kbob and Impulse, the Rostock MAX

[kbob]

foshon, it works for me. All the pictures I've posted in my build thread were attached to their messages, not hosted elsewhere.

- dan

So were mine, up until last night. dbarrans, are you still able to attach images?

[dbarrans]

Maybe. Let's see...

image.jpg (859 Bytes) Viewed 32872 times

Looks like the answer is yes.

- dan

[kbob]

I figured it out. phpBB fails if you attach an image bigger than 4096 pixels. There's probably a server setting somewhere to configure that. Does anyone know how to contact the forum maintainers? I already sent email to [email protected] but haven't heard back.

Here is the server setting. (Allegedly. I don't actually know anything about phpBB.)
https://www.phpbb.com/community/viewtop ... &t=1797035

Meanwhile, I've been building, and I've got a big photo backlog. I'll redo the earlier posts with the missing images and then post my buildlog from yesterday.

[kbob]

Repost with photos.

<strike>Last night</strike>Friday night I started building. I had two friends help me peel all the tape off the melamine and press in the nylon locknuts. That part went pretty fast.

I am going to experiment with some small departures from the official instructions. I.e., I'm going to do it wrong. (-: Or maybe I'll find some things that make it easier for the next guys.

To start with, I used a drill press and countersink bit to countersink all the holes instead of snapping the melamine disk out. One of my tape pulling friends suggested turning the drill bit upside down. That way, the smooth shaft goes into the existing hole and does not remove any more material. Here's the countersink stub.

Upside down drill bit does not bore.

I set the drill press's end stop so that the countersink stops at the correct depth. Here are two photos of the countersunk hole.

Freshly countersunk.

Sans sawdust.

[kbob]

Repost with photo.

I decided to mount the RAMBo early on. As soon as I finished the first tri-support assembly, I put the RAMBo onto it.

Why do it that way?

It's easier to screw in. Don't have to reach in through the door.
I can trim the motor wires to match the actual distance to the headers on the RAMBo. I'll leave about two inches of slack in each. That's cleaner than leaving big coils of extra wire. I'll also trim the power supply wires with maybe 6 inches of slack.

Why was this a bad idea?

Risk of static discharge or damage during construction. My board is hanging out there in a construction zone. As soon as the table is on, it will be better protected, though.

Any other reasons I should not have done this?

[ApacheXMD]

I think originally, seemecnc intended for us to countersink the holes the traditional way with a bit/drill and the rings were just an idication of where countersinks were required. Then they realized popping out the rings worked ok, so they eliminated the requirement of buying a countersink bit. Of course if you have the drill and bit handy, its probably easier to do it "right".

[kbob]

After I got the tri-supports loosely attached to the base, I went ahead and put in the power supply. That made it really easy to run the power supply wires, and it also made it easy to install all four power supply screws. The Cover Brackets (those little vertical pieces) are not obstructing the screw holes yet. I also got all the spare wires tucked neatly away between the power supply and the Z tri-support.

I don't see any downside to doing it this way at all.

Power supply in place.

Here is the wiring that I did before closing up the base. I ran power to the motherboard, hooked up all three motors, and ran three wires out for the power switch. (Three? See next post.) The power switch wires are coiled up under the masking tape in this photo.

At Rostock, the wiring goes in before the table goes on.

The Z motor line did not have a lot of slack, so I plugged it into the right hand Z motor jack. The two jacks are equivalent, right?

I did not do any wiring for the bed heater or hot end before closing the base. I may regret that later.

[kbob]

The power switch in the kit is really cheesy. I didn't care for it at all. So when I was at Oregon Electronics last week, I picked up a lighted SPST switch. It's round and black because the Rostock is round and black. It has an LED because the Rostock does not have enough LEDs.

I'm glad I put the switch in before I assembled the base, because I enlarged the hole on a drill press, then enlarged it some more with a Dremel in a vise.

The switch, still a little dusty

The switch was designed to mount in a thinner panel than this fiberboard, so I turned the panel over and drilled a larger hole from the other side. I drilled both holes blind to prevent chipping the melamine, and the first bit poked its nose through to make a pilot hole for the second one. I just love Forstner bits...

Unfortunately, the switch was bigger than 3/4" and smaller than 7/8", so I had to Dremel out the smaller hole to something in between. But the switch bezel hides my sins, so I am absolved.

Concentric drill holes

I did not wire up the switch. Until the base was assembled, the door was not permanently attached. I think I have some spade lugs in the right sizes. If I can find them, I won't have to solder the leads on.

[kbob]

I assembled the "snare drum", the base assembly, last night. It took about 15 minutes to get all the panels aligned to put the top piece on. But I got it. I torqued all the screws to "4" on the electric screwdriver's meaningless number scale. That was the lowest setting that would pull the tabs all the way into the slots. Then I ran a straightedge over all the screw heads. Those that stuck out, I hand-tightened until the straightedge wouldn't catch on them.

The table measured flat in all directions except that the unsupported edge between the Y and Z towers is drooping a millimeter or so. I don't think that will be critical. If it is, I'll have to jam a dowel or something under that edge.

The next step was to install the T-Slot nuts. My immediate reaction was, "Gee, this is hard! I should have done it before I screwed the table on." (-: It doesn't really matter, though. I had to revisit those fasteners multiple times before I got the towers aligned.

[Eaglezsoar]

The table should be absolutely flat in all directions. Shim where you must but you must start out with a flat table.
That 1mm doesn't sound like much but it will matter when you start calibrating your printer.

[kbob]

The last thing I did last night was to erect the tower. I happened onto a really slick way to align the uprights. I clamped them to a square. The square is sitting inside the T-slot. The clamp is forcing the upright against the square. Gravity is holding the square flat against the table. Therefore, the upright is square to the table (within the accuracy of the square). I have to push on it to move it to a non-square position, and it comes right back.

Auto-square mode

There are still two degrees of freedom, though. There's the height of the upright and how far from the table's center it is.

I adjusted the height with the flat blade screwdriver you see in the photo. The screwdriver acts as a lever with a big mechanical advantage. I could push down the handle and shift the post up with resolution less than the thickness of the etched alignment line. (I hadn't figured this out when I shot the photo, so the post is just resting on the screwdriver there.) Once the height was right, I squeezed the clamp, the square dropped down to the table, I unsqueezed the clamp, and the clamp forced the post into square orientation.

Then the square was holding the post up, and I could release the screwdriver. I pressed the post toward the center of the table as far as it would go with thumb and snugged the screws. It took a few iterations to work out this technique, but I readjusted all three posts once I had it.

Then I followed the procedure in geneb's manual to measure the top height. Except... I used the Birmingham Substantial Alloy Calliper (BSAC). I just couldn't bear the thought of butchering an innocent yardstick. I also wasn't sure I'd cut the yardstick accurately enough.

I put the first Idler Mount on and aligned it. Then I inserted the BSAC and adjusted it so the table and idler mount were both touching the outside of its jaws. I locked the jaw at that position. After that, I used the BSAC just like the manual says to callously exploit the victim yardstick.

No yardsticks were harmed.

Then I used the BSAC to measure the distance between all three tower pairs, both at the bottom and at the top. I got readings of 381.10 to 301.30 mm at all points. I repeated them, and they were the same. I identified the post that needed to be adjusted, loosened it and slid it out about 375 milli-titches. Then I re-measured. No difference. So I called it good. One of my towers is about the thickness of a bee's wing too close. I doubt I'll be able to make the CheapSkates that uniform.

And then I called it a night. Packed up my tools and spare parts, turned off the lights, and went home.

[kbob]

The table should be absolutely flat in all directions. Shim where you must but you must start out with a flat table.
That 1mm doesn't sound like much but it will matter when you start calibrating your printer.

When I put the Onyx on, I'll see how it is affected. If it is a problem, I'll fabricate some kind of adjustable support post and put it out at the edge of the table where it is drooping.

Right now, I'm more worried about all the reports that the Onyx warps. I'm wondering how I can mount it so it has freedom to expand.

[kbob]

I am building Impulse at the Eugene Maker Space. I would like to thank the other members who've helped me put it together this weekend.

Darrell and Weston worked Friday night. They pulled tape off of melamine, helped catalog parts, and inserted all the nylon nuts. The upside down drill bit for countersinking was Darrell's idea.

Rick helped on Saturday. He put the connectors and labels on the motor leads.

Darrell came back on Saturday and helped with the wiring. The power switch wiring is his, and he helped me with the RAMBo power connections. (I got to use ferrules for the first time, wheee!)

Thanks, guys!

I strongly recommend building your printer at a maker space. I'm a loner by nature, but it's fun to build things with friends.

[foshon]

Are you a member of PETY (People for the Ethical Treatment of Yardsticks)?


All PCB heaters warp. My MM used to use a MKV (i think), the little red one, it warped. The onyx is large so it warps fairly extremely. That is why I went with a kapton heater directly applied to alum.

[kbob]

Are you a member of PETY (People for the Ethical Treatment of Yardsticks)?


All PCB heaters warp. My MM used to use a MKV (i think), the little red one, it warped. The onyx is large so it warps fairly extremely. That is why I went with a kapton heater directly applied to alum.

Okay. I have SeeMeCNC's borosilicate plate. It will be flat; it's just a question of where it will settle and whether it heats evenly.

In the meantime, I've continued assembly.

[kbob]

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.

Looks like a delta thing.

[kbob]

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]

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.

[kbob]

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.

Delta file in a drill press. (Sorry about the white balance.)

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.

[kbob]

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.

Vise plus clamp

I clamped it in a vise to put the screws in, too.

Just a vise

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.

Countersink hole in sinkhole black

[kbob]

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.

Not overkill at all.

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.

[kbob]

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.

Still sorry about the white balance.

[jetpad]

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

[Eaglezsoar]

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

[Eaglezsoar]

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.