Brook Drumm created the wonderful original which is far more rigid and can print much better then most of you would think. It is a great design with small overall dimension but for all that with a big print area. This is the reason that there are a lot of derivates. Thank you very much Brook for that genius idea.
My intention was to be as close as possible to the original parts but with a lot improvements.
Here is one of my first prints: http://www.youtube.com/watch?v=lmT9ujijztQ
This printer is optimized for T2.5 belts and 18 teeth aluminium driving gears.
The main parts such as: bases, x-ends and x-carriage with extruder mount are in principle compatible with the original Printrbot. So it is possible to replace them. But with limitations:
The centre line of the x-idler pulley is 0.43 mm higher.
The centre line of the x-motor axis is 0.45 mm higher.
The x-carriage and the extruder mount can only be used together. Due to the different way of fastening the belt, the belt will be 4.5 mm lower.
Most of the parts have holes for tapping drill holes. If you cut the tapping drill holes you must be careful to keep them self-locking. Better use a set of three taps and use only the first one. The tapping drill holes should be as tight as possible.
The width is 100 mm. This increases the self-supporting and extend the bearing clearance of the y-bearings for more guidance bar.
The cut outs for the bearings are longer (25.6 mm) to make it possible to use also IGUS bearings.
There are two M3 tapping drill holes (y-direction) on each side. They are intended for several use:
To fasten the z smooth rod in case it became loose.
To mount a clamp, a socket outlet and plug or whatever.
In x direction are two M3 tapping drill holes.
You can use them to justify the stepper motors orthogonal if needed.
On the bottom are three M4 tapping drill holes.
One in the middle to push out the smooth rod in case it is very trapped and you want to remove it.
The other two can be use to mount the bases on a board.
The two cut outs are cable slots.
On the back side it has a nose for the z-endstop with a M3 tapping drill hole. On the top is a M3 screw nut deepening. This is only if you may have cut the threaded hole to wide. In this case you can bond a locknut into the nut deepening or try to bore up for a M4 screw.
In y- direction you can screw in a M4x12 mm screw to fasten the smooth x-rods.
Additional you can use two M3 tapping drill holes in x-direction to push out the smooth rod in case it is very trapped and you want to remove it, or to fix them if they are to short.
The same as the X-End-Motor but it has only one hole for M4 to fasten the upper smooth x-rod.
The x-carriage has a belt tensioner. You must cut a M3 tapping drill holes to use it. One more M3 tapping drill hole you have to cut for the x-stop adjustable screw.
It has a third bearing underneath the extruder motor to transfer load from the motor. I placed the motor as near as possible to the x-rods. The inner width between the NEMA 17 and the z-rods are only 2 mm. So don't use a bigger extruder motor ;-)
Furthermore the extruder mount has a cable slot. A good idea that came from the Hugo Printrbot.
The mount can be fasten with 2 screws. It is possible to remove the smooth rods by only declamp the screws on the clamp side. The other screws will keep the mounts in place. So you can disassemble the carriage or change the smooth rods without adjusting the mounts again.
Besides, two screws gives more stable connection.
one of the belt camps is invested with a belt tensioner.
They have three screws for better stable connection.
I made a separate Endstop to be free where to place it. For adjusting you have to cut a M3 tapping drill hole.
I modified the ramps holder from Hugo Printrbot to fit them to my Arduino.
Clamps for 30 mm fan for cooling the electronic. I use only one for each fan.