Problem printing ABS with ANET A8

I am new to 3D printing and have been successful with PLA prints, but I am failing with ABS. The two problems I have are slight delaminations of my layers and the first layer is lifting the tape off my heated bed. I am using Solutech glow 1.75mm filament in my printer. I am letting Slic3r pick the optimal perimeter and infill speeds and have the bed set to 100C and the extruder set to 230C. Room is normal room temperature around 70F

First the warping issue. My 3d printer has a heated bed, but can only heat to 103C, it does not seem to want to get any hotter. I am covering the bed with blue painters tape, from Harbor Freight, not name brand and then spraying the bed with AquaNet. I also print a raft and the print sticks perfectly to the tape, but the tape is lifting off the bed! Do I need different tape? Should I print directly on the aluminum? I thought about setting the bed temperature higher, around 110c and trying to achieve that temperature with a heat gun, thoughts?

Regarding my slight delamination, I think I can fix this. It was terrible at 220c and at 230C the piece is solid and won't break apart. I think I will try 235C next to see if that fixes it. Should I also put a fixed speed into my perimeter setting?

Thanks in advance,
Chris

To stop the warping, you pretty much need an enclosure.

If you can't work something out, then try putting your layer fan on very low, ie just ticking over. I'm not sure about the physics of this, but it certainly helps for me.

An enclosure is the better solution though. I've enclosed both my printers, and they work really well with ABS now. I've just printed a 100 gram part, which had really good adhesion and very little warping.

What I had to do to print ABS -do the adhesion layer (kapton tape or pipe weld cement liquid dried out), start the hotbed heating, and leave piece of cardboard on the heated bed until just before the print starts (ABS usually glass transition point 105). Quickly whip if otf the bed as the nozzle starts moving - the bed temp will drop a bit, but should give enough time to get that all important first layer down.

Printing a brim helps keep the corners down and laminated, to a certain extent.

Enclosures help a lot, but if you can eliminate draughts without one, no real difference. Easier said than done.

If it's a heated enclosure, even better. But then you are talking environmental controls, heating and cooling systems etc. Not that straightforward.

Those 12V heated beds just don't like ABS temps without a lot of nursing and hacking. Plus, you are much more likely to blow the MOSFET on RAMPS controlling the heated bed, unless you have already upgraded from the standard ST55 junk. I even had to replace all the wires from PSU to RAMPS to heated bed with thicker cable to pass enough amps to heat the thing.

MOST IMPORTANT

The REAL secret of ABS is - once a model is finished, leave it on the bed and GRADUALLY bring the heated bed temps down (and enclosure temps if you have a controllable enclosure). About 2 degrees C a minute is plenty quick enough (you will still hear it popping as it cools and shrinks, that's normal.) You can speed up the cooling as the temperature drops, but just shutting down the bed entirely at print end is NOT a smart move with ABS.

If if cools unevenly, it WILL crack, which is very upsetting until you realize what the culprit is.

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-Chris-
I think I will try 235C next to see if that fixes it. Should I also put a fixed speed into my perimeter setting?

Thanks in advance,
Chris

Borderline temperature if your hotend has a PTFE tube in it. Not necessary for ABS printing. The software settings wont solve hardware problems.

Edited 8 time(s). Last edit at 10/24/2016 10:23AM by DragonFire.

Thanks for the advice. Will an enclosure built out of 1/4" plexiglas be sufficient to keep the printer hot? I also brew beer so I am very familiar with maintaining a temperature in a chamber to +- a degree. What is the optimal chamber temperature? I use the following heater in my fermentation chamber, it would probably work perfectly for the printing chamber.



I did another print this morning, set the bed to 110C, nozzle to 235C and slowed the perimeter to 50mm/s.

I used a heat gun to heat the hot bed to 110C and it started printing.

Print came out solid with no delamination, it stuck to the tape, but once again, the tape lifted off the hot bed. Also, the bed quickly dropped to 100C once I removed the heat gun from it. Can I just print directly on the hot bed with no tape? The Kapton tape is in the mail...

It is almost like the power supply is running out of current once the whole printer is running preventing the hot bed from getting hot enough. Does this make sense?

Thanks,
Chris

Cardboard box works just as good.

There isn't an "optimal" temperature. Air is a very good thermal insulator, the snag is keeping it all in the same place, and stopping colder air from cooling the hot ABS monomers too quickly.

Mr Monomer does not like being colder at one end than the other above GTP, and tends to break up and find a monomer set more in tune with it's own thermal level when too much of a difference. Not so much of an issue with polymers like PLA.

There are 2 issues with a heated bed not getting hot enough. One is the MOSFET on RAMPS, the standard ST55 usually blows up when trying to deliver that kind of wattage.

Also, the energy in has to be greater than energy radiated, conducted and convected out. If the wires taking the power from the supply, into RAMPS, and to the hotbed, are too long and too thin, they just can't carry enough amps to get past the thermal equliibirum point you are reaching. Replacing that particular wire run (FROM the power supply, TO and FROM RAMPS, up to the hotbed itself) is the ONLY way to get more current into the hot bed. You cannot break the laws of physics. Thickest that will fit, shortest run that still gives full movement of the heated bed. Something about 5mm across, rated at 15A or better (20A recommended but it's usually a little bit thick for the RAMPS connectors). It's OK if you have to taper the ends a bit at at the connectors - that won't bottleneck the whole wire circuit too much.

How can you tell if the wires are the problem? Easy, connect the hotbed wires straight to 12V and monitor the temperature. I bet you have the same problem.

Putting insulation UNDER the bed helps a bit too, you dont have to remove it prior to printing.

ABS rarely sticks to an unlayered heated bed, and really, you DO want a sacrificial layer in case the bond is too good (too much stick) and you rip part off the bed off removing the part.

I found pipe weld cement awesome at sticking ABS. Not recommended unless you have a metal hot bed / print on to glass on top of a hot bed. It works on fiber beds, but to remove it completely (usually peels off cold) sometimes you have to resort to acetone - which does not do a fiber glass hotbed any good at all.

Fresh Kapton tape should not remove itself, either you have a bad piece at present, or it's not really Kapton tape you were sold. It is not easy to apply evenly and quite frankly I have to wrestle the stuff onto and off of glass. You could try powering everything off and giving the bed a good wipe down with surgical spirit or methylated spirits or something like that, make sure its REALLY clean before you apply the tape.

G|iving it a wipe after you've applied it with a good cleaner is also recommended, takes all the fingerprints off, before you try printing onto it.

Final point - MAXBEDTEMP in config.h. The system will usually bug out and stop heating at 15C below that anyway, so if you want 110, you have to set MAXBEDTEMP to 125.

Edited 11 time(s). Last edit at 10/24/2016 06:34PM by DragonFire.

The printer is behaving as specced on the manufacturers page;-

[www.anet3dprinter.com]

If you want better, you might have to replace the power supply - only gives 20Amps or so at 12V, which is about twice what you are asking for JUST the heated bed.

It is also running Repetier, so I have no idea how you improve the MAXBEDTEMP setting (Marlin).

Don't try putting Marlin onto it. A much better idea is to buy a replacement Arduino Mega, put Marlin on that, and you still have the Repetier Arduino to work with as you struggle to get Marlin operational.

You just pull the RAMPS board off vertically to get at the Arduino - make sure you get the pins lined up properly when putting the RAMPS back on.

Edited 3 time(s). Last edit at 10/24/2016 06:46PM by DragonFire.

Obviously I have a lot to learn. Thanks for the link to the specifications page, the hot bed isn't designed to get hotter than 100c.

To be clear, I do not have the Kapton tape yet, I just ordered it this morning. The blue painters tape is what is lifting off the bed.

Is this printer not really setup for ABS then? I guess I will try the Kapton tape and report back in a few days.

Thanks for the help.

Chris

Ha. Check the wires, it will do it - heated beds usually rated up to 120C. Even the old MK 1s were that good.

The snag is getting the amps to them, and if the firmware is set NEVER to go above 100C, then that's your problem.

Put it another way - the PARTS will do ABS. It's just not been built to quite reach 105 on the heated bed.

Like I said, to test the bed, wire the power to the hotbed straight to +12V and see what the temperature does - it should go up beyond 100, if not, the wires have been cut just so to limit it at that (another safety feature).

Do keep your hand on the power switch as it heats, you don't want it going past 120 (the typical ceiling for such 12V beds).

Oh yah, this book is GREAT for explaining i3s and a lot about 3D printers too. But it's built around getting an i3 with Marlin running on it. You are already 95% of the way there anyway.

[www.amazon.com]

Repetier is a propreitary firmware now, that's why a lot of folks here won't touch it. If you want to find out about Repetier, google it...

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DragonFire
Repetier is a propreitary firmware now, that's why a lot of folks here won't touch it. If you want to find out about Repetier, google it...

I didn't know that. It still seems to be on github with a gpl: [github.com]

Personally I like Repetier firmware, it works well, particularly with respect to the heaters. I also don't have any problems with the mk2 pcb heaters driven from ramps which will get to 100C in 6 minutes and maintain 110 without problem (without an enclosure) on a well regulated 13V supply. I don't find I need any more than that. For 1st layer adhesion I use glue stick on glass, and layer to layer adhesion benefits from printing slow, thick, wide and hot. I typically set 240C for ABS, but I haven't checked actual nozzle temperature recently. Some of my hotends have PTFE liners, some don't.

It would appear I have been misinformed... but have never had any joy downloading the thing, let alone getting it onto an Arduino.

It seems like you have to upload an existing version before you can download a new one... bit of a chicken and egg situation if you haven't got it in the first place.

Edited 1 time(s). Last edit at 10/25/2016 11:22AM by DragonFire.

I use a heat bed @100, hot end at 240, printbite cover on glass with a drop of abs slurry and no enclosure.
The only issue I have is with a bad real of abs (but that is working it self out)
My problem is that I need a new hotend to use pla.

I am in much better shape now, adding the enclosure allowed the printer to maintain the 100c bed temperature. My generic Kapton tape from Amazon also worked great although it was really hard to get it flat without wrinkles. The enclosure ramped up to 115F during the printing. My layer height is .2mm and I made the bottom 6 layers thick. I am using 10% fill with a honeycomb pattern. The bottom is still slightly warped. What is the next step? Should I increase my bottom layer thickness? Should I try a 110C bed temperature again now that I have the enclosure?

Botttam layer usually only double thickness as main print layer. Some use 195%, others 150%, but 6 times is a bit overkill...

Using a pin to pop air bubles in Kapton makes it easier to apply, if a little bit less perfect than using a flat edge to run it over a surface with,

I guess my first step would be to experiment with things like hair spray and liquid pipe weld, to find the best sticking compound for you.

Congratulations on your first ABS print.

Like I originally posted, I don't think the hotbed is going to get hotter without modificataion, that's manufacturers for you.