arse! can't use the NCP1117 to supply Vin despite it being 800mA, as it maxes out at 20V. grrrr.... does anyone know of an LDO with an output anywhere between 8 and 12v, which has about an 800mA rating and is preferably in a SOT-223 package? thx..by lkcl - RAMPS Electronics
Quotefrankvdh Quotelkcl i'd also really like to have dual 2560 and Due compatibility, as there will be some people who significantly want to save cost. Don't bother.... People who care about the $6 difference in cost between a Due and a 2560 won't buy your board anyway... they'll buy a Mega and a RAMPS 1.4. hehe, yeah - it looks like i made some mistakes where it'll be of limited functionalityby lkcl - RAMPS Electronics
QuoteDust since you have moved d1 out from under the pololu, how about replacing it with a 7809 TO-220 package would make it much easier to run the ramps on 24v and would reduce the load on the mega/due voltage regulator Presuming its still going to vin... ha! that would be a good idea - i hadn't got into actual component review, this is really helpful to prompt me to think about it. a standby lkcl - RAMPS Electronics
i just... couldn't leave it alone, could i. kept going, sort-of not-really-slept a couple of times for 45 minutes... but got it done. the protection diode i moved out the way (90 degrees), then moved the fuses down a bit. shuffled the power block down... added 2 extra terminals to what used to be a 6-pin Molex... managed to get it all wired up. didn't move the MOSFETs, added the extra one, buby lkcl - RAMPS Electronics
Quoteo_lampe Just to put more pressure on you: You could save a lot of MOSFET terminal space by providing one big common terminal for V+. ah: that would (i think) mean putting multiple wires into one terminal block, which is very risky and quite difficult. and also a hell of a lot of currrent. better to have multiple wires. also two separate fuses.by lkcl - RAMPS Electronics
ok i couldn't stand the mess after 24 hours, so i turned the buffer IC round, which allowed me to do a cleanup. allsooo... this is screaming at me "add another MOSFET, add another MOSFET!" the buffer IC is a quad, so that's not a problem. the expansion of the depth of the PCB needed to include the micro-sd card in the bottom right corner also means that there's space to move the entire lby lkcl - RAMPS Electronics
ok so added the SN74HC125, quite straightforward. the routing's a mess (gahh! cramped 2-layer PCBs! eagle!! argh!) - normally i would clean it up but it's entirely by hand, there's no push-and-shove in eagle.... *sigh*... i've expanded the PCB size along the top long side by about 0.2in to get the tracks in at the top. nice thing about that is, i can put some GND vias along the rest of thby lkcl - RAMPS Electronics
QuoteDust While you at it, please route D7 somewhere, it bugs me that its just abandoned on ramps i'll most likely use it as a "default powered off" MOSFETs line: it's right there so why not. i believe i can just put in a pull-up resistor (10k) onto D7, that should bring it lo HIGH, that in the SN74HC125 OE# terminology will make the outputs all tri-state. with all outputs tri-state the resistoby lkcl - RAMPS Electronics
QuoteDust If you do go Due, you might also want to look at SMART_RAMPS It already exists.. or just for info... appreciated.... strange: they supply external VCC (5V) or maybe it's a jumper so you can change the supply voltage.... yeh it has the standard 5 driver sockets, i need 6 (triple lead screws, X, Y, Extruder) Quote Also there is a good thread on modifying standard ramps for due...by lkcl - RAMPS Electronics
QuoteDust Quotedc42 - I'm fairly sure that the Arduino Due can't support the HSMCI interface to the SD card, it only supports the much slower SPI interface. Without HSMCI you won't get high-speed upload to the SD card over the network. According to All the HSMCI pins are mapped and broken out... so if there is an issue its software... I also see libraries eg (no idea if it works though)by lkcl - RAMPS Electronics
Quotedc42 Just a couple of warnings/suggestions: always appreciated Quote - I'm fairly sure that the Arduino Due can't support the HSMCI interface to the SD card, it only supports the much slower SPI interface. Without HSMCI you won't get high-speed upload to the SD card over the network. yeah i uploaded 1.19+6 just recently and was blown away by the microsd upload speed! no i'm not so concerby lkcl - RAMPS Electronics
Quoteo_lampe Which Marlin version will you run on the Due? Marlin4Due seemed to be in hibernation mode for a while... i'll see how that goes. whatever i use it's a new board port, a totally new set of pins will be needed. a standard atmega 2560 should actually work, even without any level-conversion: i'll see how it goes. ENC28J60 (SPI-ETH from Microchip) is actually a 3.3v part that happensby lkcl - RAMPS Electronics
it may seem strange to create another RAMPS fork, i have however been looking for something in Taiwan / Hong Kong / China (i am currently in TW) that isn't GPL violating, that's 32-bit, that isn't MKS Base so won't fall to bits, that isn't the same amount of money that you can buy an entire 3D printer for in China (yes, you can get a 3D printer for $USD 150 which is the same amount as a DuetNG!by lkcl - RAMPS Electronics
QuoteMKSA OK and how does these test cubes look at 60mm/s, 120mm/s and 180mm/s ? well now that i disccovered that i have had debug logging enabled for over 2 years on the duet 0.8.5 without realising it... *smack*... should look really good. 60 should be fine anyway. using skeinforge (it's quirky but i had a bit of a run-in with cura over some awkward slicing and rebelled....) 230 C temperaturby lkcl - Mechanics
QuoteMKSA How do you measure the speed to be so sure ? Is it average, peak etc ??? PLA is the easiest to print. What about PETG ? I bet at this speed and with all these fans, the required T° and filament output won't be achieved. yeah PETG i would expect to stutter and break up at these kinds of speeds: i've only had a little bit of experience with PETG so far and i'm not hugely fond of it (sby lkcl - Mechanics
QuoteMKSA Looks like you have far more problems than just the part cooling fan ! And definitely the speed is NOT 300mm/s. It may look like it but that is because of the noise and the shaking , typical of these playful crappy chinese bearings that must grind the rods ! it definitely is - i've been doing 150, 180 and 200mm/sec speeds for some years now, i know what they sound like: this is shakiby lkcl - Mechanics
okay! photos to follow, my friend has his fully assembled and we're doing commissioning. last main thing to do which will have to wait a couple of days is the extruder. getting the tension right to avoid slipping or overcurrent is proving challenging. also we had the printbed MOSFET go up in smoke so will be going to the markets to get a replacement TO-220 N-channel MOSFET or five. all goodby lkcl - Extruded Aluminum Frames
Quoteepicepee ImplicitCAD! It's like OpenSCAD but with a Haskell interface and a really cool way of representing geometry (function with three arguments, surface is where it equals 0). ooo niiice, i love the rounding parameter to unions and differences etc. the only reason i can't use implicitcad is because it's missing polygon, resize and a couple of other functions which are essential to theby lkcl - 3D Design tools
implicitcad has rounding added to the union() function (and others) as a parameter, r=8 for example. it's much quicker. really this should not be done in scad it should be a fundamental part of libCGAL or the c-based source code of openscad where it can be properly optimised. if you can raise a bugreport with the openscad team that would be really helpful: they will then know that yes, there aby lkcl - 3D Design tools
Quotethe_digital_dentist Either it's a work of art, or it will scare the crap out of children, or both. haha yeah. modern art makes me nervous and i'm 47 Quote Oh yeah, that's the other thing. Axial fans can't blow air through a tube. You need a radial fan, aka a blower. well i know that _now_! nnngggggh just another thing in a long line of things that need to be known when doing 3d prinby lkcl - Mechanics
QuoteMKSA Where can we see it printing at these speeds ? 0 to 300 mm/s on a 20mm long race track, gee ! (in fact more than 2 ) it's pretty fricking funny. i had to to hold it so it didn't shake the table: certain frequencies ended up with resonant harmonics and i was a bit concerned amazingly the straight edges came out perfectly fine. no stringing, no breaking - bear in mind i'd rampeby lkcl - Mechanics
QuoteMKSA Always look at the big picture. Done. OK, now, what is the purpose again ? Usually it is one 30mm fan for the hot end, one blower fan for the part. SO ? one blower is nowhere near enough to deal with 250 to 300mm / sec or above print speeds. i'm getting perfect prints at 50mm/sec even with 50 to 55 degree overhangs. but with a square 20x20x20mm test cube running at 300mm / sec the edby lkcl - Mechanics
it's alive, alive i tell you! so... it works, but the 120mm computer fans are absolute rubbish. i naively believed that bigger would mean more air-flow. instead, i remembered Mythbusters, and on close examination of the fan cowling found a whopping THREE millimetre gap between the edge of the blades and the inner ring of the cowling. you can see i tried putting a ring on it (save on 3D printiby lkcl - Mechanics
i really do seem to like that spline-curve generating functionby lkcl - Extruded Aluminum Frames
Quoteo_lampe Pulley / bearing / gap / bearing / coupler on a short shaft and pulley / bearing / big pulley / bearing / long shaft to coupler on the other. No need to put bearings on the outside of the 20T pulley. Just two bearings in a reasonable distance per shaft. "pulley - bearing - gap - bearing" hmmm.... that's awkward: it means extending a bridge over the air, or extending the base to rby lkcl - Extruded Aluminum Frames
Quoteo_lampe You mentioned the belt tension would bend the rod. is bending, yes. Quote Maybe it's the right time to split the 5mm rod and use dual bearings and flexible couplings? This way you could make it more maintenance friendly and stiffer the same time. huh. it sounds like a good idea... except... *thinks*... i like the easier maintanence bit... except... those 5mm OD rods were incredby lkcl - Extruded Aluminum Frames
Quoteo_lampe You already run it with 24V? I'm sure there is a golden spot in gear ratio. Maybe try 30:20 tooth ratio? yehyeh 24v. i have some GT2-16T around somewhere so could get close to that. it's a bit of a pain to disassemble though, requires undoing and re-tensioning all 8 belt tensioners.by lkcl - Extruded Aluminum Frames
ok so at 200 mm / sec i am still getting "skipping". this is with 0.9 deg steppers. i will be putting in the 84 oz-in 48mm long 2A beasts to see how those fare: they're 1.8 degree / step. at 150mm / sec and 1000 mm / min min-jerk speeds this is a successful print. the artefacts (stringing) is from skeinforge. still configuring there... the top view is where the "corner bulging" has been elby lkcl - Extruded Aluminum Frames
Success! ok i say "success" but it's running so fast that it's outside the rated speed of a NEMA17 motor. i will be flipping over to 1:1 on the closed loop belt now and trying that out. one on the LEFT was done at a sane speed: this completed fine. min jerk speeds were set quite low. one on the RIGHT was set at insane speeds (180mm/sec), acceleration (4000 mm / sec ^2) and min-jerk (1000by lkcl - Extruded Aluminum Frames
okaay so this is what the top looks like, now. not too much in the way of mistakes - nothing that will completely stop the printer from running in order to print replacement parts. the 360mm long 5mm OD rods however are bending an awwwful lot - far more than i'm happy with, so i will need double 625 bearings, one either side of the GT2-6mm-20T. it's the pressure on the GT2-6mm-20T from the belby lkcl - Extruded Aluminum Frames