Saturday, September 10, 2005


Meccano prototype's first restarted object

We managed to get the new 12V feeder drive controlled by a PIC, and have fitted a "goop shield" the the nozzle to prevent dribbly messes over the turntable.

The top of the turntable has been fitted with an easier to clean cardboard plate. We might raid the local pubs for beermats - hey! There's a good excuse! Our "goop shield" is a spare beer bottle cap - no relation - and we have wrapped the resistors with PTFE tape to stop "goop" dribbling through it.

We've produced two cylinders with a wall width of 1.0mm approx. The second cylinder was stopped (while we popped the EVA stick back into the heater) repositioned (Vik had knocked everything around a bit in the process) and cleanly restarted. This wasn't too difficult and the hardware is proving to be reasonably precise so far.

We have encountered a setback in that the hot-melt glue overflows from the nozzle, no matter how slow we put the feed at. This is not just causing dribble problems; it is also forcing the unmelted glue feed off to the side of the nozzle entry.

We're sure that we will find a solution soon, most likely involving gaffer tape or an old golf club.

Vik :v) and Ash.

Vik - to reduce dribbles, why not add a cleaner (maybe 10 mm cut from an old windscreen wiper) to one end of your turntable? Then the machine can periodically move over and wipe its nose...
Nice idea. Most of the mess comes out the top though, and we've now fitted a silicon tube sleeve that reduces it to acceptable levels.

We're now producing consistent, fused cylinders with 0.7mm wall thickness. Hopefully we'll get better results when we fit a real Polymorph head, but the important thing is that the Meccano prototype is now capable of producing repeatable results.

Vik :v)
There's one sitting in the middle of the turntable. I'll run some more off over the next couple of days that might be more interesting. We're reducing the flow rate so we can create finer structures, but its not quite going to plan. At low speeds the pulsing of the feed is starting to affect the shape of the printed cylinder.

This is good in a way; it means we stand an earthly chance of turning the flow off quickly enough to avoid turning the whole thing into a cobweb.

I'll get some pictures of the new rail-mounted extruder support up too.

Vik :v)
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