Sinclair ZX80 / ZX81 / Z88 Forums

Hi Mike, first of all great work that you've been doing on this! reading through this thread has been the most informative read I've found on this printer online.
I have a couple of zx printers in over all good shape but both have broken belts (although the stylus and belt parts are all there)and have been trying to find a way to get them up and running again for quite a while without much luck and then I stumbled onto this tread and see that I am not alone with this issue. I don't have access to a 3D printer to print these myself but are you selling these already or is it possible to buy from you? If not I could try and find someone with a decent enough 3D printer in Iceland to print these for me if you could give me the password to the zip files

best regards,
Vopni

Hey Vopni. Thanks for the complements. Yes, a lot of time and effort have gone into this project and none of it could have been possible without the help and information from a lot of great folks on the forum. Standing on the shoulders of giants, as it were.

I don't have them for sale yet due to a couple of stumbling blocks that I am working to resolve but hope to have out of the way soon. The design itself is solid. Francois in Canada has printed one with the built-in post and the printer output was excellent.

As far as printing the belts goes, it's easier said than done as everything has to be just right. Temperatures, nozzle size, speeds, filament brand all play a part to get it to come out just right.

If within a couple more weeks I can't get my testing done to my satisfaction I will release the files so that those who have or have access to a 3D printer can try their hand at making their own. For those who don't I will offer them as a do-it-yourself item at a low price plus shipping.

Will keep you posted.

Mike

Hi Mike,

great progress so far!

Do You know this?

http://www.mutant-caterpillar.co.uk/sho ... ts_id=4665

Is it based on the same design?

Cheers

Mathias

Yes, the printer I recently purchased came from there. Some evil unseen force coerced me into opening it up to have a look-see at the belt Ian is using. This, of course, voided the warranty, but all in the name of science, right?

Dimensionally they are for all practical purposes identical. I don't know from where his design originated, but mine came solely from the information gleaned from all the fine lads on this forum.

Mike

I recently discovered (and ordered a spool) of this semi flex filament...might be good for this?

Fiberlogy fiberflex 40D. Video review of it here.

https://youtu.be/7wMKp6q9ktE?t=353

Can be bought in USA from wolfworks3D, there is also a 30D (softer) type too.

The fiberflex showed up, would not print reliably on my Anycubic I3 Mega, didn't like going through the bowden tube...too flexible for it think. I managed to get 1/2 a print out of it before it crapped out.

So tried it on my $100 cheapo Chinese reprap printer...that prints ok after a few tweaks. As with most 3D printing the bed leveling is critical..moreso with this belt. The results were nice and flexible but not too much stretch when they did print successfully. Printed 4 belts before trying them (I have 3 printers)...too tight though on the test printer I tried, wouldn't rotate. I increased the print size to 102%, now it rotated ok with the cover off but not when it was on. (Using Mike's design btw)

That's where I'm at...going to break out the other 2 printers I have (though I think one has a screwed ULA) and try on those to see if it's a motor problem in the one i was testing with, if I get the same result I'll try to resize again, maybe 101.5%.

Currently printing at following specs

nozzle 0.4 @ 235C (fiberflex says 210 to 220 but wouldn't feed reliably at these temps)
bed @ 75c
Speed at 15mm
resolution .1

Some success tonight.

Printed belt at 101%. Painstakingly put the styli on (trimming the posts, putting the styli on and then using a short piece of wire insulator and melting it on top). Tried it on another printer, a better condition one..and success.

Not run it a whole lot yet though, I guess it needs a good burn in to ensure it's working "permanently"

Looking good

Mark

Anyone see a problem with me running the printer without paper for an extended amount of time?

Obviously with the paper being a premium I don't want to use up one of my few rolls on belt testing...presumably as long as the belt keeps rotating and the styli stay in place/attached to it, then the actual printing part is not really relevant to the testing of the belt yes?

So, any issues with overheating? If I write a little program to say run the printer for 3 to 5 mins at at time without paper...give it a few mins rest and then repeat a few times then add the paper and run a print to ensure it still prints ok...that's a reasonable belt testing proceedure?

Maybe you can buy a fax roll, and cut it for 10 cm, and use that, so there's paper between styli and printer roll.