My never-ending battle with the stepper motor "click"

[flashphilm 0]

Hi all - I've been using my Ultimaker 2 for years (since ~2014). I never upgraded it - this is the OG Ultimaker 2 design. I use it periodically, so I've never bothered to resolve many of my lingering frustrations. So here is my biggest frustration - hope you can help!

 

Since I adopted this printer, I have been consistently plagued by the dreaded feed stepper motor "click" sound. When the "click" noise occurs, I observe that the stepper motor does a ~1/8 rotation in the counter clockwise direction - opposite of the feed direction. The impact on the print is always the same - the nozzle under-extrudes for a few seconds, causing a less than perfect material deposition. This usually results in spaces between walls, crappy infill, see-through top skins, etc. It is especially prevalent during the first layers, but very often occurs throughout the print.

Over the years, I've done some research to try and resolve this issue. Reading through the forums has lead me to believe that it may be tied to excessive resistance in the feeder system, causing the motor to go through some fail-safe force relief operation - leading to the under-extrusion.  I've come to understand that this may be related to some of my misguided print configuration settings like temperature, print head speed, material flow rate, layer height, etc. I have tried many combinations of these settings, but the "click" is always there. 

 

Can anyone help - or point me to a relevant article?

 

Thanks!

 

 

[Torgeir 211]

Hi @flashphilm,

 

welcome in here.

What you describe here is "kind of" typical if your feeder "stepper current" setting is to lo (normal current setting here is 1250 mA). When it come to a certain tension the stepper suddenly cannot hold the load anymore and when the stepper motor releases, the built-up pressure in the bowden pipe will act as a compression spring, so that the stepper motor loses many steps backwards. This means that you get low extrusion, because the pressure needed to provide the necessary extrusion suddenly disappears.

 

(Based on the fact this have been an ongoing issue over the years in your UM2..) 

 

Another alternative are to slow down the printing speed, cause this will not ask for this "high" demand from the feeder.

 

Build your own gear box for your UM2.

A couple of very effective upgrade is to build a belt geared feeder using the same feeder unit (the black box) holding the knurled feeder wheel on it's own shaft 5 mm including a 32 (teeth) pulley that's also holding two bearings. 

On the new stepper motor(200 step/rev) requested you'll need a 16 (teeth) pulley (5 mm) plus a belt (same as the short one used on the X / Y stepper motors).

 

The above is what I'm using. Of course, printed my own designed gearing house including a release handle to make ease feeding the filament past the feeder unit.

There is also another feature I'm using, - turning the feeder unit upside down. This will make the feeder to grab the filament on the inside of the "looped filament" arriving from the roll. This will increase the efficiency of the feeder system due to less friction.

Using this method, you will obtain a 2:1 gear that's double the torque with no need to change the firmware..

This is a very cheap way of improving your old UM2..

 

There is several other geared units around, so just find the one for you.

 

However, you may also upgrade by using the "UM2+" versions new feeder - this require a change in your firmware.

If you go for the full upgrade to "UM2+ Kit", including an Ollson block (w 4 different nozzles) plus a spacer to replace the compression spring, two new 6 mm axes and the new feeder.

Ofc., this kit also including a new stepper motor for the feeding unit -and last the plus sign to mark your printer UM2+.

 

Just my thoughts.

The choice is all yours.

 

Thanks

Torgeir

 

 

 

 

 

 

 

[Torgeir 211]

Hi @flashphilm,

 

Here's two links how I've made a geared stepper for the filament feeder system.

You'll also see several other improvements you can do if you like.

Most of this work done in 2016 and still working great. 🙂

 

Thanks

Torgeir

 

 

 

Edited January 10, 2022 by Torgeir
Correction of text.

[flashphilm 0]

Thanks Torgeir! What a thoughtful and complete reply - I will give your suggestions a try and let you know how it goes. 

 

Thanks again!