Wednesday, March 14, 2012

First Printed Object!!

Huzzah!  After two years of muddling about I have managed to coax my Mendel into actually printing something.  And it turns out that I didn't even need a new main board!

I had noticed that the electronics would work for about 20 seconds before shutting down so I knew that the problem was not in the stepper controllers but it seemed to me that overheating could be causing a shutdown.  Then, when things had cooled down, it could be made to work again.  I reasoned that perhaps I had the current set too high on the steppers so I turned them all down and tried it again.  Lo and behold everything began working correctly so I proceeded to try printing some small parts.

I managed to get some small things to print correctly, if a little sloppily, so I decided to go for it and try to print a shot glass for the traditional toast to a new machine.  The results (.4mm layers, 200C, 50% infill and no heated bed) are below:

In the picture it appears to narrow towards the bottom but that is caused by the camera angle.  It actually came out great.  There are quite a few blobs but I will experiment with the settings to resolve that.  I suppose it is either too hot or the print head was moving too slowly.   In any case, it is water tight and shaped like it is supposed to be shaped.

I still don't have my endstops working, which means that I have to set everything up manually.  I have been editing the Gcode to remove the homing instructions before and after the print.  The most difficult part is setting the position of the Z axis prior to starting.  Since I am doing it by eye it is hard to get the height set consistently and I have had to stop several prints because I started them with the print head set too high.I could make a spacer to set the height but I think fixing the endstops is a better use of my time.

I have gone through the few feet of grey PLA that I had and I will be starting into my 5lb lot of green PLA so I went to Lowes and bought an electrical cord reel to wind it on.  

Quite a few people are using these now.  They are cheap and sturdy.  the only problem is that the reel is not split in the middle.  that means that I have to wind the whole lot of filament onto it by hand instead of splitting the reel and just dropping the roll in.  There are a number of mods for this reel on Thingiverse including a spindle for 5lb spools and some connectors that allow you to modify it so that the reels can be removed and changed.  I believe that I also came across an actual printable reel designed for these but I have to go find it again.

I have a few items that I want to get printed now that I have it working.  The highest priority, now that summer is coming again, is an  adapter to mount a set of relays under the hood of my Jaguar XJS.  I installed electric fans last year and the relays that came with them do not fit on the mounting bar of the car.  I will have to print those from ABS since it gets pretty hot under there when running the V12 in the summer heat.  I think it may get above the melting point for PLA.

I also want to print a set of clips to reinstall a piece of glass in our stereo cabinet.  None of the mirror or glass mounting clips available locally will fit this oddball installation.  The best thing about this one is that I get to show my wife how useful a Reprap can be!

Thursday, March 8, 2012

A satellite of your very own!

I am still waiting for my replacement Sanguinololu but here is a really interesting story to help pass the time:

The folks at Evadot have designed a board to be the brains of your very own satellite.  A CubeSat is a low cost micro-satellite platform that universities and others have been using for a while.  Of course, "low cost" is relative.  A basic CubeSat kit costs anywhere from 7,000 - $10,000 and the launch costs are another $40,000 at the moment.  On top of that you would have to add your own sensors, etc. for whatever mission you have in mind.  Evadot wants to open things up a bit by offering a much cheaper alternative to the present CubeSat kits on the market.

Give the article a read and keep an eye on these folks.  These boards can also be used for a variety of other cool hackerish purposes, including robotics.  Keep in mind however, that launch costs are dropping and you might actually be able to afford to launch your own satellite in a few years.