BumbleBee - Child of Prusa
LMR, meet BumbleBee ! BumbleBee, meet LMR :)
This a new printer I'm working on, a very different design compared to the Prusa Mendel. I'm doing it because the Prusa is very hard to move around so this one will be smaller and hopefully more portable.
The Hugo is beautifully designed by a German guy based on the Printrbot with various improvements for better stabilty. The design is hosted on github at: https://github.com/kr2/Hugo and a wiki page for it has been created on reprap.org: http://reprap.org/wiki/Hugo
So far it's all bits and pieces as I'm printing part by part in the evenings, and the bigger parts take around 3 hours to print on my Prusa.
There are many variables yet to be determined as I do intend to have a printing area of about 100x100 mm on it. This might change as the build advances.
The motors are rescued from some big copy machines, they are 100 steps per rotation ... remains to be seen how these guys wiil work when I have some electronics together.
Talking about the electronics I want them small so this time I'm going to get polou drivers everyone else is using, and mount them on a Gen7 pcb.
Another thing I'm trying is to use printed bushing's instead of the LM8UU to slide on the rods as the LM8UU I have on the Prusa got very noisy in time and they developed a lot of play too ... this might be dues to some mistake I have made mounting them.
Currently I have all the important parts for the Y axis, which is also used as the base for the printer, and I have started printing the parts for the X axis.
I have the yellow left side printed last night it's beautifully functional :)
Next is the right side and the carrige for the extruder. Once those are done I can determine the right length of the smooth rods to maximize printing area whille keeping a small overall size ... yes I know I said 100x100 mm but that might turn to 100x 150 or so ..
Update 3-06-2012 - Progress ...
Got the Y axis together and it works great :)
So replacing the LM8UU pith printed parts seems to work pretty good so far. Structurally PLA is very hard and I had to file a while to get them glinding smoothly on the rods. I'm pretty sure I will not have to replace them any time soon.
As for printing area I'm going to get arounf 120x180 which is great for such a little machine :) The plate is the standard Prusa size 22.5 x 22.5 cm and this is the biggest part. so the whole thing fits into a 25 x 25 cm area :D
Next on the todo list:
- square and tighten every the Y axis together.
- find rods for Z
- put the X axis together ... real tricky part as I have to figure out the exact length to cut the Z rods ... yup tricky
- print the bushings for the Z as I'm pretty sure they will have to be custom too
- print the leg parts for Y as it will definetly need a leg to support itself
- not sure yet if I need them but I might have to print the braces on top of the Z rods ... time will tell
On to what I still have to get:
- a hotend + resistor + termistor
- 4 pololu drivers
- make a gen7 PCB
- get the parts for the above
Yes this time I will not use my own drivers ... they are just too big ...
Update - 14-06-2012 - Generation7
- PCB - check
- Drivers received - check
- hotends - check
- mounted non critical parts - check
- solve the missing ATX connector issue - can't source one around here and taking it off an old board is not feasible
- power up testing
- add critical parts to board (ATMega644p, drivers, mosfets)
- tune driver
- move motors !
Update - 06-07-2012 - Body movin' !
So after the vacation break here I am at it again.
The Bumblebee is mostly togheter now, axis motors are wired up and the Gen7 + drivers seem to work just fine. I have to admit the Pololu drivers got me impressed, they pack a punch in such a small package and for 7euro or so a piece ... very interesting for other projects I tell ya.
So here is how the Gen7 looks like currently:
Yes the little green things beneath under the connectors are the drivers :)
I have the standard Reprap setup for the motor connections, so 4 drivers for 5 motors (the Z axis motors are connected in parallel).
I have solved the stupid ATX connector issue by using wires for the important powerlines and one of those electrical connectors to hook them up to an old ATX PSU. I chopped it's connector off too.
The Gen7 design is great I cannot see any problems with it so far.
The BumbleBee is mostly complete now see the picture & testing video up :)
Update 2012-Oct-04 - Prusa RIP ... long live the BumbleBee
Summer came and gone, late sunny autumn going on (we ares still in the 20 - 30 degrees C range) and somehow I have ended up with two printers which .... kinda .... worked.
Prusa was a great learning platform to get this 3d printing thing started but to be honest it never worked very well. Actually each time I wanted to start a serious printing project something did not work properly, something in this complex machine always needed some tightening, something just decided it would be time not to stay in it's place and needs epoxy .... and so on.
Looking back it was great to have the Prusa because it enabled me to understand things about 3D printing that I could not have understood if I would just have bought a kit like the MakerBot or Ultimaker. But on the long run I'm getting frustrated on always having to adjust something in order to get this thing going.
Somewhere around June I started printing the BumbleBee mostly because I wanted to have a smaller, simpler machine which I could move around easier.
Then word of Campus Party came by and I needed to rush things a little getting the machine together so I was able to get it to Berlin. So I did cut some corners here and there and while the electronics worked well the mechanics did not do so well. It did work well enough to do some demoing overthere, so job done.
Once back I just left it unassembled until yesterday when I started putting it back together and realized all the mistakes I've made first time.
Since I wasn't happy with the Prusa anymore I took the vitamins I needed to get the BumbleBee mechanics working from the Prusa ... yes ... it wasn't an easy decision :)
So now the B.B. has new stainless steel rods and LM8UU bearings from the Prusa, and I'll probably also mount the 0.35 J-head on it too.
The transplant is almost complete so expect some more BB printing news in the following weeks.
As for the Prusa ... Rest In Pieces my dear you did well !
Once I'm sure the BB works as I hope to I will donate the good plastic parts I have left from the Prusa to someone on LMR who want's them, just realize these are used parts before asking for them.
Update - 12-Oct-2012 - BumbleBee kicks ass
Yup it does :D
After finishing up ripping parts from Prusa, mounting them on BumbleBee and some calibration I did the cube (prism?) in the second video.
The model was 20.0x20.0x10.0 mm and it came out 20.0x19.95x9.8 mm which means that the X-Y accuracy is 0.05 mm, 9.8 for Z is ok as the first layer was squashed.
Now gears should come out soo much better :D
Update - 18-Oct-2012 - The real round round things
I was wrong in my last update, after a few more prints it became obvious thing weren't going so well.
I my haste to put things together and test I forgot to really tighten the belt tighteners, so after another print or two bothe X and Y belts got slack and my calibration gone totally off.
So I had to redo it ... but now I'm finally getting the results I was looking for: accurate round things.
Now I shall try reprinting the gears for TB2, make sure the holes in the case are in the correct places and print them.
Next is probably a completely new build large enough to accomodate a Pi with peripherials.... but that's a little far in the future right now.