I get a very high rate of fails at the very start of the print. The print starts but the ABS doesn't stick to the glue/glass. It starts out as a stream of ABS that slips and spins around and ends up in a wad on the tip. I have varied temps of bed and ABS and been pretty careful with the glue application. I have also done some mods to keep the peek fan from cooling the extrusion tip. Sometimes it seems to take a few seconds before the material starts to extrude at the very beginning, even if I have run last minute, and I mean very last second, 10mm extrusion tests to clear the pipe. Bed temp has been varied from 80-90 degrees. Tip from 218 to 228 degrees.
1) Is it a gap issue between glass and tip?
2) Is the ABS coming out too cold to stick?
3) Is some "retraction" going on where ABS is being withdrawn from the tip at the git-go and then comes out too cold?
4) the Kyson stepper motor is set for 160 (motor_current)....Is it filament starving the hot end?
I have other problems, but one step at a time. Thanks in advance.
retraction?
Re: retraction?
My first guess is that your first layer is too high above the glass. Try lowering until your first lines look a little squished.
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nitewatchman
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Khalid Khattak
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Re: retraction?
Some other tips i shall give you that i do most because at some location my bed is not even...
1- Always Use brim
2- Use Glue Stick on the bed.. I have glass on heatbed and i use to set bed temperature 105C so that glass get at least 80C.
3- Watch few layers closely and when you find detachment from bed just add one drop of superglue to keep the brim intact... then forget it
4- When the bed cool down the part will be pop-out
5- Just scrap glue-stick at super-glue location so that super glue easily scraped off from glass.
1- Always Use brim
2- Use Glue Stick on the bed.. I have glass on heatbed and i use to set bed temperature 105C so that glass get at least 80C.
3- Watch few layers closely and when you find detachment from bed just add one drop of superglue to keep the brim intact... then forget it
4- When the bed cool down the part will be pop-out
5- Just scrap glue-stick at super-glue location so that super glue easily scraped off from glass.
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BenTheRighteous
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Re: retraction?
I get kinda the same thing, I use a setting that I think is called "skirt" to fix it. It basically draws circles around your object before it starts printing.
It's a lot like brim except that it's not attached to your part.
The printer almost never gets the first part of the first circle correct, but by the it's finished its second pass and starts on the actual part, the extrusion is primed and perfect.
It's a lot like brim except that it's not attached to your part.
The printer almost never gets the first part of the first circle correct, but by the it's finished its second pass and starts on the actual part, the extrusion is primed and perfect.
nitewatchman wrote:it was much cleaner and easier than killing a chicken on top of the printer.
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RocketMagnet
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Re: retraction?
Agree if your Z height is wrong it wont stick and as said above if it doesn't look a bit squashed its too high.
A nice opaque layer of glue applied cold + correct Z height + bed 90 degC + is a good start.. there are other factors (e.g. too low a nozzle temp, your feed stepper is struggling due to too low current setting causing underfeed, your going too quick so slow it down etc etc).
A brim isn't needed unless the object your printing has a very low contact surface area with the bed and it's breaking free mid print.
Get your setup right and you don't need brims for most stuff unless your printing lots of very small objects... or something tall relative to its contact area..
A skirt is to prime the nozzle with plastic (you lose some when it oozes as it heats up so its starved initially) by printing away from your object for a specified length.. this can be either done with a minimum length before it starts printing the object or a number of perimeter orbits of the object if its big enough, clearly smaller objects need more orbits before printing.
So a brim is part of your object to increase it's contact surface and needs removed once you finish the print but can leave marks so really only needed as a last resort imo.. A skirt is simply a primer length to get plastic flowing.
A nice opaque layer of glue applied cold + correct Z height + bed 90 degC + is a good start.. there are other factors (e.g. too low a nozzle temp, your feed stepper is struggling due to too low current setting causing underfeed, your going too quick so slow it down etc etc).
A brim isn't needed unless the object your printing has a very low contact surface area with the bed and it's breaking free mid print.
Get your setup right and you don't need brims for most stuff unless your printing lots of very small objects... or something tall relative to its contact area..
A skirt is to prime the nozzle with plastic (you lose some when it oozes as it heats up so its starved initially) by printing away from your object for a specified length.. this can be either done with a minimum length before it starts printing the object or a number of perimeter orbits of the object if its big enough, clearly smaller objects need more orbits before printing.
So a brim is part of your object to increase it's contact surface and needs removed once you finish the print but can leave marks so really only needed as a last resort imo.. A skirt is simply a primer length to get plastic flowing.
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RocketMagnet
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Re: retraction?
Yeah lots of variables but a structured approach will get you there. As long as your just doing it for fun then the trouble shooting aspect can be fun and rewarding in itself IMO, you learn
more when stuffs going wrong than when it's all working...
I just noticed your going as low as 218 DegC which could be causing flow issues and would probably cause layer adhesion issues on thin walled objects but it
depends on your ABS source. Personally with my ABS source I'm in the range 227-233 which encompasses first layer and subsequent layers (so first layer temp @say 227 and plus 3 DegC for the rest so 230 etc).
Being in a cold draughty room can also cause issues due to increased shrinkage which can cause prints to let go (as well as look deformed even if the don't) so lots of people build enclosures. Mines in a warm room so I don't need one.
A brim can be useful in other circumstances e.g. a large box to try and prevent curling at the corners but generally for everything else outside of small objects your compensating for something else that's wrong IMO.
more when stuffs going wrong than when it's all working...
I just noticed your going as low as 218 DegC which could be causing flow issues and would probably cause layer adhesion issues on thin walled objects but it
depends on your ABS source. Personally with my ABS source I'm in the range 227-233 which encompasses first layer and subsequent layers (so first layer temp @say 227 and plus 3 DegC for the rest so 230 etc).
Being in a cold draughty room can also cause issues due to increased shrinkage which can cause prints to let go (as well as look deformed even if the don't) so lots of people build enclosures. Mines in a warm room so I don't need one.
A brim can be useful in other circumstances e.g. a large box to try and prevent curling at the corners but generally for everything else outside of small objects your compensating for something else that's wrong IMO.