High and low spots on delta print bed - need help and advice.

Hi there,

I have been having A LOT of trouble with first layer height on my delta printer. (anycubic Kossel)

I have read quite a lot about similar situations people have had, and I'm yet to find a solution.

The problem is that when I print on certain areas of the bed the nozzle is either to far or to close. I have leveled and releveled the bed countless times using the 4 point paper method.

I have been adjusting the screws on top of the carriages to level the bed. When testing the distance between the nozzle and the bed with the piece of paper the distance feels perfect at all four points.

I decided to print a test circle to see what's happening.

I have had some very successful print in the small area that is usable.

In the picture the green cross represents the area where the nozzle is to far from the bed(hard to tell from the picture I know)
Blue cross is the region with the nozzle to close.
Lastly the white cross is the small section that prints fine.

I have played around with DELTA_SMOOTH_ROD_OFFSET. I reduced the set value by 7mm and still no change at all. I have seen posts suggesting rod length causing this. Is it possible to avoid having to not buy a complete set of new rods? If I buy new rods they might also have small differences between them.

Printer details:
Hardware - Anycubic Kossel
Electronics - ramps and arduino mega set up
Firmware - marlin 1.1
Auto bed leveling - no
Heated bed - yes

Any information and help would be greatly appreciated, this has been driving me mad for a while.

Thanks

The Trigorilla RAMPS clone board that shipped with the Anycubic Kossel series, is a total piece. If you can afford it, throw that thing away as soon as possible, and get 32-bit electronics, like the Duet (top of the line) or RADDS (comparable, but far cheaper). With those boards, and RepRapFirmware, you are essentially guaranteed better prints, right off the bat, as well as giving you support for touch screen displays, which eliminate the hassle of having to upload sketch upon sketch just to change the value of one thing. It saves so much time. If you want to save your configuration, simply pop out the SD card, overwrite the files, pop the SD card back in, and it just works. Hell, you can even go simpler than that, and change the values of parameters on the fly, tell the printer to home, and it'll use those settings. No fiddling, just time savings.

In the meantime, however, find the gcode for Clear EEPROM, and do it before and after you upload a sketch. It works about half of the time.
These should do ya:

    M500 Store current settings in EEPROM for the next startup or M501.
    M501 Read all parameters from EEPROM. (Or, undo changes.)
    M502 Reset current settings to defaults, as set in Configurations.h. (Follow with M500 to reset the EEPROM too.)
    M503 Print the current settings – ''Not the settings stored in EEPROM.''

Edited 6 time(s). Last edit at 03/05/2018 04:37PM by Lobotomy.

Hi Lobotomy,

The trigorilla board is currently sitting in a drawer with all my failed prints. I am using ramps and an arduino now

I will have a lool into a 32-bit board.

Thanks

You might want to check out Panacutt's Re-ARM board, it's a smoothieware CPU board that interfaces with a Ramps shield, would let you go 32-bit without redoing the entire wire harness. I've been using one as the brains of my main delta since they came out and I haven't had any problems. Here's my blogpost documenting the installation process.

Hi Cobalt Griffon,

That sounds interesting I will definitely look into that.

Cheers