Printing With PETG

[Oliveros 11]

I wanted to give you guys an insight into printing with PETG, I know it's hard to get any since I tried myself so I wanted to give you my experience after A LOT of it.

 

First of all, PETG has a fairly high HDT of about 60C or 75C depending on what you get. Realize that there is a point of conductivity in plastic which is much lower than a lot of other materials, it's considered an insulator, so even if you have it going through a hot area for a minute or 2, it may work just fine as the heat transfer won't have enough time to heat the part up beyond it's HDT and warp it.

 

Since my application was a large dishwasher, here's what I found, in my case, it was a snap on application, high temp and somewhat needing strength.

PETG is not as flexible as it seems to be advertised. I used a Monoprice Ultimate 2 printer, fully enclosed, 60% fan speed, No bed heat for the first layer, glue stick on blue tape, 230*C nozzle, I tried different settings but this worked the best for me. I also used Monoprice's PETG filament, 1 KG roll, fresh out of the box.

 

If you print the grain of the layers longways, it's less flexible and much easier to snap, if you print them across, it's much more flexible. In my case, the object was printed laying down and installed standing up, if I printed it standing up, it would snap once I tried to get it mounted as I was relying on a snap fit. Kind of like wood, I believe there's a fancy word for it that I don't remember.

 

Depending on the density of the item, it's ability to withstand heat will be affected, BUT if you are using it in a dishwasher with stress on it (in my case ,temps were upwards of 170*F) it will warp the parts with stress, 6MM thick or 1-2MM thick, still warps where the stress was, dense or skinny.

 

It's easy to print otherwise, seems to accept paint really well, I made some other parts that didn't need to be food safe or used in the kitchen and they were painted gray, I enabled Ironing in Cura and the parts came out really, really clean on top, you could barely tell it was 3D printed from looking at the face.

 

All in all, PETG is a good material all around but it is NOT the best filament for high temp application exceeding 150-160*F in my opinion. It is FAR from as flexible and forgiving as nylon is but you CAN get it to snap on as long as you don't flex too far, it seems to always return back to where it started on less it's deformed by heat.

 

There's a lot of other filaments out there, a lot of which are hiding which are much higher HDT and still FDA approved, they are just surprisingly difficult to find.

 

As a note on bed adhesion, my best results was, 230*C nozzle, print with a brim or a raft, whatever you want, but do print something to help with bed adhesion, blue tape and glue I print with a COLD BED.

 

My printer is auto leveling and the glue dries quickly, even faster if the bed is hot, I'm using water washable glue which when wet, return to it's tacky style where stuff will stick to it, so I'll cover my bed with the glue and right before it prints, use a rag with some water on it and just wipe the bed gently where the print will be and it lays it down so it sticks really well.

 

Then i'll either turn the bed heat on later or just leave it off, it seemed to make no difference to me.

 

Hopefully this will help someone else who's trying to print PETG.