed to wood dust.
2. The most vibration on my machine is twist across the gantry - so make the gantry height ~twice the height of the lower extremity (from the table).
3. Parallel ports are increasingly harder to find - especially on laptops.
4. It doesn't take a lot of power to move a cnc machine - you will probably want to turn down the power to avoid breaking bits / bending the spindle shaft anyway - so don't specify a motor system which is stronger than your specified spindle. Anything which can be cut quickly on a strong machine, can be cut slowly on a lesser machine. $1000 is a lesser machine.
5. I have a wooden bed; I'd love an aluminum bed, but with $1000 to spend, the wooden bed isn't my biggest challenge. (It's gantry twist and probably runout for PCB Boards).
6. 3D printers want speed more than brute rigidity - most blogs on the subject of hybrids concede this point - which said - there are many parts which can be made slowly - but some parts call for a flying buttress - which does depend on a certain rate of speed.
yes I also saw that video and was a believer from that moment that we can get a nice machine for not too much money. I am sure the Monroe special edition will be even better!
wow Monroe, this looked so easy to cut!
and that guy's website has a ton of information
nice finding. not time to wipe excess saliva from the keyboard!
ha. I think Dany is where I am. I want to Monroe special. I've been re-reading the forums, and picked up on comments from Monroe such as ("I'm going to have a 3/4" bed".... Bigger is possible... etc. etc.).
Yep. That's the one I want. Just like Monroe's.
I have premium, and COMSOL & mod too run via CUDA's on my Tesla GPU.
You need to run a dynamic analysis, since it's the vibration thats the problem.
But I'm telling you all in for a big surprise when it comes to cutting Aluminum, the forces are just not constant. One sheet will cut fine, next will gum up or start breaking bits. Some parts will cut fine, others will not, even though you think your running at same feed's and speeds.
Even with good 6061T6, and a new Haas VF5, things don't always go our way :(
Which is why I personally cut all our prototyping parts, even now :)
A few simple questions, but why not just contract out for your aluminum cutting ?
Them design a machine that will work best for the other materials that are processed?
Are CNC shops charging that much there?
Someone still has to watch the machine, 100% of the time when cutting aluminum (it will break a bit or gum up), with anything you build that is light.
Monroe can answer to the technical aspect of this, but from my standpoint I want a hobby machine, and something I can try out prototypes on quickly. So, I don't want or need to contract anything out. It would be nice, as Monroe puts it, we have a machine that can mill aluminium all day, that's just icing on the cake, for me. In fact, most of the time I would be milling plastics and just using it to drill holes into aluminium plates. It's nice to have a machine that can do more, for a good price.
Thats my whole point, you can't have a light machine that will cut aluminum "all day", so you will be compromising the design trying to do it.
Again look at what others have tried for example
They claim it will cut aluminum, and it will, for 5-10 minutes, then the bit breaks or gums up. In fact they have a room they demo cutting aluminum, and they show you the parts for there own machines are being produced by these routers, but if you leave, and come back 1 hour later via the back, you see it's all BS and they are cutting there parts on a Mazak Mill.
It's the same for all router companies, for the most part.
Well, I would have no problems running my machine 5 minutes at a time for the aluminium milling. Just build the pause into the gcode and let it go at it. Also, would a broken bit not be a sign of a bad machine, but simply that you need to get a better bit, that can handle that kind of duty cycle?
I have tried router bits specifically for aluminum, some damn expensive, never could make any of them last on a light machine.... comes down to the 0.0015" per tooth rule.
And its not 5 minutes at a time, it's just a matter of time, so if you demo for 5-10 minutes, on a new bit, you can get away with it 80% of the time.
The only router I have ever seen run aluminum, looked more like a mill then a router, google "Omnitech router". It has the power / weight to run 3/16" nigara A337 series mill at 0.0015" per tooth, and so it clears the chips and runs without 100% operator time.
You mean this?
I love that LMGTFY. ;-)
I like it!
Monroe, can we build one like this for $1000? I just had to get a set of new tires for my Jeep, so my budget has been affected. ;-)
It has nothing to do with it being a gantry, the AXZY gantry doesn't work when cutting aluminum, the Omnitech does.... difference ?
MASS - nothing else
I just built a gantry, 12' x 8' x 4' travel, with 120' feed system, all at 0.0005" accurancy well ramping, so there is nothing wrong with gantry designs.
This is what I do for a living, and I believe I can't make my point any clearer, your all wasting your time trying to cut aluminum with a light machine, just give it up and design something that will work well on other materials.
I would be happy to help with that
Well best of luck then, the day you have a light weight machine that can process aluminum "all day", you will have an instant commerical success, and prove me, and many other machine designers wrong.