Still Struggling in the Deep ABS-with-Support Sea..

[huangleike]

Hi all, it's me again.

Last time I had a problem printing ABS 100% infill because of wrong extrusion settings.
After doing a calibration square (advice by Jules, thanks!), I'm able to get rid of most of the hedgehog effect and most of the things were going well.
However, there are still some problems I can't figure out the reason.
Every part is printed in Hatchbox Black ABS, 80% infill, 0.90 extrusion multiplier at 0.40 mm width (0.35 mm nozzle diameter), with 5 dense support layers (70% infill), 1 mm extra inflation distance. 100% first layer height. Print speed is at 60 mm/s and X-Y moving speed at 120 mm/s. Nozzle at 235 C and heating bed at 95 C (Elmer's washable school glue stick applied).

Picture 1:
This is the lower surface of the part. I've never been able to get the lower surface smooth or beautiful after removing supports. However as seen in the red square there is a deformation at the corner of the model, making it unusable.

Picture 2:
This is the second problem I faced. In the red square, you can see some "wave-shape" indentation. I saw it after removing the supports on it.
The third problem is in the blue square. There's still some hedgehog effect and I don't know why it happened because I already calibrated the extrusion multiplier to 0.90. (Calculation comes out 0.9099 and it's nearer to 0.91 rather than 0.90 actually, but I don't want it to over-extrude so I set it to 0.90)

Picture 3:
Still, deformation and hedgehog effect.

Picture 4:
What are these? Set outline direction to "Outside-In" but no difference. Turn on "Coast at End" at 0.20 mm but no difference. I watched it print and saw that it was generated at the stop, not the beginning of a loop.
By the way, I found the printer "ignore" small supports when Coast at End is turned on. Why? Is that really caused by Coast at End?

Picture 5:
About shaking, about waves. The printing speed is at 60 mm/s and X-Y moving speed 120 mm/s and I really don't think this is a too-fast speed. What else may cause this other than the bed's shaking?

Sorry I have so many questions. So let me conclude:
Problem 1 - Deformation
Problem 2 - "Wave-shape" indentation at supports area
Problem 3 - Hedgehog effect on a calibrated extrusion multiplier and 80% infill
Problem 4 - Blobs. "Only retract when crossing open spaces" - ON, retraction distance 1.00 mm, retraction speed 40 mm/s.
Problem 5 - Vibrations and ringings. After upgrading to V4 hotend and beginning using the default FFF setting for Makergear M2 V4 Hotend, I found that it seemed that the "acceleration" setting had been increased. Having the printing speed and X-Y movement speed set to the same number as the old FFF setting files, it still prints much faster. What else could cause the ringings?

Thanks in advance!

[3dPrintingMD]

Here is what I can advise on 4. Those are essentially Z Scar/ Stop Start points. You can line them up to create a seam.

I have the same issue with #5 ringing. I've done the 1000 max acceleration and still no real improvement.

How many shell layers are you using ? I think some of 1,2,3 are heat issues. Per hathcbox "Recommended Extrusion/Nozzle Temperature 210°C - 240°C" You are really on the hot side of the coin.

[Jules]

Keep in mind, these are just general printing issues, mainly relating to the kind of shape you are trying to print, not necessarily specific to ABS:

1. The lower surface of that handle looks rounded. That's the hardest shape to try to print with any 3D printer, because even with excellent support, you've got gravity working against you. (I tried for a week to print a little egg shape, and because the base was rounded up, i never could get it to print without those same kinds of dents in several places along the bottom curve.)

One of the guys recently (Jim?) said that those dents were caused by a heat buildup effect due to the small layer size. (not cooling fast enough). Since you're printing ABS, you can't cool it off with a fan, but you can print a sacrificial block next to it, to give the ABS time to cool while the block is printing. (That looks pretty large, but maybe since ABS is so much hotter it needs longer to cool.) Or you can print multiples of the same print if they will fit. Apparently the problem is more common with small prints.

2. If it would be possible for you to slice that in half and then glue it together, so that you had a flat surface in contact with the bed, you would get a perfect print. There is a way to do that in S3d, by placing the model halfway or so below the bed (or where-ever it makes sense to cut it), duplicating the model, and then flipping the copy over. (Jin came up with that one). The parts that are underneath the bed don't print. Then you could glue the two halves together.

3. The ringing effects are due to acceleration, not the X/Y movement speeds. To slow it down, add the code below into your Starting Script:

M201 X1000 Y1000 ; lower default accelerations

They're hard to get rid of completely, but you can minimize them with that code. (I don't know whether ABS likes to print slowly or not, but slowing it down some might also help.)

4. The dense support layers are a good idea, but I've also found that a cross-hatched support structure works a little better for providing support on tough overhangs. To set a cross hatch, use two angles of 45° and -45° in the Support Infill Angles Box. It's a little more tedious to remove, but it's a lot more stable.

5. As far as your remaining hedgehog effects go, if that part was an overhang, it's unfortunately going to happen. Even printing over support, it's printing over thin air, it's going to sag where there is no support. If that part was facing up, then there's a different problem, but no way to tell what caused it.

[swbluto]

The ringing is caused by inadequately secured motor heft with the use of a plastic motor mount (And probably also the mount's intrinsic design.), causing a spring-like effect that results in oscillations. An all metal motor mount would probably mitigate this issue, though I think a more direct securing of the motor's body (As opposed to its neck) would be beneficial as the body is where the mass, and thus the momentum, is.

This problem has been plaguing me in the form of the M2's inability to print thin column like features, which my replicators have no problems with (They, having wall street's money to hire college degreed engineers, had the collective foresight to resolve this problem at the start.). It'd be nice to think my M2 could do everything that my replicator could if it's "the best" printer out there.

[Bratag]

The ringing is caused by inadequately secured motor heft with the use of a plastic motor mount (And probably also the mount's intrinsic design.), causing a spring-like effect that results in oscillations. An all metal motor mount would probably mitigate this issue, though I think a more direct securing of the motor's body (As opposed to its neck) would be beneficial as the body is where the mass, and thus the momentum, is.

This problem has been plaguing me in the form of the M2's inability to print thin column like features, which my replicators have no problems with (They, having wall street's money to hire college degreed engineers, had the collective foresight to resolve this problem at the start.). It'd be nice to think my M2 could do everything that my replicator could if it's "the best" printer out there.

Damn dude - still with this? If you don't like the machine fine, but this passive aggressive BS just makes you seem like a petulant child. The M2 is perfectly capable of printing columns , your exact issue is the printing of fine detail in a larger surface and may be a deficiency in the design though honestly I have printed very fine details such as the ones you showed (see the blade of the vorpal sword I posted).

Now on to your point about an all metal motor mount , I believe one is coming shortly as indicated in a thread post from Rick.

The metal motor mount will be available soon.

Rick

[huangleike]

Here is what I can advise on 4. Those are essentially Z Scar/ Stop Start points. You can line them up to create a seam.

I have the same issue with #5 ringing. I've done the 1000 max acceleration and still no real improvement.

How many shell layers are you using ? I think some of 1,2,3 are heat issues. Per hathcbox "Recommended Extrusion/Nozzle Temperature 210°C - 240°C" You are really on the hot side of the coin.

Haha! I changed the max acceleration to X1200, Y800 and things seemed to get better.

I'm using 2 shells. You mean I should increase it to 5 or something?

Next time I'll try 220°C and see what happens.

Thanks!

[huangleike]

Keep in mind, these are just general printing issues, mainly relating to the kind of shape you are trying to print, not necessarily specific to ABS:

1. The lower surface of that handle looks rounded. That's the hardest shape to try to print with any 3D printer, because even with excellent support, you've got gravity working against you. (I tried for a week to print a little egg shape, and because the base was rounded up, i never could get it to print without those same kinds of dents in several places along the bottom curve.)

One of the guys recently (Jim?) said that those dents were caused by a heat buildup effect due to the small layer size. (not cooling fast enough). Since you're printing ABS, you can't cool it off with a fan, but you can print a sacrificial block next to it, to give the ABS time to cool while the block is printing. (That looks pretty large, but maybe since ABS is so much hotter it needs longer to cool.) Or you can print multiples of the same print if they will fit. Apparently the problem is more common with small prints.

2. If it would be possible for you to slice that in half and then glue it together, so that you had a flat surface in contact with the bed, you would get a perfect print. There is a way to do that in S3d, by placing the model halfway or so below the bed (or where-ever it makes sense to cut it), duplicating the model, and then flipping the copy over. (Jin came up with that one). The parts that are underneath the bed don't print. Then you could glue the two halves together.

3. The ringing effects are due to acceleration, not the X/Y movement speeds. To slow it down, add the code below into your Starting Script:

M201 X1000 Y1000 ; lower default accelerations

They're hard to get rid of completely, but you can minimize them with that code. (I don't know whether ABS likes to print slowly or not, but slowing it down some might also help.)

4. The dense support layers are a good idea, but I've also found that a cross-hatched support structure works a little better for providing support on tough overhangs. To set a cross hatch, use two angles of 45° and -45° in the Support Infill Angles Box. It's a little more tedious to remove, but it's a lot more stable.

5. As far as your remaining hedgehog effects go, if that part was an overhang, it's unfortunately going to happen. Even printing over support, it's printing over thin air, it's going to sag where there is no support. If that part was facing up, then there's a different problem, but no way to tell what caused it.

Thank you Jules! I've changed the acceleration and prints look better! Will try the 45, -45 support infill some day!

I tried for a day to print a Marvin key chain with perfect "bottom". When someone asked me to print a large, un-cut-able, high infill, need-to-be-precise-in-size print, I know I have much to learn.

I told myself this is probably because of the shape of the item, but I wonder if it's definitely not possible to solve. Is there a way, to print things with a perfect rounded bottom? SLA machine? SLS?

[Jules]

Actually, if you upgrade to the dual, and print with 100% support using a dissolvable (or different) material in the other extruder, you can get it pretty darned close to perfect. I was impressed at how much better the lower surfaces were with solid support.

I was underwhelmed with the PVA as support material, but PLA works like a dream to prop up PETG. I'm sure there's something that does the same for ABS. (Matter of fact, I would probably design the support into the file - just a solid prop for the part to rest on. Then print the separate parts from the two nozzles.)

But yeah, the lasers are probably going to be necessary to get it absolutely perfect.

[3dPrintingMD]

Here is what I can advise on 4. Those are essentially Z Scar/ Stop Start points. You can line them up to create a seam.

I have the same issue with #5 ringing. I've done the 1000 max acceleration and still no real improvement.

How many shell layers are you using ? I think some of 1,2,3 are heat issues. Per hathcbox "Recommended Extrusion/Nozzle Temperature 210°C - 240°C" You are really on the hot side of the coin.

Haha! I changed the max acceleration to X1200, Y800 and things seemed to get better.

I'm using 2 shells. You mean I should increase it to 5 or something?

Next time I'll try 220°C and see what happens.

Thanks!

The reference to shells was really for that particular model. What I'm learning to do more, and its pretty obvious, but I was just too excited to do in the beginning, is to look at the preview of the model, and look specifically in those areas for issues.

An example that I can use is, when I print something that I really care about the surface. You would be surprised to find out that I often see areas in the model along the perimeter where there is a lack of extrusion right in the preview. I can go back, add more overlap and bang all fixed. So I am learning to take sometime and check out the preview and realize its pretty damn to close to what the printout will be. You may find issues with it before you start printing.

[ednisley]

Is there a way, to print things with a perfect rounded bottom?

If you can split your object along the midline, print the parts with their rounded sides upward, then glue them together, you'll get nearly perfect results. Solvent-bonding two flat surfaces with alignment pins gives you excellent registration, an invisible joint (it lines up with the sidewall layers), and (if you do the glue properly) strength that's essentially equivalent to solid plastic (with a double-thickness bulkhead at the joint).

Otherwise, send it off to Shapeways. Their basic process also builds the object layer by layer, but they're laser-fusing plastic powder atop more powder: perfect support, all the way up, and it falls off when they pull the object out of the powder.

The process constraints are different than molten filament printing. In particular, you get a solid plastic object unless you design an interior void with a drain hole; they charge by total volume, making solid "infill" rather expensive.