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Part 11 - First Prints

<Queue dramatic 2001 theme music>

Well I'll be damned - it actually works!

To be honest, I never expected it to work at all - my track history with moving parts projects is pretty sketchy at best, so the fact that it does what it's supposed to do, and is even approaching...quite good....is a very proud moment for me! OK, so it took seven months, but it was seven months that have provided me with occasional  distraction from work, apartment decoration and illness, and allowed me to learn some new engineering concepts to boot. AND the fun is only just beginning! I can see that this will be a very useful tool going forward. I'm already planning the next two machines, another Huxley for my son, and a bigger build volume Mendel with multiple extrusion heads - oh yeah!

Anyway, I'm getting carried away with my enthusiasm, on with the first prints!

Of course, the first couple of objects are not even close to good, let alone perfect. 

I selected a couple of what looked to be medium complexity calibration prints from Thingiverse, a pyramid of 5mm cubes, and a sphere trapped in a hollow square. These turned out to be quite good selections as they clearly showed me that my Z and Y axis where not square, and that I had nowhere near enough tension on my X axis belt. In addition, the stock eMaker PLA profile sets the build area to 95c, which I found left the objects very soft and likely to sag or move during and just after printing. I've since updated my settings to have the bed at 60c which seems much more sucessful in terms of the PLA setting hard quicker, and nothing is moving during prints. As all the advise says, you need to make sure that your first layer is very low and 'squishes' the PLA onto the bed, which gives excellent adhesion at 60c. My extruder is set at 200c which is stock, and seems to be working well.

Now, the more observant will be asking, why the cube looks like I poured spagetti on top of it...well this is the other thing I learned during my first prints - REMOVE CAT FROM ROOM.

Next up is the recommended Huxley first print - board holders for the Sanguinololu, and a PSU plug holder. Again, these where pretty unusable due to the various e-steps per mm settings, retraction and infill parameters all being wrong for the material I was using. Also at this stage, I hadn't figured out that my X/Y axis needed to be squared off again - the next section will show that "Aha!" moment. Thing is, I was having so much fun just watching it doing its thing, I just let it carry on - must stop doing that though, it's a waste of material.

I had another bash at the trapped sphere, sans cat, and was very pleased at how it came out. You can see that I have some sagging at the top, which is to be expected when it's printing on mid air - frankly I'm surprised it finished as well as it did. I will investigate support options along with additional fans for future prints that require this.

While I was measuring the cube, I could see that it wasn't perfectly square. Because I'd already pulled it off the platform at that stage, I couldn't figure out for sure which axis needed adjustment, so I started the next object to help me verify.

The above three images show the support rails for the Sanguinololu board - they are pretty usable I think. As you can see the bottom and sides of the objects are looking good in terms of no stinging and good infill. The tops however are still showing gaps, so I need to play more with infill and retraction settings in the Oozestep plugin for Skeinforge.

It was when I printed the top of the Sanguinololu holder with the fan mount that I could clearly see that the  X axis was not square. In order to adjust this, I will actually be moving the Z axis bottom mounts as due to the Huxley design, the whole X assembly is supported by the Z mounts. It looks to me that it's out by about 4mm, so shouldn't be to hard to correct.

(By the way, yes, you need to cool those electronics - especially here in Russia as its averaging about 37c in my kitchen workshop and my board went into thermal shut down a couple of times)