mendel 109 printing

After several diferent firmware attempts I retried joaz's mega fork and got success.
Ive been working on tuning since i got the first shotglass print. The reprap firmware shotglass printed fully though it was a very poor quality print. after a lot of skeinforge massaging and quite a bit of assistance from tonok on irc i was able to get a reasonably high quality shot glass printed. The second skeinforge print was a wades extruder which came out realy well (after numerous aborted attempts).

I found that my x and z steps per mm settings were off and made adjustments ( i hope in the right direction) but havent had a chance to get a full print since.

note for my changes i got 106mm out of 109 for full lenght and 25mm instead of 28mm for height.

for z (which was most pronounced) i went from 400 steps to 448. dont remember what i did for x off the top of my head but i went the same direction.

working on first print

everything is assembled and functioning to a point,but having issues with extrusion and posibly positional accuracy.

first off. ive been trying to use the nema 23 bowden extrusion but all i get are striped filaments, it appears that the motor heats up too much and softens the plastic. so I tried to use wades extruder but only had a makerbot stepper to drive it which was too weak to push noodle through at any reasonable rate. After talking to some people on irc i picked up some lin motors at a reasonable price and promptly pushed my barrel right out of the ptfe insulator :( .

I may construct one of nopheads pipe covered barrels next though i may just put in my dual block extruder barrel and try it first using a cable and wades.


BUT....

I have another issue i saw in the little bit of printing i got before failure. My X/Y stepper motion is wrong. for some reason step direction is not being passed to my drivers before the step pulses. so when traveling in one direction the steppers do some of their steps forward and the rest in reverse so my print looks completely wonky. it really becomes noticeable on short segments.
Im using the Ardrino MEGA board, pololu stepper drivers and I believe joaz's mega port.
Ive tried david buzz's and mycoyn's but neither of them appeared functional when i tried them.
A couple of people suggested to just use the standard fork and do my own modifications but i have been hoping to not have to redo work that has already been done.
Has anyone else ever seen this behavior and have any suggestions?

firmware

worked on my mendel over the last several days, and installed different firmware. using http://github.com/mccoyn/reprap-firmware-fork i believe. with some minor modifications for the pin outs im using. I am still having some issues with movement but the motors are stepping now at least for the most part :)
The thermister table appears to be off but that is easily fixed. not sure yet if there is anything else missing from that firmware branch but at least it communicates with the reprap software without locking up.

mega and pololu

well, i've gotten the pololu boards soldered in and I installed buzz's mega firmware with some modifications. but.... well, every time I try to move one of the steppers it appears to lock up the board. I can get the heaters to work but havent been able to figure what the issue is yet.

There shouldnt be any reason for the board to lock up unless there is some internal conflict.

wait, i have a idea about the endstops causing this lock up. ill write more later

laser sinstering

I have been working on starting up a local hackerspace and have a computer and recycling center that is supporting the project. while i was there the other day we were talking over a dumpster full of old toner cartridges and they were mentioning that disposing of the toner its self was a problem. Then as Im looking another thought came to me, the toner is essentially powdered plastic, so why wouldn't it work as a laser sinstered powder printer.
Then today arrives in my mailbox another instructible and in it was how to make a low power laser cutter. Im thinking mix the two idea's together and you have a laser sintered powder printer.

I will post more as the project develops.

extruder issues

well, after getting the firmware installed and getting the configuration functioning ive been working on the extruder. I keep having problems getting all of my set ups functioning. All of the bowden systems ive set up have so far failed. not sure why yet but the amount of pressure required keeps pushing the bowden cable out of the connections. Some of the problem may be with the peek insulators developing to much friction on the filiment. I have tried it with pla and abs, when i use the pla it starts puddling at the top of the insulator and the filiment begins deforming from the heat. Abs just seems to jam. Eventualy i will figure out the issue but right now i just want functionality.
I have tried using one of the last of my ptfe insulators directly coupled to my original mendel extruder. Unfortunately i havent been able to fix it into the extruder mount solidly. I tried using screws but those ripped the plastic, and ive tried epoxy but that didnt develop a effective bond.

I am still working on solutions

reprap firmware and direct to stepper

Well, after seeing some of the comments to my last post I decided to try the reprap firmware again and connect the stepper driver directly to the mb using the sda/scl pins directly. The firmware appears to have uploaded to both boards so My hopes are up right now.

Another new thought came to me last night as i was working on it. I happend to look over at one of my old extruder heater expiriments that got me thinking along another line. I had tried using a stainless insulator and was using a Nordson glue gun tip in it .016 in oriface. As i looked at it all of a sudden the thought of a water jet cutting tip flashed in my head so today i threw together a pressure washer coupler, a bolt with a 1/8" hole drilled through the center and one of these tips. I was of course hoping to get enough pressure to potentialy cut through something with it but my first tries have not been promising though i have to admit we have the pressure turned way down right now due to several people cutting themselves using just regular nozzels (i think its between 900-1200psi right now) and since they are using it for production cleaning i dont have a oportunity to turn it up and see what it might do.
I also was looking at some info online and it appears the lowest pressure a commercial waterjet cutter runs at is about 20,000psi which is way higher than I want to try rigging together right now. Im hoping that i might be able to cut thin aluminum sheeting at as little as 3000# since ive seen hydraulic lines pop holes in themselves and cut through peices of sheetmetal before.

I will keep posting any info I come up with.