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gb86217

Just assembled, Great machine, try to improve

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Hi guys

Just assembled my ultimaker, took me about 15+ hours.

Tried to print some parts and very happy with what it can do. However there are some imperfections with the result, I want to find out whether everyone get it or just my machine. and how to improve.

IMG_1639.JPG

IMG_1640.JPG

IMG_1641.JPG

Do you guys get those bumps or gaps in the layers? I was using Cura with normal quality print settings, then for the forth part I tried increase print speed from 50mm/s to 80mm/s and it worked alright, slightly loose of quality but acceptable.

Anyway, thanks guys

 

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Welcome!! Those are pretty nice first prints, well done! But yes, there's always room for improvement.

What temperature are you printing at? To get better overhangs - reducing the droopy bits on the robot - you generally want to print slower, and cooler, and be sure the fan is on.

Where the prints have some gappy parts, that may be due to under-extrusion - not laying down as much plastic as you should. Increasing the temperature might help a bit, as might slowing down a bit. You also need to make sure that you are using the right filament diameter when you slice the object. Do you know the exact diameter of your filament? Cura defaults to 2.89mm I think, but that's rarely the right size - most commercial filaments tend to be 2.85 or even 2.8 in most cases. If that's the case with yours, then you'll be extruding less than you should, because Cura thinks that every mm of plastic that gets fed in is thicker than it really is - and that's how it controls how much gets extruded out of the nozzle.

As you can see from those two statements... there's no one 'right' print setting; you have to adjust for the object you're trying to print. There are competing needs of temperature, speed, and layer height that effect the end quality.

You might also check the tension on your extruder drive spring. The spring should not be fully compressed - on mine, there is about an 11mm length of spring between the body of the extruder and the head of the spring. Check the filament in the bowden tube after a print.... it should have clear teeth marks in it from the drive bolt, but not be chewed up or worn.

The 'normal' settings in Cura are a good starting point, so I'd continue to tweak things around those settings while you get the printer bedded in and understand it better - and get a feel for what sort of settings an object needs. If you have problems, it's tempting to think that the 'High Quality' settings in Cura - slower, thinner layer heights are the solution. And really they aren't. It's not higher quality in the sense of fixing problems, but rather just improving the finish - less obvious layers, and better handling of 'almost horizontal' slopes and curves. Even on 'normal' quality, with 0.2mm layers, you should be getting perfectly good results. If you aren't, then keep posting here and lets try to tweak the hardware and settings until you are.

Well done on getting started though! Those are some pretty nice first prints - you should be pleased!

 

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These prints are pretty good. Difficult to improve.

The robot has many overhang spots and of all of them, only one had the problem (circled). That part of the robot is very difficult to print because it is hanging in mid air when it prints that spot.

Whatever settings you used for the robot were slow enough - especially the antennas on the top - those look great so you must have printed them very slowly (the antennas). I don't think you can make the robot any better than that.

The other issue is more of a slicing issue. When the printer is printing *almost* level surfaces such as the top of a sphere, .2mm slices are more noticeable. This can be improved with .1mm slices. You can probably also double your speed if you slice at .1mm as the plastic will be coming out slower. But don't speed up your print so much that you have less than 10 seconds or so per layer as you will have other issues - especially with overhangs. It's critical that a lower level cool to a solid before adding the next layer. Especially for overhangs.

Next I predict you will have problems with warping when you print large parts. When you do, we will have solutions for you! Good luck.

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BTW, the lines of bumps on the heart gear piece - the right hand circle on that picture - is the z-scar where the print head is starting the layer, and changing height, leaving bit of a mark. Cura starts layers at the closest point to the home position, so depending on the geometry, this point can move about a bit. (and that moving to the start of the next layer can leave its own mark too, sometimes). You can see that it moves around a little bit where you circled, and then jumps a bit to the left for the rest of the print.

gr5 is right about thinner slices helping with curves, but I'm not sure that's what's going on here - at least not totally - the top of the curves (where the circles get small) is pretty good - the weak parts seem to be further down where the sides are still steeper - although it's hard to tell due to the angle of the photos.

 

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Welcome!! Those are pretty nice first prints, well done! But yes, there's always room for improvement.

What temperature are you printing at? To get better overhangs - reducing the droopy bits on the robot - you generally want to print slower, and cooler, and be sure the fan is on.

Where the prints have some gappy parts, that may be due to under-extrusion - not laying down as much plastic as you should. Increasing the temperature might help a bit, as might slowing down a bit. You also need to make sure that you are using the right filament diameter when you slice the object. Do you know the exact diameter of your filament? Cura defaults to 2.89mm I think, but that's rarely the right size - most commercial filaments tend to be 2.85 or even 2.8 in most cases. If that's the case with yours, then you'll be extruding less than you should, because Cura thinks that every mm of plastic that gets fed in is thicker than it really is - and that's how it controls how much gets extruded out of the nozzle.

As you can see from those two statements... there's no one 'right' print setting; you have to adjust for the object you're trying to print. There are competing needs of temperature, speed, and layer height that effect the end quality.

You might also check the tension on your extruder drive spring. The spring should not be fully compressed - on mine, there is about an 11mm length of spring between the body of the extruder and the head of the spring. Check the filament in the bowden tube after a print.... it should have clear teeth marks in it from the drive bolt, but not be chewed up or worn.

The 'normal' settings in Cura are a good starting point, so I'd continue to tweak things around those settings while you get the printer bedded in and understand it better - and get a feel for what sort of settings an object needs. If you have problems, it's tempting to think that the 'High Quality' settings in Cura - slower, thinner layer heights are the solution. And really they aren't. It's not higher quality in the sense of fixing problems, but rather just improving the finish - less obvious layers, and better handling of 'almost horizontal' slopes and curves. Even on 'normal' quality, with 0.2mm layers, you should be getting perfectly good results. If you aren't, then keep posting here and lets try to tweak the hardware and settings until you are.

Well done on getting started though! Those are some pretty nice first prints - you should be pleased!

 

 

These prints are pretty good. Difficult to improve.

The robot has many overhang spots and of all of them, only one had the problem (circled). That part of the robot is very difficult to print because it is hanging in mid air when it prints that spot.

Whatever settings you used for the robot were slow enough - especially the antennas on the top - those look great so you must have printed them very slowly (the antennas). I don't think you can make the robot any better than that.

The other issue is more of a slicing issue. When the printer is printing *almost* level surfaces such as the top of a sphere, .2mm slices are more noticeable. This can be improved with .1mm slices. You can probably also double your speed if you slice at .1mm as the plastic will be coming out slower. But don't speed up your print so much that you have less than 10 seconds or so per layer as you will have other issues - especially with overhangs. It's critical that a lower level cool to a solid before adding the next layer. Especially for overhangs.

Next I predict you will have problems with warping when you print large parts. When you do, we will have solutions for you! Good luck.

 

Ok, First of all, you guys are amazing, did not see friendly forums like this one for ages. Big thanks to both of you.

The first two things I printed out was one of the fan duct and a bowden clamp (showed on picture is not my own), cause the bowden tube keep jumps out.

CIMG5176_preview_featured.jpg

they came out really good and I am happy with them. the clamp worked good, I would recommend them for new users.

now for the questions, I kept temperature at 220C, you were right, cura's setting for filament is 2.89mm, I double checked the filament roll I got from ultimaker shop. sticker said they are 2.85, so changed that, I think it improved a little.

I will play around with the temperature settings to see whats going to happen, sorry I went to the lazy way that just asking questions around here but I am glad you guys are very helpful.

I think the extruder works fine as I can see little teeth marks on the filament. Checked screw, it was not too tightened, but, after a few hours print, I noticed one nut was loosed in the x-axies blocks, so I would recommend other new users to check around after a few print.

Will try to change the slice hight see what happens.

Could I ask whats the "warping problems" I going to have? only on large prints? so I can keep eye on it.

Thanks for all of you.

 

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Glad we could be of help :-) I remember how overwhelming it was at first (It'll be a year in a couple of days) when I was trying to figure out how all the variables interact to affect print quality.

The bowden clamp really shouldn't be necessary with the new hot end design that is fitted to your printer. People used to have a lot of problems with the tube popping off... it could happen as parts got worn, or as a result of excess pressure from printing too fast. But it really shouldn't be necessary for new printers, as a rule. Maybe something about your hot end wasn't quite right, or perhaps the assembly was slightly off in some subtle way - your prints seem pretty good though, so no worries... just be aware that something might be slightly off in your hot end, if you start getting lots of plugging problems or something.

The warping issue is basically that the plastic contracts as it cools. And it does it in a non-uniform way, which can cause parts to bend. Typically, what happens is that the corners come loose from the bed, and start to curl up. So you get a curved base - and then the head hits the curvy bits as you print, so at the very least you get shorter sides than you should - because the bottom is curving up to meet the print head, leaving less room for the sides... so the head jsut scrapes over what has been printed. Worst case, the head catches on the print so much it knock the object loose, and drags it around.

With PLA, you typically get warping with objects that have a lot of solid infill, or that are very wide and flat. Ways to minimize warping include turning the fan on as little as possible in the print (although this may affect overhangs) and also printing on blue tape that is as wide as possible (you can buy 3" rolls in DIY stores here in the US at least, and 6 or 8" rolls online) and wiping it down with isopropyl alcohol before you print. That will keep the object very firmly anchored to the bed, and help avoid the worst warping effects at the base - but depending on the shape you might still get problems elsewhere.

ABS warps even more. At the very least you need a heated bed to get it to stick, and even then warping can cause problems - as the print cools - resulting in cracks between layers etc. Some people go to the extreme of closing in the sides and top of the printer to maintain a heated chamber, in order to provide very uniform cooling.

 

Ok, First of all, you guys are amazing, did not see friendly forums like this one for ages. Big thanks to both of you.

The first two things I printed out was one of the fan duct and a bowden clamp (showed on picture is not my own), cause the bowden tube keep jumps out.

Could I ask whats the "warping problems" I going to have? only on large prints? so I can keep eye on it.

Thanks for all of you.

 

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Hi Guys, just want to show some more pics, here are some new print that I just did and want to ask some new questions.

The left robot was printed when the machine just assembled, the right one is the new one printed with new settings.

old: speed: 80, temp: 220, slice: 0.2mm, filament: 2.89

new: speed: 50, temp: 210, slice: 0.1mm, filament: 2.85 (more driver belt tension, more extruder tension)

IMG_1659.JPG

IMG_1662.JPG

I can see the surface finish and overhang problems are improved, however other problems has become more obvious. the Z scar is worse due to smoother surface, but the biggest problem at the moment is the "wave" looking behind every turning point. it's seems the hot end has been vibrating every time it's changes direction, and that was the reason I try to increase the belt tension.

The following pic shows how bad the wave can get on a smooth finish. Also noticed the right hand lower corner of the object has left up a bit. Not sure thats called warping?

IMG_1666.JPG

Any one could help please?

 

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I have no idea about temperature and noise. The voltage going to the z stepper is probably a little higher is my guess but I'm not an expert. I wouldn't worry too much - these steppers are very tough.

The X axis is connected to the rear side of the ultimaker which is a large piece of wood and I would expect that to be louder. Did you use the newer black plastic spacers for the x motor? Or did you use the wooden spacer? Supposedly the black plastic spacers are quieter.

 

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In theory, tightening or loosening the belts don't eliminate "ringing". It changes the frequency. The resonant frequency is a function of belt tension, and mass of the print head. Other things can dampen the ringing e.g. if the rubber in the belt isn't a perfect spring and has higher resistance at certain frequencies. I would expect the rubber to act less springy at high frequencies but I don't know how high is high frequencies.

So if you tighten the belt to exactly twice the current tension I would still expect ringing but closer together.

It seems to me we should be able to add a tiny box of loose sand or similar to the print head to help reduce ringing. The energy from the ringing would shake the sand and warm it up slightly and dampen the ringing.

You can also reduce the ringing by reducing the acceleration and/or the "jerk". But this slows down prints. Be aware that if you change these values you have to save them or they will get lost when you power cycle marlin. You could add them to your "start gcodes" or you could modify them using the ulticontroller.

The amount of ringing on your prints is small enough for me that I don't mind it at all.

If you want perfect prints one thing you can do is sandpaper the lines off and then paint with a thin coat of automobile primer spray paint. This is a common, standard spray paint found at auto parts stores. The problem with only sanding is you get a dull finish where you sanded. Some people reheat the plastic to get it shiny again. Some people use a solvent, but solvents for PLA are rare but you can google about this.

It's not 100% clear to me if your vertical lines comes from:

1) ringing (which should fade out left to right - this is most likely but hard to tell in your pictures)

2) STL - some stl models have vertical lines in them - visible in the cad software.

3) oscillating plastic due to high temp. Unlikely but details here:

http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/

Other slicers (not cura - try kisslicer) let you modify the vertical seam so it's on a different random position on each layer. I prefer to have it in the same spot every time so I can rotate my part to have that hidden. Don't use Joris setting to remove vertical seam unless you have a simple solid with no holes or cavities (a cup is really the only thing you can print with Joris) as Joris can wreck a print for anything more complicated than a cup.

 

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I have no idea about temperature and noise. The voltage going to the z stepper is probably a little higher is my guess but I'm not an expert. I wouldn't worry too much - these steppers are very tough.

The X axis is connected to the rear side of the ultimaker which is a large piece of wood and I would expect that to be louder. Did you use the newer black plastic spacers for the x motor? Or did you use the wooden spacer? Supposedly the black plastic spacers are quieter.

 

I am sorry, I have made a mistake, it's actually the Y motor is hotter and louder than X motor.

 

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