DIY Heated DryBox for 3D Printing filament - under $20

DIY Heated DryBox

In this blog post and Video I'm showing you how to make a simple heated drybox for your 3D printing filament that you can use whilst 3D Printing.

With just a few basic items from eBay (or similar) and some 3D design files to print (links at the bottom of this post) - you can make a drybox for both storage and in use while 3D printing.

An overview video of the heated drybox (including a #MasterSpool update) can be seen below and over on my Youtube channel here.

For an overview and background to this project, do take a look at the video, I'll dive straight into the main components in this blog post below - 

Polymaker Polybox - spotted at the recent TCT show.

During the TCT show in October last year, I had a chance to take a quick look at the Polymaker polybox. It's a neat enclosure, but I quickly realised that it is just an enclosure, that's all.

I pack all my filament in sealed zip-lock bags with desiccant. That's usually good enough for storage, but some materials do require drying or heating before use.

For some time I have been planning to build a dry heated storage box. 

Now that I know the Polybox just monitors temperature and humidity I decided to build my own, but with a heating capacity installed too.

It's surprising how simple it is to make a heated dry box with off-the-shelf components and a little 3D printing.

The polybox has a number of bearings that polymaker filament spools run on, I didn't want to do that because I use a lot more different types of materials, some use cardboard spools, and having the spool edges run on bearings, just creates cardboard fluff.

Other spools are very small (Taulman Nylon), they simply would not reach across the bearing points.

I decided to keep it simple and allow spools to be mounted on a standard sized spool mount. Different diameter mounts could then be printed as required.

As a minimum I wanted a box that would fit 2 x 1kg spools of filament and allow both to feed independently if required.

This one is a straightforward build - you should find it quite simple to print out the required 3D printed parts - assemble and make up the rest of the heated dry-box. Any questions - just ask.

The main component I used for heating is a simple flexible reptile heater - you can find these on eBay for just a few USD - Search for '15*28CM Adjustable Temperature Reptile Heating Heater Mat' 

The other main electronic component is the temperature and humidity monitor device, I opted for a round module, but you can get square and also ones with separate temperature sensing probes etc.

For the above temperature/Humidity sensor just search eBay for 'Mini LCD Celsius Digital Thermometer Hygrometer Temperature Humidity Meter Gauge'

Three 12mm cable glands make up the power in and dual filament out ports - just a simple 12mm hole will allow these to fit perfectly.

I bought a pack of 100 of  these way back in 2010 - so I have been finding uses for them ever since :)

Print out the 3D printed parts - I used FormFutura ReForm rPET filament for the above.

The printed spool holder uses a section of M8 threaded rod and two M8 nuts.

Lastly bags fg 50g desiccant can be fitted under the heater - they can easily be removed or changed at any time.

The reptile heater just slides in the grooves in the 3D printed parts.

Cable goes out of the back  of the box - allow yourself some slack cable so you can lift up the 3D printed parts to insert desiccant.

Optionally you can print out a seal for the lid - I made the above using ColorFabb nGen Flex - it has just the right level of flex, but not too floppy to easily seat onto the top of the box.

Fit the remaining two cable glands and use oversized tube to allow filament to feed out of your dry-box.

That's it. It uses 7w while being on, and does not take long to get to a stable ~30 Degrees C temperature - humidity will quite quickly drop to under 14%.

It's really useful for any type of dedicated support material - being able to be used while still inside the heated dry-box. It will also be great for Nylon, wood filaments, CF, PolySmooth and many other materials that are sensitive to moisture.

Bonus device - 

I also have a little bonus invention for monitoring your filament coils while they are in Zip-Lock-Bags - here is the SpoolCheck sensor.

It uses exactly the same thermistor and humidity sensor, and a small packet of desiccant as the heated dry box project.

Just pop it in the centre of any 'standard' filament spool (or a loaded MasterSpool ) - and pop it all in a zip-lock bag.

You basically end up with a way to monitor filament in storage, and see if any is not in tip-top-condition :)

Even overnight you should see a drop in humidity inside your 'drybag'

The files for both the heated drybox and the SpoolCheck sensor are up on -

Thingiverse here - 

And YouMagine also. - 

Please do let me know if you make a heated drybox or find the SpoolCheck sensor useful - best to catch me on Twitter usually.

* Edit - ( for clarity and to answer a common question) -

I get a lot of questions about the dry-box project - the most common are -

Will this dry out my (damp) filament? - It's designed to keep good filament in good condition and stable for printing. It's not an oven, so I still recomend drying out materials like Nylon and PETG in an oven if they have been in the open for days. - Then use the heated dry box when you use the material on a print to stop the material getting saturated with moisture.

What would be a good % of moisture to look for on the hygrometer? (Or what's the best percentage figure) -

The % shown on the hygrometer is relative to temperature, so it's not the most ideal indication as we are also using a heater inside the enclosure. You will actually see the percentage rise up after switching on the heater, this is quite normal and to be expected.

What you are looking for is stability of the system - so for me that's around a display of 30 degrees C and a percentage of also around 30%

If you use the same sensor in a sealed bag with silica gel, and the temperature drops, and the silica gel takes moisture out of the internal atmosphere, you will see readings of room temperature and percentages of around 10% to 25% if you just leave the same sensor out on the shelf, you will see much higher readings depending on where you live and the ambient conditions.

Short answer is that the heated drybox is to keep things warm, dry and stable. so a reading of 30 degrees and 30% is really good, and it's all working well. An even lower percentage is even better, but it's more important to keep things consistent, this way every time you use the material you should get the same quality print results.


And some general info on the heated dry-box system and why I use it for consistent printing - 

It's all about consistency and stability - so I can tune a material for use, and then know it's going to use the same settings next time - without the material being in a different state / damp / temperature etc. - 

The silica gel is still doing some of the work for the heated dry-box. I’m just using the heater to help maintain stability and provide some consistency, warming the air inside to around 30 degrees C and regardless of room temperature changes, keep humidity shown below 30% @ 30 Degrees C.

For storage I don’t care so much about temperature – as long as the humidity is also showing a low measurement – at this time of the year (winter in the UK) I expect around ~18 degrees C and 10-20% humidity inside a sealed dry bag with a silica gel packet. Everything is around 14% right now for me.

Good -  

• Stable temperature (not too high) and stable humidity (under 30%).
• Temperature rising and the percentage of humidity being shown going down.
• Temperature dropping and the percentage of humidity being shown going down or staying stable.
• If temperature goes up, I don’t want to see the humidity also go up, stable is good, lowering is even better.

Bad –

• Temperature rising and the percentage of humidity being shown also going up.
• An ambient temperature of ~25 Degrees C and a humidity measurement of around 50%. In these conditions Nylon will absorb enough moisture (in 6-8 hours) to make the material almost useless for 3D printing – you will see steam coming from the nozzle, bubbles on the extruded material, frosting of the Nylon being extruded, weak printed parts and poor layer bonding.

Really bad –

• Temperature lowering and the percentage of humidity being shown also going up.

* Edit

Thanks for reading, see you next time.

Rich.

Please join me on Twitter @RichRap3D

My profile and posts over on Google+

Files and designs shared on YouMagine

Files and designs shared on Thingiverse

Files and designs shared on GitHub

Files and designs shared on Repables 

My Youtube channel is here, all 3D Printing in Hi-Def video content.

Temperature effects with PLA printing / RepRap News

I did a little experimenting with temperature and PLA printing last April (2013) when building the Rostock - and it looks like I totally forgot to post a blog article about it!

I found the pictures today, and you may find it interesting, so here is what I remember about the experiment and process -

Last year when I didn't manage to get hold of any Laywood for testing, I decided to see what effect temperature had on PLA when it's printed smoothly at a controlled rate. I randomly selected Blue and Brown PLA and also used Natural (clear) as a control as I was sure that would show more obvious external differences with a change in temperature.

First test was just a simple change from printing at 192 Degrees C (lower section) then changing to 198 Degrees C (upper section)

I thought it might be neat to try a gradient effect, this is simply a change in extrusion temperature by + or - one degree C every ~3 layers over about 20 layers. 

I tried the same gradual gradient with Brown, that shows up a gradual change from matt to glossy as the temperature increases. (camera can't really show it well)

This actually didn't work as I had imagined. it's better than the photo shows, the camera is not able to pick up the gradient very well and you also get a strange optical effect as you move around the object, quite interesting.

You basically get a more obvious effect with a sharp change in extrusion temperature, here above the matt bands are 190 Degrees C and the glossy are 200. 

The speed is also important for a good change, I found running at 80mm/sec or faster was about optimal for this PLA and a J-head MK5 Extruder nozzle.

A mixture of gradual temperature change over a number of layers and sharp changes produce some really nice finishes.

To help select the bands I did make a small script to post process the G-code, but sadly this seems to have gone missing from my files.

If I do any more with this process I may produce a more friendly program to allow shades and stripes to be drawn on the Gcode, unless anyone else wants to produce something to do that.

Printing in PLA - Just a temperature change - nothing else. (the model is custom MakeALot Bud Vase btw)

Purple colours also seem to work exceptionally well for this effect.

I also destroyed one of these vases at the time to see if the temperature made any obvious differences to bonding strength. I could not find any difference while splitting and ripping the different temperature printed areas.

Let me know if you try anything like this, or with other materials (it obviously works well with Laywood), I'm sure other translucent PLA's and even PET (Taulman t-glase or Coloutfabb_XT) would also show this effect too.

Next time I do this I'll also try out a single walled 'spiral vase' print with temperature changes, I imagine that should look very neat.

RepRap News - 

If you are in the US or can travel 14-16th March, do check out the 2nd Midwest RepRap Festival - Goshen Indiana - more info Here - http://midwestreprapfest.org/ Loads of fantastic people will be there for a dev packed weekend. Sadly I can't make the festival, life gets in the way of 3D Printing some times :(

Feel the Force young developer - Force Sense Resistors - 

Johann has done some great experiments using three force sense resistors to measure pressure applied to the build platform on a mini Kossel - RepRap Wiki page here and Johann's Blog info here. 

It would be neat if only one could be installed on the hot-end itself, but that's going to take a bit more work. These sensors are very simple to measure using a spare Analogue input, more info here.

Now all we need to do is print our own force sensors rather than buy them, conductive filament at the ready :)

Cheltenham Geeks - 

I'm doing another 3D printing night at Deep Space Works in Cheltenham Monday 24th March 7:00PM - if you want to come (it's all free) sign up on Meetup here - I look forward to seeing you and if you can bring a 3D printer, 3D scanner, projects etc. let Tom Howlett know via the comments on Meetup.

And anything you want me to talk about or demo, leave me a comment here.

Rich.

1st Prusa Child & issues with ABS printing

I have been printing with the Bath Prusa Mendel for 2 weeks now. It’s been a good learning process along with discovering more things about Skeinforge, high speed printing, hot-ends, and using ABS.

I now feel comfortable about the tool-chain and using the Prusa Mendel along with some of its limits, so I can now try a few more adventurous things in the coming weeks.

Below are some of things I have printed so far, and the issues I had along the way.

PLA works well, I have used 4 different types from 3 different suppliers, and they all have a slightly different extruding temperature and flow differently.

Just as I was getting to the end of the White PLA I had a hot-end failure jam, the nozzle was flexing down and catching on objects, on closer inspection the PTFE had split around the top and the PLA was jamming in the barrel.

I replaced the split PTFE and also the Hobbed bolt as I was getting slipping and inconsistent feed

 No change in spring tension or cleaning of the teeth seemed to fix it.

The White PLA from Adrian was used up printing upgrades, spares and experimenting with speed.

First upgrade was the Prusa Z Rod Constraint by ScribbleJ shown above.

And a few of my own 8mm T-slot mounting blocks as I needed some for my other machine.

I then switched to Gold PLA and started to print a full set of upgraded Prusa parts.

This included the new Prusa Z Axis using LM8UU Linear bearings.

And Greg frost’s LM8UU X Axis and Y Holders for Linear bearings.

So after the first week I had managed to get it working well and print these.

I decided on Andrew dent’s MV6 frame and foot vertex pieces as I like the look of them and they are a little fatter than the official Prusa ones.

I was getting confident at this point and even did my first print using multiply in Skeinforge to get me 9 x M8 bar mounts printed in one go.

I printed a few fun things to keep my princess happy –

This is one of the exceptional Heart bracelets by MakeALot

And a 1.8 X scaled version of the Princess Heart Crown by syvwlch

So a few days later I had the first child set of Prusa Mendel parts I decided to name ‘Mendel-Bling’ for building up my next machine. 

At the weekend I decided to experiment with ABS. It’s the material I first started with on my original repstrap back last September and I was expecting it to be easier than PLA… it was not, but maybe that was my unfortunate choice of colour.

Sunglasses on, it really is that PINK.

As it was looking quite hard to get this ABS extruding I decided that my first ABS print should be another extruder, that was a good choice as shortly after printing this the PLA extruder melted.

It’s good that I had an ABS X carriage or that would have melted also.

Extruder replaced. Still using PLA gears for good wear resistance.

When printing with the Pink ABS it needs 263 degrees C to extrude, I’m running it at 270 because of the following issue. - At 80mm/sec and 30% infill the Hot-end power is on 95% of the time and that quickly goes to 100% when doing solid infill layers while the temperature also drops 8-10 degrees, that’s right on the limit of the power I can get into the material with this particular hot-end, any faster and the extruder will jam and grind through the filament as the temperature drops too much.

Take a look at this short video of a Pink print below, the hot ABS comes out looking slightly Purple and as it cools turns back to Pink, it’s really cool watching it print especially doing solid infill, this is my first coloured ABS so I don’t know if they all do that?

With Natural ABS I still see a temperature drop at 80mm/sec but not as much while the extruding at a lower (230) temperature.

So really I should slow down the ABS speed to be safe and then build a better hot-end that can deliver more power quickly into the filament so I can speed things up again.

I don’t see this temperature problem with PLA, but I have only gone upto 100mm/sec at the moment, I’ll wait until I have my Linear Bearing Prusa (Mendel-Bling) before going any faster.

I have a puzzle to build up tonight, the Heart Gears by emmett

Thanks for reading,

Rich.