Saturday, 12 April 2014

Bronze, Silver and Gold cogs

The 'cog' has been added as a bit of a joke currency in the new Vale LRP game. I've taken the joke one step further and made the currency real so I can be rich when I go and play next month. :) 

Thursday, 10 April 2014

Blue Laser - LED Lighting

Remember that light bulb in the blue laser that I loathe so much? I already removed it from the machine but lighting is incredibly useful to see what's being cut. I wanted to add some LED lights for decent illumination but the existing wiring just connects 240V up the that light bulb fixing. I could have put an adapter in to bring the voltage down to something use able but then I remembered about an old LED light bulb I had pulled apart.

 £2.79 will buy you an LED light bulb which operates directly from 240V. These corn cob bulbs are a collection of LED panels, each panel is 16 LED's wired in series. There are 64 LED's wired in series (4 panels) which provides sufficient voltage drop to connect it to the mains. There are two sets of panels in the light bulb wired in opposite directions so the LED's actually provide their own rectification of the AC input.

The bulb was pulled apart and the wires all extended to allow the panels to be placed in the corners of the lid.

Laser cut mounts were made to hold each panel at a slight angle in the corners of the lid. The mounts affix to the lid with a single nut. After my experiments gluing and taping things inside the lid all failed, bolting things in using the existing fixings is always preferable.

The panels were split into the corners of the lid and wired up to the existing electrical point. The lights always come one while the laser is turned on but as the LED only takes 7W it's not taking a vast amount of power.

Monday, 7 April 2014

Thick Foam Cutting Tests

Since I've been playing with foam again I took the opportunity to conduct some tests on thicker sections of foam. 
The 12mm foam cut in a single pass, 25m/s and 30% power so super fast. The trouble is that the middle of the material gets really hot and starts to melt, drawing back from the beam, this causes the curve you can see on the edge of the cut. The 30mm foam was cut in multiple passes, 25mm/s and 15% power. As you can see the laser caused ripples down the edge of the material for each pass. Both of these are pretty much unacceptable for the majority of things.

The second problem is caused by the way the laser works. As the beam passes through the final lens it takes on an hour glass shape. The neck of this hourglass should be focused onto the surface of the material. As the beam passes through the material it gets wider again at the bottom of the cut the beam is noticeably wider than the top.

These two issues can actually be used to counteract each other. If you aim the focal depth at the middle of the material the narrowest point of the cut is the point where the material shrinks away the most. It doesn't work for much thickness but it does help up to about 10mm thick.

Sunday, 6 April 2014

Herugrim Sword Gaurd

This is a foam replica of the guard on the sword, Herugrim, used by Theodin in the Lord of the rings films. Again etched into LD45 foam, this will be latexed and coloured before being put onto a LRP weapon. I should hopefully get some pictures of it on the sword. (svg here)