Thursday, February 21, 2019

Kapton Tape Sucks

That was an attention-getting title. I'm not above clickbait.

Kapton tape is really kapton film with adhesive. This stuff is thin. Because it's thin it likes to twist, ball up, not go where you want it, and generally be a pain in any sensitive part of your anatomy you want to name.

I got the wires taped up. Moderate profanity was used. One large problem was that I was doing this without disassembling the extruder. Had I taken it apart it would have been much easier. But I went the lazy way.

I'm not sure that the part is good on one of the printers. It's still doing some temperature fluctuations but that's also happening when there's some really odd airflow patterns from the part fan.

OK. Let me explain that one.

There's two fans on the extruder - the hot end fan and the part fan. They both do what the names say - the cool different parts of the process. The hot end fan isn't nearly as powerful as the part fan and keeps things constant for the heater. The part fan is a tricky beast since it's trying to cool the molten plastic without cooling it too much. There's a shroud that fits the end of the fan and tries its best to direct the air where it should go.

When I had the shelf accident I think that the part fan on one printer took enough of a hit that the bearings went wonky. It certainly rattles when it's running. 


The extruder fan is on the left. There's a hole in the extruder body to let the air in.

The part fan is on the right. The R3 upgrade put it at that angle. There's discussion whether the angle of the fan causes extra stress on the fan bearings or not.

The wires that I taped are those red ones. The tape is orange. The red wires are the nice, thick heater wires. The thermistor wires (the tiny ones) aren't seen here. But they're blue. And tiny.

I'm not replacing the fan yet for these reasons.
  1. It seems to be working;
  2. There's an upgrade planned in the near-ish future;
  3. Replacing it is a pain in the sensitive part of the anatomy (at the moment at least).
The reason replacing it is a pain is 85% the part itself and 15% me. After I do what I should have done when I last upgraded it then the split will be 95%/5%. Here's the problem. The fan is a generic notebook fan. Which is great, they're easy enough to find. But the wires are far too short for use in the printer. So that's on us.

Some people solder them. This is actually a replacement fan and I went the lazy way (go figure) of unsoldering the wires from the old fan and soldering them directly to the new fan. A little bit of futzy work but it's been fine. Going forward I was thinking I would solder them in the wire run instead.

The second printer is different. The previous owner put a connector on the wires. That way when you replace the fan you put a connector on the new fan and it's easy enough to replace it. Brilliant! I even got those same connectors. That way I would have both in the same configuration.

I didn't put the connector on when the printer was nicely in pieces. I was going to do it but went "Eh" and didn't. Now I'm paying the price for it. If I could replace it that easily I would do so. I have plenty of spares. It's more of a chore to do it now when the wires are bundled up.

Enough technical talk!

I did do some printing but that large print that failed kind of burned me out for a bit. That's another reason the printers are idle. I needed a break. I really enjoy printing but it was wearing on me to have them going all the time. I did do a test print on each one and that's how I know what's going on with the thermistors. But for now I'm letting them be idle.

On a better note I have the temporary camera stands printed and assembled. The next/last step is connecting them to the print servers and setting them up for monitoring and time lapse videos. Of course there's more steps than that but it's the general idea.

There's ALWAYS something to do when you have one of these things. Image it with two...

Thursday, February 14, 2019

The Printers are Idle

What? The printers aren't printing? What's wrong? WHAT'S WRONG?

Actually there is something wrong with both of them. It's a minor thing but something I want to fix properly before getting them up and running again.

This guy put one printer on idle:


See that part sticking out in front, on the top? Yeah. That guy. For whatever reason it caught on some wires you can't see on the other side of the print head. Those are some thin wires that really should be protected better. In and of itself that wasn't the problem. When it caught on those wires it made the print head hang when it goes side to side. When it freed itself it was in the wrong place but didn't know it. It continued to print but the layers were now about an inch to the right.

That's called 'layer shift' for very obvious reasons. And that ruined a print that had been running for over twenty four hours. I'm still going to send it to my friend because he's crafty enough he can use it to make something else.

The other printer has been having trouble with that same component but for different reasons. I've been able to print decently even though it's a problem. But since I don't have anything pressing to print I decided to idle them both and fix the darn thing once and for all.

My solution is going to be to tape those wire to the much larger ones running along side them. That serves a dual purpose of keeping them safe and keeping them out of the way. Which I guess is the same purpose really. But I'll call it two reasons.

Here's the next question. What do you use to tape something when it's right up against a block of metal being heated up to about 220 degrees Celsius? For those of us using imperial measure that's over 400 degrees Fahrenheit. Regular old electrical tape isn't going to do it here.

There's a special tape meant for high temperature use. There's a piece of it holding the heater in place under the print bed. Of course I don't have any on hand so an Amazon order was placed. In case you want to know this is kapton tape and it's used in a lot of places where high temperatures are around. It's good to have some on hand anyway. At least if you have a 3D printer it's good to have on hand.

When it arrives I'll test that the parts are working properly (heat it up, wiggle the wires, watch the temperature) and replace what is bad. Then I'll carefully align the sets of wires and spiral wrap tape them together until they pass the problem area. After that they go into the main cable bundle that's in a textile sleeve.

Until then the printers are sitting here. I unloaded the filaments so they're truly idle and kind of sad to see.

I'll have them running for a couple of months and then my next upgrades happen. Those are going to be a doozy. I'm upgrading the entire frame to extruded aluminum and there's an upgrade from the manufacturer as well. All new plastic parts will be printed. At the same time I'll do the routine maintenance I've put off. These things are literally going to be stripped down to parts and rebuilt in the process.

And I'll be spinning that design around so the sticking out bit is around back and less of a hazard for the wires when I print it again.

Sunday, February 3, 2019

I Designed and Printed Something!

Ok. It's not going to be amazing. That much I can promise. But it's something neat.

My friend painted the two (very large) new monsters for my dungeon crawl. She's such a sweetie! She used bases she had on hand that fit the monsters which is fine.

She used round bases. I use square bases. Hrm. This is a problem. At least for me it's a problem.

OpenSCAD to the rescue! If you don't want to click the link it's a text based CAD program. It's great for learning how all this works and for making pretty much anything. All the plastic parts for my printer were designed in it. And I understand words a lot better than menu commands at the moment.

I wanted a square base with a cutout for the round base. I'd done similar things. So now it was time to do it again.


Meet Carol, the carrion crawler. Actually she's a cavern crawler from Reaper Miniatures due to IP stuff. And yes. That's a metal mini so it's darn heavy.

You can see her round base fitting very nicely into the square base. A bit of double sided tape and she'll be secure enough. And I can remove her from the adapter if I want a round base.

I did the same thing with the hydra. I'll post pictures of him some other time.

It doesn't sound like much of a design challenge and it wasn't since I've been playing around in OpenSCAD for a while. But it's so nice to be able to design something you need and then make it. AND have it work!