Attached is a zip file which will unzip into Marlin 2.0.7 modified for the stock AnyCubic delta Predator using the Chitu Trigorilla Pro 32 bit board and 3.5 inch touch screen. The firmware.bin file in the pio\build\trigorilla_pro folder should directly load onto the board, using a USB cable and the STMicro Demonstrator, if the board jumpers are correctly configured.
Alternatively, you can modify any files you need to, recompile under PlatformIO, and download your new firmware.bin file.
There is no need to physically rotate the display, and the only issue that I am seeing is that perhaps the filament detection logic is reversed. I am looking into that, but you can turn OFF filament detection from the touchscreen, and store that change, as a workaround.
The "Enter" and "Cancel" touch button positions will be swapped left to right, and the previously dark blue enter button will be an easier to see blue, but otherwise the functions are all "normal Marlin".
After updating your Predator to Marlin, you must run a delta calibration and save the changes from the touch screen.
The Marlin GitHub releases change too fast, and too far, especially in the realm of the user interface, for me to keep up with, so this will likely be my last post on this topic for quite a while. If I discover an improvement I'll post, otherwise I'm done for now.
Anyone have any experience repairing or re-surfacing their print beds? After printing a part with PETG a small and relatively thin chip of glass came off the bed with it. Funny thing is I let it cool completely and didn't have to use any force to remove the part rather than what I normally do which is remove the print from the bed almost immediately after it is done.
I'm thinking of just using some JB weld to fill in the chip and use a spatula or razor to make to flatten it. It's supposed to be good to 300C, I'm just concerned it will either not adhere to the glass well enough or worse adhere too well to both the glass and the item I print and possibly take a larger chunk of the bed out.
I've never had to use any sort of glue or interface material for my prints to stick to my print bed, and I'd rather not start if possible. My bed has been working as intended for about a year now and I'd like to keep it that way if possible
Another possible alternative that comes to mind would be to re-surface the bed, possibly with some sort of coating similar to what they used for the ultrabase material. Has anyone heard of anything like this?
I guess another option would be to just get a heat bed plate, but those are about as expensive as a replacement bed from Anycubic.
So I went nuts, and directly mounted the Predator extruder to the hotend heatsink. It's trivially easy to do:
1) Remove the extruder from the Predator
2) Disassemble the extruder. Don't let the filament tensioning spring get away!
3) Remove the bowden tube and bowden clips from the extruder adapter and heatsink
4) Go to the hardware store, and buy a brass 1/8-27 NPT male close or hex pipe coupling ($0.89), and 4 washers 2 mm thick. #6 is good, and thickness isn't super critical. The washers take the place of the 2mm thick spring fastening plate on the extruder
5) Screw the pipe coupling into the top of the heatsink, and into the bottom of the bowden adapter you removed from the extruder
6) Push a length of bowden tube firmly into the heatsink/extruder adapter assembly, and cut it off smooth and flush with the top of the bowden adapter
7) Rotate the extruder stepper 90 degrees, so that its electrical connector is UP
8) Reassemble everything, using the 4 washers to replace the 2 mm thick spring fastening plate
9) Remove the flyng extruder springs from the Predator
10) Remove the top of the Predator, and "stretch" the extruder motor lead. There was more than enough "extra" lead length in the top of my Predator so that I didn't have to splice, or otherwise modify, the extruder stepper motor lead
The result is MUCH less vibration at the effector end from the extruder gyrating on the springs. You can feel the difference if you gently rest a finger on the effector while the machine is printing. There is less filament ooze and stringing, because the "snake in a pipe" effect of the filament in a bowden tube is eliminated. Retracts and bridging are MUCH cleaner. I think a real E3D V6 hotend will improve things even more, but I was impressed with the quality of the stock Predator extruder after having it apart. An even thinner "pancake" stepper is easily available, and would drop the weight even more, but I don't see the necessity.
The test cube photo starts at 40 mm/sec at the bottom, and is increased by 100% in speed every 20% of the print, ending at 240 mm/sec for the last 10% of the print. I had to goose the PETG temp to 240C at 120 mm/sec. I made no effort to modify any slicer settings in Cura to compensate for the increasing speed, and my custom test cube shows that, but overall the results were very worthwhile and very impressive. I'm currently printing a Benchy at "standard" 40mm/sec, and I think this $1, and 1 hour, mod is a must do.
Just my $0.02
After converting my Predator to direct drive extrusion, I was reminded here on the forum that it might be a good idea to revisit the extruder calibration. And a good thing I did!
The Predator is programmed via Chitu g-code, and the extruder calibration command is:
The first line is the g-code directive to the TriGorilla board to use the S parameter for millimeters per step. Don't ask me why Chitu decided not to use steps per millimeter, but that's the way it is.
The second line (M8500) forces a store of the first command to EEPROM, so that the Predator will actually do what it has been told. You MUST issue this command each and every time you make a firmware change, or the Predator will simply revert to what its current settings tell it to do.
In any case, out of the box, the Predator was set to an S parameter of 0.002540, or roughly 390 steps per millimeter of filament. This was, by measurement, grossly underextruding, so I reset the S parameter by trial and error to 0.002450 (408 steps per mm), which was spot on. Until I got rid of the bowden tube.
The new S parameter is 0.002280, or 357 steps per millimeter, a huge difference. I find it hard to believe that the bowden tube introduced so much wiggle room in the filament length, but there you are. I checked the results with both Pronterface and Repetier Host as the manual control and g-code programmers, and the results are very consistent, even across different filament feed rates.
Incidentally, Repetier has a hard time staying connected to the Predator. I had to bounce back and forth between 115200 and 250000 baud. Pronterface locked on at 115200 baud, and stayed connected reliably.
Keep in mind that if you reload the predator firmware, you'll have to re-issue the M8011 and M8500 commands. Or you can modify them in the factory g-code before you install it.
Hope this helps.
Remove any extra mass at the top of the printer. Having the filament spool up there just begs the frame to resonate, which is never a good thing. I took the spool holder off of the top of my Anycubic Predator, and screwed it to the ceiling of my shop. The difference in printer frame vibration is detectable by touch, and certainly by examination of the final prints. Much less ghosting and ringing.
Isolate the printer even further from its environment. My Predator sits on three 1/4 inch thick Teflon plates, drilled to align with the printer's feet. The Teflon plates in turn rest on 40 OO Sorbothane pads. The Teflon prevents "stiction" and allows the printer frame to expand and contract without warping, and the Sorbothane is a very effective vibration damper, commonly used for precision industrial machines. Yes, these materials are expensive, but not as expensive as wasting filament when you're trying to get the last micron of precision.
Both materials are available from McMaster-Carr. Just my $0.02 worth.