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geneb wrote:Printing ABS with an un-verified thermistor is risky. If it's under-reading, you run the risk of ruining the PEEK section of the hot end - Harbor Fright sells a nice little meter that has a good thermocouple on it for under $40. (I'm lucky, I've got three HFs within easy driving distance! )

I've found that I'm getting MUCH better prints from PLA than I ever got from ABS. I think it's a combination of different properties in the material and maybe PLA is a bit more forgiving of my uncoordinated stumbling around.

Blobbing and stringing boils down to slicer adjustments - I'm not good enough at that yet to recommend anything to anybody.

When you print a cube of known dimensions, how accurate is the result you're getting? BTW, a 20%-25% infill is plenty for most things you'll be printing.

Congrats on finishing your build and thank you very much for the feedback you've given on the 2nd edition!

g.

Old Chinese proverb: Man with Harbor Freight in town always know where to buy tools. Man with three Harbor Freight never sure.

I didn't make it clear -- I don't have a thermocouple thermistor YET. I haven't had a chance this week to visit the solitary, lonely HF that's nearby.

Polygonhell wrote:The 100% fill clube looks pretty good at 100%
The tower is a notoriously difficult print, the fact it even looks like a tower is a win. The issue is heat, if you really want to print a better one, pint 4 at a time, it gives them time to cool between layers, active cooling can also help.
You will get seams on parts, the start and endpoints have to overlap, the size of the seam is dependent on the slicer, and the settings in it.
The strings can be cleaned up with the retraction settings, 3mm is probably too little for the stock SeeMeCNC hotend, try 5mm of retract at 30mm/s and 5mm of Wipe in KisSlicer.

Thanks, Polygon. I will try 5mm at 30mm/s.

My questions were all over the map in that last post. Here's something a little more focused.

What are the interesting retract settings? Distance and speed, is that it?

Is there some set of tests that will tell me if my retract is too little, too much, too slow, or too fast? Ideally, something that iterates toward some good settings?

If you use Slic3r or Cura the only settings you have to control retract are distance and speed, in KisSlicer you also get wipe, plus some control when retract happens.
The way I usually tune retract is to create a cylinder model 20-30mm in diameter, I put 2 of them on the build plate and print them as single wall objects.
You are looking for 3 things the strings between them, whether the perimeter is closed, and if extrusion is consistent.
I would suggest starting with 5mm retract/prime at 30mm/s with 5mm of wipe if using KISSlicer, change one thing at a time, as you increase retract you'll find that the strings lessen, too much and you start having gaps appear at the start of the layers, too slow and you get blobs because the head sits in one location retracting for too long.

Thanks. I will run some cylinder tests this weekend.

But first, the printer is going to Maker Faire tomorrow!

A lot has happened since my last post.

First, my Rostock MAX was on the local TV news. It was a story on 3D printers in the area. You can see the Rostock (and my left ear) on screen for about 1.5 seconds; the MakerBot was the main attraction. (Rick gives much better interviews than I do.) http://www.kval.com/news/tech/211477411.html

Second, my Rostock MAX went to Eugene Maker Faire. It was completely mobbed all day. Fortunately, it was printing well (if too slowly), considering that it was less than four days old at that point (and was my first 3D printer). I made a single-wall Teethy Tiki ( http://www.thingiverse.com/thing:49334 ). That print ran for three hours of the six hour show. Single-wall prints are easy.

Since then, I've continued to print. My thermocouple thermometer came from Amazon on Wednesday. I finally got around to calibrating the thermistor tonight. My thermistor reads 4℃ low at 150℃ and 11℃ low at 260.

Now I have two problems.

• I need to work through the math to figure out how much to adjust GENERIC_THERM1_BETA to give the right amount of compensation. That's no big deal.
• I can't reflash my RAMBo. Apparently my RAMBo has the missing bootloader described here. http://forum.seemecnc.com/viewtopic.php ... =10#p13887

For now, I'll just manually adjust temperatures. I will need to reflash that board eventually, though.

Well (and that's a deep subject) it does require a LOT of soldering! And more, and more, and more...Damn, I need a Weller Station. Hahahahaha

For some reason, I've taken my printer apart. It started when I was wondering whether the limit switches were adjusted right. I designed and printed a dial indicator mount, and with the dial I observed that the bed is about 0.002-0.003 inches (0.05-0.08 mm) higher in the back than in the front. And then I wondered whether the towers are square with the glass surface. They were square with the melamine when I built it, but the machine has been in and out of the car a dozen times since then, and I'd never checked that the glass was level with the melamine.

The towers and glass are not square. They are almost ½° off.

So I thought I'd take the top off and resquare the towers. This time, I'll square them against the glass at working temperature, not the melamine. I've gotten as far as removing the belts. I think I have to both pull the top off and disassemble the Cheapskates.

And then kerbymills asked about checking a tower for twist.

OTOH, I have a really neat dial indicator mount. I'll post it to Thingiverse shortly.

NO! The towers should be square to the base! If you have a problem with the glass level, you change it THERE not by manipulating the tower geometry.

g.

geneb wrote:NO! The towers should be square to the base! If you have a problem with the glass level, you change it THERE not by manipulating the tower geometry.

g.

What's your rationale for that, Gene? It seems to me that the only important thing is that the axes of motion be perpendicular to the printing surface.

I think you just want to see if I'll pull the bed off the printer, too. (-:

if you plumb the towers to the melamine, if you ever change build surfaces, you're not faced with the task of realligning your whole machine. If your leveling is out of whack because of a errant piece of glass, you'd probably be better of just getting a better piece of glass. Or if it's the Onyx/spacers, insulating snowflake, or whatever that's causing the geometry problem, you should fix it there rather than getting the towers to match whatever the glass ends up.

Kbob,

I love your sense of humor. I'm serious...I'm about to buy one of these rascals (I'll probably call it Bastard) and this build thread is hilarious.

Thank you.

-Doc

jetpad wrote:I don't know if it is a better way but it was a different way. I've had no problems with the hot end since I did it. I just used Silicon tape for everything on my hot end. Here are a couple pictures of it.

http://forum.seemecnc.com/viewtopic.php ... 5&start=10

Thanks, JP. I am going to rebuild my hot end, and I will try to create something very similar to what you have.

ApacheXMD wrote:if you plumb the towers to the melamine, if you ever change build surfaces, you're not faced with the task of realligning your whole machine. If your leveling is out of whack because of a errant piece of glass, you'd probably be better of just getting a better piece of glass. Or if it's the Onyx/spacers, insulating snowflake, or whatever that's causing the geometry problem, you should fix it there rather than getting the towers to match whatever the glass ends up.

Thanks, that makes sense. So I'll pull the Onyx off too. I am pretty sure the towers have moved since the machine was first assembled.

doctorgonzo wrote:Kbob,

I love your sense of humor. I'm serious...I'm about to buy one of these rascals (I'll probably call it Bastard) and this build thread is hilarious.

Thank you.

-Doc

Thanks. I'll look forward to your build log.

My RAMBo had no bootloader. Tonight I burnt a bootloader onto it. I took it to the maker space and got some help, and it did not work the first time (nor the eighth), but the actual burning was pretty straightforward.

I've reinstalled RepetierMAX, but won't have the board back into the printer until tomorrow. Then I'll find out whether I need to reload the EPROM settings.

Now I can...

• calibrate the hot end thermistor.
• adjust the delta radius.
• track future Repetier firmware releases.

But I'm not doing any of that stuff until I see the printer working as well as it was before I pulled the board. (-:

I printed this. I scaled it 200%, so it stands about 9½ inches tall (240 mm).
Fun facts:

It is a single-wall print. (one perimeter, zero fill) 0.2mm layer height, 0.55mm layer thickness.

ABS, neon orange from Toner.

I printed it at 60mm/sec, I think.

The model is here. http://www.thingiverse.com/thing:49348

Single-wall prints are easy and fast. Since the extrusion never stops or backs up, you don't have to dial in the retraction.

Does it hold water? Either the vase or the laptop?

doctorgonzo wrote:Does it hold water? Either the vase or the laptop?

Excellent question! I just tried it, and it does not. There are two hairline cracks where layers did not adhere. I've had the same problem with other single-wall shapes -- I think I need to either increase the temperature a bit or do something to prevent random air currents on the printer.

I don't put water in the laptop. I just upload my water to Dripbox and store it in the Cloud.

Maybe a brush and acetone will make it hold water...Now I'm going to blow stuff up and prepare cheeseburgers (not blow-up-able, sigh). Happy 4th, kbob.

I think I'll just print some ABS flowers that don't need water. (-:

Happy Independence Day to you, too. We are spending the four day weekend AFP (away from printer).

I bet the laptop would hold water if you tried it. My daughter tried to hold water with my wife's IBM laptop, the down side was the $200 repair on the keyboard. but the laptop did hold water for quite awhile.

CJGerard wrote:I bet the laptop would hold water if you tried it. My daughter tried to hold water with my wife's IBM laptop, the down side was the $200 repair on the keyboard. but the laptop did hold water for quite awhile.

I did try that! I dumped most of a glass of iced tea into the keyboard of my old ThinkPad. I took it apart and found out that the keyboard is designed to channel water through to drain holes on the bottom. Unfortunately, the flood breached the levee. I did surgery twice, and kept it running for about eight months longer. Then I got a cheap Dell. After living with a cheap Dell for a couple of months, I got a MacBook. It's the least repairable laptop ever, so I won't have to fix this one.

You mentioned bracing the towers over on your build thread. I've modeled this, and I've printed an earlier version. The idea is to put threaded rods through the end holes and nuts inside the boxes. Adjust the nuts to fine-tune the intra-tower distance.
This is an early iteration, mostly just to see if I can make something attach to the towers. I have to make the bottom ones much thinner so they will go under the Onyx, and the top ones have to somehow cooperate with the limit switches and upper idler wheels. And the T-slot nut where the belt is will have to go.

I like where your going with that design on the brackets, I think we would get more support if the bracket fully enclosed the tower.

CJGerard wrote:I like where your going with that design on the brackets, I think we would get more support if the bracket fully enclosed the tower.

Thank you.

I was not originally thinking, "Make it rigid." I was thinking, "Position it accurately before tightening the T-slot nuts."

OTOH, that piece is absurdly strong for an alignment jig. Maybe I just don't know what I'm thinking. (-:

What's the point of the alignment jig, other than alignment of the arms? Super-stiffness?