Hot answers tagged

19

There are three reasons (I can think of): A large problem you'd face with allowing the bed to cool after first layer is you stand the chance of losing adhesion after it cools. When you heat the bed, it expands somewhat. When it cools it contracts. It has been known for parts to actually pop off the bed if left on there to cool (after a print). If you allow ...


11

Slow down! 80 mm/s is much too fast for PETG. Try 45 or 50 mm/s instead, even for infill, supports, and other less-visible areas.


8

What you describe is usually the result of using a too high of a part cooling fan rotational speed. Like ABS, PETG doesn't require much cooling (if needed at all that is). If you do cool too much, layers and perimeters do not bond optimally (you can get string cheese like printed parts on failure). Why should you use cooling for PETG? Cooling helps cool ...


7

Different brands and blends of PET filaments seem to do this to different degrees. Esun's PETG is definitely one that tends to glob onto the nozzle. Basically, the nozzle plows through the top surface of the filament and lifts up some plastic, much like the bow of a ship lifting up some water at high speeds. PET's viscosity and stickiness seem to amplify ...


7

Many manufactures list their filaments as being food safe, but I would not treat this as "gospel truth". Apparently, the FDA considers PETG to be safe for food contact, but they are probably thinking about injection-moulded and vacuum-formed parts. Unfortunately, an initial search of the FDA's website did not yield any definitive information. Even if a ...


6

The simple answer is: No There are two basic reasons for this: The sun will not get the filament hot enough to evaporate any moisture which has been absorbed. While sitting out in the sun, it will continue to absorb more moisture, which defeats the purpose. On Matter Hackers, they give a very reliable way to dry filament: Preheat your oven to 160-180°F (...


6

PETG works as support material for PLA, see video In theory, PLA printed on top of PETG will be fine because PETG softens and gets sticky at higher temperatures. Printing PETG support on top of PLA may cause remelting of PLA, but if PETG is kept quite cold (220 °C) the issue will likely be minor. As shown in the video, it ...


4

Piecing this answer together from the comments on OP's post. Myself and R.. noted that a layer height of 0.35 mm, nozzle width of 1.2 mm, and a fairly high feedrate (200 % according to OP, no reference to what 100 % is), is an exceptionally large amount of plastic to try and melt through almost any hotend on the market except possibly the ...


4

The Ender 3 can print PETG alright - in some regards, such as warping and adhesion issues, even better than PLA. But you do need the right settings. 230-240 °C is too low, especially at the extremely high speed you're trying - you're going to get serious under extrusion and likely stringing. My PETG settings are 80 °C bed, 250 °C hotend, and ...


4

Five top layers should normally be more than enough to create a seamless top layer. Indeed, PETG prints a little differently than PLA. It requires a higher hot end temperature, less part cooling (to improve sticking to previous layers), a higher build plate temperature and usually care in choosing the right initial layer height. Once the printer needs to ...


4

I have printed kilometers of PETG and found the sweet-spot for my brand to be 240 °C for the hotend and 70 °C for the build plate (for my Ultimaker 3 that is, the extruder temp is 5 °C higher for my home build HyperCube Evolution). The reason for the 70 °C is that the glass temperature of PETG is around 70 °C. The PETG is flexible at that ...


4

It could be that you're having issues now due to the filament absorbing moisture. I had a big problem with it doing that when I had waited for a few months after opening my filament. Dehydrated it using just my heated plate and a foil lined box over the top and it fixed it right up. If that's something you haven't tried yet perhaps that is what is causing ...


4

Here is my suggestion for a cheap, well and temperature accurate drying manner of a filament. I've done it several times for PETG that is actually a very moisture absorbing filament and pops it up when using by ruining the job. Why not using your own printer's heat bed to dry the filament (PETG about 6 hours in 65 degrees of Celsius)? I can guarantee that it ...


4

You cannot endlessly increase the retraction distance, doing so leads to different problems as you encountered. As a rule of thumb, the retraction distance should not exceed the length of your nozzle. Depending on the type of extruder, many printers use a value between 2 and 7 mm (e.g. the Ultimaker Cura retraction length is 6.5 mm at 25 mm/s, ...


4

How much glue do you put on it? I use PVA based spray, barely visible, very evenly spread and no problem whatsoever of sticking paper to the glue layer. Just level the bed as you normally would and apply a sparsely coat of glue, preferably from a spray can. Having printed literally kilometers of PETG on various build platforms (various glass sheets with or ...


4

According to kmac-plastics, PETG is stable at temperatures below 50°C specifically for citric acid (also acetic acid) and others on the linked list. It is also safe with diesel oil and many alcohols. The list is illuminating with respect to the variation of tested compounds.


4

One thought I had, does PETG need a different clearance between the nozzle and the bed than PLA? Short answer: "Yes, for some it does". The results from your image are typically seen when the initial layer height for PETG is too small. PETG likes an additional gap on top of the usual that is used to print e.g. PLA. For me personally I don't experience ...


4

Thermal runaway protection (see What is Thermal Runaway Protection?) is triggered when the scheduled voltage to the heater element does not result in a specified increase in temperature within a specified timeframe. The exit of hot filament from the nozzle and the loss of heat of the heater block and the conduction heat loss through the heat break to the ...


3

For me, none of the classic solutions to PETG zits worked; these include extra retraction, slower/faster retraction, lower extrusion width, lower extrusion multiplier, avoid perimeters etc. It was especially disappointing to see lower extrusion multiplier making no difference whatsoever in reducing the zits, but only resulting in a mechanically weaker and ...


3

tl dr: For the most part, yes it should be color fast in the sun. It should be good for outdoor use. This website claims the following: Filament materials ... for outdoor use include ASA and PETG that are perfect for use in extreme conditions without changing shape or appearance. Printed pieces do not change colour either with the sun's UV rays and do ...


3

Here is the mental framework that I use to reason about PETG: In a nutshell you want to avoid nozzle contact. Unlike most other plastics, PETG sticks to hot brass really well and every time the nozzle moves through material it will pick up some of it. Material around the the nozzle then sticks to a random place creating a blob. It can also cook, turn ...


3

PETG doesn't bond well if the layers aren't both at a fairly high temperature, as noted by the other answers. As mentioned, try reducing or simply turning off layer cooling. Additionally, try printing at a smaller layer height, or increased line width, to force the layers to bond more effectively. A final solution would possibly be to print a wall around the ...


3

None of your prints look like they are sticking well to the bed. You didn't specify the bed material. For many bed types, you might have success with Aqua Net hair spray. Like any material, if it isn't solidly sticking to the bed, the print won't be good. This probably is not related to your problem, but you may need to reduce the drive gear pressure or "...


3

I had problems with jamming PETG due to retraction. My model had many retraction moves, such that the amount of filament used during a printing move was less than the retraction distance. I found that several trips through the feed gear flattened the filament, which caused two problems. The flattened (or ovaled) filament had trouble fitting through the ...


3

230 °C is way too cool for PETG and will result in underextrusion unless you print really slow, and poor bonding. Underextrusion in turn leads to stringing because of pressure build-up. I print PETG at 250 °C.


3

PETG requires a heated bed otherwise it will shrink, detach from the platform and begin curling at the edges. PLA, however in some situations does not require a heated build platform. It depends on the build surface. Some surfaces need to be hot to work, and some do not. Keeping it on helps stop the part from cooling too quickly as well. However with the ...


3

For long prints, if turning off bed heating saves money, throwing out the filament from a detached print costs you more. The risk to gain ratio is very skewed. The “savings” in turning off the bed are considerably negative, and, as pointed out, the risk of losing the print is increased.


3

Are you using Z-hop? Is there any play in the Z-axis direction? It appears that parts of the first layer are printed much thinner than other parts. What can happen if there is a little play in the Z-axis direction that the nozzle doesn't return to the same level after a Z-hop movement (e.g. backlash in the leadscrew nuts). The "transparent" printed part ...


3

I saw PETG printed at 100 mm/s, but 150! That's a lot. One solution to avoid blobs may be to limit the maximum speed to a value you can actually achieve with reliable results. Simple test to find your machine limits (each combination filament brand + nozzle + temperature has a different value): extrude filament in the air at increasing speeds, see how the ...


3

This does sound a lot like you are experiencing the effects of heat creep (How is heat creep characterized?). You should lower the temperature of the hotend and increase the printing speed and retraction speed and possibly lower the retraction length. If this is heat creep, a new extruder will not help you until you solve the heat creep first. A new hotend ...


Only top voted, non community-wiki answers of a minimum length are eligible