Month: November 2014

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Makerbot Build Platform Flatness Testing

If you’ve ever printed with a FDM style 3D printer such as MakerBox, I’m sure you know that the build platform has to be pretty flat and level for you to have a successful build.

The first layer is critical.  If you do not get the first layer right, things go bad.  I wrote about this a while ago here: https://blog.gahooa.com/2013/08/10/makerbot-replicator-2-tip-first-layer-just-right/

I was having continuous problems with the first layer being too close in the center and too far on the edges of the build plate.  It was like a lose/lose on a bigger build.  On smaller parts I could calibrate it so it would work fine, but larger parts inevitably ended up being wrong either in the middle or the sides.

Enough is enough.  A Mitutoyo Digital Indicator, a Starrett Indicator Holder, a Precision Granite Surface Plate, and time to figure this out.

While there are more conventional ways to do this, I did not have the right equipment.  So I took a steel bar and flattened it on a granite surface plate with sandpaper (60 – 2000 grit).  It ended up with a very flat mirror finish on the bottom.

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I did not take the time to get all of the pits out of the steel, but here is a closeup of the steel after sanding:

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Next I measured out a grid on the Acrylic Build Plate.  IMG_2864

Using the digital indicator mounted to the steel block, I was able to take height measurements on the grid.

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Here is a wider view, including my high tech data collection process.IMG_2870

Note: I did this with both the Acrylic OEM plate and a Glass Aftermarket Plate. 

Once I had the data points collected, I made an exaggerated model in Sketchup, and plotted the points in 3D.

Screen Shot 2013-08-17 at 12.46.02 AM

The one that is wildly out of specs is the Acrylic, and the one that has a slight dip in the middle is the Glass.

Screen Shot 2013-08-17 at 1.02.52 AM

Screen Shot 2013-08-17 at 1.03.51 AM

Screen Shot 2013-08-17 at 1.03.28 AM

Both plates were fairly warped in my opinion.  The glass was a lot more workable.  I eventually bought a CNC machined aluminum plate, but did not take the time to measure it in this same way.

I feel that the manufacturers of low end 3D printers are not paying enough attention to the stiffness of their 3-Axis mechanisms.  While a FDM printer does not (should not) experience side or vertical loads during disposition, they still need to be fairly immune to vibration and even the weight of the build plate.

This was a MakerBot Replicator II – an obvious improvement over the MakerBot Replicator, and I’m sure they will continue to improve this aspect of 3D printing.

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We saw four geese… and first snow!

We saw four geese on our property the other day!  Maybe we should tell them they are late in flying south  :)

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Here are a few facts on geese.

  • Geese are a type of waterfowl belonging to the group of Anserini.
  • Geese mostly eat greens vegetation and grains.
  • There are three kinds of true geese gray geese, white geese ,and black geese.

Some Geese do amazing things while they are migrating.  There is a species in Asia, Bar-headed Geese (Aner indicus), that migrate over the tallest mountain in the world (can you guess?) in the Himalayan Mountains.  The air temperature is as low as -60 Degrees F.

Now that is a “wow”.

References:

  1. Wikipedia contributors, “Goose,” Wikipedia, The Free Encyclopedia, http://en.wikipedia.org/w/index.php?title=Goose&oldid=633827032 (accessed November 19, 2014).
  2. “Migrating Geese”, Chipper Woods Bird Observatory, http://www.wbu.com/chipperwoods/photos/geese.htm (accessed November 19, 2014)
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Old hand forged nails

We have some old hand forged nails. The nails were made by a blacksmith.

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We polished them with a Dremel tool using a wire brush.  Did you know that a Dremel tool can spin 500 times per second?  Wow.  We wore safety glasses to protect our eyes.

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Here is a polished nail.

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Here are some facts on old nails.

  • Old nails were once so valuable that when a building burnt or fell down people went through with magnets to find the nails and save them.
  • Nails provide one of the best clues to help determine the age of historic buildings, especially those constructed during the nineteenth century.
  • Between the 1790s and the early 1800s, various machines were invented in the United States for making nails from bars of iron.

 

Here is the a chart for nails. (Copyright Thomas Visser)

nails

 

You can read more about it here: http://www.uvm.edu/histpres/203/nails.html

That is all for now!

 

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