HydraRaptor's second child

Back in March I had a visit from Marcin Jakubowski, the founder of Open Source Ecology. He was over here in Manchester presenting at a conference and asked if he could come and see HydraRaptor, as he wants to use RepRap machines on Factor e Farm. Like RepRap, his project also aims to change the world.

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.