TOPIC:

Leveling the bed was a nightmare, and I ended up doing a half-good job. I suspect I will have trouble if I print larger items where the bed leveling is more crucial.
I also have problems with the PLA not sticking good enough to the bed. It looks like heating the bed to 65 deg.C for the first few layers, and then reduce to 60 deg.C for the rest of the process helps a bit.

Last evening I did my first try on the CRP bracket TommieG sent me, and that was not a success. But, with some more fiddling with the settings I think it should be possible.

yogi-bear wrote:

thats awesome, it looks like yours is printing nice and consistently. Once I'd done my test print, I ended up having heaps of trouble printing, mainly to do with levelling the print bed and getting the print to stick. I've since worked out what to do, but I still have the odd issue. So I am in the process of upgrading parts to make this better and easier.

larbut wrote:

Leveling the bed was a nightmare, and I ended up doing a half-good job. I suspect I will have trouble if I print larger items where the bed leveling is more crucial.

yeah, once I got good at levelling most of my prints were successful. I was even able to do a 16 hours print of a 1/24th scale Volvo body. One of the downsides I learnt (well certainly for the CTC printer I have) is that the frame that holds the bed is quite flimsy and easy to bump. So this is an upgrade priority for me, and I will machine some 2mm thick aluminium brackets.

larbut wrote:

I also have problems with the PLA not sticking good enough to the bed. It looks like heating the bed to 65 deg.C for the first few layers, and then reduce to 60 deg.C for the rest of the process helps a bit.

I would suspect once you get better at levelling, a lot of the sticking problems should go away. The other thing to try is adding some rafting to your prints. This is a quick layer before the main print. Thats help me in many cases, mainly larger prints though. I've also been running my heat bed at 110C for PLA, which is probably too high, but doesn't seem to have caused me issues. Before I did this though, I added clear sides to my machine to make the print volume more thermally stable.

My print bed is currently just the aluminium heat plate and painters masking tape. I will eventually upgrade to glass and glue. Matman on Tamiyaclub who has the same printer as I, did this upgrade as he was having lots of problems with prints sticking and found this to be very worthwhile.

larbut wrote:

Last evening I did my first try on the CRP bracket TommieG sent me, and that was not a success. But, with some more fiddling with the settings I think it should be possible.

yeah, I don't know if its good or bad, but there are lots of things you can adjust!

Just having a quick nose...
I built a Prusa I3 ripoff about a year ago. It's okay, but there was a lot of faffing about to find the best settings etc to get usable prints off it. I'm using the Cura slicer & using 3d AutoCAD to generate the models. Bed size is 200x200x180mm. Like the internet, it sucks up hours/days/weeks of your life before you realise it!
Some tips:
1) get the machine rigidly mounted on a hefty baseboard (Solves loads of problems)
2) Set the nozzle-to-bed gap at 0.05mm with a feeler gauge, with everything at working temperature.
3) Glass bed & raft works well for PLA, use double-sided tape for better adhesion. The less heat (Bed & nozzle) the better - more heat causes curling during cooling & the print will peel itself off the bed. If you can enclose the machine it will help by keeping the air surrounding the print a similar temperature to the print & reduce the problems with the print distorting & unsticking due to it cooling & shrinking.
4) Minimise "Solid" parts, try to do hollow bits with thin walls & adjust the density of the "Fill" to around 20% (If your slicer will allow it) - again, this will combat warping & unsticking

Looks like your machine is giving some nice smooth results though. What nozzle size & layer thicknesses are you working with?

Hi eddrick, good to see you drop by !

I have already realised that the 3D printer will steal time as both Tamiya and Internet do...

I've concluded, as you that I need to bolt down the construction to something sturdy, for many reasons. The most practical reason is it's hard to mode around, as the electronics are currently floating around inside the bottom structure.

Also, as mentioned in a previous post I have to level the bed better and re-calibrate the nozzle to bed gap again. I suspect I'm way too high as it is now, hence the lifting problems.

I'm happy with the results from testing so far. I've watched quite a few videos online of people having worse results than me, so that must be e good thing.

I'm using 0,4 mm nozzle size and the tests seen here has layer height of 0,2 mm.

I do have a nose on occasion, but time is always against me nowadays.
This time was because I suddenly found myself interested in that there Land Freeder - it looks like a good package for the money & I'm sorely tempted to buy one just so I can build something new & shiny!

The prints are really good for those settings, or are the pictures better than the print actually is?

I check my bed level for every print, it's the only way to minimise the unsticking problems. I take it you haven't played with ABS yet? That'll make you cry - the heat & speed settings become critical & you need to use some form of sticking agent to keep the print stuck for the duration (I use a watery mix of ABS scraps dissolved in thinners spread on a 90degC glass bed)

No, not even thought of ABS yet, although I have to try it sometime.

I believe the pictures are quite accurate to the print, but the finer details are of course hard to see on a picture.

Do you have any thoughts on glass vs aluminium bed?
I currently have aluminium.

Haven't tried aluminium, my bed is glass with a PCB heater under it.
I can tell you the glass bed needs to be thoroughly clean & degreased for PLA to stick to it though.
I've tried a variety of recommended methods to get PLA to stick, but so far just the plain clean glass works best, & it seems more important to keep the heat to a minimum (Or rather restrict how much & how quickly the print cools relative to the temperature of the molten extrusion).

a thin smear of contact adhesive works really well, but it's messy & needs cleaning off with thinners immediately after you're done printing