How to tighten a loose feed tube - Me3D Support

How to tighten a loose feed tube



Only run through the steps in this article if you have already tried calibrating the Z offset and have checked the Z axis belt. If you are still encountering a low Z offset after checking these things, it may be worth running through the troubleshooting steps in this article. If you need any assistance, submit a support request. 

When to check for a loose feed tube

The nozzle assembly of the extruder is fixed in place using a grub screw. In the course of normal operation this shouldn't come loose, but repeated head collisions may loosen the tip. With a loose feed tube grub screw, the action of extruding plastic pushes the nozzle down and away from the extruder body, throwing your calibration off.

If your Z offset calibration seems to constantly be too low even after calibrating it, resulting in failed prints, the nozzle scraping against the print bed and not producing the first layer, the grub screw on the feed tube may be loose.


How to check for a loose feed tube

- Have a look at the extruder from the side. You should be able to see the top of the feed tube butt up against the underside of the extruder drive housing. If the tube is all the way up then a loose grub screw is unlikely to be your problem. However, if you can see that the feed tube has been pushed down like in the following picture, you will need to tighten the feed tube:


- Make sure the nozzle is cold and move the extruder arm to a position where you can work in BuildBee. 

- With one hand hold the extruder steady and gently wiggle the yellow heat block attached to the feed tube and attempt to pull it down. If you can get the feed tube to move with hand pressure alone, then the grub screw holding it in place will need to be tightened.

 

What do I need?

- 1.5mm hex key (included in your printers maintenance kit).
- 2mm hex key (included in your printers maintenance kit).

How to tighten the feed tube

Step 1 - Raise the extruder off the print bed

- Power up the 3D printer and connect to BuildBee.
- On the 'CONTROL' page in the maintenance console, use the movement buttons to lift the Z axis clear of the bed by about 100 mm.
Take caution when running through these steps if your printer is part of a BuildBee enterprise subscription. Others may still be able to access the printer while you are performing maintenance. Do not perform these actions unless the extruder has cooled down first.

Step 2 - Move the fan

- Using a 2mm hex key, undo 3 of the screws on the fan on the front of the extruder, leaving one to allow you rotate the fan out of the way.



- You should now be able to see the feed tube grub screw just below the heat sink:



Step 3 - Tighten the feed tube

- Push the feed tube up into the extruder assembly and make sure the top of the feed tube butts up against the extruder drive housing:


- Using a 1.5mm hex key, carefully tighten the grub screw.

Don’t attempt to tighten the screws too much, you may round off the grub screw. This will make it difficult to remove.

- Rotate the fan back into place and replace the screws. Do not over tighten the fan screws. 

Step 4 - Test the fix

- With one hand hold the extruder steady and gently wiggle the yellow heat block attached to the feed tube and attempt to pull it down. If you can get the feed tube to move with hand pressure alone, then the grub screw holding it in place will need to be tightened.

- Print a Cali-cat from 'Featured Models' in BuildBee and pay observe for any scraping or knocking sounds coming from the extruder. Check to see if the feed tube has slipped after attempting to print something.

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