January 13, 2013

As 2013 gets going I notice that’s it been a while since the last post. To be honest, this is partly because I got far too excited about receiving my RepRap Huxley kit; distracted after building it and mostly because I got lazy after a few months of not posting. Now, it’s a new year and time to start again, I think. I’ll endeavour to keep posting at least once a month, even if it’s just to excuse myself for not posting!

The Huxley has been printing well but I’ve been having a lot of problems with the heated aluminium bed collecting stray bits of PLA. which I could not get off in order to keep the bed clean. When I did some asking on IRC and forum hunting the best I could find was lots of advice on using acetone to remove ABS but nothing on what will remove PLA. I suspect that acetone won’t work but I may see if I can cajole the chemist at work to let me borrow some to try. Until then I’ve tried a kitchen scouring pad which works OK but tends to be abrasive and gives everything I print a silver coating of aluminium powder on it’s base: I also got it all over my desk and keyboard the first time as well.

I’m currently trying out a thin sheet of glass which works very well but as it’s too narrow and too long to fit on the bed it’s reduced my print size; is not fixed tightly to the bed; might crack under the heat (not tempered) and looks a bit silly. I also have some Kapton tape on order but Amazon are botching my deliveries so goodness knows when it’ll turn up.

Another problem I did encounter was using “Crystal Clear” PLA, the stuff seems to be so hydrophilic that it became unusable after about four months and kept popping the Bowden tube from the Extruder. I got some luck with drying it out in the oven a few times but in general I think I’ll have to write off the rest of the reel which is a shame as the prints looked awesome.

All this is besides the point as my hot-end stopped working before Christmas, whenever I turn it on the electronics resets. Checking with a multimeter the wire-wound power resistor that does the heating has a short across it but I’m not sure that this is down to the resistor itself being fused or if it’s the lead has worn through the heat-shrink/insulation and is touching the block or each other. I need to investigate a little further but there’s no rush as the replacement resistor (my favourite theory) is out of stock at RepRapPro and Mouser and I can’t find an alternative on FEC/CPC with a small enough diameter to fit in the block. I may email RepRapPro to ask if they have any suggestions. If I need a new resistor that I’ll probably also need to find some more of the high temperature heat-shrink and crimps.

Before I go, this afternoon I heard the sad news that my first boss passed away on Friday after a long illness.  He gave me my first job as a work placement when I was still at University and I’m still there today, 14 years on. Dr. Tom was an enthusiastic supporter of young entrepreneurs and was still touring schools and colleges telling everyone about his successes and failures until quite recently. In fact, I remember him visiting my Tertiary College to give the same talk with the same old slides and overheads many years ago but the truth and inspiration that he brought with him was the same then as it was the last time I saw him. A great loss.



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