Dicecreator's Blog
Handmade dice, for the fun of it.

Well, finally got to finish one machine that works! (do you see little laser engraver?…you could learn something from her…)

It has a digital temperature controller, and a digital timer. It is “missing” some elements I’d like to incorporate, like a second temperature controller, and differential cartridge and machine switches. Why do I need want a second temperature controller? Well, mainly because I can. No, don’t get me wrong, what I meant with that pun, was that the machine has room for two temperature sensors, one sits 10mm above the working surface, whereas the second, was an unintentional byproduct of ebay purchasing. When seeking the heater cartridge, I just wen for the one that best suited my needs, without paying much attention to other than  size, power and voltage. So, I ended with a heater that has an internal sensor too.This machine tough, needs it’s sensor as close as it can be from the surface, to well know the temperature that I’m aplying to the dice (and even so, the digital controller needs to be 20 degrees above the temperature I measured on my old heat element), so the heater cartridge sensor is unused.

Anyhow, I’ve seen the failure of not only one, but two digitally controled soldering irons, and seeing how a tool that you’re supposed to hold in your hand, get bright orange…is really scary (in a certain way). This machine also has various plastic bits around, and getting past it’s operative temperature of 120ºC (248ºF) is something that I DO NOT WANT TO SEE. (yeah, in big letters, because I respect any machine that works with 220Vac, and it’s job is to simply get hot. So, I plan on using a second miniature temperature controller to monitor the cartridge temperature. It’s temperature setting will always be a lot hotter than the working surface (and the working temperature), but should the surface sensor or controller fail in any way, this could detect it and shut it down.

Personally, I think that if both controllers fail, and the machine just melts itself down…I’ll throw it out the window…

Some might also have notticed the strange looking whire loop on one side of the machine. That loop’s purpose is to absorb the 7mm up/down movement that the heater can have (with springs*). The sensor cables coming out of the cartridge heater, seem to be rather fragile (they broke easily with a pair of somewhat gentle folds. Altough I was not going to use the sensor cables, and the power cables seemed a lot more resistant, I decided to play safe and just add that loop. Also, it helps to alleviate another possible future problem. When I did the cartridge hole on one side of the aluminium piece, the leftover gap between the cartridge and the aluminium was a bit too big. I used termoconductive silicone, but being a bit more like grease than a solid glue, if I just leave it as is, with the repeated twisting movement that the cartridge was going to get, it could dislodge itself, or worse, allow air to make cavities between the heater and the aluminium. Some could say that I could have clamped the heater, but I was unsure of the expanding ratios of both materials, and also, that the silicone has a small expansion coefficient, but using so many of it (in relative terms, compared to a computer processor) the expansion might be notticeable, leading to unintended silicone spills…and that stuff is nasty! it will just white stain everything it touches!

A simple spring loaded retainer keeps the heater in place (using a plug made of high temperature resin) to keep it centered and make an airtight seal with the silicone that might get out. (after using the machine a bit, the silicone that got out, was not that much, but when cooling, it acted as a vacuum seal, leaving the silicone at less pressure than outside, and now the cartridge won’t move a bit, as it is sealed by the pressure differential. (I hope the explanation was ok ^^U  )

*That extra spring cushioning is there just to prevent excessive pressure from the machine, as the gears that move it, can exert a quite large amount of force on the dice. Not that it could break the dice themselves, but it could damage the termoconductive silicone that sits between the aluminium and the dice themselves.

There is also that strange thin metal bar that protrudes from the machine and just gently touches the aluminium heater, It’s the timer sensor.

If you just do a bunch of dice, counting with the 100x technique will do the job, but when you’re doing tons of dice, one is incapable of just being so focused as to keep counting…It is one of those repetitive tasks that gets harder and harder to do, altough it’s just simply aplying the heat, and counting up to 15. So, I added the timer, and when you touch the dice with the heat element, and apply a bit of extra force (to compress those security springs mentioned before), the timer starts counting, and when it finishes, you can clearly hear it’s relay activating (if you where not looking at the timer itself). Some extra bits remain to be added  to the machine that will make use of the timer capabilities, but as it is, the machine is perfectly functional.

Here’s a short video with the machine doing a single face, it is not a tutorial, but don’t worry, one will be made soon.

And here’s what came out, in high resolution:

Once the laser engraver gets finished (and works for more than 2 hours…) They’ll get properly named. The laser engraver is a He, whereas the heat press is She.