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!

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.

Success and Disaster!

I have been unable to resolve my endstop issue so I will probably remove them and go to the limit switches which I have already tested and found to work fine.  In the meantime I decided to go ahead and test the machine without them by manually setting the home position and editing the G-code to remove the homing instructions.

Success - I managed to print a part on my second try.  The first time I set the extruder position too high and it simply sprayed the filament into a big pile even though it was moving correctly in the X and Y.  I still had it positioned about one millimeter too high on my second try but it created the outer shell of the part correctly.  The infill did not fare so well.  Since there were many quick movements and changes of direction the  filament did not have time to drop into position before the hot end moved. and the holes in the part were blocked by a mass of filament caused by the suspended thread being dragged over the hole before it dropped into place.  They could be drilled out however so I am counting it as a success.  Very big day and I was extremely happy.

Then the Gremlins arrived.  When I adjusted the height again and started the third print it stopped dead in the middle of the first layer.  I found that the green LED was no longer lit on the Sanguinololu and I got a message on the workstation: "USB port has exceeded voltage limits".  Now everything is dead so I believe that something has been blown on the main board.  Whenever I plug in the USB I get the "Exceeded Voltage" message and nothing happens.  Maybe a short?  One other disturbing symptom - When I power up the 12v supply the mosfet down by the thermistor connectors becomes immediately hot enough to burn my finger, and I mean immediately, like from cool to burning in less than a second!

So I may have a trashed main board.  Need to do some more troubleshooting but I am too depressed right now.  At least I actually printed something so that is progress.

Hardware Complete!

This is a real milestone for me.  I believe that all the hardware is finally working properly so I only have a couple of software issues to resolve. 

I replaced the endstops last night with a set of spares that I had bought with the original Techzone electronics.  I always figured that I would burn out one or two and they were cheap so I bought a full set of replacements.  These are slightly different from the ones I am replacing.  They have LED's on them so I can see that they are getting power and are working properly.

Unfortunately they don't seem to be doing anything.  It makes no difference whether the optical signal is interrupted or not.  I can jog all three axis in both directions even with a card inserted in the endstop.  I think that this is an issue in the setup in Sprinter so I am going to look through the configuration code today.

I also need to reinstall Pronterface since it won't load an STL file.  This shouldn't be a big deal since I have confirmed that my other computer, on which I also installed Pronterface, can load them just fine.  I probably messed up the install of one of the several apps that Pronterface depends on so I will clean it all out and start the install from scratch.

As a final note I should mention that I started working with Sketchup 8 this week.  I downloaded a free addon that allows import and export of STL files and I have been able to create a couple of fairly simple part files for items that I would like to print.  I found it simple to learn and easy to use.