Gina

Meanwhile, I can do some calculations. Thread pitch 1mm so 1mm per revolution of the rods. 800 revs for full Z travel (if I stick with 800mm build height - could probably go a bit more). Z steps/mm will depend on timing pulley ratio on the drive from the motor. With 1:1 that would be 200steps/mm or 3200 microsteps/mm.

Plenty to get on with though ooznest order of wider X rail and all those metal wheels due to arrive today There's also the timing pulleys and bearings for the rods to see about. Also, the proper power supplies and a few other things to attach to the frame.

Now for the wait!!! Twiddles thumbs"

Ordered!

If I buy 1m x 4 off and 500mm x 3 off (for my Titan printer), the total is £78.98 including a 5% discount for 2+ items. With 3D printers and the things I make with them (eg. clocks and astro) being my No.1 interest, this is not out of the way

Quickest delivery is for the 1m ones and they also fulfill my desires for the printer. Using three instead of four saves £16 plus cost of other bits but leaves doubt about efficacy. No, I think this ultimate printer needs the ultimate effort to get as near perfect results as humanly possible. The funds for this project are coming out of the return I got from selling astro stuff so I'm just funding one project from another effectively. I'm not sure where all this is going to end but I've already spent many hundreds on this printer though nothing like my astro projects!

Yes - found 1m ones but at over twice the price of 800mm ones. Much shorter delivery though. Estimated between Thu. 26 Apr. and Fri. 27 Apr. 4 off for £64.44. If I could strengthen the XY carriage I could get away with three of them but wonder if I could strengthen it enough... EDIT - Latest delivery estimate is Tuesday 24th April.

Found 800mm ones that would be adequate for my Giant printer though I was hoping for maybe 1m. Estimated between Wed. 2 May. and Mon. 21 May. Cost £30.72 plus £1 postage or for £20 extra I cab save a few weeks delivery time. About £52 for expedited delivery. Estimated between Wed. 25 Apr. and Wed. 2 May.

Thanks Dave Hmm... Slow boat from China and not really long enough for my Giant printer. Would do for my Titan printer though, just. Nice and cheap

@tekkydave I've found the part of your D-Bot thread referring to the single-start 8mm rod but no link to where to get them.

Yes, single-start screws are what I want Dave. Been looking through your D-Bot thread as I thought you mentioned it there but not found it as yet. Can you please post a link to your source of single-start rods? I'm planning to use 4 as my XY frame isn't very rigid at the corners.

For faster printing this printer needs some "beefing up". Changing from cord to timing belts and pulleys, larger wheels made of steel, double width X rail and all printed parts more bulky and made of PETG. I shall also probably change to trapeziodal screw rods for the Z drive for greater accuracy. Here are screenshots of the X and Y carriage models in SketchUp. I have yet to add the belt clamps to the X carriage.

Latest print after plenty of tweaking and trial runs. 150mm diameter and 30mm high. PLA.

X carriage redesigned to arrange for putting the extruder on. Here are some photos of the assembly. Parts just placed roughly in position and not yet screwed together.

I believe it to be the Bowden tube (or end fittings) that are causing the problem and have decided to change to direct feed. Also when I tried PLA it produced too much drag in the tube and wouldn't extrude.

I suppose there must have been the odd piece of astro kit I regretted buying but I can't think of any. I have been well pleased with practically everything I have bought. What I'm not pleased about is the number of times I can use the kit!!

Made a new start yesterday and made much better progress. First layer is now alright but other layers, particularly the wall need more tweaking. Also made a new, stronger Y carriage for one that had broken and raised the bed to relieve tension on Bowden tube.

With a cold bed I have removed the print with a little difficulty. The first layer is alright but second layer is worse so it seems the second layer height needs reducing. Bed adhesion of the first layer is more than adequate and the speed can be increased - currently 25% of the 40mm/s of the main peripherals. Think I'll try 33% and leave the main speed alone. That speeds up the first layer but the only change for the second layer will be layer height. ie. changing just one parameter at a time per layer.

New test run. Hotend took just over a minute to get from room temperature to 280°C and the bed 4m to 120°C. Better but still leaves a lot to be desired.

Filament was still stuck to the bed when cold but was quite easily pulled off. Next test run will be at twice the speed with 40mm/s the fastest and higher extrusion temperature for second layer onwards. With PETG I have the first layer height at 2mm so the extrusion rate is high but the nozzle heating is coping well but this also means that the ratio of speeds between first layer and the rest wants to be greater. Other layers are now set at 1.8mm with the 2mm nozzle, previously 1.5mm, though I might be going the wrong way

PETG sticks very well to the aluminium bed. The first layer is not a problem - at least not at this low speed. Second layer is still troublesome.

I have the print bed just perched on pieces of wood across the frame ATM but it will have to be fixed properly because the rough laid filament is catching the nozzle has pushed the bed to one side. Higher temperatures might help and I'll try that tomorrow. The bed should be heavy enough to stay put by its own weight at 4Kg but I was intending to fix it anyway. The XY frame and fixed bed system seems fine otherwise. So far I haven't needed to increase the motor power from the default 800mA except for the extruder which I increased to 1.5A to get enough power to drive the extrusion. Of course, I'm only running at very low speed currently.

The PETG is printing and much better than ABS. I think it needs higher temperatures though. I'll see how this test print goes. I shall want to increase speed as ATM it would be quicker to print with a O.6mm nozzle and Volcano on my Titan printer. We may need a longer heater block and nozzle but I have still to tweak settings - it's early days yet. I don't think I'll use ABS in the Giant printer until I have it boxed in and fume extraction. Little prints on the Mini printer are one thing but this is "a whole different ball game". The Titan has fume extraction and still will have when rebuilt. If I want to use ABS in the Giant it will have to be in a different room and/or boxed in with fume extraction.

I managed to clear the hotend just by heating. Disconnected the Bowden tube and extracted some filament so that I could cut it just above the heatsink. Then heated the hotend to 210°C and was able to push the filament out with a thin Allen key. Then replaced the filament with PETG and extruded a bit. Have now set up parameters for PETG for the Giant printer and about to try a print.

I wonder why PLA seems to have this problem but other types of filament don't.