3D Printer Project: Printhead Assembly

The next step in assembling the printer was fabricating the printhead.  The printhead attaches to the X/Y carriage via three alignment pins.  These ensure a perfect alignment and make it easy to switch out multiple types of printheads quickly and easily.  The initial printhead I've fabricated is a dual extruder direct drive configuration.  I also have designs for a single extruder, dual and quad bowden extruders, and others.

The 3D printed version of the base plate that connects the pins and the motor was sufficiently rigid to use for actual run-time testing of the printhead.   On the other hand the plate that holds the hotends to the motors had to be CNC machined to ensure a proper alignment.  This was the first time I was able to use my new Automatic Tool Changer and Tool Height touch-off.  It worked out very well once I figured out the process.

The current printer prototype hands the motors below the XY carriage.  However in the second prototype I plan on flipping this to have the motors on top.  Thus the printhead plates and brackets are designed to be reversible for either configuration:

Motors below:

Motors above:

And since this is the configuration I'm really aiming for I wanted to make sure there was enough clearance for the hotends to pass through the carriage block. Everything looked good.  Obviously the plastic version of the carriage block is only temporary, but even that should be sufficient for some initial testing:

And here's the assembled printhead attached to the carriage in the printer:

I have a few more odds-and-ends to work on and it should be ready for the first test print.

 

Posted on April 22, 2015 and filed under 3D Printers, Projects, CNC Machining.

CNC Plasma Dinosaur Project

I worked on a quick side project today as a wedding present.  I used my Grunblau CNC to plasma cut a dinosaur and then welded it together with the TIG welder.  It was a good chance to test some changes I made to the packaging of the torch height control electronics and the effectiveness of the water table.

I had some initial issues with the tip plunging into the material, but after replacing the consumables and fiddling with the THC settings a bit it ended up working quite well.  The cuts came out pretty clean:

Also, the water table worked very well for reducing the smoke and fumes.  Moreover the grate is still working well for supporting the pieces.  There is very little cut-through so far and the holes are small enough to prevent parts from falling through.

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I made a vide of the cutting and welding process:

And the end result turned out well:

Now back to the 3D printer project!

 

 

 

 

 

 

 

Posted on April 15, 2015 and filed under Projects, CNC Machining.

3D Printer Project: Fabrication #6

I'm trying to finish up the fabrication and assembly steps of the printer quickly so that I can move on to test runs.  I finished assembling the Z axis structure this week and mounted it in the frame.  I probably over-engineered it a bit, but the stiffness of the table is very critical to the precision of the print.  I can always go back lighter an cut out more metal.

Unfortunately my cable routing scheme interferes with the Z axis motor, so I'm going to have to drill new holes to route the cables. The Version 2 design has the X/Y plate flipped which will make cable routing *much* easier.  

Next steps are to CNC mill the aluminum build plate assembly and extruder motor assembly.  I've 3D printed a mockup of the head mounting plate to test the design:

 

 

 

 

 

 

Posted on March 28, 2015 and filed under Projects, CNC Machining, 3D Printers.