Almost done

So I am all but done bringing the Z402 back to life, only minor issues now. To recap this is what I have had to do so far:

1. Found mispositioned ribbon cable that prevented the internal PC from booting.
4. Removed printer assembly to clean "car wash" then removed gantry to thoroughly clean.
3. Cleared blockage to input of binder filter.
4. Replaced o-rings on priming pump so it works.
5. Found damage to print head ribbon cable and repaired
6. Slow axis then failed, found problem with control relays, temporarily bi-passed.
7. Repaired binder low-level sensor, this was just a broken wire and an annoying constant error message :).
8. Replaced roller scraper, I used a piece of polypropylene from a plastic folder copying the old scraper and using a soldering iron to make neat holes (scrape off the kerf with knife).
9. Generally cleaned the heck out of it.

Yet to do:

1. Replace the relays on the interface board
2. Make or obtain binder
3. Make new gantry "curtains"
4. Work out why the laptop doesn't work.
5. Possibly replace some binder hoses.
6. Light bulb
7. Replace missing fixings

My god, it actually works!

There, I fixed it

So after some intermittent powder spreading, the slow axis (the gantry) stopped working all together. I spent the day trying to draw out the circuit for the servo stage which includes an h-bridge chip and some relays. The relays are used to interlock the axis so it cannot move when the lid is open and also to apply a brake by shorting the motor terminals. I felt sure it would be the relays but after a lot of playing still did not know how to prove it for sure, they get power but did they switch, and did I dare apply my own power to test the switching? So I decided to bi-pass, don't try this at home kids:

I have tacked the wires on to the output pins of the h-bridge and pushed them into the red connector at the bottom, I even got the polarity right (by accident). And .....

It works!!  So I will order replacement relays and sort out some binder, the original Zcorp binder is crazy expensive so I will make my own. I also have 6 BC-20 ink cartridges on there way to me so I am covered there too.

"binder"

The part printed!! Well sort of.

I waited a while and proceeded with removal which involves a vacuum cleaner and a lot of care. Ooops, there goes part of the model, hang on a minute..... It looks like the bottle of binder actually just contains water! I can see that the parts printed OK but they have zero structural integrity!!

Then I came to re-spread the powder and the old issue of intermittent spreading reared its head. Not sure what it causing this, it never happens during the build and it can happen even when the feed bin is lowered and no powder is being pushed. I have added grease to the linear bearings too. Hard to diagnose the issue and no useful error messages. Perhaps the roller mech is having problems and the gantry stops because of that or perhaps there is just too much friction in the gantry but that makes no sense as it always works fine when printing. Mysterious!

I really wish I had finished my homebrew Zcorp printer, it would probably be less hassle than this ;)

The model consisted of some chain, this is part of one of the links that did not shatter, on the left impregnated with cyno on the right as it came out on the machine.

Here we go...

I know this is a blog not twitter but I am currently watching the Zcorp print and I think it will finish. There was definitely a problem with my laptop or the usb to serial converter, possibly because I had to force it to be COM1. Now using an old Dell and all seems well.

Now, I suppose I should read the manual because I am not sure what I do next :)

Every cloud

It looked like both of the projects I have on the go at the moment had stalled, the Zcorp because of a lack of an ink cartridge and the laser scanner because of a lack of component availability. So I settled to have a weekend doing all of the things I should have been doing this past week. I emptied a ton of rubbish from my car, emptied the bins and even started to look at the washing up. While considering which box I could use to tidy up all the Zcorp bits into I noticed a small cardboard box, could it be, no don't get your hopes up, YES another cartridge, an original zcorp spare even! . . .

OK I got a little excited taking off the protective cap!

Success! Well another good step, this is printed in binder and it seems to have worked. I have a few powder spreading issues, I definitely need to replace the scraper on top of the roller/spreader but it's better, definitely better. But then .....

Nooooo! This has happened a few times, might be the PC end not the machine, will try again and then with another PC.

Better than nothing

The results of replacing the repaired ribbon cable are promising. Perhaps I killed the cartridge running it with the broken cable and so only some jets are firing? I will try again with the proper cart and binder.

This is a layer from the middle of a demo object consisting of a chain and a little disk stating the build time. But it should not be so stripy!

Micro surgery

So here is how one repairs a flex PCB, well at least I think it is repaired, the proof will be in trying it on the 3D printer. Photos are from my phone peering into the eye piece of a stereo microscope.

Well, there is one very obvious break! The line above was also broken at the point where the Kapton covering ends. I made two light cuts through the tape and peeled it back and trimmed it. Then I scraped any remaining adhesive from the tracks.

Now the tracks were tinned with a lead/tin/silver solder, it is the thinnest I have at 0.5mm and a lower melting point than most.

To make the repair I took a single strand of tinned copper wire from a piece of multicore hook up wire and flattened it in smooth pliers, then I tinned it and soldered it in place using a flux pen to ensure the solder flowed even if it took me a while. I flattened the wire because I was worried that it might sit higher than the little nipples that form the contacts. So that is two done, finished! Yeah right.

On higher mag I could see that this poor line had a further two breaks!

Much clearer when the Kapton is peeled back

This time I used a thinner wire from the multicore that is found in mice leads. It is really nice wire for many projects so save those mice cables! Here you can see how I made a little handle using the wire, if the wire and tracks are tinned you just need to press down with the iron and they bond, extra flux does help. The wire was trimmed by placing the scalpel on it before wiggling it a little, remember this is super thin stuff!

The other repair was on a bend and does not look so pretty. This joint and the others where carefully shaved with a scalpel to reduce their height, probably not needed but did not hurt.

All done! Well not quite, when I found someone to assist I did electrical tests from the other end of the ribbon to this end and found two more breaks, again always at the boundary of the Kapton, this is simply where stress concentrates. I hope it works after all this effort. If it does I can start looking for an old printer to ravage.