- February 25, 2018 at 10:36 am #53689
Not to muddle the conversation, but I’ve been messing with TMC2130 drivers using the SPI interface and I think our LCD also uses SPI, so that might be another reason to try the ASCII ones.February 25, 2018 at 10:44 am #53690
SquidPlanParticipantI doubt I have that kind of EE skill but after I get the 660 pimped out then I will crack open the 611. I guess it could be a possibility to use the built in speed control.
I feel like an oscilloscope would be in order. Those scare me. 😛February 25, 2018 at 11:06 am #53694
Honestly I was very intimidated by the LCD stuff. In all the arduino stuff I had done I have never touched the LCD any more than just the marlin boot screen logo. I love learning something new and getting over my stupid fear. Admittedly the Ascii is probably as simple as it gets.
I am going for a short hike then work on this some more.February 25, 2018 at 9:26 pm #53722
So, now that you have speed control down pat … how feasible would it be to take one of our favorite routers and build a CNC lathe? I’m thinking of something suitable for wood (can you say ‘pool cue’?) and using conduit to allow for pieces in the 3-4 foot length and up to 4″ in diameter. My 7×14 mini-lathe is too small.
1 user thanked author for this post.February 26, 2018 at 12:09 am #53725
I’ve been thinking about CNC Lathes a lot lately, how hard could a 13″ metal lathe be…February 26, 2018 at 1:22 am #53726
Does the router make less noise at a lower speed, or more noise?
I’m after speed control on a motor that would run at a constant 200 rpm, the work happening here seems to fit into that idea perfectly, I was originally intending to use a 24V DC motor, but I feel like a mains power motor may run a bit more silently…Only issue is the motor is probably closer rated to 1750rpm, would something like that still work at lower speeds?February 26, 2018 at 7:37 am #53732CNC Lathes
I know nothing about them. I have seen some crazy stuff but I guess I am going to need to look into them a little more. I can’t imagine anything being better than some sort of conversion though.
JJ, they do make a lot less noise but the 660 is rated for 30k rpm and seems to not be very stable under 8k.February 26, 2018 at 7:52 am #53735
For a lathe you are really going to have to slow things down. Now you are talking about spinning the work and moving the cutting edge which is held stationary. Going to need some serious rigidity, lots of torque, and slower speeds. And likely you will end up with a random electric motor and a gear drive to accomplish what you need. They are not complicated machines but there is a reason they are typically heavy. Thats a lot of mass thats spinning around vs with a router when the work is stationary and the moving mass is relatively light.February 26, 2018 at 12:23 pm #53783
I visualize a MPCNC laid out with a 48″x6″ work area, no Y conduit in the center and two Xs 4″ apart (tied together so one pair of steppers, just like the MPCNC, or perhaps a lead screw and one stepper instead). There’s a platform on X that holds the cutter, and the cutter mount to the platform is where most of the rigidity is needed. No need for a Z axis, though you might do motor speed control with it. Y axis is likely belt driven, due to the length. Y axis moves using similar roller assemblies as the MPCNC, X likely uses linear bearings and smooth rod. DeWalt mount off center at one end and either uses gears or pulleys to divide speed into something reasonable, then uses the new PID controller for fine increments. Pulley/gear mounts on pillow block with bearings and other side has chuck with 0-4″ grip range. Other end has a drill style chuck to hold centering pin, drill bit or threading tap.
I’m not sure how to get the software working, X axis moves ‘draw’ on both sides of the center at once. Depth of cut on X, so maybe we’re really looking at a Y and Z axis and carving a line that moves ‘up and down’.
February 26, 2018 at 2:09 pm #53801
- This reply was modified 2 weeks, 4 days ago by Bill.
So you’re saying there would be a spinning bit, and a spinning workpiece? And the bit would be on the side, the closer it got to the rotational center of the workpiece, the deeper it would cut?
Cam would have to know what depth per pass it could cut and how fast it could travel on Y. Making it be Z would be easier, but you’d still have to be basically carving along a line, not along a surface.
Something like you’ve drawn a line in CAD, with a certain depth profile. The CAM needs to travel along that line only, and not exceed a certain depth per pass, or speed along the line, or total depth for the profile… Hmmm. That’s a tough one. Maybe there’s a way to take a profile and easily make an STL that would work.
If it was an XY design, then it would have to always start at the top, and not exceed a depth in X, which it has no constraint for so far.
Maybe because it’s a single pattern, it could be done with some simple code instead of using EstlCAM or something.
I don’t really understand why this needs PID speed control either. Are you planning on controlling the speed of the lathe? I have seen spinning lathes against spinning router bits before. I think that would take a lot of the guesswork and rigidity out of it. You’d still have a real mess if you ever dug too deep.February 26, 2018 at 4:25 pm #53832
As Johnny says, there’s a lot of mass when spinning your work, especially when changing speed, but since the center of mass is pretty close to the center of your work piece in most situations the torque needed to keep it spinning is much lower. Either of our routers should have plenty of torque as long as we’re not trying to spin up a good sized stump.
Of more importance is the design of the tool holder. You want as little flex as possible, so lots of back bracing.February 26, 2018 at 4:33 pm #53836
No spinning bit, the router is used as the lathe motor. The bit is held against the spinning work piece and it’s the movement of the piece against the bit that cuts. think of a long skinny MPCNC layout except what’s normally the X axis is connected to the Z stepper. The center of your spinning piece is zero for the Z, the outside of your piece is your ‘top of piece’ for Z. You cut down Z in your normal increments and never need to move the X axis. At one end of your Y axis is the router, spinning the piece through gears or pulleys, at the other end is something that either holds the end steady or cuts in at Z zero.February 26, 2018 at 5:20 pm #53846
If you really wanted a lathe type machine a rotary axis on the MPCNC is pretty much ready to go with a 2 or 3 options on thingiverse already. Keep the endmill spinning fast and the material spinning slow.
PID first (I hope), then I think I have a solid MPCNC update in mind, before I get to any new toys.February 26, 2018 at 6:20 pm #53853
Well I havn’t made any progress because I can’t freaking figure out how to get the dang code uploaded to github….grrrrr. Using it like I always do but for some reason sourcetree won’t let me login to the new repo I created online. Sometimes stupid little things really put a damper on progress.February 26, 2018 at 6:34 pm #53854
Sorry man. I don’t do windows. 😛February 26, 2018 at 6:37 pm #53855
oh dude this is so irritating. I can do all my firmware stuff just fine….that has 1.453 million zillion files. The PID has 2 text files….I don’t get it. One more try this evening before I give up again.February 26, 2018 at 6:53 pm #53856
One possibly helpful thing. When you make a new repo in github, it initializes it with license and readme files. If you created a new repo on your computer, then you’ve already got two branches without common ancestors. Try just creating the repo on GitHub, cloning it with your program to a fresh folder, and then copying your files there and adding/committing them there.February 26, 2018 at 6:58 pm #53858
That is how I started. Then no go. So I deleted the local stuff, started fresh, cloned the 2 docs. Tried to push a readme update, then a fork. No go on either. There is something wrong with the login from sourcetree to github. Or more likely I missed some sort of setting and can’t push.February 26, 2018 at 7:53 pm #53861
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