New Vertex and Cura 3.6.0


#1

Hi all,

I recently assembled my Vertex Delta printer. Didn’t have any problems building it. The keychain gcode file prints without any issues. I have a Mac and I am already familiar with Cura, so I installed that to slice my designs. I followed the instructions as described here, but I can’t get anything to print correctly.

Whatever settings I use, it seems the nozzle is too close to the print bed, resulting in a very thin first layer. Also, the extruder starts making clicking noises and the filament is being pushed back when it does that. A sign of the filament not getting out of the nozzle at the speed it is supposed to, I think.

When I let the print continue, there’s filament clogging up around the nozzle, especially at the left side of the print bed. When the print continues to the second layer, the print head will crash: the rods are falling out of the cups, because there is filament in the way.

I tried printing at 0.1 and 0.2 mm layer height, but both are not working. I looked at the gcode for start and end of the keychain file and compared that to what Cura is creating and I can’t find anything in there that would cause this.

Again: keychain is working fine and in very good quality, but anything I created with Cura won’t work. Anyone have any clue what could be happening here?


#2

The clicking extruder and clogging filament are probably secondary symptoms of a bed leveling problem. If the head is too close to the bed, the filament cant get out, causing back pressure that can make the extruder motor skip steps. If the first layer is malformed it can cause the print head to derail as the job progresses.

So I would focus on getting the bed to level and calibrate, and then your other problems should resolve themselves.

One question I have is whether the part that cannot print is significantly larger than the keychain? Maybe you are using more of the bed area than the keychain sample?

The very first thing I would try is to increase the piezo sensitivity to make sure a gentle tap will light the sensor LED, then recalibrate the height and bed level.

I also have had better luck printing on the bare glass side of the bed instead of using the BuildTak. (For best results, treat the glass with a glue stick.) The surface of the BuildTak can bubble or lift slightly, possibly causing uneven spots on your build plate.

Make sure the brass bearings and magnetic balls are all properly lubricated, and clean the vertical rods regularly, especially when the printer is brand new. The brass bushings are expected to break in over the first several uses.

If that doesn’t help, posting some pictures/video and/or gcode may help someone here spot the problem.


#3

You can try to reduce the first layer speed 13 to 17 mm/s is a good start.
I had some issues with my profiles after updating to Cura 3.6 so I went back to 3.5.1.
Calibrate often and oil the brass bushings but be careful that the excess does not flow inside the printer.


#4

Maybe try tweaking the Z-offset. There is an option on the printer but if you’re using the stock Marlin it will not work great (at least in my experience it didn’t).

To adjust it as Velleman intended: in cura go to the machine settings and search for the start g-code script.
There is a routine for the prime blob (after all the warm-up and leveling code), in this part you can see a comment that mentions the Z-offset (sorry for not being specific, I’m at work).

You adjust the “correction” that the printer makes to the Z axis by telling it it’s not in fact 1mm from the bed but say 0.85 or 1.1, thats why the comment says the value must be 1-(z offset). Try decreasing the value (hence increasing the z offset) by say 0.1 mm and look for improvement.


#5

I think the problem is solved now, mostly thanks to Dr_Vegetable’s reply. The object I couldn’t print was indeed larger than the keychain. Once I increased the piezo sensitivity, I was able to print other objects. I’m still tweaking to get it perfect. I noticed that going to sensitive will make the filament not stick to the buildtak. Make the piezo’s not sensitive enough: extruder clicking and filament clogging.

Thank you all for your suggestions!