The PEEK Performance Project Part 4: PEEK, and the problems start

You know, if I'm gonna be doing this thing I'll have to eat this crazy $600/kg cost at some point.

I buy 250g of PEEK for $150. That hurt.

PEEK: The first attempt

It came in on my birthday! How nice!

The 3D printing discord had been talking to me about printing a low-poly Pikachu, named the PEEKachu, for a while now. So, that's what I decided to do as my first print. 390C hotend, 160C bed, 90C chamber, and let's go!

(Side note: I learned here that PEEK extrudes as a translucent gold, very much like Ultem, and solidifies an opaque tan. In fact, the first time I loaded PEEK I ended up purging way too much, because I thought what was coming out of the nozzle was still Ultem.)

That turned out...surprisingly good, actually! The geometry looks accurate and the surface were smooth. Overhangs weren't bad either.

That being said, there's some pretty odd coloration throughout the print. The PEEK we know from pictures and ads is a solid, opaque tan. Parts of this print looked right, but most of it was the same odd translucent gold as when it was extruding.

What's more, the entire print was extremely brittle. You could hear it cracking just from grabbing it and twisting it gently.

I went ahead and tried to do a MK3S fan shroud to replace the Ultem one I'd been using.

It broke during assembly.

Maybe I'm not ready for this yet. I chalk it up to the still limited 95C my chamber tops out, and decide to put PEEK on the backburner. Guess I'll go back to printing with Ultem, as well as stressing about the impending school year.

You know what's gotten incredibly annoying? This stupid glue scraping procedure. Every time I finish a print, the glue has charred and I have to scrape it off, then I have to go through that apply glue > bake > scrape > repeat process again. It takes 30 minutes just to prepare the bed before each print.

Nano Polymer Adhesive: The Solution to All Problems (no, seriously)

Disclaimer: I am not sponsored in any way by Vision Miner, and they have not sent me any free product. I purchased and paid for all products mentioned with my own money, and these are my true, unbiased thoughts.

No, that disclaimer shouldn't be necessary. It wouldn't be necessary in any other situation. It's just my thoughts on this stuff are so positive that I risk sounding like a shill if I don't state this outright.

This sums up my thoughts on it pretty nicely:

A couple weeks into having started printing, I found out that Vision Miner apparently has a 5ml sample bottle for just $8 shipped. I still couldn't swallow the full $50 price, but for $8 I might as well try the sample.

It came in, and I was surprised at how small the bottle was. By the looks of it, this would only last me a week or so. I went ahead and applied a coating to my bed plate.

Interesting...it went on very thin, somewhat like the consistency of water or isopropyl alcohol. It dried in just a few seconds, and when it dried it turned quite hard and glassy. In fact, I couldn't scrape it back off with a metal scraper. 

Let's try PC first.

Hey, it holds PC down quite nicely. The glue stick scrape method never worked nearly as well with PC. Also, for once instead of yellowing and turning ugly, it stays clear.

Ultem next?

Wow...this is sticking down brilliantly. Way better than the old glue stick. It also pops off nicely when cooled down.

And get this: It doesn't always need to be reapplied for prints. Even for Ultem. I can usually get 3-4 prints on a single application before I need to reapply, and unlike glue stick where reapplication means scraping off the charred and baked on glue, with Nano Polymer you just brush another coat on. I've now suddenly cut my bed prep time from 20-30 minutes every print to 30 seconds every 3-4 prints.

It can't be all perfect, right? I keep throwing more and more filaments at it to see what it does. Ultem 9085, PPSF, Nylon, ABS, even a bit of PEEK once again. It handles everything amazingly well, and for lower temperature filaments like ABS it doesn't need to be reapplied for dozens of prints.

This tiny bottle ends up lasting me from 7/29/2019 to 7/3/2020. Yes, you read that right - it lasted me nearly a full year.

When I finally ran out, dropping $50 on the full sized bottle was the easiest decision of my life.

Parts purchased: 

Nano Polymer Adhesive ($50)

Total project cost: $1025

The Revenge of the Janky Chamber Heater

Hey, remember the chamber heater we haphazardously mounted to the left wall? Yeah...that thing hasn't exactly been reliable. As it turns out PC is not sufficient for printing structural elements that the heater is blowing 150C air straight at, and as a result the heater started drooping rather badly over time. It got bad enough that I was propping up the chamber heater using a spare stepper motor I had lying around just to keep it from falling down all the way.

Also, let's be honest, 95C is a bit weak when I was originally shooting for 100C. I think we're overdue for an upgrade, don't you?

I'd actually been giving this problem a good bit of thought for months now, since this jank chamber heater never was intended to be permanent. Again, I had the same space constraints, which were proving to be difficult to work around. I went through many solutions - old oven heating elements, toaster heating elements, custom nichrome things - none of them could seem to work out.

The solution turned out to be pretty simple. I found this one PTC heater that was 300W, and just 20mm tall. I drew a quick mockup with this PTC heater stacked with a fan. Hey, this thing could fit just under my bed!

I ordered two heaters and two fans. (I explicitly chose 105C rated fans for this. Treating fans as consumables is all well and good, but I won't say no to higher temp parts when they're available.)

The "PTC" in PTC heaters stands for Positive Temperature Coefficient. What this basically means is that the heater has a sharp drop-off in heating power once it reaches a certain temperature, so that it becomes very difficult for the heater to exceed that temperature. This is very beneficial for safety.

Unfortunately, that max intended temperature was not specified for these heaters on their product page. This might have become an issue if their max temp was, say, 120C, which is not enough of a delta over 95C to bring the chamber temperatures up above it like I wanted.

Luckily, I tested it and they reach about 180C. Bullet dodged!

I finalized the chamber heater design and prototyped it. The fan is purposely offset a bit away from the heater, to avoid overheating the fan. This time, PC should be fine because the bottom of the case is the coolest, and the PC is not coming in contact with any hot parts.

I then tore out the old chamber heater and mounted the new ones here. They're short enough that they leave about 5mm clearance from the bed with the bed in the lowest position. Nice!

Electrically, there were a few new differences.

• My old heaters were 120W, 24v DC each, and so they could be driven off the mainboard. These heaters are 300W, 110VAC each, and so instead I used an SSR to control them.
• My old heater fan was also 24v, so it could be driven directly in parallel with the heaters. These new fans are 5v. Why must they be difficult? (Because they were the only ones rated for 105C, Karl) I ended up hooking up a buck converter into the old 24v board output to power the fans.

New chamber heater done! Total heating power = 600W.

I test heated and...whoa, these are really powerful. I underestimated 600W. The chamber temperature display shoots up like a rocket, and I now top out at about 124C. Without any bed heat contribution!

On the other hand, my printer now draws 1200W peak. (600W chamber, 500W bed, 50W hotend, 50W everything else).

Maybe I should cut down on my household air conditioning use?

Parts discarded: 

Old chamber heater (-$50)

Parts purchased: 

2x 300W 110VAC PTC heaters ($25)
2x 5v 50mm fans ($10)
DC-AC SSR ($15)

Total cost of printer: $865

Total project cost: $1075

A New Challenger Approaches: The BMG extruder

Throughout most of this time I kinda forgot that I was still using a genuine BMG made from SLS nylon. Bondtech rates their nylon for a 100C max temp.

After the chamber heater upgrade, I started getting weird striations in my prints that looked very obviously extruder-related. After a little bit of investigation, it turns out the idler arm on my BMG had significantly deformed due to constant exposure to 100C+ ambients. 

Now, I like genuine parts. I try to buy genuine parts whenever I can, to support the developers. But what am I supposed to do when the genuine part can't support the use case I have in mind for it?

Somewhat reluctantly, I bought a cloned, all-metal BMG.

It actually seems very well made and quite reliable. There was a slight hiccup where the clone was just a bit thinner than the original, which I solved by stacking a washer in each screw hole between the extruder and the back mounting plate.

Parts discarded: 

Genuine BMG (-$80)

Parts purchased: 

Cloned, all-metal BMG ($35)

Total cost of printer: $820

Total project cost: $1125

Part 5: PEEK, and redemption