DIY Moon Phase Dial

[Gina]

I'm planning to use a split-flap display as used in railway stations etc.  It's the only way I can see to fit the display in the space - I don't like LED displays as they aren't really clear enough nor in keeping with the clock design.  See my Calendar thread - DIY Automatic Perpetual Calendar - Day & Date Display - ideas

[Gina]

The moon dial mechanism has jammed again so yet another look needed   The RGB LED strip hasn't arrived yet nor has the sticky spray for 3D printers so the moon globe casing is on hold   But I am making progress on the day/date display - working on the day split-flap display and looks like it will work

[Gina]

Had another look at the moon dial mechanism - turned the moon dial back a couple of notches and then tried turning the clock forward by hand.  The moon advance mechanism worked perfectly right past the point of failure so I don't know what the problem was.  I think I'll have to just see how well it works in practice though I shall be running it in for a while yet while I wait for orders to arrive that will allow me to finish the clock.

From watching the moon dial advance mechanism it struck me that with the day/date display directly below the clock and maybe incorporated as one unit, that I could use the same sort of mechanism to drive the day of week display.  Currently the test mechanism for this display has ratchet wheels with 7 notches but if I changed it to 14 it could be run from the hour shaft - in fact an extension of the moon drive cam follower.  OK so to get the day display to change at midnight might be difficult but since I'm usually in bed at that time until 7 or 8am it wouldn't matter if the day changed in the early hours.

[Gina]

This is the change in ratchet wheel pairs for 12h operation.

[Gina]

I was going to drive the calendar diaplay from an Arduino with Real Time Clock, providing a perpetual calendar but I could make the day displays just advance from the clock and advance the day number from 28, 29 or 30 to 01 and advance the month by hand.  OTOH the perpertual calendar could be run from the same Arduino as the clock.

[Gina]

The 3D printer spray and the RGB LED strip have arrived so I'm hoping to do some more to the clock tomorrow.  It will have to take second place to the observatory repairs though.

[happy-kat]

Good luck with the repairs.

[Gina]

Thank you

[Gina]

Repairs completed - I think, though there could be some more yet.

Been trying the sticky spray and it seems to work but I think the black ABS filament I've been using may be a problem so I've just swapped over to a new reel of a different make and trying that.

[Gina]

Neither lot of black ABS is printing properly ATM.  The new spray certainly makes it stick to the glass bed but it needs to cool to pretty much cold before it will come off - a very long time amd I'm considering a cooling fan to help reduce this time.  But that isn't the problem - it's that the layers aren't sticking to each other even with the filament at 280°C and bed at 115°C.  I've run out of the dark blue ABS that worked alright   That would have been a good substitute and quite acceptable.  I have deep purple ABS or I might try black PLA that struggled to stick to the glass before - shouldn't have that problem now.

[ChrisLX200]

Neither lot of black ABS is printing properly ATM.  The new spray certainly makes it stick to the glass bed but it needs to cool to pretty much cold before it will come off - a very long time amd I'm considering a cooling fan to help reduce this time.  But that isn't the problem - it's that the layers aren't sticking to each other even with the filament at 280°C and bed at 115°C.  I've run out of the dark blue ABS that worked alright   That would have been a good substitute and quite acceptable.  I have deep purple ABS or I might try black PLA that struggled to stick to the glass before - shouldn't have that problem now.

Wow Gina, that's... bizarre. At 280C you should be printing puddles of plastic not having difficulty getting layers to stick together! I would suspect you aren't getting the temperature you think and the sensor is telling porkies! 

You're right about the sticky spray, it does need to be stone cold before it releases. A fan is a good idea, or I;ve seen freezing spray being used, or I actually remove the glass from the bed as that cools much quicker on its own.

ChrisH

[Gina]

I think you may be right about the sensor tellimg porkies.  The glass on my Titan printer is held in place by 3D printed clamps that hold glass, heater, and half inch of poyurethane foam down onto a foot square of plywood.  They are screwed to the plywood underbeath and not a quick job to remove.  So a fan seems the answer though I may have a problem getting air over the whole area.

I'm currently trying black PLA but it seems reluctant to extrude the filament so I reckon you're right about porkies.  Trying the PLA again with higher nozzle temp setting.

[Gina]

Had the moon drive fail again so decided to take another look at it - made a change from all the observatory stuff   Found the gears were jamming again and tried to fix it but I think some parts need reprinting.  Also, getting the friction right to stop the ratchet wheel turning backwards when the paul retracts is pretty tricky so I think I'll go back to the original idea of having another paul to stop it.

[Gina]

Done a bit more to the moon clock tonight.  Reprinted the gear for the ratchet wheel and glued it on plus designed and printed a second paul with fixed pivot to stop the ratchet wheel turning backward when the drive paul is drawn back.  Here are some photos.

[Pan Euro]

Hopefully this will work smoothly.

[Gina]

Hopefully this will work smoothly.

Thank you   Manual testing by turning the hands seems fine now so I'm hopeful   Fingers crossed

[Gina]

I think the moon phase drive is working alright but something else is wrong and whilst the seconds hand is turning fine, the minute and hour hands aren't   I think there's some stickiness somewhere - turning the minute hand there's extra drag at two parts of the hour hand rotation.  I think this could be due to the moon drive but not the ratchet wheel or moon gear/shaft as they are free to turn now.  So the clock is going on the bench/table to be looked at.  Makes a change from struggling with Arduino/onewire code anyway

[ChrisLX200]

That spray sounds like what I need. I have some nice white PLA that always sticks without problem. I also have some green PLA that always curls up at corners. It seems a bit waxy compared to the other filament I have bought. Must be a cheap batch or something.

Just a heads-up, be careful with that spray laquer - I don't know if I used too much or what (I only use a short burst of spray) but my last print just took a chunk of glass off my build plate! It was 'stuck' just a bit too well. I hadn't forced anything, just waited for it to cool and I heard it 'pop' off as it contracted. So I have to buy a new glass plate now...

ChrisH

[Gina]

Thanks for that Chris.  Maybe that spray is not such a good idea after all.  Must admit, I don't like having to wait until the glass is cold to remove the print.  40°C is not too bad but having to wait until it gets down to under 20°C is a bit much.

[ChrisLX200]

In future I think the only time I'll use it will be for awkward ABS prints that are lifting, the old glue stick seemed to work most of the time anyway. The reason might be that I recently started using a metal box-cutter blade to clean the residue off the glass, that could have left tiny scratches which were a weak point to start the glass scabbing, so I'll also make myself plastic scraper which cannot scratch the glass.

Chris

[Gina]

After a fair bit more tittivating the clock seems to be running well   Just one little thing - it's running backwards

[ChrisLX200]

After a fair bit more tittivating the clock seems to be running well   Just one little thing - it's running backwards

Oops! 

Chris

[Gina]

Thought you might find that amusing

[ChrisLX200]

I just discovered the benefits of active cooling, old hands likely already use it but it's new to me. I found a design for a cooler bracket and managed to print it (just - pretty mangled with the thin parts and bridging), then using the cooler re-printed the parts again. What a difference! Much cleaner print. This is with ABS too and not PLA (PLA really needs the cooling but ABS benefits too)

The cooler is the blue bit with the fan...

The difference it makes can be seen in the print - the mangled one was printed without cooler

This is the final print of a new version of the cooler bracket using slightly mangled earlier version ;-) It came out perfectly - including those pesky bridges on the top edge, but it was also crisper overall.

ChrisH

[Gina]

I used print cooling with the predecessor of my Pilot printer with mostly Velleman parts.  That was with PLA.  PLA is said to want print cooling.  Can't remember if I tried it with ABS.