Wednesday, January 5, 2011

Progress over christmas

Well i've had to abandon using round rods, too much sag and other problems, instead a collegue of mine realized that there were some linear telescopic rails in the test department not being used, so I took a bunch, as we were doing a big clean up on the last day of work for the year.

I found that I can mod them sufficently to have just 1 rail with ball cage and internal rail, with a bit of cutting and drilling.

Another collegue saw the, *ahem* printer, and suggested that i'd be better off with mounting any linear bearing vertically, i'd toyed with this idea but wanted more range in travel, so as an experiment over the holidays i've drilled some 400mm angled aluminium and the rail, to the Z axis, while I don't have any, literally, money for even screws I had to temporaily use what I had at hand to test it out.

Using just 1 linear rail vertically seems like it could work, and because the Z axis moves in line with the Y axis, the slight wobble, can be attributed to not actually screwing anything down, lols, will have to see when I get some screws and countersink some holes.

I also bought from NopHead, the Mendel plastic parts that include the Adrian geared extruder, though I cannot locally source the brass sleeve, however my mates that work at Next Window, have leased a 3D printer, and I hope to at least get them to print out for me the wade extruder, if y 3D printer doesn't get done. Might just ask them anyway, as a backup if mine fails somehow.

As well as that, and because i'm still bored at home, with no money, literally nothing, till I get paid, hopefully tonight, I had decided to play with the RAMPS electronics, adding features and changes I felt were needed.
JohnnyR did the original design before I started to work on it, after what Adrian had suggested as printable electronics. JohnnyR had the same idea I had and worked on it.

Things I wanted to do differently are, less vias, less wire jumpers (failed) locking header connectors (barely fits) use the MAX6675 as the thermocouple sensor, SMD jumper pads for micro stepping options.

It's not a great picture, and have to work on the layout more, not too happy about a couple of things, not today though, it's sunny today and I might just go GeoCaching

I see also that Jeff has his printer mostly calibrated, he mentioned about problems with microstepping on the makerbot electronics, if I find out I have the same issue with my RepStrap, i'll be switching to my RAMPS v1.2, as I need the thermocouple.

Warning! Rant inbound.

It fustrates me to no end about people suggesting using thermistors for the hot end, don't they realize that they are only designed to work up to 150 degrees C continous? 250 degrees is the max for short durations.
That and PTFE thermal breaks, this is unsafe when there is thermal runaway, which has happened on my machine during early test stages, though I was glad i'm using BakeLite, PEEK is ok as well but very expensive.
The BakeLiete i've got is from a frying pan that I specifically bought for its handle, it was cheap, had to be for my budget, ie no money or next to nothing.

More to come, just had to post this, and ask that my blog be added to the pipe.
Makes it easier to post about it here than on the forum, which should be used for questions and answers, and not blogging, which is what I seem to be doing for my version of RAMPS v1.2


  1. Thermistors can be rated for operating temperatures of 300C or more. Meanwhile bakelite has a max operating temp of 121C. So there you go.

  2. Yes the recommended Epcos thermistor is "For temperature measurement up to 300C". They give a lower system cost than thermocouples.