gr5

Raft is old technology. You shouldn't need it anymore. The 3d community mostly stopped using rafts and have moved on to better. But for a few years it was the best we knew how to do ABS. I've never heard that underextrusion hurts or helps overhangs. Certainly these green lizards don't look underextruded. There is a huge discussion on why overhangs don't print well and do strange things while printing (they lift up) along with great slow motion video but it will take you a long time to find all the jewels of information among the bad guesses of whats going on: ========= What causes raised edges and crappy quality on overhangs. http://umforum.ultimaker.com/index.php?/topic/4094-raised-edges/ Skip right to "page 2" and look at foehnstrum's video and read all the posts after that possibly. It's not until around post #39 and later that we really begin to understand what causes the issue. The problem has to do with the fact that liquid PLA is stretchy like melted mozzarella cheese or like mucus. The liquid plastic is pulling like a rubber band as it goes down and creates a lip or raised edge where there is an overhang. The effect gets stronger on each succeeding layer. It is what causes the lower quality "look" of overhangs. Sometimes the part will actually rip free from the bed because of this (which is easily fixed by making parts stick like hell - another topic).

She was at our booth also - holding the gray plastic amazingly detailed head. I don't remember seeing her - I might have been away from the booth then. Or she just wasn't memorable? More likely I wasn't there.

Yeah I saw them in this video by "rainbow girl" and I could see the UM booth in the background. Even though I spent maybe 8 hours walking around that fair and I thought I went everywhere in our building as well I realized after seeing that video that I never went down that particular "lane". 32 seconds into the video - the eiffel tower scene you can see both raise3d and ultimaker in one shot:

Yeah I'm not happy with that. They changed the firmware to limit to 100C. I have no idea why. You could try the tinker version of firmware - not sure what temp that goes up to: https://github.com/TinkerGnome/Ultimaker2Marlin/releases tinker Marlin is worth installing whether or not it goes to 110C.

Maybe it's the mk7 hobbed gear causing those blobs. Each blob is when the next tooth touches the filament?

Didn't you just say the blobs appear on glass with nonhacked driver and are gone with hacked driver? Then you went back to non hacked driver and blobs came back? It sure sounds like you have strong evidence that it's probably the driver hack, no? I mean I find it hard to believe but isn't that your claim? I don't get why you say "different issue"?

Oh another difference - in reprap mode your printer WILL NOT home. It will not prime the head. That stuff is done in the "start gcodes" and "end gcodes" which are also part of the printer configuration for both cura 15.04 and 2.1.2

In cura 15.04.* you go to machine settings and set it for reprap mode. This changes 2 things - it makes the extruder moves in mm (versus volumetric) which is normal and what you need for usb printing and it also includes fan speeds, temperature settings. Fan speeds and temp settings are no big deal as you can just do those manually in on the printer before you start printing. But having extruder in volumetric mode is a problem. In cura 2.1.2 I don't know how you do it. I know you can definitely do it but you probably have to go edit the printer configuration files somewhere. I don't even remember where those files are but I know they exist as I looked at them many months ago when cura 2 was still beta. Notice that cura 2.1.2 allows you to use the profile for dozens of non-ultimaker printers. Probably all of those are in normal reprap mode and not volumetric mode. So if you can find the config files for all those printers and for your printer you can see what the changes are. It's simpler than I'm making it sound.

I really love this color by the way.

Nice. I recommend you move your glass closer to your nozzle. Simply turn the 3 leveling screws about 1/3 turn counter clockwise from below. Stay away from the automated procedure. I say this because your bottom layer is a bit underextruded due to nozzle being too far from glass. The rest of your print of course is unaffected. If you don't do this your parts won't stick well either.

Also leveling issue. What you describe sounds like nozzle was too far from glass. It takes about 1 second to test this theory. When it is happening just push up on the bed from below. You can use your nose or chin if you can't use hands. The height of the olsson block and nozzle versus the original is of course different so you need to relevel after changing that out. Not having fingers that can turn those 3 leveling screws would really suck. Makes me want to write a leveling procedure just for handicapped people (I forget if you are handicapped or not - I know there's at least one person in england on this list...).

Wow! Serious variability in extrusion before replacing the ptfe.

I was going to suggest protopasta HT. HT=high temp. Printing all high-glass-temp plastics is much more difficult than printing PLA but with protopasta you (in theory) get the best of both worlds - it prints like normal PLA (low glass temp) but then you bake it and it ends up being a high glass temp material. Let us know if it's as easy to print and how long it lasts in your pickup bed!

Instead of spending several prints learning to be a blue tape expert I strongly suggest you become a "hot glass" expert. You thought you knew what you were doing on glass until you got to this horse. It's possible to get things to stick incredibly well to glass but then pop off when cooled. It's all about the leveling. both with tape and glass once the bed is level you need to set the distance between the nozzle and glass to determine if the bottom layer is squished or not. If you want dimensional accuracy you want no squishing (or add a chamfer like IRobertI does). The best way to achieve this is while printing the skirt around your horse you adjust the 3 screws. Halt, clean plate, and restart this print several times (maybe 5 times if you are new at this) until your skirt traces are .4mm wide (if .4mm nozzle). Measure with micrometer. This is only if dimensional accuracy is more important than having the part sitck to the glass. If sticking is more important than move the glass closer to the nozzle by turning the 3 screws the same amount. Don't keep re-running the stupid leveling procedure. That gets you level and it gets you close to the right distance but adjusting based on the skirt trace width is much more accurate. There's a HUGE difference in how much the part sticks to the glass. About 5X difference between the normal bottom layer height and squished height. This is true for both blue tape and glass. So there's no advantage to go to blue tape. As far as glue - most people use too much. Put on 1/10 as much glue and spread it around with wet tissue. When done the glue should be invisible. As far as getting off blue tape - I recommend you rip up the tape off the glass then soak the part in rubbing alcohol for about 1 minute and then the tape comes right off (maybe 4 minutes? It's been a few years). Or compromise, use a very sharp putty knife (sharpened with a file to be as sharp as a steak knife) and don't worry about destroying the blue tape.

I'm not sure the extended is still for sale. It looks like they took it off the UM website so if you want one you might have to hurry to get the last few available. Or get a used one. The quality is just as good as UM2 as far as I can tell (I have both). As far as motion at the top - PLA is stiff enough that you can print tall skinny parts without much of a problem. If the part is 1:10 ratio (e.g. 1cm wide, 10cm tall or maybe 3cm wide and 30cm tall) you are starting to push the limits where the quality at the top edge won't be as good because the part is vibrating a little bit. But you can sand it, fill it, paint it, and it should be perfect. However going to 1:20 ratio and it's just too much. I'm not sure where that point is exactly (1:10 or 1:20 or 1:30) but somewhere around 1:10 or 1:20 and it's too difficult to print with reasonable quality.

Again, look at it in xray view. Anything that is red (not blue or white) is a problem. Make sure spiralize is turned off. Make sure top/bottom are both checked. You might want to also make sure infill % is > 0 but that is not mandatory to get a top in the slice view.

Photos of the 2 different prints please. Layer height, print speed, fan speed, nozzle temp and brand of PLA make a difference on overhang quality. In general you want to print slow, cool and with fans at 100%.

I guess your extruder is overstepping every 16 steps and creating a little extra blob? Makes no sense to me.

> DRV8825 hack to the extruder driver. Um. yeah. I think this is unrelated. The zebra strips on benchy only happen if you have a vertical wall that is *not* quite vertical (tilted a few degrees) and also not lined up with X or Y axis. In other words the part needs to be rotated in Z axis by about 1 degree and then tilt the walls in by a degree to get the issue that is discussed in this topic. what you are showing is... I don't know what.

Yes - I understand. I could see in the video that the Y moves slowly and then it can't go any farther but it keeps trying and the stepper motor misses steps. When a stepper motor misses steps it makes a very loud noise. I'm quite famiar. The problem is that the postition it's moving to (I believe it's the "prime extruder" position) is past the end of your printer. So either a bug in the firmware (wrong location) or your printer is smaller. Or both.

>but perhaps with this many small objects, guaranteeing adhesion would be good. That's my thought also.

Oh - and the reason the first line in the table is off - I guess you have to figure in failures - opamp missing/unloaded/broken, wires/traces missing or shorted or cut. So you can in theory get a reading back from the ADC of 0. You want the table to fail somewhat gracefully maybe? maybe the code will get an error if you don't? Anyway it will display like 0C if it gets 0V. I seem to remember if it is at 0C it gets some king of "temp sensor broken" error or something similar. A guy on the forum in england keeps his printer in his cold garage in winter and he has to use the hair dryer to heat up the nozzle and bed to 5C before he can let the firmware heat it up the rest, lol.

Anyway - the point is now you understand how ALL of it is supposed to work. and you verified I believe that the right voltage is getting to the UMO control board, right? And I doubt it's the firmware. That leaves the signal on the UMO control board - maybe check the voltage right at the arduino pin. If it's still good maybe replace the Arduino - I think they cost like $10 in USA if it's a chinese made arduino copy. Try ebay. I think it's just a standard "arduino 2560Mega".

The same table is used for nozzle temps on all UM printers but UMO. The same PT100 sensor (the same chip anyway) is used on all UM heated beds (UM2, UMO, etc) and also on all UM2 nozzles and the UMO+ nozzle. The only place it's not used is the UMO nozzle which has a thermocouple. So going up to 500C is probably reasonable . Certainly some people print regularly at 300C (obviously they are making serious modifications to the hot end!). 1100C seems a bit extreme, lol.

I'd love to see a video of the homing end. Does it hit the Y switch? Is the Y endstop switch crooked? Bent? Normal? Does something else get in the way of the head when it homes Y? Is that step very very noisy becuase it's hitting something?