MakerGear Forum

I was also thinking that a heavier bead is going to hold the heat longer which could improve the bonding.

zemlin wrote:Will also test black PETG.

I'm going to have to improve my test methods, as my samples now exceed the capacity of my bending test - but I printed some black eSun PETG with the .5mm nozzle and it appears to have bending strength and fracture characteristics comparable to the clear. Going to have to design a new test rig before i can get numbers.

jimc wrote:Your additional layer bonding strength is probably more from extruding such a wide line compared to your nozzle dia and layer height.

I've been gravitating toward a 2:1 width/height ratio for no particular reason but it seemed to be working. What's your typical target on extrusion height * width?

zemlin wrote:

jimc wrote:Your additional layer bonding strength is probably more from extruding such a wide line compared to your nozzle dia and layer height.

I've been gravitating toward a 2:1 width/height ratio for no particular reason but it seemed to be working. What's your typical target on extrusion height * width?

Optimal is 1.8:1. Anything less than 1.3:1 and you start to see bonding issues. Anything over 1.8:1 is fine generally as long as you keep the extruded width of the thread less than the OD of the flat face of the nozzle. (So 2:1 is cool.)

(That's not my determination....there was a study done to determine the optimal width/height ratio for best bonding between threads and plate, while maintaining placement accuracy.)

Jules wrote:Optimal is 1.8:1. Anything less than 1.3:1 and you start to see bonding issues. Anything over 1.8:1 is fine generally as long as you keep the extruded width of the thread less than the OD of the flat face of the nozzle.

Great info - thanks. And I'm glad you clarified that this came from an outside source - 'cuz you don't seem to have much credibility around here.

zemlin wrote:

Jules wrote:Optimal is 1.8:1. Anything less than 1.3:1 and you start to see bonding issues. Anything over 1.8:1 is fine generally as long as you keep the extruded width of the thread less than the OD of the flat face of the nozzle.

Great info - thanks. And I'm glad you clarified that this came from an outside source - 'cuz you don't seem to have much credibility around here.

You noticed that too?

(Oh no, wait - I'm confusing ya'll with my better half - who tends to pat me on the head and then go on doing just what he was doing.)

jimc wrote:zemlin, interested to see what you think of the black gizmo dorks pc.

Been printing the Gizmo Dorks black PC today. So far I'm losing the battle. Tried the same settings I used for the eSun ePC - 100C PEI bed and 270 nozzle. Printing a pretty chunky and dense part that's about 50mm x 75mm x 10mm. Using the .5mm nozzle and .35mm layers. Only got a few layers down before it was curling. Tried it again with a nozzle temp of 290. Better, but not good enough.

I'm cleaning the PEI with acetone before starting the build.

I tried ABS slurry on Kapton over Glass at 110C. Never used slurry before, so my technique might need work - but that failed very quickly. I can see on the bed that the slurry stuck to the build when the part failed.

Cranked the temp on the PEI/Mic6 as high as it would go - 120C on my machine. Printing with that now. About 2/3rds through the build and seeing noticeable lift on one edge.

Not sure what I'm going to try next. May need to work on my ABS juice mix again. I used eSun ABS+ because that's all I had in black. I have some Hatchbox ABS in orange I might try dissolving to see if that works any better.

Already printed a very similar part in the clear ePC, but will probably run off another to see if it turns out OK before I continue the battle with the Gizmo Dorks material. Would love to have a black option for PC.

PC is notoriously bad for warping. Nearly unusably so. You may have some luck enclosing your printer; a cheap option is a big cardboard box.

eSun makes a modified PC that people say has tamed the warping.

jsc wrote:PC is notoriously bad for warping. Nearly unusably so. You may have some luck enclosing your printer; a cheap option is a big cardboard box.

eSun makes a modified PC that people say has tamed the warping.

Yes, I just pulled parts of the deck printed with eSun ePC - same factory file I used for the Gizmo Dorks except I dropped the extruder and PEI bed temps to 270 and 110. Those parts look great. No warp at all. Just wish eSun had a black.

I've been using ABS for almost everything, but the big project I'm working on currently is all PETG and I've concluded that it is a superior material and will be switching to it as my go-to material for everything. I tried PETG last year, but it was more expensive then and I didn't notice much difference on the parts I was using it for. The parts I'm working on currently really show off its strengths though, and the fact that it can be printed without an enclosure without having warping or stinky fumes really saved my project. There's no way I could have run three open air printers around the clock with ABS and not made myself sick. With PETG, you get awesome bed adhesion, no warping, no fumes, no worrying about having to orient the grain direction to keep stress from cracking parts along the layer lines like you do ABS, less blobs, better handling of unsupported overhangs and it's just a stronger material. It's more difficult to sand than ABS, but that also translates to better resistance to abrasion. You do get more thing stringers when printing at high temps (I print it at 265), but these are easy to remove all at once with a quick flash from a blowtorch (the torch can also be used to increase transparency or create a more polished surface if you are careful with it). I just did a PETG print where I accidentally caused a corner to lift off the plate when trying to pull off a blob with the tweasers at the start of a print. With ABS, that lifted corner would have creeped over time to be larger and larger until the part was ruined, but with PETG it finished out the whole 9 hour print without ever increasing and the part was usable.

So since this project I'm working on is going through so much PETG, I'm using it as an opportunity to test filament from different manufacturers. I'm only testing white and clear though. Clear seems to be the strongest material, so it is likely that the color pigments they add tend to weaken the plastic slightly. So far the best clear PETG I've found in terms of strength and clean printing is Gizmo Dork and Maker Filament. Gizmo Dork is expensive though, whereas Maker Filament is half the cost and has a lot more color options Maker Filament is one of the cheapest PETG suppliers out there at $24 per Kg, which is even cheaper than eSun's $26/Kg. You get a lot more surface defects and stringers with eSun. Maker Filamenet prints so clean that when some of my printed parts were mixed in with a box that also contained the same part printed on a Form 2 printer, my client was having to double check to tell them apart. Gizmo Dork is very clean too, but it's hard to justify paying twice as much when you can get the same quality from Maker Filament.

http://www.makergeeks.com/pet3dfilament.html