I had that problem when I was doing 0.24mm printing with a lot of backlash in the Z gearing due to wear. To print at 0.12mm, I think you need either very little backlash in the Z axis, or for the Z axis to move up only. So my suggestion is to try levelling the bed manually, and turn off the bed compensation, so that the Z axis never moves down.by dc42 - Ormerod
I believe that putting a load on the +5V and/or +3.3V rails would increase the voltage on the 12V supply, but I'm not at all sure it would improve the regulation. I don't think the poor 12V regulation is a problem anyway, at least when printing with PLA. The real problem is that the bed heater and extruder heater driver electronics produce a lot of electrical noise, which the current Duet board dby dc42 - Ormerod
Hmm... there seems to be some disagreement on the amount of energy stored in the bed heater inductance. I estimated 40uJ based on the length of time that the mosfet is avalanching. You say 250uJ. Dennis says the inductance is 2.2uH, which at 10A gives 110uJ. I don't know which 1A Schottky diode Dennis is using, but rectifier diodes usually have a surge current rating well above the RMS rating. Fby dc42 - Ormerod
Thanks Ian, I've just ordered the 25A version (it was only £1 more than the 20A one) - and I can see from the photo that there is indeed a preset to adjust the output voltage.by dc42 - Ormerod
As to self-sourcing, my parts list so far (not counting tools) is: 1 x RS Ormerod kit 6 x resistors (2 to improve performance of the IR sensor, 2 to fix the manufacturing fault that affected the first 220 Duet boards, 2 to make the Duet board less noisy electrically) 3 x capacitors (to make the Duet board less noisy electrically, and improve the tolerance to mains brownouts) 1 x 623ZZ bearing (tby dc42 - Ormerod
I've now loaded the firmware I built, and run some tests on the bed heater, checking XYZ axis movement at intervals. It's been running for 30 50 minutes now with no problems. So the rebuilt firmware seems OK. I also took a look at the map file. If the .bin file is a straight binary image, with no extra header, then the 0x3948 offset where the code is different corresponds exactly to the addressby dc42 - Ormerod
I've just done some tests on bed temperature. First, I measured the 12V supply with bed heater on but extruder heater off: At terminals on ATX power board: 11.44V At terminals on Duet board:11.38V Across bed heater pads on Duet board: 11.33V At bed heater: 11.05V I then raised the bed temperature to 65C as I normally do, then on to 100C. It only took a few more minutes. I then set it to 120C, wby dc42 - Ormerod
1. I think you are supposed to run the bed compensation with all the M556 values zero, then do an M556 to set the values for your machine - as you are doing. 2. I get much better results using white PVC tape instead of alu tape on the bed corners. Ian says that white paper works too. 3. Have you re-measured your G31/nozzle height value, as I suggested already? 4. I always start the G32 with thby dc42 - Ormerod
PS - another thing that can cause your G31 readings to change at a given nozzle height is if the hot end is sagging. This happened to me after a few prints, and I had to reposition and tighten up the screws holding the hot end to the nozzle mount. I suggest you re-do your G31 calibration, and see whether the value is significantly different from the value you have entered in config.g.by dc42 - Ormerod
Has the lighting changed? The Z sensor is very sensitive to ambient light (both sunlight and incandescent light) unless you change some component values.by dc42 - Ormerod
1. Check that there is not a solder short across those 2 pins with 0V across them. 2. There are 2 SMD resistors on the board, one above the other. The lower one is the series resistor. Check that both ends are soldered, and that it reads 160 ohms. The right hand end should be at +3.3V, the left hand end is connected to the transmitter and so would be at +1.2V if everything is connected. Use theby dc42 - Ormerod
PS - looking at the back of the board as mounted on the x-carriage, the transmitter pins are the pair on the right. The transmitter series resistor is the lower of the 2 resistors, and should measure 160 ohms on an unmodified board.by dc42 - Ormerod
OK, your sensor is responding to ambient light, so the problem is that the IR emitter is not working. However the +5V and Gnd connections to the sensor board must be OK. The sensor itself is right at the bottom of the board and has 2 pairs of pins. There should be 3.3V across one pair (the receiver), and 1.2V across the other (the transmitter). If you get 3.3V across both, then the transmitter iby dc42 - Ormerod
Hi tru168, The Duet board is supposed to be good for up to 35V input, so 15V would hardly be stressing it. The stepper drivers are constant current chopper type ones. So the only component that might get overstressed @ 15V is the extruder heater, and a series resistor of about 0.68 ohms would take care of that.by dc42 - Ormerod
I would say that if you don't want to be on the bleeding edge, give it a month, then check back on this forum to see whether the problems (in particular, software problems) have been fixed. If you are not into soldering, wait until the power distribution issues on the electronics board have been fixed too. I haven't used a 3d printer before, but the prints I am getting on my Ormerod appear to beby dc42 - Ormerod
In that case, either you are reading just noise, or you are reading just ambient light. Do the readings increase if you shine an incandescent light on the bed or at the sensor? If you have a DMM hen you can check the voltages on the sensor board.by dc42 - Ormerod
Very neatly done! I think the capacitor between source and drain used by Radian is also a good (and easier) alternative to the gate resistor, given that the mosfet turn-on is so slow, although personally I would try 0.47uF rather than 1uF. I added only a 1uF decoupling capacitor, and that seems to be sufficient for my board - there is another 400uF not too far away on the board already, and 1uFby dc42 - Ormerod
Check that the pink wire from the proximity sensor is in the right Duet pin, and that you have the 3-pin connector the right way round on the sensor board. If those are OK then it sounds to me that the IR emitter in your sensor may not be working. What is the G31 value when the sensor is 1mm above the alu tape or white tape on the corner of the bed? Some of us need to put a piece of white or aluby dc42 - Ormerod
Hi tru168, The 12V rail on the Alpine PSU supplied to me is rated at 32A, so I think it should be OK running at 16A, which I believe is about what the Ormerod takes with everything running. But I take your point about the 12V supply not being independently regulated from the 5V supply in low-cost ATX PSUs. I'm wondering whether to get a 12V 20A psu such as this one. Or maybe this 15V PSU if it tby dc42 - Ormerod
Hi victors, thanks for sharing your experience. I too had a number of difficulties getting #072 to work, but it's working quite well now. Some comments: - Y axis plywood popping off the single bearing: I've not had this problem, but another user has reported the same thing on this forum. - Y- belt: I find it easy enough to tension and fit by myself. I don't have anything wedging it in the slot,by dc42 - Ormerod
I agree with you, capacitor to ground is best. With the capacitor across the load, the current drawn from +12V will still drop abruptly to zero, which is what gives the positive spike on the +12V supply in the absence of a local decoupling capacitor.by dc42 - Ormerod
It happened again.. your post crossed with my edit to my previous post.by dc42 - Ormerod
Thinking about this a little more, there is another effect. Without the gate resistor, the inductive energy in the bed is dissipated as avalanche energy in the mosfet. There is 45-50V on the mosfet drain for a little under 200ns, and during this time the current will drop smoothly from 10A to zero. So I estimate that around 40uJ of avalanche energy is dissipated in the mosfet. Your capacitor suppby dc42 - Ormerod
I don't want to put a dampener on markbee's design - which looks excellent to me - but I should point out that the fans supplied to some of us do not have recesses in the screw holes, so the screw caps sit proud: The only way I can use that design is to cut the lugs off, drill holes in it and countersink them, and then use countersunk screws to hold the louvre/fan/fan duct/heatsink assembly toby dc42 - Ormerod
Hi Radian, I appreciate what you are trying to do, but I don't agree with your rationale. QuoteWithout knowing exactly what the present (or future) firmware is going to do with the gate drive, keeping the MOSFET in it's semi-conducting region with 10A flowing could soon turn into excessive dissipation. What I mean is, it depends on the number of on/off cycles in a given amount of time and we doby dc42 - Ormerod
If the bed is not flat then I think you need to resolve that rather than use more levelling points. Someone else has suggested using 4mm float glass instead of 3mm.by dc42 - Ormerod
Glad you got it working. I too have an Alpine PSU, and it seems to be working OK, although the fan slow-down is very noticeable when the bed heater turns on. I guess you got a bad unit, and suggest you ask RRP for another one.by dc42 - Ormerod
The original X-axis rib and plate I received did not fit well. It seemed that one of the slots in the plate (the one nearest the motor) was at least 1mm out w.r.t. the corresponding tab in the rib. The other 2 slots were perfectly aligned with the tabs. So I had to bend the plate if I wanted to fit all 3 tabs in it. I think this must have been a design error, unless the laser cutting is very imprby dc42 - Ormerod
Hi KK, I would love to fix some of the firmware issues, but unfortunately neither myself nor another Ormerod user is able to reproduce the Duet firmware build at present. See the end of this thread.by dc42 - Ormerod