Jump to content
Cura Connect | Survey Read more... ×
Ultimaker Community of 3D Printing Experts
Sign in to follow this  
restinpieces

UM2 start procedure??? (Dip in the puddle)

Recommended Posts

Some time ago the start procedure on my UM2 changed. Unfortunately I don't know which update it was.

Now the printhead moves to the front left side and extrudes a hole blob of material into the air (printbed is 2cm beneath). Then the nozzle dips into the blob and after that, the whole mess moves to the actual print.

I learned that start.gcode is not used by the UM2 but where is this behavior coded then? I would really like to change it.

 

Share this post


Link to post
Share on other sites

"then the nozzle dips into the blob". Hmm. I'm not sure that's what I see: I see a x-y move to the approx center of the bed while the bed is being raised. I believe the idea is to lay the priming material in a run along the glass where it hopefully starts the brim.

In practice the xy-move leaves a wisp of material hanging loose. I've had occasions when the print head catches this and peels part of the print off the table. So, I prefer to be there when the filament is priming, allowing it to fall between the points of a pair of tweezers. When the xy-move starts I pinch off the primed material and dispose of it. Seems to work ok.

 

Share this post


Link to post
Share on other sites

I had this too!! after priming in the SW corner ca 2cm above the glass, it first dips into the blob and tries to carry it

to print start. I swore at it and needed to have a print ready and it was a mess and I chased it with tools and tried to

remove it "in situ".. NO luck.

I fixed it by renewing the FW, I updated the FW again, I also installed Cura.

I also re sliced the part.

I cannot say what fixed it.

Daid: If the bed could stay lower when priming, ie 5cm or more, then it would work better ( not for THIS particular snag), but it would work better always! The gravity would help a lot.

Thank you.

 

Share this post


Link to post
Share on other sites

It is in the gcode. It happens only with Cura.

 

Unless you've changed the Gcode flavour to RepRap in the machine settings, it is not in the Gcode. This behaviour is set in the firmware for the UM2. That said, I can't remember seeing that behaviour before (where the nozzle goes straight down into the priming blob). I would try re-flashing the firmware and see if that helps.

 

Share this post


Link to post
Share on other sites

Someone else complained of this recently. I've never seen the behavior.

You can look through Marlin (the firmware) if you want - it's pretty easy to read and shouldn't be hard to find this code but if you make your own custom firmware and new features come out... or you can do a pull request. Let us know if you figure out if this is a Marlin thing and which version has the bug.

If, in Cura, you choose "rep rap" flavor then it's controlled in Cura and in the gcode. You can customze the "start.gcode" setting in cura (only visible in "rep rap" mode - change this in machine settings) and set any damn start procedure you want. But I really prefer utligcode mode.

Marlin source for ultimaker 2 is here on github:

https://github.com/Ultimaker/Ultimaker2Marlin

 

Share this post


Link to post
Share on other sites

Hmmm. I remember that my UMO used to do that, but at some point there was a change in the order of the start code and now it lifts and primes after homing. It then goes directly to the start of the print. I can't remember why I had problems fixing that behavior at the time. Seems like it should all be in the startup gcode.

Share this post


Link to post
Share on other sites

@aviphysics: The UM2 is strange in this way - normally we use cura in "ultigcode" mode which doesn't specify the start sequence anymore - so the homing, priming, warming up is all done in firmware now. Unless you export to a gcode file in "reprap" mode. In that case it is all done using gcodes. Supposedly the advantage is you can slice once for an ABS and PLA part and separate the slicing process from the material used. So on the UM2 you select the material which sets approximately 5 settings (bed temp, nozzle temp, retraction distance, retraction speed, fan speed multiplier (if at 50% then all fan commands do 50% of what gcode asks for)). I don't really think that's much of an advantage as I never print the same part in 2 different materials.

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Our picks

    • Architect Design Contest | People
      The goal of this contest is to design a set of people figurines that could be used in such a project to make an area, office or mall seem populated. 
      Think of different types of people in different environments, like walking people, people standing still, working people, and both men and women.
       
      • 9 replies
    • Taking Advantage of DfAM
      This is a statement that’s often made about AM/3DP. I'll focus on the way DfAM can take advantage of some of the unique capabilities that AM and 3DP have to offer. I personally think that the use of AM/3DP for light-weighting is one of it’s most exciting possibilities and one that could play a key part in the sustainability of design and manufacturing in the future.
        • Like
      • 3 replies
×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!