Thanks David. While testing I was able to determine that accelerations above 6-7000 produce very small decreases in travel time at least at speeds upwards of 300mm/s and 100mm travel distance. Soon to understand those relationships at slower speeds and shorter distances.

Nice thank you.

@peter247 said in Silicone Heated Bed: . Now I've come to the opinion the best way is thin aluminium plate 3 or 4mm and flat glass / shims , what is the point of a heavy plate if it bowed ? @peter247 sounds like a great idea. I didnt like the aluminum bed because of the weight and because 40% of it is outside the printable area. Not an efficient approach in my opinion on a machine that moves the bed in x or y. A lot of wasted energy. I here many claim the poor thermal conductivity of glass as being the reason for aluminum but the glass is thin (relative) and has a high rate of heat flow even though it is a poor conductor. If you ended up with a flat piece of aluminum you may be able to plop it down on a layer of PVA glue and call it a day bypassing the shims

Was your PT100 board supplied with a 100 ohm resistor? If so, connect it between pins 2 and 3 of the daughter board terminal block in place of the wires to the effector. It should give you a reading of 0C.

I have bought several 2 wire axial fans over the last few years and all have worked with PWM except the E3D ones. Sometimes I needed to reduce the PWM frequency to 100Hz. I have had less success with centrifugal blowers.

Is that right that your X and Y jerk speeds are 0? That would lead to a complete stop and pause to change directions I think. That would be the cause of the over extrusion on corners. Try a low value like 1 or 0.5 and see if that helps. Also try increasing your extruder jerk and accelerations, say 600 jerk and 10000 accel. That's a cool printer by the way. Definitely large format! How much Z height can you get on that?

@dc42 I do not see the nasty consequences.. Can you elaborate?. I imagine this as a driving a car. I start the engine and start accelerating until I reach the maximum speed on the road (80Mps for the shake of the story). Then I maintain the velocity and to do that I do not apply any more acceleration to the car (acceleration =0). If I see a curve, I push the brake and reduce velocity a bit to 60Mps (decceleration) and at the exit of the curve I push the accelerator to increase speed again to 80Mps for the next road segment. In this drive, there is an inflexion point when the car reaches the minimum speed and before it starts accelerating again (gains more velocity). If the movement is smooth the speed profile would be like a "U" with the minimum speed reached at 60Mps. On the bottom of the U, the tangent (acceleration) is horizontal and therefore the acceleration is 0, and this does not produce discontinuities or nasty consequences. Also a third order motion profile will have 0 acceleration at the start end new of each move and will have the same consequences so I see no differences (except for the fact that it will have jerk).

@deckingman said in [Off Topic] Searching the limits.... the small limits...: You'd need to keep the filament really clean - fit one of those dust filter thingies maybe. It won't take much debris to block a nozzle that small. My workshop is definitely not a clean room, so I've been using a dust filter from the get go and I'm always astonished by how much crud builds up in a month. I'd also think that you'd want to use premium filament with consistent diameter with such small nozzles. Not much margin for error.

The biggest improvement of stability I found for the DBot was making the bed a square frame secured front and back on 3 screws. That kept the bed from bouncing as it tends to do on the stock cantilevered design. The wheels and plastic mounts just have too much flex to support much weight. After that I replaced any plastic part I could with aluminum. Corner plates and brackets. That reduced flex quite a bit. There are no other frame modifications than this. Aluminum wheel spacers and shims allow for proper tightening of the wheels without binding them. That combined with 3 wheel tensioners keep them nice and tight. No slop. Then I replaced the idler bearings with actual smooth and toothed idlers. That removed some of the belt vibration. I've tried both steel and glass belt. The glass belt was a bit quieter and had less vibration. The diameter of the toother idlers are still too small to use with the steel belt, but interestingly I've noticed less ringing with the steel belt than with the glass when properly tensioned. I also switched to a carriage with belt tensioners built in which make it much easier to get equal tension on the belts. The printer sits on a very heavy (300 pounds) bench which was originally designed to be a fish tank stand capable of holding 1000 pounds (double the weight of the tank), so there is no sympathetic vibration in the stand. Since the Dbot has the XY movement at the top, it tends to wobble a bit. At first I tried to add some weight at the bottom of the frame to clamp it down to the table more. This worked ok, but was louder. Then I sat the printer on some thick dense foam blocks. The printer sways a bit more on fast travel moves, but is far quieter, and ringing seems to be less. It's as if the foam is absorbing the force rather than springing it back, so there's less oscillations. Travel moves are comfortable up to 220mm/s. I usually keep them to 180, but 250 worked, but felt a little violent. Perimeter and infill print moves up to 150mm/s are doable and I use that for my draft settings. Good quality with no artifacts up to 90mm/s. I'm still tuning my accell and jerk settings. I think I'm going to switch over to Cura again to have more fine grained control over the jerk and accel settings for different moves. 2000 accel is fine for infill, but for outer walls 500 keeps ringing down while still letting me hit 90mm/s on long walls. This is all on a 24v setup with 2a 0.9 degree motors with a Titan Aero. Reducing the mass of the extruder is tempting. The stock Dbot uses a short bowden tube setup and reduces weight compared to direct drive substantially, but all of the carriages I've seen tend to be tall and stick the hotend fairly far out from the plane of the cross bar, whereas the Titan aero carriage i'm using is very short and compact and slings most of the weight directly under the crossbar. The new CoreXY printer E3D is working on is very interesting. Extreme rigidity from the tooling plate top frame and carbon fiber cross bar and bowden setup for light weight. They haven't really talked much about print speed from what I can see, but I would think it could be quite the mover. Ha, sorry for the essay, but I've been playing with the Dbot design for the passed year. It's a great design in the stock form and leaves the door open for a lot of improvement. A perfect tinkering platform. I look forward to see what you come up with on your Dbot.

Not a problem as long as the cable resistance is not too high. Aim for no more than 0.2 ohms per conductor.

@dc42 Thanks a lot, will do!

thanks. will do

I think the limitation is that the Duet isn't a host device. Using an IP camera to pass a stream into the website is a way of sidestepping the limitation. I recommend using a Raspberry Pi Zero W with camera as an IP cam, or setup Octoprint on a Pi3 to use a USB camera.

@ivang, perhaps you are loading a mesh using G29 S1? If you clear bed compensation by sending G29 S2 then the Z axis should not move when you move X or Y.

@dc42 said in Tool 0 was not driven heater not high enought: @kivlow said in Tool 0 was not driven heater not high enought: I am testing printer so i dont have load filament. From what temp it allow me to test all ?? Unless you use M302 to enable cold extrusion, AFAIR the minimum temperature for extrusion os 160C. As always dc42 you the best !

@dc42 said in auto save on loss of power from a different pin (endstop?): M226 is intended for use in the GCode file being printed, for example to pause after a particular layer has completed. So it waits until all the moves in the queue have been completed. M25 is intended for use from a different source of GCodes. I have updated the gcode documentation to reflect this.

This isn't my field of expertise at all but I doubt if the bed temperature is actually changing that fast due to the thermal inertia that it must have. It looks more like a noisy signal to my untrained eye.

That's all you should need to do. Future firmware versions may also require S1 to enable pause on filament error.

I just checked and yes, you can change the speeds for mesh bed probing as well - check the documentation for M558 (https://duet3d.dozuki.com/Wiki/Gcode#Section_M558_Set_Z_probe_type), and pay attention to the F and T parameters.

@dc42 : only one dwc connection, tried a 2MB file and a 12MB file and both failed. did some more testing and had success with a 1MB file. Just to be clear, the file is correctly uploaded but DWC disconnects at the end.