Sunday, July 25, 2010

ABS leftovers turn to glue

When printing, you're bound to have a heap of little scraps of extruded ABS (rafts, test extrusions, clogs). Untill the day comes when granulated ABS can be extruded, here's a great way to utilize something you would otherwise throw away!

Take your scraps and crush/cut them up as small as you can, then put them in a GLASS container (an old drinking glass for instance). USE GLASS because acetone dissolves certain plastics (polymers, like abs!!).
Pour in Acetone and stir it around every half hour or so. Repeat the stiring for about a day. Add more acetone untill your solution has the desired thickness. Now, acetone is very fleeting when exposed to oxygen, so cover the glass - unless your mixture is too thin and in that case leave it uncovered. Make sure to keep the mixtuer in a well vented area when uncovered. Eitherway keep it in a vented area because Acetone stinks and can cause a nasty headache. Depending on the pureness of the acetone, it might evaporate fast or slower.

A good way to seal the glass is to use parafilm. This is used in chemistry labs and is a great way of sealing the beaker. Don't use any type of plastic (polymer based) cling film, because the acetone vapor will dissolve it (like household cling film).

ABS is used in allot of products, including car parts. You could use the ABS glue to touch up parts of your bumper or any other application that uses ABS. With a bit of creativity you could even use the mixture to mould things.

Saturday, June 19, 2010

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.

Thursday, June 17, 2010

Feeding the Filament... with a spool!

Jared Spool : "Good design, when it's done well, becomes invisible"

Let's say that for the 3D printer jared's argument isn't always necesarily true. For quite some time i had filament strips that had two main reasons. Not having adjusted the idler wheel deep enough, and not feeding the filament 'smoothly' enough. Adjusting the idler wheel was obvious - but i kept looking past it for a few weeks because i was convinced i had set it correctly.

The ABS filament i got with the deluxe kit was a mess. I had no clue how to handle it and reasoned it's a spool - and if it goes haywire i'll just rewind it. This might be so for electrical wire, it isn't so for ABS. That stuff has no organisational qualities. The way my filament went into the cupcake was all tangled, twisted and what not. Didn't really catch my eye untill one day it stripped cause it bent almost double.

You don't have to be blond to be stupid, as illustrated by the above. Browsing around in thingiverse i found quite a number of people with spool variations. Some clever, some highly ingenious, some so wonderfully simple!. So i decided to go with KISS (keep it simple stupid). What can be more environamentaly friendly then to make your stuff out of cardboard! The user charlespax on thingiverse came up with a cardboard spool made from pizza boxes. I however used an old box from a computer i had lying around. Which is good thick cardboard. The build is really really simple, and surprisingly sturdy. You would need a spool holder for your shiny new toy, i made mine from a cardboard box. I inserted a metal rod through the spool, and hold the spool as a whole inside a cardboard box that's deep enough. Just make two holes in the box and tadaaa you have yourself a DIY - no effort spool holder.


Howto: level your z stage

“Vertigo is the conflict between the fear of falling and the desire to fall.”
is what Salman Rushdie said.

We've all seen our Z stage crash into the build platform. The Z stage design is frail and prone to flaw. If you haven't payed allot of attention to the horizontal level of your stage, reconsider. Some print errors can come from a miss calibrated stage.

The problem with the z-stage comes from two issues:
- The nuts that hold the stage horizontaly in place

- The differing height variation between those 4 nuts respectively.

From personal experience i've found that leveling the z-stage horizontaly as a whole compared to the build platform is not 'THAT' important. I've found that the build stage can be off by millimeters and still result in a good print. What IS important however is that the nuts support the stage on all 4 points. The Z-stage can not have a tilt in it or it will result in bad prints. When all four nuts support the z-stage, the stage itself can (even visualy) look slanted - provinding there's no more then 5mm (give or take) height difference between the nuts. If you end up with more, you'll have to take a closer look at your build.

Saturday, May 29, 2010

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
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.