He asked lots of questions and made a couple of videos of my answers for his blog, which you can see here.
I volunteered to print a set of Darwin parts to help get Factor e Farm up and running with 3D printing. I was confident that I would have my Darwin running in time to churn out the parts. However, because I spent a lot of time experimenting with extruder designs in an attempt to get something more reliable, I ran out of time and had to print the parts on HydraRaptor.
Here they are, all 109 of them: -
All the parts were printed with 0.5mm filament at 16mm/s with 32mm/s moves. Most were sliced with Skeinforge set to 25% fill and larger objects have double outlines to maintain strength.
Here are some stats: -
|Build time||Plastic volume||Quantity required||Total build time||Total plastic||Weight||Cost||Percentage of total |
|Corner bracket @ 90%||02:44:44||29.1 cc||8||21:57:49||233.1 cc||291 g||$5.83||29%|
|Diagonal tie bracket-chris ||00:27:00||4.8 cc||20||09:00:06||96.4 cc||120 g||$2.41||12%|
|Bed corner||01:32:06||15.5 cc||4||06:08:25||62.1 cc||78 g||$1.55||8%|
|Z-motor-bracket-chris||01:23:12||14.6 cc||4||05:32:47||58.2 cc||73 g||$1.46||7%|
|X motor bracket||03:56:35||37.2 cc||1||03:56:35||37.2 cc||46 g||$0.93||5%|
|X-carriage ||03:51:39||40.2 cc||1||03:51:39||40.2 cc||50 g||$1.00||5%|
|Y housing||00:56:36||9.9 cc||3||02:49:47||29.8 cc||37 g||$0.74||4%|
|Extruder drive block||02:30:44||26.5 cc||1||02:30:44||26.5 cc||33 g||$0.66||3%|
|X idler bracket||02:28:06||25.4 cc||1||02:28:06||25.4 cc||32 g||$0.64||3%|
|Y motor bracket||01:51:06||19.6 cc||1||01:51:06||19.6 cc||25 g||$0.49||2%|
|Bed constraint||00:43:20||7.5 cc||2||01:26:39||15.1 cc||19 g||$0.38||2%|
|Bed clamp||00:21:39||3.7 cc||4||01:26:36||14.7 cc||18 g||$0.37||2%|
|Extruder base||01:13:19||13.1 cc||1||01:13:19||13.1 cc||16 g||$0.33||2%|
|Z-coupler-airpax||00:14:21||2.6 cc||4||00:57:26||10.2 cc||13 g||$0.26||1%|
|Opto bracket @ 50%||00:19:00||3.1 cc||3||00:56:59||9.4 cc||12 g||$0.23||1%|
|X-belt-clamp||00:10:46||1.9 cc||5||00:53:50||9.5 cc||12 g||$0.24||1%|
|Wiper-diagonal-bracket||00:43:50||7.6 cc||1||00:43:50||7.6 cc||9 g||$0.19||1%|
|Wiper-brace||00:13:24||2.3 cc||3||00:40:11||6.9 cc||9 g||$0.17||1%|
|X-constraint-bracket||00:38:10||6.6 cc||1||00:38:10||6.6 cc||8 g||$0.17||1%|
|Pulley||00:12:35||2.2 cc||3||00:37:44||6.7 cc||8 g||$0.17||1%|
|Bolt plug||00:04:36||0.8 cc||7||00:32:11||5.8 cc||7 g||$0.14||1%|
|Tall foot||00:14:27||2.6 cc||2||00:28:54||5.3 cc||7 g||$0.13||1%|
|Y motor coupling||00:25:02||4.5 cc||1||00:25:02||4.5 cc||6 g||$0.11||1%|
|Z-adjuster-housing||00:24:12||4.1 cc||1||00:24:12||4.1 cc||5 g||$0.10||1%|
|Short foot||00:11:21||2.1 cc||2||00:22:42||4.2 cc||5 g||$0.10||1%|
|Fan base||00:22:29||4.0 cc||1||00:22:29||4.0 cc||5 g||$0.10||1%|
|Y belt clamp||00:03:43||0.7 cc||4||00:14:50||2.6 cc||3 g||$0.07||0%|
|Fan-leg||00:15:48||2.8 cc||1||00:15:48||2.8 cc||4 g||$0.07||0%|
|X-motor washer||00:15:27||2.8 cc||1||00:15:27||2.8 cc||3 g||$0.07||0%|
|Z-flag-slider||00:13:00||2.3 cc||1||00:13:00||2.3 cc||3 g||$0.06||0%|
|Bearing 360 run||00:02:47||0.5 cc||4||00:11:09||2.0 cc||3 g||$0.05||0%||HDPE|
|Extruder PCB holder||00:09:45||1.7 cc||1||00:09:45||1.7 cc||2 g||$0.04||0%|
|Z-opto-flag||00:08:45||1.6 cc||1||00:08:45||1.6 cc||2 g||$0.04||0%||Black ABS|
|X-carriage-bearing||00:08:39||1.1 cc||1||00:08:39||1.1 cc||1 g||$0.03||0%||HDPE|
|Y-opto-flag||00:07:43||1.4 cc||1||00:07:43||1.4 cc||2 g||$0.03||0%||Black ABS|
|Bearing 360 jam||00:02:49||0.5 cc||2||00:05:38||1.0 cc||1 g||$0.03||0%||Black ABS|
|X-opto-flag||00:04:43||0.8 cc||1||00:04:43||0.8 cc||1 g||$0.02||0%||Black ABS|
|Wiper-lever||00:04:26||0.7 cc||1||00:04:26||0.7 cc||1 g||$0.02||0%|
|Z-flag-clamp||00:03:20||0.6 cc||1||00:03:20||0.6 cc||1 g||$0.01||0%|
|Circlip||00:01:26||0.3 cc||2||00:02:53||0.5 cc||1 g||$0.01||0%|
|Bearing 180-x||00:02:38||0.5 cc||1||00:02:38||0.5 cc||1 g||$0.01||0%||HDPE|
|Bearing 180-z||00:02:03||0.4 cc||1||00:02:03||0.4 cc||0 g||$0.01||0%||ABS|
|109||74:28:04||778 cc ||973 g ||$19.47||100.00%|
The times and weights are calculated, and don't include the raft time, which is significant, or the time waiting for temperature changes and raft cooling. I weighed the parts on kitchen scales and they came out at 931g, so pretty close to the calculation. The cost shown is on the basis of ABS at $20 / Kg.
I save all the rafts for the day when we get recycling working. I weighed them in at ~ 200g, that is about 20% wastage and will bring the actual printing time up to about 100 hours.
I also wasted 150g in failed prints, for silly reasons, more on that later. It gives a measure of the reliability I am achieving at the moment, i.e. 8 parts failed out of 117 prints so 93% success rate. Of course the bigger the part is, the more chance something will go wrong, so by weight and time it is much worse .
I used plain ABS for most of the parts because it seems to bond better than coloured. I used black for the opto tabs. No guarantee that they will be opaque to IR, but I think black ABS usually is. The green parts are just ones I had left over from experiments.
I made some of the bearings in HDPE as that should be a better bearing material than ABS, lower friction and longer lasting. The black ones are "jam" bearings so I left them in ABS as they want maximum friction.
Some of the parts are my own design. Most significant are the z-axis parts described in the previous post. Here is a list of the other design tweaks, with links to the article describing them:- simplified diagonal tie brackets, X-motor washer, x-carriage bearing and the feet.
Some parts I had never printed before. The Pinch wheel extruder: -
The nozzle wiper assembly has appeared in the latest Darwin release but I can't find any assembly instructions. I leave it as a puzzle for Edward Miller, the guy who is actually going to build this machine.
Similarly the new adjustable z-opto flag assembly: -
I aimed to print these parts over the course of a week, three batches a day, but the machine had other plans and it actually took me two weeks. I will give more details tomorrow.