CoreXY has both advantages and disadvantages when compared to the H-Bot belt path, but I think that in general it is overrated by hobbiysts. I prefer H-Bot to CoreXY. Stratasys uses the H-Bot belt path in some of their printers, and H-Bots are also very common in high performance industrial systems (pick and place type stuff). In contrast, the CoreXY design is only found in very low cost hobbiby 691175002 - CoreXY Machines
Rigidity is limited by the weakest component in your build, so its hard to find a single change that will eliminate ringing. Major contributors of compliance will be the frame, belt, pulley mounts, and stepper motors. Timing belts are sufficient for this application, but you need proper width and tension (I suspect some of the chinese belts act like rubber bands as well). People also give stepby 691175002 - General
Along with from the usual precautions, you might want to swap out the wires for something more flexible. My Keenovo bed came with wires that are fairly coarsely stranded and I imagine they will fatigue and crack over time.by 691175002 - General
I'm pretty confused as to what is being asked in this thread. Rotary encoders don't provide any information a stepper does not already have unless the stepper is stalling or otherwise missing steps. Quote[...] So the arduino can calibrate it's step rate itself and not have the painstaking task of using either calibration prints or marker and vernier gauge to calibrate your step rate.[...] Theby 691175002 - CoreXY Machines
Quoterealthor Hmm, that's a pity. But it would be nice to have that feature in the motor drivers, so that they can let the firmware know when resistance was detected (tooth-on-tooth contact), so that the firmware only calculates distances based on that point onwards, basically neglecting the backlash. You would have to purposely lock the stage to measure backlash by stalling the motor, the motorby 691175002 - General
The cost/benefit tradeoff just doesn't make sense. There is no point in adding a bunch of wiring, sensors, and software when you could just spend $20 building a more rigid frame to begin with. Trying to fix low-quality physical systems in software sounds smart, but is nearly impossible in practice. Cheap mechanical systems do not fail in predictable or linear ways. Sensor data is too noisy toby 691175002 - General
No need for the cable, you can just stack the gears and put a spring between them. It gets even easier if you are printing helical gears because you can just put them on a spline or keyed shaft and slip a spring washer between them. This has the advantage of not being backdrivable so the anti-backlash properties persist even under high load. Your tooth form needs to be flawless for this to bby 691175002 - Mechanics
Why not extend/retract direct drive extruders using a solenoid or short travel Z stage? I'm not seeing any advantages of dual x stages over such a system. Splitting the weight across two X carriages does not provide any advantage because the Y axis still has to move the entire load and you want acceleration to be symmetrical across the XY axes or your prints will look different depending on oriby 691175002 - General
Adding bearings to existing pulleys isn't really an option, it is very hard to do concentric work on a timing pulley even if you have a lathe. Runout in your pulleys or idlers will introduce periodic error to the motion which is far worse than whatever artifacts smooth idlers may produce. From a geometry perspective using a smooth idler won't produce any positional artifacts but will introduceby 691175002 - Mechanics
QuotefmaBTW, do you confirm it is mandatory to have teeth on the passive pulley, for a 3GT (3mm pitch) belt? Toothed idlers will be recommended in the documentation, but in practice many low cost designs use bearings instead. I expect smooth idlers reduce belt life because they apply uneven pressure to the teeth. Belts must be under very high tension to achieve maximum performance in positioniby 691175002 - Mechanics
The answers to your questions depend almost entirely on what process is being used. Quoten9jcvIf I were to have metal parts made by a CNC shop, at the cheapest rate, what tolerance could I expect. For example, if my file calls for a 5mm hole, what would be acceptable 4.8 -5.2mm?? Again, I have no idea of what is typical. If your part is "flat" and can be cut by tilt-compensated waterjet (or lby 691175002 - General
I did some baseline math and a 2mm pitch x 9mm wide belt is rated to apply roughly 2Kg of force, so if you plan to achieve 2m/s^2 of acceleration the moving weight of the printer should be less than 1Kg. 3mm pitch belts are roughly 4 times as strong for a given pitch diameter. Many hobby 3d printers use very small belts at high accelerations but end up deforming the frame and producing ringingby 691175002 - Mechanics
You can get them from Misumi, although they run roughly $30 a pop. Note that despite confusion over nomenclature, GT2 and GT3 are distinct belt tooth profiles and both come in 2, 3, and 5mm pitches. The pulley tooth profile is identical for both GT2 and GT3 belts of the same pitch. For example part number 2MGT is a GT3 tooth profile with 2mm pitch, and would be functionally identical to GT2by 691175002 - Mechanics
Quotethe_digital_dentist Do you work for Misumi or sell Misumi products? No, its just that they are generally cheaper than 8020 and will cut, drill, and tap as well. They were good to us when I was on a student team, and even gave $150 of credit to each new customer a while back.by 691175002 - Mechanics
You can mount linear rail to extrusion just fine. The required flatness for linear rail mounting is only necessary to guarantee their accuracy specs, its not like the rail will bind if you bolt it to extrusion. You can get milled extrusion for Misumi that is explicitly intended for linear rail but I'm not convinced it will achieve anything given the accuracy requirements and rigidity of a typicby 691175002 - Mechanics
I'd feel safe putting ~4A through a regular D-Sub connector. Gecko does it on their stepper drivers and their products are very reliable: Beyond that, you can get circular connectors on ebay with some pretty ridiculous pin counts and current capacity: The power variants of d-sub are pretty nifty as well, but are kinda expensive and hard to find: Separate the high current lines and encodersby 691175002 - General
Unthreaded spacers can be used for imperial or metric screws since a bit of play is acceptable. Its hard to know how much room there is for improvement once you have stainless. Even with perfectly insulated fasteners, radiation and convection will allow the heat to transfer to the frame.by 691175002 - Developers
Just use stainless fasteners (standoffs/spacers). Stainless is a relatively poor conductor of heat (used in hotend heatbreaks) and quite cheap. If you want complete overkill you can get ceramic spacers very cheaply: A stainless fasterner through a ceramic flange and unthreaded spacer will have no metal on metal contact and only cost a few bucks. Suitable plastics are really too expensive toby 691175002 - Developers
It almost never makes sense to combine a 3d printer and a mill. Milling controllers are not suitable for 3d printing (with the possible exception of a complex LinuxCNC configuration) and 3d printer controllers are incredibly limited. I would never run a mill without work offsets or a tool table. Losing canned cycles and conversational would be quite painful as well. By the time you throw in aby 691175002 - General
Quoteo_lampe Wouldn´t the higher pitch of a lead screw outweight the acceleration issue? Saying, it doesn´t have to turn fast to achieve high speed at the gantry? -Olaf There are of course many workarounds, but all else being equal a belt drive will always accelerate faster than a screw just because it weighs less. High pitch screws and servos are both good options, but if you are willing to puby 691175002 - General
You can hit essentially zero backlash just by lightly spring-loading two nuts. This strategy is sometimes used in machine tools but is limited by rigidity and force constraints. A 3d printer has fairly tame loads so there aren't many drawbacks. Leadscrews are generally a poor choice when you are looking for high accelerations. If you look at motor sizing calculations you will discover that thby 691175002 - General
If the room temperature is chilly or there are drafts I wouldn't be surprised to see a PCB bed top out at 100c. I cranked the potentiometer on my power supply to 14V and put insulation on the bottom. Before it would take a really long time to hit 105c and now I can get 110 or 120 pretty quickly. The fan was really loud at 14V so I put it on a pwm channel at 80% duty cycle.by 691175002 - Reprappers
Quotemike3I believe its the most bang for the buck.. all for 269.00 well below anything else in it class... I agree completely. I still see people talking about the Aliexpress/Hobbyking printers at $300+ with inferior build quality. Why would you gamble on a box of lasercut acrylic when this printer is available? Support might not be great but when there is a 50 page thread on forums.reprap.cby 691175002 - Prusa i3 and variants
Both midwest and mcmaster sell the stuff as well. Midwest has very low pricing and will cut to size. They also frequently send out discount emails.by 691175002 - Reprappers
QuoteMetalmannYou should witness the slack/slop, in belts of large equipment; especially on the humongous old machines, such as VTL's and Planers. Naturally, small equipment usually requires higher belt tension. Large equipment almost never use belts for positioning, just for the spindle/hydraulics and other power transfer applications. Belts used in low backlash applications must be extremelyby 691175002 - Mechanics
You don't want to use WD40, but pretty much anything else will be acceptable. If you want the "correct" lubricant you can venture into the datasheets of the parts in question (if available). They will normally recommend a very specific lubricant under which the component lifetimes were tested. I generally go with Mobil Vactra 2 which is designed for machine slideways and includes tackifiers toby 691175002 - Reprappers
My approach has always been to ensure the frame is rigid before resorting to workarounds. Moving up an extrusion size and buying some linear rail will also improve print quality and is arguably more robust.by 691175002 - Developers
QuotecorryBiggest issue: to those who say they got the kit assembled in 4 hours are you *SURE* you have those t nuts rotated in the slots 90 degrees? All of them? They're awful. I know misumi's preinstall t nuts cost a bit, but those (m4) post install t nuts are absolute garbage. Spent hours on single bolts sometimes. Was ready to go to the garage make some thermite just to burn those witchby 691175002 - Prusa i3 and variants
I built an enclosure with half a 10$ sheet of foam and some tape. Works almost too well.by 691175002 - Prusa i3 and variants