Computing stuff tied to the physical world

More 3D trials

In Hardware on Jan 28, 2010 at 00:01

It’s not as simple as it seems…

Well, the CupCake worked straight out of the box, which is of course fantastic. But printing does seem to have two tricky bits, called “extrusion” and “rafts”.

Here’s the printer making its third part:

DSC_0963.jpg

What’s about to happen, is that the “raft” (that woven mat laid out on the bottom to hold the rest of the construction) is about to come off the base. In the above picture you can see two other problems: the raft itself coming apart, and a blob of plastic (front right) when the printer decided to pause for a few seconds, while the extruder kept pushing out plastic…

The problem seems to be that when the plastic cools down fully it becomes quite springy and rigid. Which is great for the final object, but causes trouble in keeping it stuck to the acrylic base. I suspect that the heated platform which people are experimenting with is to overcome this problem, by keeping the base slightly sticky for the duration of the build.

Or maybe a few wires extending further out from the raft would help, by “tacking down” the whole thing.

The other purpose of the raft is to even out the surface. In my case there is a slight difference in height across the base. I should probably try to get rid of that first.

Anyway, here are the objects made so far:

DSC_0964.jpg

The meandering plastic retains its shape – that’s probably part of the magic behind all this.

PS. The stepper motors are noisy. I don’t think the software I’m using is micro-stepping right now.

  1. Awesome, I must confess I envy you.

    Is the plastic easy to get here in Europe ? Importing it would be pretty expensive, because it is too heavy.

    Cheers Rubi

  2. I am an outsider of this whole plastic molding thingy, but would it be of help if a raster of simple thread is placed/wound on the table so that the initial plastic raft would be bonded to that? And afterwards you cut the thread loose from the table

    • This is really the function of the raft itself – which now works fine, see the next post.

Comments are closed.