My current impression is that, while developing some form of "standards" might be forecoming (but historically most of them are de facto arrangements around some already established dominant practice) we still have huge needs of "filling in the blanks" for example around the physics and characteristics of our machines. The design is too much of a moving target, what we're still much into is haby Lanthan - Developers
OK, here it is. Starting point was the dxf of Adrian's modified Y mount. Easy to print, should provide a more stable Y mount, since the pulley will be supported from both ends. you'll need 3 m3x40 bolts and two m3x8, and one 12x28x8 bearing, 6001RS or similar. There's a gazillion ways of improving it. Shoudn't be too hard to modify an printable pulley to fit in the bearing hole, or to aby Lanthan - General
@mikey: was mulling something around that at the beginning, but now I think there's a much better solution. I am working on a torsion box mount for the y axis that would only require one 12x28x8 bearing and three m3x40 bolts , secure the pulley on both sides, seriously reduce forces exerted on the motor bearing, and would not require whole truckloads of plastic. I think the concept could easilyby Lanthan - General
@ahmetcenturan: Unpause, from what I understand, does some preventive acceleration when doing arcs. This is supposed to keep hole diameters near their intended size. Acceleration is very visible. From the code: "The unpause script is based on the Shane Hathaway's patch to speed up a line segment to compensate for the delay of the microprocessor" ... def getUnpausedMovement(self, distance, liby Lanthan - Skeinforge
Running out of the stock of zip ties (and sometimes of patience) here. I have found the belt slipping along the pulley problem to be actually related to the flexion of the motor mount (happens with the y motor mount, but also with the X motor mount) under the (still moderate) tension of the belt. Disclaimer: I am _not_ overtensioning those belts, they are optimized to be used with some tension!by Lanthan - General
I had a look at SFACT yesterday, some good clarifications all around, some yet to be done. Increases overall usability IMHO. Good job, Ahmetcemturan! But several still-useful plugins dropped, for example unpause. Kindly request is to keep it in future SF42... (and SFACT)by Lanthan - Skeinforge
@All: Thx for the inputs! So it would seem there's quite some bags o'plastic in the wait. Re-melting at some point in the future is in the prospects. Anyone tried microwaving? @Andrew Diehl: "Everything else gets recycled": is this through some dispositive of yours, or by using "municipal" recycling services and similar? (here they said external services tend to put all of the plastics exceptedby Lanthan - General
Cool slows down indeed, allowing to set a minimal time to be spent per layer, this seems to do a good job when printing small parts. What would be the the reason to want to suppress this feature?by Lanthan - Skeinforge
Dear all, After about 40 days of plastic melting & extruding bliss, I've got a nice box of good pieces & toys, a completed Prusa Mendel, and a bag of tests/calibration/failed/experimental pieces & blobs, most of them PLA. I'm wondering what to do with them, maybe prepare a mold and put 'em in an oven? Yes, there have been a couple of "test cities" on display in Thingiverse. So Iby Lanthan - General
@Droftarts, about vibrations and motors on top: There are actually some very serious cases where you want to have increased mass on top of a structure BTW the tuned mass damper on first page looks furiously like a Mendel successor ;-) --- I am also highly interested by the vertical smooth bars X axis solutions under independent development by Emmanuel and the Cypress guys. There is a poby Lanthan - General Mendel Topics
Thank you Nophead, outstanding work on Thermocouples! Given the need to desolder and the general uncertainties about thermocouples, I think I'm going to keep the two thermistor inputs as they are, and mod the code to use another (free) analogic input pin.by Lanthan - RAMPS Electronics
Nophead's couplers are a lot stiffer than aluminium couplers with spiral cuts indeed. Very nice build, Droftarts, with a lot of creativity involved! Yes with that level of deflexion of the Z axes you need very compliant couplings. It is good also to show that "this works" and that we shouldn't get too fixed on details while bootstrapping. My point is for later evolution of the Mendel: it has beby Lanthan - General Mendel Topics
Yeah, I received the coupon and ordered a tiny NEMA11 to build Adrian's mini extruder plus a couple of SY42STH47-1684B for future projects. In my view: the 1684Bs are really fine for the reprap uses, and the high power makes them most "recyclable" of all the lot. I've been doing some plotting tests with the new build, that Edgar Poe guy exercised a lot the Z axis. The X and Y motors just get sliby Lanthan - General Mendel Topics
about eBay: some months ago I got a couple of RAMPS 1.25 PCBs (Martijn in The Netherlands I think) and soldered the necessary stuff myself. Very straightforward and easy, big parts, if you do electronic projects from time to time you already have most of the needed components and get to significant savings. I think the 1.2 branch with big through-hole components is well worth being kept alive anby Lanthan - RAMPS Electronics
Hi! I also have a nice AD595CQ all wired up and ready to be connected. The AD595 delivers an analog voltage proportional to the temperature, no SPI. I've got a RAMPS 1.2 to connect them. Checking the code in Tonokip/Sprinter, it seems it expects the AD595 to be connected to the same pins used for the thermistors. But the thermistor circuit has already a dividing 4.7K resistance and a capacitby Lanthan - RAMPS Electronics
May I also disgress about couplers: I first tried aluminium couplers (cheap eBay, those have a spiral cut and 2 set screws 90 degrees apart) but they are not stable on the Z direction, they just act like big fat springs when the X axis is hanging on 'em. No joy. Then I put aquarium air hose around both motor shafts and installed "Yet another Prusa Mendel Z Coupling by Nophead" I agree they areby Lanthan - General Mendel Topics
Greg, I agree that the crude adjustment provided by sliding motor mounts is not the most refined. Could do the job, though. The "canonical" way to have fully adjustable motor centering would use three bolts in the circumference spaced 120 degrees apart. Presumably three M3x30 socket caps, plus three captive nuts, that isn't ready a lot of vitamins, and we are using the precision given by metalby Lanthan - General Mendel Topics
PCBs require less forces than plexiglass. The Prusa Mendel shows slight but noticeable vibration even with the motors isolated from the frame by cork. In my view: the diagonals may help, but we'll still have significant vibration problems while milling with those 8mm threaded bar designs. Not optimized for that. Thinking about composites, combinations of dampening and stiff materials. Metal bby Lanthan - General New Machines Topics
So how did that build go? Updates?by Lanthan - General New Machines Topics
About Greg's new x-ends: Here is - more or less- what I meant in the previous post, at least for the new idler end (no bridges and no zip tie holes). Still need to add control of those features by configuration variables. The motor end is putting to test my rudimentary openscad skills. I did away with the hourglass design of the motor mount, which, apart from aesthetic criteria, is mostly weby Lanthan - General Mendel Topics
Wtih StepStick / RAMPS & SY42STH47-1684B: I ldid not decrease the driver's current. No problems so far. Have the Z axis set in the firmware to turn off power to the motors when not in use (default config by now)by Lanthan - General Mendel Topics
PLA-wood: I have been using standard epoxy ("Araldite") with good results, bonds strongly to both materials. Cures in about 8 hours. "rapid" Araldite cures in barely 10 minutes, gives similar results altough is reputed slightly less strong. Holes in both surfaces can help increase bond surface and grip. For impregnation of PLA surfaces and fills (increases resistance and rigidity), try a bath ofby Lanthan - General Mendel Topics
From my experience routing sourcing and building a cupcake: Most probably you won't save much in comparison to the kit's cost, but will learn much more in the journey. If that is really what you want (like: be prepared to read tons, comb the forums ad the whole net for information, gather the right materials and imagine creative solutions for whatever does not perfectly fit in, dedicate time anby Lanthan - General New Machines Topics
Ok I have it. My clone of your repository was a bit old. I like the design improvements and will definitely give 'em a try. Also the smooth channel allowing for two LM8UU or a single LM8LUU is good. What could (IMHO) be improved: - The zip tie channels are single points of failure (I've had PrusaJr's design break clean just in that place while pushing the bearing in) and probably unnecessary. Fby Lanthan - General Mendel Topics
Hi Greg, Very interesting design ! I'd love to take a look at it. is it in your github? Side note: the cheap LM8UU bearings we are all using seem very prone to losing small steel balls each time we take them on and off the rods. So this is a manipulation I'd limit to a minimum... (hence the need to evolve the quick-change carriage)by Lanthan - General Mendel Topics
In short: T5 = 5 mm periodicity / pitch T2.5 = 2.5 mm periodicity / pitch Are you printing your own pulleys? If yes, definitely they are for T5. T2.5 is currently beyond usual reprap printing capabilities If you're using vitamin pulleys and have easy access to a variety of belts, you've got the choice.by Lanthan - General Mendel Topics
Hi again, I am under the (theoretical) impression that, with the current Prusa Mendel design, for various reasons the holding force exerted by the motor and idler ends on the smooth X rods is insufficient, given the axial traction forces of the carriage. This could cause slippage, precision issues and need frequent retensioning of the X belt. Are you guys encountering any of those problems inby Lanthan - General Mendel Topics
Added to the wiki Mendel Prusa page. Noticed that information about wiring two steppers in series is quite scarce on the Internet. Maybe we should create a specific page about that in the wiki. Would need input about theory and practice (inductance, torque, power... and also the eventual shortcomings, for now I do not see many).by Lanthan - General Mendel Topics
To close the question: couldn't test the dual driver because it appears non functional after one year gathering dust in various places.. So: I wired the motors in series as described in that is: pin 1 -- black -- motor1 --green -- black -- motor2 -- green -- pin2 pin3 -- red -- motor 1 -- blue -- red -- motor2 -- blue -- pin4 and Z axis performance is outstanding now. tested up to F500by Lanthan - General Mendel Topics
Thank you all! The information is first rate. Further testing (after reverting to a totally default configuration and gettng rid of several "improvements"): Z+ is reasonably reliable up to F50, over this small obstacles will result in lost steps and oscillations. The motor on the left (the one that bears the load of the X motor) is indeed the most prone to losing steps, as reported in several plby Lanthan - General Mendel Topics