Sunday, May 5, 2013

When a Raft Makes Sense to a Raft Hater

I hate rafts and supports and avoid them as fervently as I can.  In fact, you could say that I'm a bit rabid about the topic.

To be honest, of hundreds of objects I've printed with the Cube printer, the number that required supports could be counted on one hand that had lost a couple of fingers.  In fact, I think it was only one... when I first got the 1st generation Cube.

But, recently, I have run into some designs that just would NOT stick to the table for the length of time they needed to remain attached.  Of course, I blamed it entirely on the glue and made my feelings known to the Cubify design team. 

Then it dawned on me that while there might be some potential for a stickier long lasting glue, the real issue just might be my adament refusal to consider using a raft.  So, I decided to test that theory and reprint one of my non-raft failures with a raft.

Ooops!  Duh... that worked like a charm.

I think I know why.  I was trying to print 8 beam-like objects that were 130mm x 10mm x 6mm.  The adhesion had to work with the 6mm edge.   The length offered more than a little opportunity for warping.  So, I cut pentagonal holes along the length hoping to help mitigate that potential.  While it helped, it probably didn't take enough stress off to completely stop warping. 

You would think that a perfectly flat surface would adhere better than waffle surface.  But, upon reflection, I can see why that might not be accurate.  A raft probably offers more surface area for adhesion because the glue, which has some depth of its own, has the opportunity to ooz up into the seams between the first layer of lines of the raft and wrap around the filament adding a bit more grip vertically as well as under the filament.  The actual area is probably considerably bigger than offered by the flat side alone.

Whatever the reason, one can't argue with the results.  So, I've decided to be a bit more flexible about my no raft rule.  When you need it, you need it... sigh....


  1. Hi Tom,
    As usual, your blog is the best! I, too, was wondering about rafts (and supports). I got my cube last week and have been printing micro beehives (I am a beekeeper). I've designed a complete set of hive equipment at full scale with an eye toward the day when 3D printers become capable of printing these large items. When printing on the cube, I print the bee hive components at 15% scale, which works well.

    During one of the prints, I printed the component with a raft to see what it would do. While the raft is obvious, I am not quite sure yet as to when you would want to use it.

    Another option would be to design a couple of small "glue pads". These would be something like small round discs (maybe the size of a dime) with a short tapered post supporting the main item. The glue pads would help stabilize the print but could be removed afterwards.
    Steve the beeguy

    1. Hi I stumbled upon your very old post right after reading this recent article that could interest you:

    2. That is SO COOL!

      I will definitely want to write a full blog article on the 3D printed Flow Hive. I always check links posted in comments and usually delete them. But, this one is a winner.

  2. I'm betting that this is something that will really interest other Cube owners. I certainly would love to see some images. So, please feel free to send some to me with the address found on the right side of this blog if you wish to share what you are doing. Nice!

  3. Tom / Anyone

    What are you guys using to remove rafts? I tried a raft print and they are a mess afterwards. I was thinking it's dremel sander time once I get the main rafts cut out. Tips on raft removal please

  4. Raft removal has been a complete nightmare for me on the Cube 2. We have a Replicator 2 at work and usually rafts will snap right off. I really wish somebody had a silver bullet for it, because most of my prints will not print at all without a raft, and trying to get rid of them and make the print look nice is almost impossible. Im so frustrated that I am about ready to sell my Cube 2 and jump over to the Makerbot Replicator 2.

  5. Without actually seeing the part, it is impossible to offer any suggestions. But, I agree that rafts and supports are no fun and di my best to avoid them.

    The Cube 3 will be able to print in two different materials at one time. Even though the best approach to removing supports in a 2 material situation is to use a solution bath in an ultrasonic tank, I'm hoping that just the material differences might make manually removing supports at least a bit easier.