Makerbot Z18 issue

[Rednels]

Hello everyone,
I just got a new makerbot Z18 (because we had to have the build volume) and I am having some trouble. I am not new to simplify3d as this is my 3rd printer but I am having trouble getting it to print correctly. Here is my problem....

It appears there is something wrong with the z-axis. As I print these pretty tall prints after 5-6 inches of the print, the nozzle begins touching the print and eventually knocking the print over causing a fail. I have calibrated the extruder to make sure its not over or under extruding and I have also dialed in the x and y axis.

Anyone else had this issue? Is there a way to adjust the z calibration? If I print these parts using the makerbot software (which sucks) they print just fine so I know the printer works properly. But I need total control over supports and I can't do that in their software.

[CompoundCarl]

You may want to try enabling the "Vertical Z lift" on the Extruders tab. That will lift the nozzle up each time it makes a move, which can help prevent the extruder from knocking over your part. If you want it to lift for every single move, you will need to disable the "only retract when crossing open spaces" option on the Advanced tab, since it will only lift when it is retracting, since otherwise you would get a big mess.

Also, you may want to try adding a brim with a few outlines to help secure the bottom of the part to the bed. That way it won't knock over so easily. More info on that here: https://www.simplify3d.com/support/tuto ... and-brims/

[Rednels]

I appreciate the response. I will try the vertical z lift option.

[Rednels]

I am still having an issue with the z-axis on the z18. Same as before, the tall prints get knocked over because the nozzle eventually hits the model. It doesn't happen early on in the print.

When I print with the makerbot software it doesn't do this. Any ideas what to look for as a difference in how the z is controlled between the 2 softwares?

[CompoundCarl]

I'm not sure there's any other suggestions other than what I already said above... are you using vertical lift? did you add a nice large brim to help hold the part down?

[Rednels]

Yeah I have a nice large brim. I literally could not find the vertical lift option. I looked all over. I did notice that the z axis movement speed was set to 20mm/s and on the makerbot software that is set at 3mm/s. So that's a pretty large difference.

[CompoundCarl]

It's on the Extruders tab. It's called "Retraction vertical lift". Set that to maybe 2mm and it will make sure that your nozzle lifts before moving. You may also want to go to the Advanced tab and disable the "only retract when crossing open spaces" option so that it retracts and lifts before every move. That's the best combination if you want to avoid quick movements knocking over your part.

[NoahHornberger]

Very likely the default print settings are simply extruding too much plastic. It is not going to be a problem at first.

But as time goes on, a slight over-extrusion builds up and the part ends up getting slightly taller than it should be. After a while the pressure is too high and this can cause strange compression along the Z.

This compression can also cause intermittent registration errors and skips because the nozzle gets bumped by previously extruded plastic.

Try reducing the extrusion rate by .-02 (.93 , .91, .89 etc.) at a time and see if it helps. This number might need to change when you change filament brands or if your filament is not consistent from batch to batch.

[Rednels]

Thanks I am trying it right now, reducing the plastic coming from the extruder. I already had it down to .95 and it was still knocking it over. But I also know something else is going on because it just looks really ugly. And it fits with too much extrusion.

[Rednels]

OK I figured out the problem. When I set up the software with the setup wizard and I selected the Makerbot Z18 it defaulted to the RepRap firmware and not the makerbot firmware. I changed that setting and I was able to run a full print.

Now, I had a ton of stringing, so once I get that under control I think I will be good to go.