Monday, December 29, 2008

Extruder assembled and running s-l-o-w-l-y.

I've succeeded in assembling the BfB extruder and gave it a test run. It is able to heat the HDPE and can extrude the material but at a rate of only about 4mm/min.
I don't know what the appropriate rate is so if anyone can tell me I'd be grateful. The test bed consisted of a 12V 2A supply for the heater and a 6V supply for the G3 feed motor while using a VOM to monitor the resistance on the thermistor. After successfully extruding a small amount of HDPE I gave the machine a rest and tried it again later. I discovered that the thermistor fried out after only a few hours of use, I'm attributing this to unknowingly placing the thermistor too close to the heating wire.
I took a spare thermistor and wrapped it to the outside tube with PTFE and resumed my tests this seems to be acceptable, so far. I'm considering either increasing the diameter of the extrude hole or determining if the feed path has too much resistance.

I'm also at the stage that I think reconfiguring the circuit boards would be beneficial.

Thursday, December 4, 2008

At last it arrives!

The extrude head that I bought in October from has finally arrived. It's like Christmas in December, wait a minute... never mind.

Anyhow, it's a very complete package. It would be even better with detailed printed instructions but it's not too hard to figure out from the assembly pdf on their web site.
My advice is don't try to go cheap on the delivery like I did. Six weeks of anticipation is a little much. Pay the bucks to have it mailed with some sort of tracking.

The parts arrived like this.

These are the parts spread out.

I hope to start on the heating element this weekend and post photos of the progress.

Tuesday, November 25, 2008

The First Blog I've Ever Posted In My Life!

I've been working on a repstrap machine ever since the first reprap blogs appeared and now feel that I've gotten enough momentum to actually blog about it myself.

My progress has been slow due to the dual difficulty of funds and materials, regardless I've managed to get McWire to at least do the initial motions and IF my BitsFromBytes extrude head ever arrives and IF I can get a decent download of 0.7ReprapDVD (bitTorrent has never worked for me) I could be reprapping till GM is profitable again.

Here are some views of what I've done so far.
This is a good view of the Cartesian Bot so far. This is shown without the electronics. Unlike the Darwin machine this machine moves the XY platform and lifts the Z for printing, much like a CNC milling machine.

This is the front of the McWire made using parts from Home Depot and misc. hardware stores. I've also built and added the boards from Reprap Research Foundation, Thanks Zach!