Welcome to the SeeMeCNC Community

The last photo here was taken Saturday night This is a build log; let me log the building.

Sunday: Installed limit switches and upper idlers. Assembled the first Cheapskate, including the sanding.

Monday night: Stayed home. Wired up the power switch on the door, including the LED.

Tuesday night: Assembled the other two Cheapskates. Used a power tool (Dremel) and made the sanding go a lot faster. I could remove 80% of the material in a couple of minutes, then sand, test, sand, test until it fit well. Then I assembled the effector platform. I did not use the Dremel, but I did use a file to remove lots of material. I finished with 180 grit sandpaper. I looked at one of the delta arms, but I had no idea how to sand it. Meanwhile, Darrell offered to help again, so he assembled the extruder mount/spool holder.

Wednesday night (last night): I sanded all six delta arms. I had to use a small file to ream the holes out. I attached the delta arms to the effector platform and cheapskates. Then I assembled the EZStruder.

I did not install the belts; I wanted to feel how freely the whole assembly moves. It does not bind anywhere that I can feel. When I jiggle the Cheapskates in any of the five directions they should not move, I do not see the effector platform move at all. So that's good. But I can jiggle the effector platform. In certain places near the sides of the build volume, I can move it most of a millimeter. Near the center, the play is much less.

I am going to leave it like that until assembly is finished. I will return when free play is limiting my print quality. I will need to find a source for 0.3 or 0.4 mm shims for a couple of U joints on the Cheapskates.

Here is a photo. It looks like a delta thing now, instead of a gazebo.

I have to figure out the wiring. The whole extruder mount/spool holder assembly (EM/SHA) wants to fall off when I put the printer in the car. (I have to lay the printer diagonally on the front seat.) So I want a connector there so that assembly is removable for transport.

But I'm also interested in upgrading later to a top mounted extruder mount. So I ought to make the wires long enough to make that possible. Or maybe I should just plan to replace the wiring when I upgrade.

I have some Molex Micro-Fit connectors in my parts box. I'm thinking about using them. They're rated for 5A, they lock solidly, and they crimp on. I also have the JST-SM connectors. They're smaller, but they have leads molded in. I'd have to splice the leads.

I am seeing the expected cosmetic damage where the EM/SHA has been repeatedly removed. The melamine is chipping off. Maybe I'll put down a layer of electrician's tape where the parts touch.

Update: Is everyone familiar with the trick of using paracord for wire sheath? I am on a deadline to get this machine ready for Eugene Maker Faire on June 16th, so I don't have time to dress the wires. But I'd like to go back and clean it up later.

kbob wrote:I have to figure out the wiring.

I've wired the extruder.

It turns out that there are about 10 feet of wire in the kit for the motor. I needed a little more than a foot to reach the extruder in its original location. So I cut a wire for that, and I still have over eight feet left for a future top-mounted extruder.

I did use the Molex Micro-Fit connector. The crimp connectors were a pain -- they don't lock into the connector housing as well as the connectors RAMBo uses. But they appear to be thoroughly connected.

As for the extruder mount being loose under transport, I solved it the other way. I fastened it securely so it can't move when the printer is tilted. I added a bolt and a standoff between the Extruder Clamp #68389 and the table, and I added a cable tie between the lowest Extruder Support Spacer #68388 and the base. I slipped the cable tie through one of the vent holes in the base. I will acquire photos.

And I did put down electrician's tape where the melamine was chipping. It has stopped the chipping for now.

Actually, it worked pretty well. I did not over-enlarge any of the holes in the delta arms. I did not even put an eye out.
This is a small delta file in a drill press. I used it to ream out the holes in the delta arms*. It removed a whole lot of material very quickly. I basically just touched the spinning file to the hole, then re-tested the fit. Most holes were big enough after a single touch; a couple needed a second go.

I did not have any real reaming tools, so I improvised.

* I'll leave the delta puns to you guys.

The photos of the split LCD panel ends in Gene's manual made me very very cautious about splitting mine. I pressed the pieces between two other pieces of melamine using both a vise and a clamp before i drilled the pilot holes. The blue tape is there so I could mark where to drill. Pencil on blackened fiberboard was not visible.
I clamped it in a vise to put the screws in, too.
There was no splitting. I also carved out extra clearance around the SD slot with an X-Acto knife so the left end would slide all the way onto the board. The right end needed just a little carving to clear the rotary encoder's pins.

A black Sharpie dressed up the countersink holes. The fiberboard sucks up Sharpie ink like a sponge.

I just wanted to ensure a good round hole in the RTV applicator. It's not like i used a torque wrench on the drill chuck or anything.
In other news, the bed thermistor, the hot end thermistor, and the hot end resistors are encased in RTV. They should be cured now, but they're at the maker space and I'm not.

Better Way to Bond Resistors?

I estimated 24 turns of aluminum foil around those resistors. I wound it as tightly as I could, but 24 successive air gaps, even tiny air gaps, make a pretty good insulator. I wish I knew a better way to put the resistors in there. I thought about the thermal paste that you use with heatsinks, and I thought about some kind of oil bath, but I wasn't convinced either one would be compatible with the RTV.

But I'll be interested if someone finds a better way to bond the resistors to the hot end.

These worked very well at the Cheapskate end of the delta arms to eliminate play. I got 36 (that's enough for 12 printers) for $2.49 at Target.

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

Now I am confused. You apparently are running two build logs at the same time, this one and the David Smith's (Jetpad) Build?

kbob wrote:I just wanted to ensure a good round hole in the RTV applicator. It's not like i used a torque wrench on the drill chuck or anything.

IMG_9706.JPG

In other news, the bed thermistor, the hot end thermistor, and the hot end resistors are encased in RTV. They should be cured now, but they're at the maker space and I'm not.

Better Way to Bond Resistors?

I estimated 24 turns of aluminum foil around those resistors. I wound it as tightly as I could, but 24 successive air gaps, even tiny air gaps, make a pretty good insulator. I wish I knew a better way to put the resistors in there. I thought about the thermal paste that you use with heatsinks, and I thought about some kind of oil bath, but I wasn't convinced either one would be compatible with the RTV.

But I'll be interested if someone finds a better way to bond the resistors to the hot end.

The best way is to invest in one of the cartridge type heaters. They are 40 watt and 6mm in diameter. Much better than using resistors.

Eaglezsoar wrote:The best way is to invest in one of the cartridge type heaters. They are 40 watt and 6mm in diameter. Much better than using resistors.

Oooh, goody! Another upgrade to look forward to!

But wouldn't cartridges have the same problem? How do you bond them to the hot end cavity for good heat transfer? My cavities are full of RTV, but I measured them at 0.25" (6.35mm) yesterday.

Some hot ends are being made with a set screw that holds the cartridge in place, for those that do not you would
need to wrap it with aluminum foil until it is snug. You should not have to use RTV and it virtually eliminates shorts.

I finished assembling the printer early this morning. At lunch time, I set the printer on my desk, plugged it in, and promised myself I wouldn't turn it on until I finish work tonight. About 2:30 PM, I left my office for a couple of minutes and came back to thick smoke pouring out of the power supply.

No photos, sorry. By the time I got the power supply out of the chassis, it was just a little warm. The only visible damage outside the power supply case is that it is leaking brown fluid. Would that be a burst capacitor?

There's a 1000 watt Corsair power supply somewhere around here that's just over a year old. I think I'll dig that one out of whichever machine it's in and cut its connectors off. I still want to get this machine running for this Saturday's regional Maker Faire, but it just got a little less likely.

I pulled a Seasonic SSR-550RM out of a PC here. After a few hours remaking the wiring harness, the new power supply is in. I've powered the printer on, I've tested the limit switches and have just started testing the motors. I had to reverse the leads on all three motors -- I suspect an error in the manual. (-:

Not only is the new power supply a little bigger, it is also over two pounds heavier.
it was tight getting the bigger brick into the Rostock base, but it did fit.

It has a single +12V rail rated for 45A (vs. 16A for the Logisys). I am no longer worried about overloading the power supply. (-:

The Rostock MAX also makes a fine soldering vise.

Glad everything is ok. Electrical fires are scary.

Was there a power switch on the old power supply and was that on at the time?

Any insight on what may have happened?

ApacheXMD wrote:Glad everything is ok. Electrical fires are scary.

Was there a power switch on the old power supply and was that on at the time?

Any insight on what may have happened?

The Logisys power supply did have a hard power switch. It was on. The soft power switch on the Rostock front panel was off, so the power supply was in standby mode. It had been plugged in for two hours when it started smoking. It had not been turned on at all. I was not doing anything with it, just using a laptop near it.

I already mentioned the brown fluid that leaked out afterwards.

I think one of two things happened. Either I'd managed to get some metal into the power supply (e.g., a wire snipping) or a component gradually failed into a short. I haven't looked inside the supply.

Meanwhile, at this very moment I am watching my Rostock print a thing. Wheee!

Sounds to me like you had a catastrophic capacitor failure. I bet if you open it up, you'll find a split one. Have you contacted SeeMeCNC about it?

g.

geneb wrote:Sounds to me like you had a catastrophic capacitor failure. I bet if you open it up, you'll find a split one. Have you contacted SeeMeCNC about it?

g.

Yeah, I exchanged some email with John. By the time he got back to me, I had already gotten the new power supply installed and all the electricals debugged except the fan. (I owe you more errata about the fan.) I told him there was no point in sending me a new PS, so he didn't. (-:

Last night I was printing long after dark. Since there isn't a task light near my printer, I installed an LED lighting system. Sort of.
Those colorful clothespins are from Horrible Fright. http://www.harborfreight.com/22-piece-s ... 69374.html I use them to hold the Cheapskates in place when I transport the printer in the car.

Note the Onyx nail polish remover bottle. Only use genuine Onyx brand acetone; it was formulated specifically for your Onyx bed!

Off topic: Nice flashlight! I was sooo tempted to get one of those hexbrights, but I have too many flashlights as is.

ApacheXMD wrote:Off topic: Nice flashlight! I was sooo tempted to get one of those hexbrights, but I have too many flashlights as is.

Thanks. I find myself using it a lot more than I thought I would.

Now the printer is operational, it's time to dial it in.

I've read Gene's manual and followed the procedures.

I've read polygonhell's tips on tuning the amount of extrusion. I don't have a caliper with sufficient resolution yet (UPS is delivering it tomorrow). My digital caliper says the single layer wall thickness is 0.6 mm. Or 0.8mm. In lieu of the right tool, I tried printing the solid blocks with different infill percentages. There are visible gaps all the way up to 90% infill, so I set Slic3r's Extrusion Multiplier to 0.95 and called it good. I will revisit that when I get a new caliper.
Am I right? Am I way off? These were all printed with 0.2mm layer height and 0.55mm default extrusion width.

Is there another calibration document I should know about?

So that's what I've got. But here are the problems I know of.

• I have brown spots (burns, I think) on the underside of many prints. Here are some of those same blocks agin.
  

  

  Same blocks, brown spots on bottom

• I get strings. Here is the Lava Vase at 1/4 scale.
  

  

  Lava Vase, 1/4 scale, very stringy

  I've set retract length to 3mm. Is that too much? Not enough? Are there other retract parameters to set?
• I printed the 50mm tower with a single layer perimeter and no infill. It came out crooked with a bead down its back. Should I be concerned? What is this object supposed to test?
  

  

  50mm tower. Crooked.

  

  Same tower, close up.

• I have no idea whether my hot end temperature or bed temperature is high, low, or just right. I have not yet bought a thermocouple-based thermometer to calibrate the thermistor. If I did, what temperature would I aim for? (ABS)
• I am using a lot of ABS juice. Anything else and the prints curl right up off the glass. Elmer's glue stick did not work well. I've tried bed temperatures up to 95℃ (uncalibrated); the Onyx can't get to 100℃. Would a different bed temperature help?

So I guess my top level question is, how do I dial this printer in now that it's sort of working? Where do I go from here?

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.

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.