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Monthly Archives: March 2012

3D printed pencil sharpener… The final part

If you browse back through this blog you will be able to see how one of my students has attempted to design an improved pencil sharpener.

His designs started out as a desktop model and by looking back at his specification for the design decided that something more portable and easier to use for small hands would be a better route to follow.

His next design was really quite innovative and involved fold out cross pieces that formed a handle for better leverage. It also incorporated a standard metal pencil sharpener to do the main job of sharpening… However he was still not entirely satisfied. It was now close to becoming a marketable product but having to rely on another manufacturers sharpener wasn’t really a good idea, and the pointy ends of the fold out handles wasn’t very aesthetically pleasing… So…

The final iteration of his design addressed these issues… And matches the specification beautifully as you can see in the photos.

I firmly believe that without being able to do 3D printing for his prototypes and adopting an iterative design process this student would still be looking at a chunky desktop product and would never have developed his design in such detail.

New 3D Year 9 printed projects

This term I have been working pretty hard with year 8 and year 9 students doing some CAD/CAM projects. We mainly concentrate on 2D CAD in year 8 and 3D in year 9 with students doing some 3D printing of their projects using our 3D Systems Bits from Bytes machines.

One of the favourite projects with the year 9 students is to follow a teaching and learning resource I have made freely available on the BfB wiki called “Mobile Mate” … Designing and making mobile phone stands. You can of course download it here. http://wiki.bitsfrombytes.com/index.php/Mobile_Mate

Just thought you might like to see one of the first prints from the current batch of students,

Making metal castings from 3D prints

Why do I listen to my students? It only causes me to have crazy ideas.

So here is the full story.

The student who designed the barman’s bottle opener (see a previous post) was looking at how his design would be manufactured “for real” and decided that it would probably need to be die cast… Of course we couldn’t contemplate doing that but we do have some casting facilities in school… And we have heard of “lost wax casting”, but what about “lost plastic casting” in a traditional sand mould? Errrrr?? This got me thinking, surely at the temperature that aluminium melts the plastic print from our 3D printer would just burn away to nothing. Time for a bit of testing!

With the fume extraction going full blast we placed a sample of ABS in our brazing hearth and played a flame over it… Result a black blob and lots of black smoke. But what about PLA? Tried this too… Result it completely disappeared just leaving a small stain on the fire bricks. Maybe there was some mileage in this, so time for a full test.

We unearthed all the casting boxes, crucibles, leather aprons, face masks, gaiters and other other paraphernalia, made a sand mould with petrobond (oil bound) sand with suitable runners and risers and then fired up the furnace. All very exciting stuff as we don’t get to do this sort of thing very often in school these days.

After a bit of a wait we degassed the molten aluminium and the moment of truth had arrived… Time to pour it into the mould! Everything went smoothly, we now only had to wait for the aluminium to solidify and cool down… The excitement was mounting! And the smell of scorched sand was pervading the whole department much to the disgust of my colleagues.

But now the time had come to break open the mould… Bated breath as the sand was crumbled out of the casting box….. And….. FAILURE!!!…. It hadn’t worked! The 3D printed PLA object was only slightly melted on one side, surely it couldn’t have resisted that sort of heat, but it had.

So, back to the drawing board and a bit more thinking is needed… I’m convinced that it should work but we just have to find out exactly how to do it.

On the other hand, perhaps I shouldn’t keep listening to my students.


Axon 2 … Full version released

5th March saw the release of the full (non beta) version of Axon 2 … The 3DS BfB software for converting .stl files into the gcode that drives RapMan, 3DTouch and BfB 3000 3D printers.

The interface will look very familiar to users of the previous versions but Andrew at BfB has done a lot of tweaks and tidying up.

There are loads of changes… Far to many to list them all here… Some of the nice ones are.

Drag and drop files into the program.

Objects that are moved too far on the print bed show up as “out of bounds” and lines are displayed on the bed to show the limits of the extruders (this matches the number of extruders installed on the machine.

Tidy materials editor including materials cost… An estimate of the printed object cost is shown after generating the gcode.

Warning if trying to exit without saving the gcode.

Bug fixes ..many of these.. Such as the object now moves in the correct direction when moved on the print bed. And changing a material profile no longer needs a restart of the program…. And more.

“thin wall” settings removed as skeinforge (the engine that drives Axon in the background) handles these better.

A revert to default button… Fantastic when after tinkering with the settings has gone horribly wrong… Must have happened to us all at some time or other.

And one of my favourites … Right click switches from 3D view to a 2D top view (great for moving the object around on the print bed and checking layers of the gcode.

A huge thank you to Andrew at 3DS BfB as many of these improvements have come about because of constructive feedback from users… And I’m really pleased to see that a few of my suggestions have been implemented.

So all in all Axon 2 is looking and working very well and as always produces excellent results straight out of the box… Great for students and teachers alike.

Oh and watch out for the new icon… It took me ages to find it on the far too cluttered desktop on my battered old laptop!


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