MakerGear Forum

I've had no issues with smaller parts running Hatchbox (black) PETG using the stock 0.35mm nozzle right on the polyimide (85c). For larger parts I've added a layer or two (typically just one) of Aqua Net which has helped noticeably with adhesion (usually at the perimeter).

I have also had good results with PETG on polyimide - just don't try to remove the part while the plate is still hot. For larger parts I generally run the .5mm nozzle just for the reduced build time. I've run some pretty big PETG parts on the polyimide without issue. My experience with hair spray isn't quite as good. It works quite well, but I often get slight lifting on a corner - not using a brim or anything. The thing that's nice with hair spray is that once things cool down, the part just falls off the plate. The bed I used with hairspray is aluminum, lightly sanded. PEI is the most reliable for PETG.

Thanks! I guess I will just try the polyimide & see what happens. The brackets will have a roughly 3" x 3" foot print on the bed.

Given that the parts are fairy large, I figured the 0.5mm nozzle would be fine, and eliminate the risk of getting a clog. The new nozzle is due to arrive today.

You know, I've been wondering how to speed up some larger parts I've been working with, and well, sometimes just overlook the obvious .. I'm going to get going on ordering some 0.5mm nozzles prompted by the discussion here.

It's a bit of a tangential topic, but what's the largest layer thickness you've used with the larger nozzle @zemlin? I'm thinking 0.4mm should be fine? (I'll start reviewing some of the related threads on this topic too).

Larry wrote:but what's the largest layer thickness you've used with the larger nozzle @zemlin? I'm thinking 0.4mm should be fine? (I'll start reviewing some of the related threads on this topic too).

I think the heaviest I've run is .35. I often run .3mm with a .6mm width. You can certainly try running heavier - might be fine.

Thanks .. will do some experimenting.

(I do realize from the discussion between @Ed and others on an alternate thread that there a few 'knobs to turn' - trace width/height as well as print speed, etc. - to accommodate the increased flow volume associated with the larger nozzle. I'll jump over there or initiate another discussion if I have any questions. Thanks again).

After reading through all 18 pages of Jules' PETG settings thread, I've run a calibration with the HatchBox white PETG, and played with a few settings to try to get rid of strings. Other than some residual VERY tiny strings, the test prints I've done look good. I now have a lifetime supply of filament spool clips...

I'm actually very impressed with the strength of this stuff. Even the tiniest strings are amazingly strong.

The one thing that I've noticed is that this stuff REALLY likes to stick to the polyimide surface on the bed. I've got a new machine, so the polyimide is pristine, and I clean it with alcohol between prints. I let the bed cool down to room temperature after each job, but things are still really stuck. The test parts are thin enough that I could flex them and get them to pop loose. The two pass skirt is another story. I've finally resorted to hitting it with aerosol circuit freeze (actually, a freon duster can turned upside down, which is the same...). That seems to thermally shock it enough that I can eventually pop it loose with a few sideways whacks with a wooden "chisel".

The final prints I need to do will be pretty rigid, and have a large thick flat base. Probably about 8 square inches of contact with the bed. If my small tests are any indication, I shouldn't have any problem with corners lifting, but I expect a real battle popping them loose. I found one recommendation to put the whole bed in the freezer, so I may try that. I don't want to chew up the polyimide with the metal spatulas & pry bars some people seem to use.

Is there such a thing as having too much bed adhesion? Is the freezer the best approach for popping a large print loose?

Thanks!

Gwhite wrote:having too much bed adhesion

I use hairspray on 90 °C glass, which causes (eSun) PETG to stick like it was glued down, with no edge lifting at all. When the platform cools to room temperature (actually, anything under about 50 °C), the parts lift off the glass, no matter how large they are, with fingertip pressure or a slight tap from the chisel I use to get under the skirt thread.

No hassle, no muss, no fuss.

Your mileage will, of course, vary, but it's been working that way ever since I switched to PETG.

I wasn't quite getting the correct wall width when I ran my calibration, and I decided to tweak the extrusion multiplier further. I am still using my 0.35mm nozzle, and have the width set to 0.45. I started out with my multiplier set at 0.82, and I got a 0.42mm wall. I kicked it up to 0.87, and that only got me to 0.43mm. I'm up to 92 now, and I'm still only getting 0.44. Unless I don't understand the process, going from 82 to 92 should have increased the wall thickness from 0.42 to ~ 0.47mm.

I'm running my extruder at 240C. Is it possible that is too cool, and that I can't quite squirt enough material though at that temperature? I am using the settings from Jules' PETG thread, but that was for eSun material. He gave a range of 240-242C. In the first post in this thread, Zemlin said he was running black HatchBox at 265C. HatchBox recommends a temperature range for their PETG material as 230-260C, so he is cooking it pretty good.

I'm also using white PETG. I have no idea how consistent the settings might be for different colors. I'm trying to keep the temperature down to minimize brown zorched bits in the print. Little bits & strings get stuck on the nozzle, get toasted to a nice brown color and and then fall into the print in inconvenient locations...

I'm running a test print that will take several more hours. If I have time, I may be able to run another calibration at a higher temperature to see if that is the problem.

I'll post an update if I figure anything out. In the meantime, are other people running HatchBox PETG at temperatures as high as Zemlin?

Thanks!

I'm making progress... I tried printing on the polyimide, and that stuck like glue. It was all I could do to pry the print loose with only minor damage to the film. The next attempt was glue stick on the polyimide, and that was only a tiny bit more forgiving. I managed to get the print up without any further damage to the film, but it took two cycles in the freezer and a lot of careful prying to do it. I added a small pocket on one side to give me a place to pry... These were with test prints 3" x 4", and about 0.2" thick.

Last night, I flipped the build plate and coated the glass side with hairspray. This time I printed the final object, which has the same base plate, but some added features on top. When I checked this morning, I barely touched it and it popped loose! The bad news is that one corner lifted a bit due to warping. It looks like the warping occurred while it was doing the base plate, and not due to the additional structures. The layers in the base are mashed together a bit in that area, but the top surface is fairly flat.

I gave the build plate another quick coat of hair spray, kicked the bed temperature up 5 degrees to 85C, and that worked much better. The print has some minor issues, but nothign important for this application.