The latest preview build of Windows 10 (can't remember the release number, but it was released in the last few days) caused some very strange problems with my printer electronics (RAMPS and Arduino) which seem to be down to an issue with the USB serial driver. YMMV depending if the issue only affects specific USB hardware, but here's what happened in case anyone else hits the same problem. I'veby plankton - General
Perfectly possible I think, but be prepared for more work/troubleshooting than you would get if you spent a little more on key parts. You will save yourself a lot of grief if you don't skimp on the hotend, and a cheap heatbed can be a lottery (it may heat unevenly, and/or not be able to reach ABS temperatures). I would order one or 2 spares of items such as stepper drivers and bearings, if you arby plankton - Reprappers
I've not had any problems with it, all Slic3r does is substitute the actual temperature required, for the variable name when it's slicing, so the resultant Gcode file looks identical to if you had specified a manual temperature (as in your example). So for example, here's the Gcode header from a print I did a few days ago (using that start Gcode): ; generated by Slic3r 1.1.7 on 2015-01-12 at 1by plankton - Mendel90
You know you can use variables instead of absolute temperatures in your start Gcode? This way you don't have to edit start Gcode every time you change filament, I just keep the same start Gcode, like this (for PLA): M140 S ; set bed temp and don't wait G28 ; home all axes G1 Z5 F5000 ; move z to 5mm G1 X150 Y0 F4000 ; move 150mm along the front edge G1 Z0 ; drop nozzle to prevent ooze G4 P100by plankton - Mendel90
Can't think off the top of my head what else you would need to change, I've had a max endstop working with those settings, however you are not the first person to use RAMPS with a Mendel90, have a search on the forums and see what other people did. Alternatively you could just use one of the Mendel90 flavours of Marlin, I've not looked but I think that Neil's version probably supports RAMPS, seeby plankton - Mendel90
Either your heatbed is faulty, or you are measuring from the 24v connections (Mk2b heatbeds have 12 and 24 volt connections) Take a look at the wikiby plankton - Reprappers
Assuming you're talking about printing PLA, and a standard PCB print bed, then the answer is, maybe. The glass has 2 main functions, firstly it gives a flat surface which is essential for printing (the print head needs to be a consistent distance from the print bed, across the whole bed). PCB's tend not to be particularly flat, and flex fairly easily, so you would need to find a way to mount itby plankton - Reprappers
If you mean my 4 bullet points, yes make all 4 changes.by plankton - Mendel90
If this is a Nophead kit then use his supplied version of Marlin which should be correctly configured. I've only ever done it with vanila Marlin and RAMPS, but the principles are: make sure the z endstop is physically connected to the MAX pins on your controller, not MIN enable max pins in pins.h , that would be "#define Z_MAX_PIN 19" for RAMPS (no idea what it is for Melzi) you can also set Z_by plankton - Mendel90
After homing, send an M114, check that z position is reporting as 200 something (it sounds as if you have z=0 at the top)by plankton - Mendel90
I've put a new page on the Wiki aimed at all the posters asking "why does my heat bed take so long to heat", it's just meant to answer some of the commonly asked questions. Feel free to comment, or disagree with my conclusions (I'm still learning this stuff too).by plankton - Reprappers
Thanks for the hint. I added this line to ribbon_clamp.scad, and now the missing STL gets generated. module ribbon_clamp_20_33NB_stl() ribbon_clamp_stl(20, M3_cap_screw, nutty = true, slotted = false); Note to self: I really must put aside some time to teach myself the basics of OpenScadby plankton - Mendel90
So as I already have a reel of 26 way IDC cable, I thought it would make sense to use that to the extruder (default is 20) as well as the heatbed, giving additional spare wires for future options like a Z probe (needs 4 wires, 2 for servo, and 2 for the switch), or an E3D hotend (has an additional fan). I was prepared to make up some modified cable clamps etc in Sketchup, however looking at theby plankton - Mendel90
Many people just use a 47 ohm resistor on the 5v rail, check the resistance of your fan, but I expect that will work. This page on the Wiki explains the reasoning, I don't know if it's entirely true (as stated on that page) that recent ATX power supplies don't need any load on the 5v rail (it may just be that they suffer less from voltage drop).by plankton - Reprappers
You need to put a load on the PSU_ON, not just ground it, that's probably why you're seeing such a large voltage drop when you power on the heatbed. Nophead also advocates a load on the 3.3v as well, although YMMV depending on model of PSU.by plankton - Reprappers
Err, it isn't "approximate"! If you put the correct figures in Prussa's calculator then it will give you the exact steps to use. If you're not getting the correct result then you input a wrong number (most probably you are using a different pitch thread on your rods).by plankton - Mendel90
As I may have already mentioned, I'm sourcing parts for my M90 Sturdy. I thought I had everything covered, then I came to the PTFE tube for the spool holder, and noticed it is 750mm long (I had just assumed it was a short length used as a guide near the spool holder, probably because main.scad shows a simplified view like that), 750mm is long enough to connect to the extruder, but I can't find anby plankton - Mendel90
I'm currently sourcing parts for a M90 Sturdy using GT2 belts (I'm not expecting my M90 to outperform all the non-GT2 M90's out there though ), as far as I can see the definitions for GT2 are now included in the scad files, so I assume Chris updated them since this thread was started. If you look in belts.scad you can see these types defined: T5x6 = [ 5, 6, 2.25]; T5x10 = [ 5, 10, 2.25]; Tby plankton - Mendel90
Cheap steppers don't have an endstop on the pot, so yes, it will turn indefenitly. You "could" tune it by trial and error, but the Pololu driver can output 2A at its max setting, so depending on your model of motor that could be enough to damage it. The safest way to adjust these is by measuring Vref with a multimeter, the Pololu website tells you how to calculate that (or search on this forum, Iby plankton - Reprappers
As a very rough guide (to see if your thermistor is reporting in the right ball park) try heating the hotend to 200C, then try to feed some PLA by hand. If plastic comes out of your nozzle then I'd say Pronterface is closer to the mark than your IR thermometer.by plankton - Mendel90
Quotedawa I wonder if it is possible to prevent skeinforge from saving the settings for every click you perform in the GUI. Not that I've found yet. QuoteTo counter that behaviour I have a backup file tree, and remove/overwrite the working tree regularly, replacing it with the backup tree, to "undo the autosave". But when you create new profiles you copy one of the existing profiles, so you coby plankton - Mendel90
Further update: So I mentioned that Skeinforge didn't like one of my variables (which had worked fine in Slic3r), in fact it didn't like any of them, but for some reason only that one variable name caused it to crash. I use variables in my start Gcode to set temperatures according to whatever the profile specifies, that saves having to use a separate start.gcode file for each filament profile.by plankton - Mendel90
Doh! So the answer was in my start.gcode file, I was using a variable "first_layer_height" which it didn't like (I use several other variables, like "first_layer_bed_temperature", which it doesn't complain about, so maybe these variables have to be defined in Skeinforge somewhere) G1 Z ; move nozzle to print height just changed this to a constant, like this: G1 Z0.35 ; move nozzle to printby plankton - Mendel90
I think I need to get my head around Skeinforge in order to print the parts correctly for my Mendel90 build, Slic3r doesn't seem to be handling these correctly (I tried a test print of the X axis, idler end, and the M8 brass nut trap came out as solid infill). So I had a few quiet hours on Christmas morning (yes, that is possible) seemed the perfect time to try this, but I'm starting to think thaby plankton - Mendel90
1. Loose, or too tight belts, or binding on the axis, can cause skipping. Adjust the belts so they give a dull twang when plucked, lubricate your smooth rods. 2. Acceleration, speed, and jerk settings in firmware, can cause skipping (in Marlin the default settings are way too high for many printers). 3. Stepper motor drivers overheating, can cause skipping (they trigger thermal cutout, when theby plankton - General
@Dentist, I'd be interested to see the STL, thanks. Shafts are 5mm motor, 8mm threaded rod, probably (see below), and I'd prefer to use an M3 grub screw (6 or 8mm). I see you specify ABS for your design, any reason that won't work in PLA? I have an i3 box, which I plan to upgrade to the Mendel90 after printing the parts, but I haven't got around to printing in ABS yet (though I've got a reel sittby plankton - Mechanics
I'm trying to source parts for a Mendel90, specifically the Z axis coupling which connects my 5mm motor shafts to 8mm threaded rod. Nophead uses Neoprene hose to expand the motor shaft diameter to 8mm, then clamps both shafts in a printed coupling, however finding someone who can sell me a few centimeters of rubber hose for less than silly money proved harder than expected, so I started looking aby plankton - Mechanics
Could be that you have a cheap or faulty heatbed (have you measured it's resistance?), but another option is PID, have you tuned PID for this heatbed? A good clue is to look at the heatbed LED, if your PID is correctly tuned the LED should be on constantly until you reach your target temperature, if you see it flickering rapidly before target is reached that indicates incorrectly tuned PID.by plankton - Reprappers
There are 2 different issues here: The Mk2 PCB heatbed is a cheap but adequate solution for most people, you will get some temperature differential across the bed, but on a good quality PCB this will not be a big issue. However the majority of cheap MK2's on eBay are not great quality (specifically, they don't have enough copper on the traces), take a look on the Wiki page at Joseph Prusa's warnby plankton - General