Our first date with the printer

This post is about the sun-dappled and frosty morning on which Amazon delivered the much anticipated Printrbot. I didn’t want to open the box without Jen there, so it sat on my dining room table until she got off work. We unpacked it immediately,  but it was so foreign to us that we didn’t set it up right away.

It was toy-like with its wooden parts, streaked with some kind of burn marks, and it reminded me of a childhood Christmas present. (That’s how old I am… when I was a child they gave wood burning tools to 6 year olds.) We could identify metal rods, and some screws, and there was string that ran from end to end. This was the machine that was going to save the environment? This was the beginning of the 3rd industrial revolution?

We ate dinner with the Printrbot still on the table, and we eyed it suspiciously through desert. Even after a generous glass of wine we still weren’t comfortable with the contraption in front of us. Upon close examination, we simply could not tell how it worked.

Eventually we snapped open the laptops and got to business. We had done our homework, so that first night we were able to blindly plug other people’s numbers into the indecipherable software. When we were finished, we opened up Pronterface and we moved the hot end.  We used Pronterface because we couldn’t get Repetier-host to work. I don’t know why, but once we got Pronterface to talk to the printer, Repetier-host never had any more problems.

In the early days of learning something, you have to hold yourself back from troubleshooting everything. There’s a sort of noobie-juju at work. Odd things happen and then never happen again. Example: the first time our friend Pam sat down at a computer, she threw away THE TRASH CAN.  Noobie-juju.

Anyway, back to the printrbot’s hot end, which had just moved 1mm. It was thrilling. We made happy noises and clapped. We drank more wine. It seemed like magic because it really was…we had no idea what we had actually done. The little machine worked, and our next step was to print a calibration cube.

Mesmerized, we watched the cube being built. Perfect yellow lines, straight as train tracks across Kansas, were laid down against deep blue painter’s tape. And for the first time, we heard the printrbots’ mellifluous singing.

I think the music the Printrbot makes is one of the best things about it… I wish someone would write an orchestral piece based on the singing Printrbot.

We didn’t speak the entire time the cube was being built, and our eyes never left the bed. Now that I’ve had more time to surf the interwebz and read about other people’s first prints, I realize how fortunate we were to have such a lovely first experience. Many people don’t get satisfaction for quite a while, and their early works  look like melted spaghetti.

We didn’t actually use that cube to calibrate. We didn’t have a calipers. But our square looked so heavenly that we were just sure that our machine was perfectly calibrated.

You can’t see me right now, but I am chuckling over my keyboard at that last sentence. I know what happens next…..

SOAP: Home corner on print platform problem

OK. I’m closing this soap because it’s become too messy. We probably do have the Y Sag listed below, but it looks like the whole thing needs physical adjustment… the amount our bed is off is too much for Y SAG alone. I’ll fix it by the time you get back, Jen, and you shouldn’t have to worry about any of this. Read it, though…. you’ll need to know about it….but there’s no need to check back.

 

SOLVED. (Please note that we reserve the right to be completely, utterly wrong.) This is a known problem called “Y SAG”, combined with the fact that it was time for recalibration.  Y sag is commonly a 1-2mm difference in height between the front and back of the bed. It happens because extruder weighs things down as it reaches out from the main support of the printrbot, stretching out the zip ties. Other owners are saying that it doesn’t keep you from leveling your bed, so it shouldn’t cause problems. but it IS causing problems for us because the screws are tightened down so much that they’ve chewed into the base of the printer.

When the printer is not in use, we should probably park the head close to the body of the printer to relieve the stress on the zip ties over long periods of time.

Some people say that as the Printrbot is used, it settles down and the Y Sag will lessen, which doesn’t make much sense to me. Maybe I’m not remembering this correctly, and they really said we wouldn’t need to calibrate the bed as often. That makes more sense.

An alternate opinion is that as the zip ties loosen over time it will get worse. I’m voting for this prediction, and we don’t have the luxury of letting it get worse. There are counterbalances we can trick the bot out with, as well as other upgrades, like belts. Actually, the kit we have to upgrade the simple to a larger size may take care of the issue.  I’ll open up a new SOAP for the Y sag when we need to deal with it. 

(Click on photos to enlarge)

Subjective: The front left corner quadrant (AKA the Home corner) prints worse than the other 3 quadrants. Sometimes it’s droopy, sometimes it lifts up, sometimes it’s messy, sometimes it’s missing. The effect increases as it approaches the limits of the print area.

Bad honeycomb in home corner.

Home corner bolt tightened all the way down.

Slouchy base and break in perimeter of home corner.

Droopy home corner with acne improves with height.

The rest of the infill in the banana clip looks great.

Objective: Above are photos of an ashtray and a banana clip showing Home Corner issues. The banana clip shows a distortion of the honeycomb fill. The ashtray shows compression on this corner from the first levels, but it improves with height. When laying down the initial border before printing, the printer never lays down complete filament in that quadrant. Additionally, although the building platform has been leveled by us on March 21, 2014, visually the home corner is tightened much more than the other corners.

Assessment: Perhaps the platform has gone out of level or was never truly leveled.
Plan: Check levels on bed again*. Run a leveling pattern in filament.

3/24 pm result:
Subjective: The printer ran great all day after leveling the bed, until suddenly I got bubbling lines and general print issues.
Objective: Checked bed level: it was all out of whack again after 5 hours use. Screws needed to be tightened, too.
Assessment: I think the vibration just loosens things up. The Home corner is not alleviated completely, so may be a different issue.
Plan:  Expect to do some maintenance after every 5 hours of printing or so. Now that I’ve tightened everything up, we may see longer sessions of printing Nirvana. I think it may be better to level 2 diagonally opposite corners first, because they will impact the other corners. I was doing it clockwise, and found I had to undo any changes I had made to the first corner. I read that it’s best to do the leveling with the hot end hot…worth a try. (edit: YES. Calibrate with the hot end heated. Also, we don’t have to raise the hot end to access the screws by the fan…. we can just slide the bed out of the way. It doesn’t hurt anything.)

3/26 PM  I did a totally new XYZ calibration. In the process, I’ve learned of some ways we can get more precision in the future, and there’s math involved. I’ll do it that way next time and report. Anyway, we still ended up with that Home Corner being really smushed down in compared to the others, and I found out it was causing problems with the bed. The screw in that corner went so low, it ran into the body of the Printrbot, ripping away at the wood. Now we have a little track through there. The prints are looking better though. Still have to do the whole-bed test.
Assessment: Something is off about the build.
Plan: I don’t know. I hate to take off that bed and see if the rods are off kilter, especially since the prints are looking nice, but I think that may need to be done. The screws shouldn’t be damaging the body of the Printrbot.

Assessment: Perhaps the fan is having an influence.
Plan: Try turning off fan for the first few layers. Try running the fan at 80%.
3/27 I think this is not the problem. We can still work at improving our base layer, but the droopiness and acne was alleviated with the XYZ calibration.

Assessment: Perhaps the blue tape is not working anymore.
Plan: Change tape.
3/27 Droopiness and acne was fixed with XYZ calibration, tape is holding print fine.

Assessment: Perhaps it’s a filament issue.
Plan:  Try extruding filament before printing. Try raising temperature a few degrees.
3/27 Found a setting in Slic3r that may sets extruding. Will investigate.

Assessment: Maybe the extruder is too heavy by the time it reaches that far corner?
Plan:  Wait and rule out other things. There’s no reason ours should be different than everyone else’s, unless we did something while reassembling the printer after swapping out the hot end. We were confused about those wires going under the extruder….
3/27 I am beginning to think this is an actual issue, although you would think we would see the same problem on the right front of the bed as well. I’m still considering this a last resort assessment.

 

 

*=done

New Pages added!

I’ve added 3 new pages to this blog. You can find the links at the top of the page.

One will be a working glossary, where Jen and I can throw all the new words and concepts we have to look up.

One will be a page that lists all the current questions we’re trying to figure out. When one of us finds the answer, we’ll make a post out of it.

And there’s one page that explains SOAP charting, which is how we’ve decided to tag-team all this learning we’re about to do.

Have fun, and feel free to make any comments. They’re always appreciated.