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Re: Overengineered CoreXY - 7 years ago
SOooo, you're planning on a welded frame made from angle iron? Then also plan to machine all the linear guide surfaces.by prot0typ1cal - CoreXY Machines
Re: What type of machine would this be - 7 years ago
Quoteo_lampe Quote... unlike Delta and Polar configurations that each require completely different G-code. They run on the same gcode, but require a different firmware. I'm sure that's what you wanted to say? Yea thanksby prot0typ1cal - General
Re: My coreXY design is progressing to the build stage - 7 years ago
The "Rino", it's a worm drive? For the Z, that makes total sense.by prot0typ1cal - CoreXY Machines
Re: My coreXY design is progressing to the build stage - 7 years ago
DC clutch/break on the Z motor, or any toothed pulley for that matter, may be an alternative. Though if properly counter-balanced, the detent torque of the Z stepper may well be enough. Absolutely, belt ratios will help. Most designers don't consider "what-if". Very proactive of you.by prot0typ1cal - CoreXY Machines
Re: What type of machine would this be - 7 years ago
You still have a motor on the gantry for the X drive belt. Bowden removes the extruder motor from the X-carriage, opposed to the direct drive method. I was tempted to get the Folgertech FT-5, because they use 2x motors to drive the Y to compensate the extra Y-gantry mass. Solid design, XY linear guides. easy to build. The only thing I didn't like about the FT-5 is the melamine, though there's alby prot0typ1cal - General
Re: My coreXY design is progressing to the build stage - 7 years ago
Wouldn't be easier, and more precise to place an accelerometer on the bed? Something like a Adafruit ADXL326 3AXIS ACCEL BREAKOUT BRD, lists for under $20.by prot0typ1cal - CoreXY Machines
Re: How can I fix belt shifting? - 7 years ago
Those smooth idlers look kinda small. Not that it matters much, but the offset idlers on you're Y carriage will torque the linear guide blocks. If they're cheap Chinese blocks they'll ratchet some. Regarding your belt path to the X-carriage: Since the back lengths are at an angle, this will cause the belt to stretch/slacken during X moves. Basic trigonometry, or simpler, Pythagorean theorem. Twiby prot0typ1cal - CoreXY Machines
Re: Newbie to CoreXY with DBOT build - 7 years ago
What DD said. Threaded rod, leadscrews, and especially ballscrews, have more than enough mechanical advantage to drive a 3d printer bed. The 3 belted screw approach is probably the best for support and balance, and provides leveling while the set screws on the pulleys are loose. Set it, and forget it. The big disadvantage of multiple motors is they are not guaranteed to be 100% in Z-synch afteby prot0typ1cal - CoreXY Machines
Re: My coreXY design is progressing to the build stage - 7 years ago
Seems odd you didn't put the X leveling arms as far from the single Y pivot as possible. Adjusting the Y will result in the greatest change in roll ATM. Plus, you're gonna to have to rely on a spring and/or position heavy builds so the CG is inside the 3 points. Springs are cool and will probably work just peachy, yet having been a machinist, and indicating in all kinds of countless stuff, lastby prot0typ1cal - CoreXY Machines
Re: Fastest 3D-Printer in the World - 7 years ago
Airwolf Axiom gets my vote for state of the art. Fastest would be the 3DP by MadeInSpace, escape velocity is like 25,000 mph!by prot0typ1cal - General
Re: Newbie to CoreXY with DBOT build - 7 years ago
Spiffcow's "Spiffbot: and JonnayLin's "J-Bot": are remixes of the famous D-Bot, that use 4x guides on the Z rails. Problem with the roller guides is they obscure the possibility of an easy enclosure, you need to add another box outside the bot Good luck on your CoreXY buildby prot0typ1cal - CoreXY Machines
Re: How can I fix belt shifting? - 7 years ago
Dude, at that speed it isn't torque trouble, it's something jammed or sticking.by prot0typ1cal - CoreXY Machines
Re: CoreXY "Arm" Variant - 7 years ago
I like the design referenced in the youtube GRAYWOLF posted. Access to the print bed is really good, part count is low. Belt lengths are shorter than a standard CoreXY Z-Column adds to the foot print some, and needs a filament guide. Looks to be good enough for 3d printing.by prot0typ1cal - CoreXY Machines
Re: How can I fix belt shifting? - 7 years ago
Quotethe_digital_dentistThe width of the belt doesn't change the pulley diameter recommendation. Agreed. Wider belts help transmit more torque (less slip), which seems be the case here. Thanks about the suggestion on lowering Jerk settings, something I'm not familiar with.by prot0typ1cal - CoreXY Machines
Re: How can I fix belt shifting? - 8 years ago
Drive pulley may be too small. Recommended minimum pulley size for GT2 belts is 40 teeth, and a minimum engagement of 9 teeth. About the only way round this is use wider belts, or create more wrap on the drive pulley by adding an idler so the belt wraps the drive pulley by more than 180 degrees. Guessing you have a CoreXY, as this is the CoreXY sub forum. DD is right about the 45/135 move. Onlyby prot0typ1cal - CoreXY Machines
Re: Are the two different masses of the XCarriage and whole Y+X gantries for the other mass a real issue? - 8 years ago
Amen brotherby prot0typ1cal - CoreXY Machines
Re: My coreXY design is progressing to the build stage - 8 years ago
Considering you have a heated enclosure, can't see there's going to be a significant heat loss in the ears. Plus, they'll have fillets, not sharp corners like your models, so stress is no longer a concern for me. Not that that matters, given its 8mm thick Yep, thermal expansion. The heated enclosure will keep the differential between the bed and Z-frame to around 0.4 mm total, for a 300 mm span bby prot0typ1cal - CoreXY Machines
Re: Are the two different masses of the XCarriage and whole Y+X gantries for the other mass a real issue? - 8 years ago
You can make a brick fly with enough thrust. Every build is going to be a combination of mass, force, friction, strength and rigidity, regardless of configuration (CoreXY, Ultimaker, H-bot, Cartesian, etc) Where those limits are will depend on those variables. It's only a problem if the design uses a bad combination. Calculating accel/decel curves so there's no missed steps or stutter, is whereby prot0typ1cal - CoreXY Machines
Re: Are the two different masses of the XCarriage and whole Y+X gantries for the other mass a real issue? - 8 years ago
QuoteDjDemonD So which unbalanced loads in a standard corexy does the design above compensate for then? Inertia... The Ultimaker style XY carriage provides for the same mass being moved in both axis, something that most other configurations don't. Don't be misled by the kinematic equations for CoreXY, it does not incorporate mass (variables). Forces are balanced in a CoreXY at the out board idby prot0typ1cal - CoreXY Machines
Re: Are the two different masses of the XCarriage and whole Y+X gantries for the other mass a real issue? - 8 years ago
One way to balance loads in a coreXY would be to mate it with the cross beam design of the Ultimaker. Their kid's coyote ugly, here's the required late night sketch with twice the hardware and the ultimately unnecessary long belt runs:by prot0typ1cal - CoreXY Machines
Re: CoreXY "Arm" Variant - 8 years ago
Looks like an H-bot with the right side cut off, and the orphaned motor moved to the left side. Even more prone to racking, and without the extra support, more wobble. The AxiDraw is similar in kenimatics. Though you most likely have parallel rods in a vertical plane, rather than horizontal. Suggestions: You could put a idler with bearings on the motor shaft, along with a drive pulley, if the sby prot0typ1cal - CoreXY Machines
Re: Work in progress - new build taking shape - 8 years ago
Yea, I'd be concerned too about the Z. Chances are the preload on the linear truck isn't much. Bolt a long something on the cantilever to see what play you have and take it from there. About dual carriages, instead of going cartesian (IDEX), you can jump from CoreXY to CoreXYU:by prot0typ1cal - Reprappers
Re: From Delta to CoreXY - 8 years ago
Going from Delta to CoreXY, you're gonna need a lot more pulleys. And there's probably 4 or 5 ways to implement CoreXY. Search Thingiverse.com for CoreXY. Tons of designs, true most use rods or V-slots. There's also few good ones here that use linear guides. Just start browsing this sub-forum.by prot0typ1cal - CoreXY Machines
Re: My coreXY design is progressing to the build stage - 8 years ago
Yea, if you're milling it out, radius is a given. Lots of choices for process these days. True, 8 mm is kinda thick, and for printing more than strong enough. It's when brute force is needed to remove prints, that bending or breaking happens. Without even a thermal analysis, being narrow, the legs are actually better at pulling heat. With a higher surface area to volume ratio, are more likely toby prot0typ1cal - CoreXY Machines
Re: My coreXY design is progressing to the build stage - 8 years ago
Another solution would be tooling balls, shanks pressed into the bed (they're always hardened and ground), and cups on jack screws from the frame/support. The jacks even could over hang the end of the aluminum extrusions for easy access. Down side, tooling balls are pricey, and you need three. An opportunity for improvement is the leveling legs. Why so narrow? Currently, there's 3 stress risers:by prot0typ1cal - CoreXY Machines
Re: Hlidskjalf, Dual CoreXY - 8 years ago
Quoteanvoice Out of curiosity, what are you planning to have it mill? I doubt that the frame is rigid enough for metal work, so I'm guessing plastic/wood, or engraving? With high speed machining, I'm hoping to do some aluminium. No full width cuts, typically only 10-20% cutter width and 1/8" diameter cutter max, and depths of only .05-.10 mm deep at 50mm/sec or less. Not done with the frame yetby prot0typ1cal - CoreXY Machines
Re: Hlidskjalf, Dual CoreXY - 8 years ago
Quotedc42 It makes sense to me, but you need to add the drive system constraint delta A - delta B = delta C minus delta D. Done, also fixed the delta C and delta D vectors, they were on the wrong side of the loop :pby prot0typ1cal - CoreXY Machines
Re: Are the two different masses of the XCarriage and whole Y+X gantries for the other mass a real issue? - 8 years ago
Quotethe_digital_dentist "negative energy", "fluctuating equilibrium"? Gimme a break... I think you've been studying too many youtube videos of perpetual motion/free energy scams. LOL Based on your observations then, would the graph for "contributed motion" be a sine wave? That is to say, there's two horizontal parallel lines, one is Motor A at 100% with B at zero, the lower line B @ 100% andby prot0typ1cal - CoreXY Machines
Re: Hlidskjalf, Dual CoreXY - 8 years ago
Just throwing this pic out there, please tell me if it makes sense:by prot0typ1cal - CoreXY Machines
Re: Are the two different masses of the XCarriage and whole Y+X gantries for the other mass a real issue? - 8 years ago
Quotethe_digital_dentist When I manually move one motor in my coreXY mechanism, the detent torque of the other motor (and friction) is sufficient to prevent it from turning. The second motor is not contributing to the motion whether it is powered or not. The locking torque must counter act the inertial loading of the combined masses of the gantry and X-carriage moving, thereby significantly afby prot0typ1cal - CoreXY Machines