Lubricating the Bowden tube?

[Dim3nsioneer 377]

Hi there

As I am hunting an underextrusion issue for several days now I'm having a closer look at the slip resistance of the filament inside the Bowden tube.

This is a known problem when printing soft PLA, I guess, as it was discussed already in the forum (http://umforum.ultimaker.com/index.php?/topic/2110-trouble-making-soft-pla-prints/?hl=%2Bresistance+%2Bbowden+%2Btube&do=findComment&comment=14759).

However, as I have some standard PLA the thickness of which is close to 3mm (and which is significantly harder to push into the Bowden tube compared to other filament), I have some serious thoughts about how the slip resistance could influence the print quality.

So, this is my question: Is anyone of you using any kind of lubricant for the Bowden tube? What are the consequences for the print (heat or particles)?

 

[3dcase 37]

Hi there to,

Indeed I use Glecerin/glycerol for the Soft Pla.

I am no chemist, but as far as I can see, it did no harm to the print.

Saw a video of guy making his own PLA with it.

You need only a dropplet in the tube.

So no harm done I guess.

 

[gr5 962]

If the PLA is wider than the inside of the tube, no amount of oil will help. You could try reducing the pressure on the feeder so that PLA stays more round I suppose.

Personally I would just throw it away. Or purchase a larger Bowden. A few people have purchased larger Bowden tubes. I don't remember the details.

 

[irongland 1]

Once I was helping a friend get his faulty replicator 2 working (this was brand new a month or so after the release). Due to the previous design, a lot of friction was being generated. One of the suggestions that worked there was using less than a drop of corn oil (or something with as high of a smoke point as possible) to reduce the friction generated by their silly derlin plunger design.

I mention this because there were no discernible effects on the print. I tried comparing parts printed on another printer with similar filament, but I couldn't see any difference. We ran the machine through an entire roll and a half on this method before we acquired the parts to make a better extruder head.

Also if you try this with an ultimaker, be careful to not get any on your knurled bolt.