Skeinforge settings vs Great Rafts

In short: a raft is a printable, flat thick layer to even out your build platform. Through testing and whatnot your build platform takes a couple for the team and in time becoms uneven (holes, scars). The raft is there to make sure the build surface is flat, and also tries to assure good first layer adhesion to the platform.

My first rafts were thin candy string like threads that offered virtualy no support and actualy did the opposite of what it was supposed to do. The fatter base layers and the thinner support layer didn't assure first layer adhesion, except on very small builds.

A raft is important when you're printing with the standard build platform, and to a lesser extent when you're pinting on a heated build platform. Since printing with a heated build platform is very different from the standard, there's a separate post devoted to just that.

First off, i've learned through trial and error and many comments on the google makerbot operators group that the interface layer (thinner threaded 2nd raft layer) isn't necesary by default. If you learn how to make a nice fat spread base layer that's all you really need.

To get the raft you see here on the right, you need to manualy reposition the z-axis on the first line that's going down when the raft starts printing. Position your nozzle about 1mm above the build platform and start your print, then just lower the nozzle by hand untill your raft lines touch each other, but make sure they don't overlap. If the lines overlap you will see a very thin (like a hair) thread on top of the raft lines. That could mess up your first layer, but could also strip out your filament. By making such fat lines you could end up blocking the extrusion by feeding more into then the nozzle can lay down. So make sure the lines don't overlap. It'll take a couple of tries, so start out with a small raft to get the hang of it.

Makerbot Heated Build Platform - Build and first use summary

After being unsuccesfull in printing the main part of the Printruder II printable plastruder i needed a way to print large part.

I could print about 15 layers before warping kicked in. Which in general isn't bad considering allot of people get warping almost instantly (some even on the raft).

At 14ish layers the left front corner of my printruder head started to curl up. I had hoped the warping would be contained to one corner and was praying for a good outcome. Needless to say (and judging by the picture on the right) the warping had become so bad that the print head ended up outside the object and was crashing into it repeatedly. I quickly stopped the build, afraid my extruder could become damaged from crashing into a fairly thick wall already.

So i ordered a Makerbot Heated Build Platform v2 and assembled it.

The build
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Putting the HBP together was a bit overwhelming at first, because i had never SMT soldered before. The whole hot plate thing sounded a truckload of work (and allot of money to spend for something i'll probably only use once). Luckely i could turn to an electronical engineer at work who said you can SMT solder by hand without a hot plate. You just need a good soldering iron and good quality solder. He showed me how to do it, and behold - i SMT soldered ALL the components perfectly without prior experience and WITHOUT a hot plate :)

If you follow the manual on the wiki it's all very straight forward. There's no pitfalls - just take your time, solder in a very well lit environment and use magnifiers (those come in handy!).

Take note of the orientation for the leds, the green markings are horribly small.

When everything was assembled i sawed off the tips off the nuts. Next time i'm in a hardware store i'll search for screws i can sink into the metal so nothing sticks out on top. But sawed off i don't loose any build space either.