Madmike8's Funbot build #2

I knew I'd seen discussion about these mosfets before. Seems like they won a shootout a few years ago here: [reprap.org]
Seems like a sensible move and they're on my shopping list now.

That explains it.. I might have to do that, because I have to keep a fan on mine at the moment.


Thank you sir

Glad I could help!

Looks like I got more Mosfets to order along with some sort of terminal connection for the hotends, thermistors, and fans. Kinda think I want to be able to swap out my chimera for a j-head easily. Still have some testing to do on my knockoff and this makergeeks pla just hates me on the chimera

does the pla keep jamming in the chimera?

Yeah but only the makergeeks stuff

Post up your ideas on quick change hotend, I'd be interested in that.

I'm using some Esun Silver PLA from Hobbyking.com in Funbot#1 right now. Seems to be working good @190C.

On the knockoff all metal hotends. I like the ones with the ptfe tube in the threaded nozzle, but you need to disassemble and check to make sure everything looks right and reassemble before use.

I will be using terminal blocks like this one pictured for all connections between the ramps board and devices. I am not sure about using it for the hot end connection.

About the MK3 heatbed:
What do I have to adjust to use it?
Do I need longer rods for the X and Y axis?
How exactly do you mount it?

I bought one of the aluminum bed plates from folgertech on eBay. That was pre-drilled for the heatbed. Then used the Funbot Bed Drill Guide #1 to drill the mounting holes for the Funbot. That aligns it correctly for the Funbot. I had bought 12" x 3/8" K&S rods/tubes from eBay (you can usually get them at your local hobby store too). When I drilled my base with the paper base drill guide, I drilled all holes normally except the Y base mounts. I marked those with a pencil, and then used a straight edge ruler to Mark a line through them to both ends of the base plate. I measured from the outside edge to the mounting holes of each Y base mount. I then measured and marked the plate along the previous lines for the mounting holes. Then I drilled those holes. This allowed me to move the Y mounts to the very edge of the plate.

For the X axis. I mounted the X end pulley mount on the very end of the tubes. (Don't forget to slide on your X carriage bushings.) I then slid/tapped them into the Z carriage enough to get coverage of the print bed and tightened the X rods set screws. I use a level to make sure the rods are vertical before tightening the set screws completely. I then drill a slightly smaller then 3mm holes in the X end to tighten the rods there too with M3 screws that self tap into the plastic.

I hope that helps.

Mike



Edited 1 time(s). Last edit at 05/31/2015 05:37PM by madmike8.

Thanks, it should indeed.
I ordered two of the pre-drilled bed plates from Aliexpress (as two gave a better price and I'm already planning the next printer, lol), and one MK3 aluminium heatbed.

But I have another question:
How do you mount the steppers? It seems that it is planned to use two of the stepper's own screws each, but the screws from my steppers come loose already when I unscrew them for a few millimeters, meaning they're much too short to mount the stepper to anything.
I can get short UNC 4-40 screws here (for PC use), but it's next to impossible to get long ones.

Any ideas?

Ok, found a solution. It's actually possible to drill a M3 thread into an existing 4-40 one.
So I converted two of the stepper's threads to M3, and can now use as long screws as I want.

My steppers used m3 threads. I used a m3x50mm screw to replace the stock stepper screws. Screw them from the bottom to the top of the stepper.

Edited 1 time(s). Last edit at 05/31/2015 05:41PM by madmike8.

One additional question:
What dimensions did you use for the base plate?
The same ones (280x240mm) that Cliff used? Or bigger, because of the MK2 heatbed?

p.s., how are the adjustment screws mounted?
Head of the screw on top, then the spring, then the aluminium plate with threads?
Or the other way around?
Or do you use threaded bolts in between?
Maybe a detailed picture of one screw would be nice.

Edited 1 time(s). Last edit at 06/01/2015 08:19AM by uhrheber.

I'm using a 11 3/4" D x 12"W board.

The heatbed is mounted screw through top of heat bed, the nut, then 15mm length of 3mm high temp silicone tubing, then bed plate, then adjusting wing nut.

Ah, ok.
Clever to use silicone tubing.
Many thanks for the photo.

Here mike is my progress on funbot pro
[www.youtube.com]

Looking Good Cliff.

good job
you really need to move the gt2 pinion closer to the bearing to avoid flexion in the rod!

Edited 2 time(s). Last edit at 06/04/2015 01:25AM by fabrice974.

Quote
fabrice974
good job
you really need to move the gt2 pinion closer to the bearing to avoid flexion in the rod!

It will have 2 more bearings in the front like the back have but haven't done a design for it so far

I have started my Funbot build but the holes in the Z axis base seem to small for the 3/8" solid aluminum rods that I purchased. So much that I have to hammer them in with a hammer. The first rod I tried is in about half way. Should I continue or back it back out and drill the holes out bigger? If I continue hammering the rod in do you think the plastic will split? I have chamford/beveled the rod ends but that didn't help.

You can drill out or use a lighter to gently heat up the plastic so it will expand. If not the plastic layers will separate

I had to tap mine in. I set the base on a table and tapped them in from the top. You can take a smaller drill bit and just lightly ream around the holes to clean them up a bit. The taller new version base was a bit harder to get the rods in to though. I don't think it will split as long as your tapping down while it's on a hard surface, but if it does let me know and i'll print you another one...

Thanks for the info Mike, I'll continue with the tapping and see what happens.

I can hear the sound of cracking plastic in the back of my head.
Kinda creepy.

Huh? If your plastic skull plate is cracking, you might want to have that looked at...

Here is the promised video with it in action
Pro gets closer to release
[youtu.be]

its first ever print


Edited 1 time(s). Last edit at 06/17/2015 08:13AM by Cliff Mellangård.

Well, I finally got #2 up and printing. Feels good to get some of these back logged projects finished up.

Everything is working well, but I don't like the PLA Bushings as well as I like the Bronze Bushings in #1.
I might change those out in the future.

Sadly so do the printed ones nead some grinding before they are well.
As soon as I have moved to my new place so will I start on all the upgrades and updates
Should be earlu august