ZX Printer Belt

[mhudson52]

Hey Paul, no problem my friend.

If anyone is interested, here is the .STL file without any stylus mounting provision. That will need to be done by hand I'm betting.

[mhudson52]

Last entry for the day. Here is the latest version with integrated stylus posts. Haven't printed yet, but feeling confident. May need to go to the .2mm nozzle.

[mhudson52]

Printing the belt using PLA filament yielded excellent results using the .4mm nozzle. It is quite flexible with the belt being so thin (.5mm), but will need some testing to verify durability.

Tried again with TPU (more flexible) filament with disappointing results. The belt itself turned out nearly as well as the PLA, but really struggled with the stylus posts. Will try the TPU again when smaller nozzles (.2mm) arrive in a few days.

On another note, I have found a way to also reproduce the styli and will be doing some trials also in a few days. After all, what good is a belt without the styli. Maybe this will save some old ZX printers from being binned.

Wish me luck.


Mike

[FrancoisLanciault]

Printing the belt using PLA filament yielded excellent results using the .4mm nozzle. It is quite flexible with the belt being so thin (.5mm), but will need some testing to verify durability.

Tried again with TPU (more flexible) filament with disappointing results. The belt itself turned out nearly as well as the PLA, but really struggled with the stylus posts. Will try the TPU again when smaller nozzles (.2mm) arrive in a few days.

On another note, I have found a way to also reproduce the styli and will be doing some trials also in a few days. After all, what good is a belt without the styli. Maybe this will save some old ZX printers from being binned.

Wish me luck.


Mike

Mike,

A colleague of mine will bring me a 3 feet length of TPU this Monday. So I will be able to print it Monday night with my 0.25mm nozzle. However I have never used TPU nor the 0.25mm nozzle so thing might get messy. I will let you know.

François

[mhudson52]

As long as you don't forget to change nozzle size and temp in your slicer and slow print speed down to 20-30 mms you should do OK. My Ninjaflex specifies 235c for the hot end. Bed temp is not critical, but I usually give my glass bed a squirt or two of cheap hair spray for good measure.

Here is one I did this morning with white PLA.

Let me know how it turns out

[FrancoisLanciault]

As long as you don't forget to change nozzle size and temp in your slicer and slow print speed down to 20-30 mms you should do OK. My Ninjaflex specifies 235c for the hot end. Bed temp is not critical, but I usually give my glass bed a squirt or two of cheap hair spray for good measure.

Here is one I did this morning with white PLA.

Let me know how it turns out

Hi Mike,

I got my meter long TPU filament today. However after reading about nozzle change I chickened out and decided I would wait till I got more time to understand correctly how to do it. I did however print three copy of the belt with my .45mm nozzle, the first one in PLA and the two other with TPU.

The PLA version looks a lot like yours. The two posts where clean and of the correct height. The TPU version looks even better but, like you, the posts got messed up. My own experience about trying to built up tiny posts with a 3D printed showed me that the thicker the layers are the better the result. So I will try again later this week with a layer height of .2mm or more.

That being said, I clean the post with a sharp cutter and I think that what's left should be enough to insert the stylus as they are so thin. The stylus could then be fixed in place by melting the top of the post with a solder iron or anything hot enough.

I will try to send you pictures tomorrow.

François

[mhudson52]

Have you checked the fit of the PLA version on your printer? Hopefully there are no issues there with it being either too loose or too tight. I was wondering if you could do a test "print" without the styli on it to see how it will function during actual use.

My 0.2 nozzles should arrive today and will see if that will help with TPU and the posts.
BTW, what kind/brand of printer do you have, and which slicer are you using?

Will keep you posted.

Mike

[FrancoisLanciault]

Have you checked the fit of the PLA version on your printer? Hopefully there are no issues there with it being either too loose or too tight. I was wondering if you could do a test "print" without the styli on it to see how it will function during actual use.

My 0.2 nozzles should arrive today and will see if that will help with TPU and the posts.
BTW, what kind/brand of printer do you have, and which slicer are you using?

Will keep you posted.

Mike

Yes I will check the fit tonight with both the PLA version and the TPU one.

My printer is a Prusa Mk2 and I am using SLIC3R pre-configured for it.

François

[FrancoisLanciault]

Update:

I put the TPU belt into one of my zx-printer (no stylus).

The fit seems ok, the belt teeth fit perfectly into the sprocket slots. When installed with the top cover open, the belt seems loose, but I remember it was the same with the original belt as the sprockets ends up in their final position only when the top cover is installed.

I hooked up the printer to my zx81 and issued a COPY command. The printer started to run and would not stop. I don't know if its normal or not (when you don't have the stylus), but it is quite possible this printer has other issues beside the belt. I let it run for a few minutes. The printer was noisier than I remember, probably because the lubricant has dried out years ago.

After opening the printer again, the belt was still in one piece. I cannot see any damage.

I believe the weak point will be the stylus posts. But they were not tested as the stylus were not installed.

No time again for pictures tonight, hopefully tomorrow.

François

[mhudson52]

That is great news, especially the fit of the teeth in the sprocket grooves. I couldn't have gotten them that close without the actual pieces you sent.

As for not having the styli attached during your test, I would suspect that the printer doesn't know (or care) whether they are there or not.

With the exception of the mounting posts, TPU would indeed seem to be the filament of choice. We may have a situation where we have to deviate from the original design and use a small pin to attach the stylus. A little experimentation may be in order here.

On your next test, you might try something like a For-Next loop to tell it to "print" a defined number of lines and see if it stops normally.

My printer is currently down so I can perfect the perpendicularity of the X-Y axis, but should be back running in a day or so.

Great work!

Mike