Erik's Blog: Discussing IT, personal fabrication and a new and better world

After receiving all those bits (from bytes) I had to postpone my build further because of an exam. That's done now. I can finally start RepRapping!!!

To document my build, it would be nice to have images and even nicer to have moving images. And nicest to have time-lapse! I bought a Logitec QC Pro 9000. Very decent cam, works out of the box on Ubuntu. I made this tiny script to make a time lapse of my build:

#!/bin/bash
FILENAME=`date +%F-%T`.mjpeg
gst-launch v4l2src ! videorate ! \
  video/x-raw-yuv,width=960,height=720,framerate=\(fraction\)1/5 ! \
  ffmpegcolorspace ! jpegenc ! multipartmux ! filesink location=$FILENAME
mplayer $FILENAME -fps 10

The one-liner for the actual time-lapse is adapted from: http://wiki.laptop.org/go/GStreamer

or

download view at blip.tv

When I started cutting the rods with a hacksaw, it was almost instantly ruined. The steel of the rods was harder than the cutting blade. I resorted to using a DREMELtool with a cutting disc which worked better for the following reason (besides not being ruined after 10 seconds):

1. Won't cost you much effort compared to using a hacksaw
2. The disc seems to last pretty long, From 10 cuts it's 1 mm smaller in diameter
3. It looks cooler
4. You can use it to smooth sharp edges after a cut

The down-side is that you have to be very careful not to: get molten metal powder sparks in your eyes and become blind for the rest of your life, burn your fingers on the rods that become very hot (use a wet towel, apply evaporative cooling), be careful that the disc doesn't break and parts fly into your body or other important stuff such as girlfriend, computer, the RepRap sub-assembly you just had finished, etc.

Tapping the grub screw holes

Click To Play

This is how I prepared the grub screw holes. I put a M5x30 Cap screw into the drill and carefully drill it in. This way you will tap a thread into the holes.

With a bigger drill it is easier to keep it straight than with a small (short) Allen key. The drill is not to save time per se, it will allow you to turn it a couple of rotations while keeping it steady. If you feel more resistance, you're tapping to much thread at once, and you need to go back and forth a couple of times before you go deeper. A little grease might help make the screw go a little more smooth.

You have to be very careful that your part will not start to rotate because you could hurt yourself. Because of the friction, the screw may become pretty hot, so allow it to cool often and be careful not to burn yourself! Also the drill will break the part if you insert the screw to deep and it hits something (or at least ruin the just tapped thread). Always keep in mind that if you're using a power tool for a precision job you have to be extra careful or not do it at all.

More time-lapse video's will follow...

The bits finally arived! Too bad I have an exam tomorrow. This kind of suspense is probably lethal. Anyway, here are some pictures and a small review.

I'm really satisfied with the quality of the plastic parts. They are not
moulds like I've never seen them before, but I really think they will do
the job for you.
Things (such as stepper to RP parts and RP to RP) fit quite neatly together.

I'm also really glad the machined parts for the extruder. The kit seems quite complete. I'd really be
lost if I still had to make those myself without a lathe and it would
take forever to find the right parts. Finding screws and bolts is pretty
easy, but those brass things are more of a specialty product for plumbing.

About the steppers: Only when got them in my hands, I completely
understood why these steppers are the more expensive parts. They are
really heavy steppers, nothing compared to what I've scavenged from
printers over the years.

The total weight of all RP parts was about 1.5 kg. This means that if the density of HDPE is similar to this, I would be able to print one set from the 2.35 kg of fillament I have now. Because shipping is a large part of the costs of the fillament (25 dollars becomes 70+ dollars including shipping + import taxes), I'm really hoping for a functional granulate extruder. I'll even help with that, but first things first:

I'm going to start building wednesday!

A while ago, while I was waiting for the BitsFromBytes stuff, I had to do something. So I decided to tidy the things I already had made. This is the result of the PIC based electronics. All wires are now arranged pretty neatly and there's a fan on top blowing along the X-, Y- and Z axis boards, and then the two extruder boards. Since the NEMA steppers had such a low resistance they would draw some amps, so I wanted to be prepared when they arrived!

I have all boards together since I didn't want the TTL communication lines (TX and RX) to become very long and I prefer to have these things all in one place. Also, the boards on the X carriage (on top of the extruder) seemed to me extra weight (compared to just cables going there). I think I'll use (helixoid) phone cords to wire the X and Y axes. This can stretch a lot and contains 6 leads (1 stepper and something else). I hope it can handle the current, but I'll just see if it heats up with full load. Otherwise I'll use loudspeaker wire, I think.

This is from a survey among industry leaders in Rapid Manufactoring:

"Krailling near Munich, January 28th, 2008: Mass production in the Western world is on the brink of a silent revolution and e-Manufacturing is an important part of that change. These are some of the conclusions of a survey conducted by EOS at recent trade shows in Germany. EOS, the world-leading manufacturer of laser-sintering systems, interviewed industry experts at the K 2007 show in Duesseldorf and Euromold 2007 in Frankfurt."

Source: RM-Platform

I doubt that many in the industry knows about the RepRap project yet. I'd say that 20% is still pretty strong support, and that's for a 20 years time window. On the longer term I can only imagine (end user) personal fabrication having a higher market penetration/saturation.