HydraRaptor’s Second Child

Chris Palmer of the HydraRaptor project just printed us a copy of parts for RepRap – the 3D printer that can print a copy of itself. Chris is an avid developer on the RepRap team, and the documentation of his work is superb. He has already printed a copy of RepRap for himself, so the Factor e Farm RepRap is HydraRaptor’s second childbirth. Edward Miller is putting our RepRap together – see the RepRap wiki page. With that said, I’m copying Chris’s blog post on this proud moment here:

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 aims 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%

(note: table is cut off. See source for weights and costs of materials)

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 an puzzle for Edward Miller, the guy who is actually going to build this machine.

Similarly the new adjustable z-opto flag assembly: –