Show all posts by user
Rostock, Kossel, Simpson, 3DR, and more. See: http://reprap.org/wiki/Category:Delta. Previously named "Delta Robots and Stewart Platform"
Re: Z-axis suddenly going nuts - 2 years ago
In my experience motors and drivers don't degrade over time but power supplies do wear out eventually. The capacitors dry out and you get more ripple on the supply lines. That could be hard to detect without a scope but the average voltage might go down. It should be about 12.2V when the bed is off and about 11.8V when the bed is on.by nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
The Melzis supplied were set to 1.25A but current affects torque, so with no load on the screws there should be plenty of torque to spare. When one motor stalls it stops generating back EMF, so there is more voltage for the other. If that is spinning it implies there is not enough voltage for both but there is enough for one and voltage affects the maximum speed. Try explicitly moving them at 4by nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
Just seems like you are trying to run them a little too fast. That is exactly what they would do. And other than the supply voltage being too low I can't see what else would cause it.by nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
I noticed you changed the X & Y steps per mm in gcode. Is it possible you loaded some g-code that changed the Z motion parameters? I noticed in your video that the Z acceleration sounds lower than normal. The firmware I supplied did not have EEPROM enabled but it would remember new settings until you powered it down or pressed the reset button. Or have you loaded a version with EEPROM enableby nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
When the motors are wired in series, if one stalls the other tends to keep running. If they are wired in parallel then if one stops they both tend to stop, but you get half the torque that way. What happens if you change line 8 of your start gcode to G1 Z0.05 F200? I can't see how that file ever printed correctly because the bed temperature will not be set.by nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
What is actually happening on the video? At first there is a loud whine and no movement then repeated stop-start movement. The closest I can get with my machine and Octoprint is repeated 0.1mm movements but they are not as close together as yours. When you print the Z speed in your example is 9000mm/m but it is capped by the firmware, in my case 4mm/s. When you move with OctoPrint the Z speedby nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
I wonder if the power supply is failing. Have you tried measuring the 12V rail? I have never known a stepper motor to fail. The only moving parts subject to wear are the ball bearings and the Z axis doesn't do much mileage compared to X and Y. I had a weird fault on my first DiBond machine a few months ago where it would print some layers with far too much plastic. It took me ages to work out wby nophead - Mendel90
Re: Z-axis suddenly going nuts - 2 years ago
Perhaps it needs a little oil or light grease on the lead screws and the bearings if it is sticking and stalling the motors. That would make them buzz. Have you updated the firmware at all? You could have slicer settings that are too fast for Z but the firmware previously capped it. A loose connection on the Z motor wiring could cause them to stall and buzz.by nophead - Mendel90
Re: Problem when reanimating Mendel90 - 2 years ago
When the terminals are loose and drop some voltage they get very hot and can affect the PCB solder joints. It's a good idea to look at the back of the board and perhaps re-solder them. Hard to see how tightening them could make it worse otherwise.by nophead - Mendel90
Re: Problem when reanimating Mendel90 - 2 years ago
Check that the ground connection on the Melzi terminal is tight. Classic sign of it being a bad connection is the bed current flows down the USB lead and causes a disconnect.by nophead - Mendel90
Re: Mendel90 issues after replacing controller - 2 years ago
I don't think my version of Marlin contains the string " Debug communication ". If the message is from Pronterface I have not idea how it could tell if a motor was working or not unless it was a more advanced stepper driver with a serial link. What do the motors do when you try to move them?by nophead - Mendel90
Re: New thermistor for Orcabot 0.43?? - 2 years ago
Why are you asking about Orcabot in the Mendel90 section of the forum? Mendel90 is a specific machine that uses a different hot and and a different thermistor.by nophead - Mendel90
Re: Printer stops - 2 years ago
It shouldn't matter where you measure the 5V as they are all connected together. I think the easiest is on the jumper that selects between regulated power and USB power. Most likely all your problems are bad power connections. If the PSU ground is not good it causes bed current to flow down the USB cable and that will cause the USB connection to drop out.by nophead - Mendel90
Re: Printer stops - 2 years ago
Perhaps monitor the 12V in at the terminal screws and see if the power dips or has excessive ripple on it. Could be the PSU going bad due to the capacitors wearing out. Also check the 5V rail is actually 5V.by nophead - Mendel90
Re: Are newer printers better? - 2 years ago
The X bearings are a tight fit in the X ends so they are held rigidly once snapped in. Yes the third bearing mount is designed to float in the Y direction, so that it won't bind if the X rod spacing is not exactly right. I have only printed the parts in ABS, so I don't know how they would last in other plastics. In theory it doesn't need to flex if everything is perfectly aligned.by nophead - Mendel90
Re: Are newer printers better? - 2 years ago
Yes the frame can twist but if it is standing on a solid flat surface then it will be stable and braced against the forces generated by the axes moving. I would imagine a frame built from extrusions would also conform to the surface it was standing on unless it had only three feet. If it was totally rigid it would rock but it would need to be extremely stiff to do that without being a box frameby nophead - Mendel90
Re: Are newer printers better? - 2 years ago
The J-Head shouldn't melt at 240C, I run them up to 255C for the white ABS the kits are made from. I think you must not have the right thermistor if you replaced it. Thermistors don't normally fail when they are cemented in unless molten plastic gets into the cement. They then read high and the hot end temperature falls. PEI melts at 217C so you can easily melt it if you crash the nozzle into itby nophead - Mendel90
Re: Mendel 90 and Cura 3.x+ - 3 years ago
There is no difference between G0 and G1 in the version of Marlin I use. Both should move to the bottom. In standard G code G0 is a travel move to get there as fast as possible and G1 is a coordinated move where the axes are kept in sync for cutting. I think in CNC G code they each maintain a separate feed rate. What firmware are you using?by nophead - Mendel90
Re: Mendel 90 and Cura 3.x+ - 3 years ago
No Idea but AFAIK all slicers have Z=0 to mean nozzle on the bed and go upwards from that. The firmware maps that to physical locations. I don't know of any machines where the axis is inverted. Obviously some move the nozzle up and others move the bed down but the gcode should be the same with Z increasing from 0. What do the first few Z values in the gcode look like?by nophead - Mendel90
Re: Have I damaged my hot end ? - 3 years ago
Perhaps it is PLA that has leaked and then cooked for a long time. Without a picture I am just guessing. The exhaust putty is like grey cement. It is rock hard once cured and there shouldn't be any excess. It is only around the resistor and the thermistor. I use those hot ends at 255C for ABS, so 200C is no problem at all. If the hot end is not starting to separate at the join but leaking justby nophead - Mendel90
Re: X-Carriage replacement and problem - 3 years ago
Other than perhaps the belts being very slack, I can't think what would reduce the size by so much in both x and y. Tighter belts stretch slightly so will have a slightly bigger pitch but I don't think it normally makes so much difference.by nophead - Mendel90
Re: Z axis Lowering speed issue - 3 years ago
I don't know about the latest Marlin but the Z speed should be capped to 4mm/s by this line The homing speed is defined separately.by nophead - Mendel90
Re: Powering Pi for Octoprint - 3 years ago
The 10R resistor is needed to get the 12V rail to be close to 12V. Without it the PSU throttles back to keep the 5V from being too high and then the 12V rails drops when the bed is on. I would keep it in circuit. I use the 5V standby rail to power my RPIs and then use GPIO to control the main PSU. Seeby nophead - Mendel90
Re: cura settings - 3 years ago
I have printed E3D edge, which is form of PETG but it only needs 240C. I printed all the kit parts with ABS at 255C for the first layer and 250C for the rest, so J-Heads can definitely can handle that for thousands of prints, even in a chamber at 45C. I know their spec says less but with the more accurate thermistor that I use I have not found it to be a problem.by nophead - Mendel90
Re: cura settings - 3 years ago
Ethyl acetate is a better solvent for PLA. I use that to clean the glass when printing PLA. One thing I have been meaning to try is to dissolve PLA in it an try 'PLA juice' as a bed adhesive like ABS juice made with acetone. So far I have not needed it as a hot bed for the first layer works well for me. I print ABS with a the J-head up to 255C. You can fit a E3DV6 to the standard Wade's block usby nophead - Mendel90
Re: cura settings - 3 years ago
Yes PLA should stick to plain glass as long as it is free from grease. I run the bed at 100C for the first layer and 70C on subsequent layers. Extruder 220C for Prusament, which is what I am printing at the moment. Never used hairspray or an form of adhesive. Just plain glass for PLA.by nophead - Mendel90
Re: cura settings - 3 years ago
Seems like the Z calibration is too low. Print an outline and adjust so it is exactly the first layer height as per the Mendel90 manual. When it is a lot too low you get a thin first layer rather that zero thickness because the pressure of the plastic is enough to lift the nozzle but it then doesn't lift enough for the second layer.by nophead - Mendel90
Re: No terminal window in Skeinforge - 3 years ago
On Windows or Linux I don't expect to get a new terminal window if I run a command from the terminal. The output should just go to the terminal it is started from. Not sure what happens if I run it from the GUI. Some programs do open a new terminal then. I am not at home to try it. I can't think why you would get garbage. Perhaps it is a character set problem.by nophead - Mendel90
Re: No terminal window in Skeinforge - 3 years ago
Not sure what you mean. I run it from a terminal window and it brings up a GUI and prints some commentary to the terminal I ran it from.by nophead - Mendel90