Printing ABS on the Ultimaker 2 with Fan Running

The art of 3D printing is a balancing act.   On the Ultimaker 2 the fan comes into play as a particular challenge when printing ABS.   In my experience you need a fan to achieve good quality on details when printing ABS, whether on the Ultimaker 2 or my Wanhao Duplicator 4S.  I have read that others can achieve quality prints without the fan by ensuring that print temperatures and speed are low enough to allow for cooling that the fan can provide.

There are downsides of low temperature and low speeds that a fan can help avoid.   Low temperatures can lead to problems with bonding between layers and low speeds are just too slow!  I also find it to be a struggle to hit my low temperature target without undershooting ... and when you are printing that low of a temperature that can lead to a bad layer or a nozzle jam.   This is even though I use Simplify 3D and hit my target temperature by lowering a degree a layer.

The above picture illustrates the challenge that I, anyway, experience.  The best looking Marvin (center) was printed with the normal Ultimaker 2 fan running starting from layer 2 at 60%.   The total mess in the front was also running with those parameters and the fan combined with poor first layer adhesion resulted in a pop off from the build platform.   The Marvin on the left was printed with no fan and the one on the right was printed with my Ultimaker 2 fan modification described earlier.

I think that I can adjust my fan modification to replicate the quality of the center Marvin and still avoid the fate of the Marvin in front.  It is all a balancing act that requires extreme levels of patience though!

Ultimaker 2 Improvements

My Ultimaker 2 is a really nice printer.  It should be as it cost a fortune!  Over twice that of my Wanhao Duplicator 4S, which is a Chinese knock-off of the Makerbot Replicator which carries a more premium price tag (though not that of the Ultimaker 2).

The almost exorbitant cost of the Ultimaker 2 comes with the following advantages (in no particular order):

• Out of the box it looks and feels like a high quality, precision, piece of hardware.  It is really sharp.  My first thought in seeing the design and build quality was to compare it to an Apple product.  It is also quite small (70% the width of my Duplicator).
• Also out of the box...it simply works.  Loaded a model into Cura, sliced it to an SD card, and printed it quite nicely.  This was not my experience with the Duplicator.   I have gone on to do significant tuning using Simplify3D as my slicer but for many users this would be over kill.
• Possibly most importantly there is the quality and precision of the prints the Ultimaker 2 produces.  Resolution of up to 0.06mm with the precision to back that up.
• Finally, and the reason for this post, the open design of the Ultimaker 2 is also attractive to me as it allows for easy after market mods to be made available and implemented.  

The remainder of this post discusses the mods that I have done to and around my Ultimaker 2 in order of their utility (from lowest to highest).

Vibration Reducing Feet

I am not sure they even work but they give me room for the below storage tray so I am happy with them in any case.

http://www.thingiverse.com/thing:977500

Under Printer Storage

Not my best of designs as I was in a hurry!  But it works.  Printed with layer height of .4mm from an .8mm nozzle ... fast!

http://www.thingiverse.com/thing:977517

Filament Reel Holder

I found the reel on the back cumbersome for easy and fast material changes and didn't particularily feel that it feeds as well as it could from there either.  Found this design on Thingiverse and did a remix of it to change the way spools are secured on the turn table.  I like the result a lot.

https://www.thingiverse.com/thing:891232

Top Enclosure and Door

There are people that profess to be able to print ABS on the Ultimaker 2 without an enclosure but I am not one of them.  What ever the reason my solution was upon me when I found the below enclosure from a company in Germany:

Earlier blog post about this enclosure with a link to the source.

Improved Fan Mount/Duct

In my experience the right cooling solution is essential for printing ABS reliably and with good quality.  On my Wanhao Duplicator 4S that meant this ducted fan solution which made this kind of difference in printing.  On my Ultimaker 2 I had to implement a two part solution...one that I am still evolving.  Here is an image of the current state and a link to a blog entry about this solution.  NOTE that my parasitic duct only fits the upgraded nozzle discussed below (as it is longer).

Earlier blog entry about this cooling solution

Custom Heater Block with Interchangeable Nozzles

The first three improvements that I talk about above are really just nice to haves.  They are certainly not game changers but they do make life easier.

The next two made it possible for me to print ABS on my Ultimaker 2 with the same level of reliability and precision as I am used to on my Wanhao Duplicator 4S (an enclosed printer with a customized cooling solution).  For me these were essential if I was to print ABS but they may not be for everyone.

This last improvement, however, is the best of them all.  Of course it is something that you can get by without...but...once you have it you will wonder how!

With the custom heater block and interchangeable nozzle solution from 3DSolex I can switch between a specialty filament that requires a steel nozzle, to a tiny detailed print that needs an equally tiny nozzle, to a draft print that can take advantage of a huge nozzle.  In between I can have 0.4mm nozzles for PLA and one for ABS...or maybe even one for each colour that I print!  Changing them takes less than a minute.  It takes longer to change the material than the nozzle though they become past of the same process.

There is more about this mod in these two previous posts..FIRST ONE and SECOND ONE.  

Another Post on 3D Print Quality

Here are some more examples of the relationship between layer height (resolution) and visual print quality:

0.4 - 17 Minutes to Print

0.3 - 30 Minutes to Print

0.25 - 37 Minutes to Print

0.20 - 46 Minutes to Print

0.15 - 1 Hour to Print

0.10 - 1 Hour and 20 Minutes to Print

And here is the entire assembly printed at with a layer height of 0.25 and then the difference at 0.15:

0.25 - 2:50 to Print

0.15 - 5:21 to Print

And finally, the difference that speed can make.  In general slower is always better.  On some prints this will be very obvious and on others less so.  I consider speeds of above 35mm/sec as acceptable and below that as very good.  While a printer may be able to achieve 50mm/sec or better there will be challenges with material feed and other quality issues.   If you don't understand something that looks weird with a print...try slowing down.

Here are some examples of a speed artifact using the same model as above:

At 1500mm/min (25mm/sec)

At 3000mm/min (50mm/sec)

This is called "Ringing" and there is a good description of it here on the Visual Ultimaker 2 Troubleshooting Guide.   As you can see, speed was the problem, and the solution.

Intriqued by Specialty Filament Materials - Part 2

It was a bit more of a struggle than it needed to be but I finally have my first good print using a carbon fiber reinforced material!

I had assumed that any new material was going to require some calibration and this did take a little time and a couple prints.   What I had not anticipated was that my attempt to save some time by leveling my build platform using some PLA filament would jam up my new stainless steel nozzle!   The result of this was a complete and total inability to consistently achieve good adhesion of that all important first layer!

The filament that I am using is from ColorFabb (XT-CF20) so I contacted them first.   They were very responsive and me through some settings to try but to no avail.   I then contacted Carl at 3dSolex (who was also very responsive) and a couple of emails into the conversation he hit on the PLA issue as a possibility.  I asked if an atomic clean would help and he suggested maybe ten or so!

Having nothing to lose I started doing some atomic cleans.  First I tried with the XT-CF20 and no matter how hard I tried using different extraction temperatures the filament was breaking off above the nozzle.   I also tried some ABS with the same result.   Then some more XT-CF20 also with the same result.   Then it occurred to me that the reason I invested in a stainless steel nozzle was because of the abrasive properties of the carbon fiber filament so I just sat there and pumped some filament through the nozzle.

The end result was a nozzle that layed down the XT-CF20 nicely!  Basically just like my other filaments with a couple of caveats that will be discussed below.

So learning #1:  Don't print PLA through your nice new stainless steel nozzle!  That is what the brass ones are supposed to be used for (and why you invested in that nice upgrade that lets you change nozzles in under a minute)!

My other learnings in regards to calibrating for the XT-CF20 material were as follows:

• Even with the nozzle working again the XT-CF20 seems to be more sensitive to the condition of the build platform than PLA or ABS.  Make sure it is level and then clean it really well.   I used a liberal layer of hair spray as that is one of my go-to bonding agents but others will probably work as well.   
• The stainless steel nozzle does not heat as well as brass which demands a slower print speed than you might be used to with other nozzles/materials.   I use Simplify3D with a base speed of 2400-2800mm/min for most stuff that I print in PLA or ABS.   I will use 1800-2000mm/min for really quality results.  With the stainless steel nozzle I printed the above piece at 1400mm/min!   I suspect that I can go faster but will need to find out where the ceiling actually is.

The Simplify3D profile that I used can be found here.  Some of the key attributes of that profile are as follows:

• Extruder temperature of 255c from beginning to end.
• Build platform temperature of 90c to start and 80c after layer 1.
• Fan of 40% to start and 100% after layer 1.  This seems counter intuitive to the higher build platform temperature for layer 1 but I did find that it helped where layer 2 started on top of fresh layer 1 material (which Simplify3D is apt to do given its tuning for speed).
• First layer 100% extrusion rate (make sure your bed is level and don't use this setting to try and cheat)!
• First layer 50% speed (50% of slow is really slow)!

I think the above sums up the most important of the parameters.

As I mention above, I am now able to consistently print with the carbon fiber reinforced material.  I think that I still can improve on the calibration a little but now I need to remember what it was that I really needed to print with this really cool stuff!

In my next post on this topic I may try some rigidity and strength tests but we will see what else distracts me first!

Intrigued by Specialty Filament Materials - Part 1

Since I started 3D printing I have been intrigued by some of the specialty materials that are available for prints.  You can get filament that looks like stone, or wood, or metal.   You can also get filament that is reinforced with Carbon Fiber which is what I decided that I needed to be able to print with.   Not sure why I think this but I do.

I knew that printing with a carbon fiber reinforced filament was going to be hard on my nozzle so I had to consider how I was going to deal with this.  The normal brass nozzle was just not going to be practical as erosion from even one print will have widened the nozzle!  I have upgraded nozzles on my Wanhao Duplicator 4S but really wanted to be able to print the specialty materials on my Ultimaker 2.

The above led me to shop around for an upgrade that would allow me to easily switch nozzles on the Ultimaker 2.  What I found was 3dSolex:

3dSolex Ultimaker 2 Upgrades | Hot End Upgrades & Lifesavers For 3d Printers

They state a 10 second change butI think that is the Olympic Gold Medal timing.  I can do it in less than a minute which is still pretty great!  It really is pretty cool though installation is not for the faint of heart.

The upgrade consists of a new heater block into which the interchangeable nozzles fit.  Installing this new heater block requires that you disassemble the hot end of your Ultimaker 2 and then that you extract the heating element and temperature sensor from the old heater block.  This is where it got interesting for me.   The heater came out pretty easily as part of it protruded outside of the heater block.   The temperature sensor, however, had been mounted in the old block such that there was no way to grab it to be able to get it out of the block.

Had I known the challenge that I was going to face I would still have done the upgrade but I would have bought a new temperature sensor at the same time as the nozzle upgrade.  In fact, you can get one with the nozzle upgrade!   There are also cheap clones available on eBay though I am not sure how well they work.  The lesson here, if you are considering doing this upgrade, is to take a look at your existing heater block and see if you are going to be able to extract the current temperature sensor.   If it looks problematic order a new sensor (or do not order the nozzle upgrade)!

Installing the new heater block was pretty straight forward.   There are excellent instructions on the 3DSolex website.   Follow them!   

Running the new temperature sensor control lead was actually the most challenging part of the operation.  I did not want to take the whole wiring harness apart so I used the wire from the old temperature sensor to fish the new temperature sensor through the wiring harness,  Not necessarily easy but it worked well!

Two more recommendations in regards to this upgrade.    Print the torque wrench found at this link:

Torque Wrench

It really takes the uncertainty out of how much to tighten the nozzles.  Finally, when using this wrench, you will need to have the nozzle heated to remove one that has been used.  You should also heat the nozzle and re-tighten once you mount a new one.

In my next post I will talk about actually printing using ColorFabb' XT-CF20 filament.