Step 4: Dry Box

Excessive moisture in the nylon filament will boil off as the filament goes through the hot end. This causes steam to push its way out along with the extruded line which will result in bubbles and poor layer to layer adhesion. Besides making the print unsightly, it will also make it more prone to delamination. Moisture control is definitely something to consider when printing in nylon and can also effect ABS and PLA when the humidity is extreme. In the summer months, I use the dry box for all my filaments and store those not in use in a giant seal-able bin.

Materials for Drybox:

  1. Air-tight tupperware-like box that is an appropriate shape for the spool (Mine was a rubbermade that I believe was made to accommodate cereal).
  2. 608 bearings X2
  3. body of a ball-point pen or dowel rod
  4. 1/4 in tubing push connector
  5. 1/4 in tubing ~ 1 meter
  6. 3D printed bearing holder
  7. foam rubber
  8. silica desiccant beads ( I purchased some of mine from protoparadigm.com)

The design for this is extremely simple and although I listed specific components, they certainly can be replaced with anything that will function in a similar fashion. The two most important considerations are that the box can be sealed, more or less airtight, and that the filament can be spooled out of the box with as little friction as possible.This second point is absolutely key.

  1. Print the bearing holders that will go over your bearings and provide a surface on to which you can glue your rubber grippers. I will attache the STL's for the holders I used for my 608 bearings, but if you have different bearings, its is literally one of the simplest shapes to generate in sketchup. Its just an extruded square with a circle pushed down into it.
  2. Place the bearings inside the bearing holders and glue the foam rubber grips to the flat side.
  3. Cut a length of tubing or dowel that will both fit inside the bearings inner ring snugly and be just long enough to press against the sides of container when the bearings are attached to each end. I used the body of a ball point pen.
  4. Drill a hole in the lid for the push connector and screw in push connector.
  5. Push in length of tubing* (I should note here that I ended up threading another bit of PTFE tubing, of the type that I had used for my bowden extruder, inside the regular PVC tubing in an effort to reduce the friction and it helped quite a bit. I didn't have the push connector that fit the PTFE tubing I already had, so that's why I went with the 1/4in. This isn't necessary if you have the correct connectors and could just go straight to your bowden tubing. Ultimately, you want a very slippery tubing that is only slightly larger than your filament so as to reduce the amount of air that can pass through the tube and into the drybox while not causing too much friction that the filament cannot feed properly).
  6. Add silica beads to the drybox to help absorb the moisture and keep the humidity in the box low. If you live in a moist climate or are frequently changing the spool, you may want to occasionally dry out your beads using a microwave or oven. They aren't toxic, but I would advocate using a container that would keep them from spilling into an area where your food might be prepared.

That's it, now you have a mobile drybox storage container and filament spool holder. This drastically improved the quality of my prints, especially with 618 and 645 nylon. Bridge seems to be a little more resistant to moisture absorption, but I still use a drybox with it.

<p>I just did a successful Taulman Nylon Bridge print on my Zortrax M200. Only thing is the material is very prone to humidity absorption. </p><p>It hasn't been 3 days since I open the Bridge package and I stored it with my other materials in a closed container but when I printed with it, the material smoked and popped. While it made a successful print, it was not aesthetically pleasing. Now I will have to bake the material for a few hours to eliminate the water and seal in a plastic bag for storage with silicone bags. </p><p>After I go through that hassle I will try again to make a visually pleasing print. </p>
<p>Bake the Nylon at around 150-200 degrees for 2-4 hours before you print to get rid of excess moisture.</p>
<p>Hi,</p><p>Could you please share how you made it work on the Zortrax ? What material type did you select ?</p><p>Thanks</p>
<p>I posted something a minute ago and I can't see it. Hmmm... Anyway I used Zultrat with minus 20 to 40 on Z-Temp with no heat bed. Will try Zglass with minus 10 to 20 this time as the diameter of filament became an issue and wouldn't feed through machine so Taulman sent new material and I hadn't tried it out yet. Will post after I try it in the next few weeks. </p>
<p>This is after the initial Print and the material collected moisture. make sure it is air sealed after use.</p>
I will post after I print again. This time I will be using the Zglass profile and probably -10 to -20 temp since the Zglass profile may be more suited to the material and it shuts the heat off of the bed.
<p>Using Z-Temp, I set the profile to Zultrat and used -40 and -20 temp, with I believe no heat bed. Had a nice print but about a week later I went to print and it was bubbling because it collected moisture so I baked the material and then I couldn't get the material to print because the diameter of the filament in the spool was too small. Had fluctuation in the size from 1.65 to 1.58. I don't know if it was just because or if the baking did it.</p><p>Taulman is a very good company as they replaced the spools of filament so they diameter would be 1.75 instead of 1.58. Thats the key, the diameter has to be almost perfect to be fed through the stepper. I plan on printing a roll of material in the coming weeks. I just hope the diameter is proper. Here is one I printed after my initial nice print but I can't post the original as it is proprietary.</p>
<p>I've been playing with Bridge Nylon, does your warpage on build plate go away with drying? </p><p>Can you tell me how much more rigid 645 is vs Bridge?</p>
<p>Thank you for bringing some of the details to light. I'm about to attempt nylon soon. I have the Solidoodle 2, but was hoping to use a delta built at school. Without a heated bed, have you had success with any other option?</p>

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Bio: I love making things out of discarded materials. When someone tells me something is "broken" I see it as, "it just doesn't know what ... More »
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