5th Gen Replicator printing too close to plate

[Deans21]

Hey everyone,

First time poster here. In the past I have used Google Groups to pick brains but I figured I would branch out and try somewhere else.

Anyway... I work for a public library and we purchased a 5th Gen Replicator in March of 2014. We've actually been pretty lucky and haven't had too many issues with it until now. Whenever someone starts a print, the nozzle is so close to the plate that no filament is able to come out. I have maxed out the Z Offset under Device Preferences but still have the issue. I have also leveled the plate numerous times both using the automated leveling process and manually using a bubble level.

The extruder in use has been opened before so my initial thought was that it was not re-assembled very well. I have since taken it apart and re-assembled 3 times and have had the same result each time. We're running Windows 7, MakerBot Desktop 3.7 and the latest firmware (I think it's 1.7.somethingorother). The only thing I have not yet tried is rolling back software and firmware. I have kept a collection of the downloads along the way so this may be my next step. I have also heard of people sticking a business card under the nozzle during the Homing Process to offset this issue but because it is a public printer, this really isn't a good solution for us.

Anyone have any tips or advice?

Thanks!

[Roberto]

hi there
Look like your extruder have stiff nozzle.
Try to move it a little up - down.
If it moves freely then OK, if not then you have to clean it.
This is the source of most problems like your. When printing start with initial leveling and nozzle doesn't give proper feedback then usualy it start print too close to build table.

Regards
Roberto

[Deans21]

I'll mess around with the nozzle a bit then. I have noticed that when it is homing, it seems to ram into the plate much harder than it needs to. It almost forces the extruder off of the... gantry? Is that the right term? I can only assume this is resulting in a horribly skewed Z start position.

[MBSupport]

Roberto gives great advice! If the nozzle is stiff forcibly move it up and down until it moves freely. If the issue persists I'd be happy to send you a replacement Smart Extruder.

[Deans21]

Roberto gives great advice! If the nozzle is stiff forcibly move it up and down until it moves freely. If the issue persists I'd be happy to send you a replacement Smart Extruder.

The nozzle currently moves pretty freely. I'll see if I can loosen it up anymore though.

During the Homing process, is the plate supposed to stop rising as soon as it touches the nozzle? Or is it supposed to push the nozzle up a little before it realizes it has made contact? Because right now it pushes the nozzle up as far as it can go and then raises a little more. It just seems like way too much.

Unfortunately our printer is out of warranty and being a work printer, I need approval before I can order another extruder which could take weeks to go through. We're also in Canada which tends to make things a little more difficult as well.

[Roberto]

Hi there,
During homing process, plate is pushing nozzle up for a bit then it stops.
There is sensor in SE, and if it works fine then it stops plate from moving.
Of course, nozzle itself must be able to freely move.
But if build plate push nozzle up too much (and ram into plate itself) then look like your sensor is not working properly.
If so, you will have to think about replacing SE, I'm sorry.

Use latest firmware 1.7 together with Destop 3.7

Regards,
Roberto

[Deans21]

Well I took the extruder apart again. This time I stretched out the spring a little that moves the magnet/sensor up and down. It was extremely compressed so maybe that was causing the nozzle to not drop back down properly. I've run a few leveling test prints and they have been much better. Hopefully this isn't a fluke and things keep working well.

Thanks for the advice so far!

[MBSupport]

Well I took the extruder apart again. This time I stretched out the spring a little that moves the magnet/sensor up and down. It was extremely compressed so maybe that was causing the nozzle to not drop back down properly. I've run a few leveling test prints and they have been much better. Hopefully this isn't a fluke and things keep working well.

Thanks for the advice so far!

If the issue persists please do not hesitate to open a case at makerbot.com/support. We'd love to help!