The Everything 3D Printer Thread

[draco_1967]

The color/sheen change could be from the layers having more opportunity to cool as the printer goes between both parts on the plate. Once the shorter part is done printing, the layers on the taller part will print faster, with less cooling between layers. That looks like a transparent PETG, which will often have different finish appearance based on speed, layer temperatures, layer height, etc.

 

[Old tool guy]

It is transparent purple petg, looks nice when done properly. I did reduce the purge volume, i’ll put it back to 1. What test prints should i consider running?

 

[pcrov]

I did reduce the purge volume, i’ll put it back to 1.

You will likely need to increase the value in the table above that too (I know it doesn't look editable but click on it.) Even if it's just a little too low while you might not get a split your print will be extremely weak at that layer boundary. PETG just really doesn't want to stick to any amount of PLA.

 

[Citation]

Can’t change the design, only options are number of walls and fill. This one had honeycomb, you think gyroid would be better? Would it help to be in an enclosure?

An enclosure should help. Read up on some of the tricks the people used to print ABS. This sort of shrinkage problem was a big deal with ABS. A friend did some box like enclosures with abs on an open printer. He covered the whole thing with a box and designed in a big, wide base for his part. The base got cut off in the end.

 

[moto_ridah]

Need help … desperately. Bambu A1 petg. This is the second time this has happened, two different parts. One problem is the split and the warped edge. The split lines up with the top layer of pla supports, same on the other one. Also curious about the color shift and sheen change. There were 2 parts printing at the same time, the other part had supports at a higher level … and that aligns with the color shift.
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I hate losing the filament, but even more i hate losing the time. This was about 20 hrs.

The warping is a cooling issue or bed adhesion; some of those larger TMT parts might pull the bed corners up but this isn't one of those parts. An enclosure would help but it could also be fan settings.

I would recommend dropping the PLA support when printing PETG for these TMT parts unless you get a dual nozzle machine. To me it looks like the pla is contaminating the PETG up to the last support layer of the other part you mentioned. You can dial in the support settings to get them to release pretty well, plus your print speeds are going to go up without all PETG to PLA switching and your waste is going to go down.

There's a separate TMT thread on here that has a decent amount of info. There's even more info and on the forum on the 3D-mobility website and a growing Facebook group.

 

[jeepxj]

dumb question: where is your A1 located? any way to put a box over it?

 

[Old tool guy]

It’s on a work table in my office/workroom. Plenty of room, but i have recently read that an enclosure can overheat the brain.
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Recent (yesterday) research made me realize i might have caused some of the failures myself.
* I had changed the 0.20 mm standard to 0.16 thinking that would increase the strength. It actually makes it weaker but smoother. So now i’m using the 0.20 mm Strength setting
* i had reduced the purge volume way down, didn’t realize there would be contamination. I’m leaving it at 1. I was trying to reduce the color change time. Backfired.
* somewhere i saw a recommendation to turn the fan off. I set it to a max of 30%.
* i did a temperature tower test, and have raised the temp from 250 to 260.
* one of the builders on the tmt site had posted a comment yesterday (timely!) about changing the “support object first layer gap” from 0.2 to 0.35 which would make it easier to remove the supports from dovetails.

 

[moto_ridah]

It’s on a work table in my office/workroom. Plenty of room, but i have recently read that an enclosure can overheat the brain.
.
Recent (yesterday) research made me realize i might have caused some of the failures myself.
* I had changed the 0.20 mm standard to 0.16 thinking that would increase the strength. It actually makes it weaker but smoother. So now i’m using the 0.20 mm Strength setting
* i had reduced the purge volume way down, didn’t realize there would be contamination. I’m leaving it at 1. I was trying to reduce the color change time. Backfired.
* somewhere i saw a recommendation to turn the fan off. I set it to a max of 30%.
* i did a temperature tower test, and have raised the temp from 250 to 260.
* one of the builders on the tmt site had posted a comment yesterday (timely!) about changing the “support object first layer gap” from 0.2 to 0.35 which would make it easier to remove the supports from dovetails.

- The box and question about placement is more about considering drafts in the room. Warping is from the temperature differentials between nozzle, part, bed and air.
- You have to purge a ton to get rid of PLA to switch to PETG during support and layer changes. Not recommended to mix the two in the same nozzle, especially in these builds were part strength is a safety concern.
- 30% isn't too bad but I would leave it off for first 3 layers or so, you might still have air draft issues. Printing directly from the maker world profile would eliminate some variables.
- Higher nozzle temps make the temperature differential greater which can contribute further to warping.
- Support first layer gap is more about the support brim not sticking to the part. Look at top Z interface spacing. The recommendation (from NWCC) is 0.35mm for 0.6mm nozzle (0.3mm layer) and like 0.28mm for 0.4mm nozzle (0.2mm layer). I use 0.3-0.28mm and 0.24mm respectively; little bit hard to remove but easy enough and it seems to give me less joint post processing for proper fit.

Might recommend moving to the other thread for TMT discussion, since people didn't like it clogging up the normal 3D print thread. https://www.garagejournal.com/forum...shoot-thread-wheelchairs-for-toddlers.555626/
(edit to add link)

 

[Old tool guy]

I want to use pla for easier removal of the supports, i don’t have a second nozzle.
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One of the parts that failed last week is printing now, looking forward to seeing how it finishes.

I put the questions here because, to me, they are generic printing questions, not specific to the tmt device.

 

[burger]

I put the questions here because, to me, they are generic printing questions, not specific to the tmt device.

I have been reading and following. Not upset. These do seem like general printing problems.