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Apr 2016

3D Printing has come a long way since the first days of additive manufacturing. So much so that alternative materials are the norm however they are so difficult to print with. One such material is Flexible filament 5. The brand that I have been experimenting with is called GP3D and is readily available at Fry’s Electronics, which in and of itself is a great convenience and one I plan on taking full advantage of.

However there are a lot of articles out there warning of the difficulties of printing with this troublesome filament. Some of those difficulties include:

  • Inconsistent prints
  • Stringy prints
  • Pimple prints and other surface defects
  • and most pressing, Poor Print Bed Adhesion.

Some of these issues can be taken care of with slower print speeds, increased extruder retraction to minimize ooze, better slicers to reduce point to point string connections. I have printed a whole spool of this material so far and the only solution that helped me to increase print bed adhesion, I haven’t seen on the net so far.

That solution is to dual print your raft. What I mean by this is printing with a material that has great bed adhesion, PLA, then switching to your flex filament. To be more exact, my process was this:

Printing on a Makerbot Replicator 5th Gen 2, Smart Extruder, Out of the box print settings: (Temp: 215, 200 microns, Standard print settings).

  • Begin the print with the PLA of your choice, (Natural “Color” is more inexpensive usually)
  • Before the last layer of the raft begins to print, switch to the flexible filament
    • The standard settings for the raft use one base layer, two intermediate layers, and two finishing layers
    • Using the last layer for the switch allows for proper raft to model adhesion while providing the superior bed adhesion with the PLA
  • Let your print finish as normal

This method allowed for great bed adhesion throughout the entire print. Before trying this, I used the flexible filament for the entire process and saw the print lift from the bed mid-way through. This warping on the base layers, similar to other materials with the same lifting problems (Like ABS), would affect the rest of the print by pushing the print in the later paths of the extruder head. This causes a few issues, the extruder head to digs into the print, little to no material is laid down, and frequent filament jams. If you experience this, it is always better to cut your losses and save your material rather than try to rescue or force the rest of the print. You will not be happy with the results. But I digress, the process outlined above allowed me to successfully print a pair of Sandals 3for my Fiancee (A thingiverse.com 2 model remix I made).

An Example of a flex Filament Jam

An Example of a successful print with a PLA raft

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    Apr '16
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    Apr '16
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Did you try printing without rafts? I have no issues with flexible filament when printing raftless.

Your use of PLA to ensure a properly trammed base is a nice workaround for those that cannot reliably print raftless.

Base layer of rafts generally rely on heavy over-extrusion of material being squeezed into the bed and deforming outward to ensure a solid adhesion to the bed and to ensure consistent starting height for uneven beds. The consequence of this is very high back-pressure that can cause jamming.

Thanks for sharing this, did you also used some glue or is it kapton tape i see on the pictures ?

secondly how did the bottom surface look like if I may ask ? i’ve a similar problem… i’m fighting to print a flexible piece where the bottom surface is in sight, hence need to be smooth… I only succeeded with using a brim on heated bed and then taped the brim using makers tape, but i guess also the brand of filament plays a significant role to succeed.

cheers, Dave

Hey Dave,

Happy to share. Blue Painters tape works like magic for PLA so that is what I have been using. Since the top layer of the raft was the same material as the flex filament, the bottom surface of the print turned out like a fairly normal print would. I have only recently began printing without rafts again for PLA, I was scared off by some bad experiences, but I know think I have the hang of it. Not sure what you mean by brim, would love to see pictures!

Jason

I have tried printing without rafts with this flex filament, but the same lifting/adhesion problem. It was a fairly large surface area, I am sure it would be less if at all a problem if it was a smaller print.

I am glad you mentioned over extruding for the first layer, but you are absolutely right, this material jammed frequently with even a little bit of back pressure. It was a babysitting job for sure, but the dual material raft with its better adhesion reduced jamming substantially.

Thank you! Not yet, but I certainly will and post the results. I just have to find something that I want to print with flex filament on thingiverse first :smiley:

ok that’s interesting… I guess the filament need to be changed quickly to avoid cooling down of the last layer of the first filament.

Brim is another adhesion method printed on first layer only , it has a 0 mm offset of your model and basically expands outwards to create a bigger bottom surface, you can peal it off quite easy when the model is finished but at least it is not printed underneath your model. I didn’t tried rafts as it looks to me it will leave ugly scarfs on the bottom, but maybe i should give it a try because the model i’m trying to print comes loose at 5mm height consistently, but i was mainly playing around with flow, glue, cooling, speed and bed temperature. i do not have pictures right now of such a print.

The best thing to improve print bed adhesion is to lower the first layer height.

This will stick your first layer closer to your bed and have a much better adhesion.

I have a lor of experience with Filaflex filament. Have a look at my hub https://www.3dhubs.com/bregenz/hubs/dawinci 9