Improvements/Thoughts

I have been printing a while with the Ormerod and had some ideas/issues which I think can be resolved easily:

1. X carriage Slippage on the LMU12 bearings: After about 10 prints or so, I noticed that my prints were coming mis-aligned. After close inspection, I found that the X-carriage had slipped on the LMU12 bearings. In the Mendel design there were 3 such bearings (and the fit was tighter) - so did not have this issue. I fixed my loose carriage using some paper - but I think if the X-carriage can be made a tighter fit - and with an edge barrier (to prevent slipping in 1 direction), it might make it better.

2. Air ducts on the nozzle head for cooling - A great idea to direct air from the cooling fan through the 3 air-ducts on to the filament - But the downside is that since the air-ducts and the nozzle cover are so low, they graze over the bed surface (even when the nozzle angle adjust screw on the X-rib is fully tightened) If the filament does not stick on the surface bed tightly, the nozzle cover can drag the print and spoil the entire job. Wonder if the nozzle ducts could not be raised slightly so that the entire cover is at a higher height than the nozzle and brass nut. (Of course the angle of the nozzle ducts will have to be changed as well so that air is directed to the freshly spewed out filament.

3. Remove the filament stand from the Duet board cover - A good idea to have a filament spool stand integrated with the Ormerod - but I noticed that when the spool turns, it causes some vibrations/jerks - wonder if that would affect the print. I had printed out a simple spool stand and so use that rather than mount the spool on the Ormerod.

Would appreciate comments/suggestions on my ideas from the forum..

Thanks
Sumant

Edited 1 time(s). Last edit at 02/09/2014 02:24PM by 7sumantb.

Hi Sumant,

1) My X cariage slipped on the bearings too, when I reprinted it I left a small skirt/brim that sits in the distal groove of the bearing (I don't use the IR sensor so also clipped this off - if you use a full size carriage there may be steric effects for homing X)
2) I sawed the bottom of my fan block off, and taped over the bottom so that there's no downwards irflow (I made a hole at the top of the enclosure so the fan still moves air), it's now around a centimetre higher than t was was, and I don't see any ill-effects (I van still bridge 2c,m or so with ABS or PLA)
3 I built a stand out of standard UK plumbing parts, that suit the 1KG reels I use, and have this mounted 2 metres away from the ormerod to allow easy unspooling - it was pointed out recently that the rear-mounted 300g spool mount on the Ormerod is intended to be used along with a PTFE sleeve (provided in the kit but not mentioned in the instructions) that prevents jerking (you feed the filament through the tube once you've placed the tube in the groove behind the X axis motor)

Cheers

Ray

Thanks for your thoughts. Some comments:

1. I have a modification described in another thread that mounts the IT sensor on the print head, so that the sensor is much less sensitive to head sag (which can vary for a number of reasons). This leave room for a cable tie around the x-carriage and bearing where the sensor was. This could be coupled with an edge barrier at the other end, if necessary.

2. It sounds to me that your print head is sagging. Lots of us had this problem, the slot that the x-runner screw fits in isn't long enough. I had to file mine out (and fettle out the nut trap as well), AND replace the 9mm bearing by a 10mm one to eliminate head sag. I reprinted the x-carriage, and I had to do exactly the same with the reprint. I really think RRP got the dimensions wrong here - maybe they were using 6mm acrylic originally. RRP announced a week or two ago that they had modified the x-carriage design to include a longer slot and nut trap, but they don't seem to have committed the STL to the master branch in the repository yet. Someone (I forget who) has also done a modified x-carriage with a longer slot.

Another cause of print head sag is that the original nozzle mount doesn't hold the screw heads well. I am using Matt's nozzle mount design, which uses holes instead of slots.

You can also sand down the end of the fan duct by at 1mm or so.

3. I agree, in any case the filament stand supplied can't support a standard 1kg roll of filament.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].