Evolution of a Blog

This blog has evolved as I have as a maker. It starts at the beginning of my journey where I began to re-tread my tires in the useful lore of micro electronics and the open-source software that can drive them. While building solutions around micro-electronics are still an occasional topic my more recent focus has been on the 3D Printing side of making.

Monday, February 29, 2016

Ultimaker 2 Cooling Hack

When I first got my Ultimaker I struggled to print ABS.  This is a little ironic as I had printed nothing but ABS on my previous printer, a Wanhao Duplicator 4S, as I struggled to print PLA on it!  

I have since been able to get past my issues of build plate adhesion and warping and print ABS quite successfully for many things.  I now have an enclosure for the printer and have decided that Klapton tape is my printing surface of choice.  I still struggle with fine details and in particular when printing at high resolution (<100 microns).

Speaking of fine detail at high resolution...I have similar issues with PLA but only when printing the final layers. 

This first picture shows two tanks with the top printed in PLA and the bottom in ABS.  They are 1:100 scale models and are about 2.5 inches long so there is quite a bit of detail there.  It is not a completely fair comparison, however, since the PLA print was done with a 250 micron nozzle and the ABS print with a 400 micron nozzle.  The PLA print is 60 micron resolution and the ABS print is 80 or 100.  

Ok, not a great apples to apples test but what is clear on both prints is the problem that I am trying to solve.  On the lower, ABS, print you can see the poor quality on the small dots on the engine compartment, on the periscopes forward of the turret hole, and on the top of the fuel tank.  The lines are not as sharp either (corners you would expect to be better on the PLA due to the nozzle).

On the top print, the PLA one, the issue is the top of the fuel tank and the periscopes at the bow of the vehicle.  In both cases they are somewhat smudged.

My solution to the PLA problem has been to either print multiple parts or to print a "sacrificial" part or two that accomplish the same thing.  I have already slowed down the print using the S3D feature that allows one to adjust speed for layers below some number of seconds.  I use 15 seconds as the threshold and 20% as the factor.

I have not had a good solution for ABS but I know from my Wanhoa Duplicator 4S that cooling is the key.  On that printer I had installed a highly directed ducted fan and it made a huge difference.  So enter the below hack:

This is not the first of these experiments that I have tried in the cooling space.  My first attempt, which had limited success, was a piece of plastic that clipped onto the print head assembly and focused the cooling flow onto the area below the nozzle.  I talk about it elsewhere but it was not the cat's meow.

Below is a test print done in PLA that shows the same g-code printed on a printer with standard cooling and the other with my directed fan.  It is obvious which is which.  

My first test with ABS shows a significant improvement as well but as I do not have an apples to apples comparison that will have to wait.

I would be interested in knowing what people think of this idea.  I would also like to hear any feedback into whether my printer is going to explode from running with the Olson block exposed!  I am doing a two hour long print in PLA as we speak and will then try an even longer one later.  I have heard from gr5 on the Ultimaker User Forum that I am not at risk of exploding my printer.  He indicates that the cowling around the block is there to protect my fingers.  Cool!

A couple of final notes.  The image is of the exhaust adapters for a "normal" Ultimaker kind of cooling flow from the fans.  This was my second to last thing to do for this assembly...the last thing will be to work in some mechanism that latches these exhaust adapters to the mount!

And finally...this model was printed in ABS on a Wanhao Duplicator 4S, a Makerbot Clone, with an active, and directed, fan.   The detail is remarkable.   I want to be able to do this on my Ultimaker (in ABS)!

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