Rostock Build Blog.
November 12, 2012
DeltaBot Google Group- Fellow adventurers
By combining our resources into a group order, we were able to make kits and ship them for about $650 for each kit. One might be able to self source one of these for less money and dedicate more time, but we were after guaranteed parts and may have saved ourselves the worry of resourcing incompatible parts and more troubleshooting than we need in the future.
One aspect of this design that I like is the real simplicity of it all. Each axis is identical and the frame is built with a top and bottom platform and six rails. You can export the dimensions for the frame pieces from the creator of Rostock's source on Github, and I have also included a DXF with mounting holes on the attached files here.
or check out these awesome new pieces! http://www.thingiverse.com/thing:34570 -D
For now, we are starting with a “stock” version, with a build area of about 180mm x 180mm x 400mm. You can actually scale the length of the rods on the entire machine to fit your custom purposes.
After you have bolted the printed pieces for motors onto the bottom set, you can set the rails into them. Give them a good cleaning and tighten them in with M3 bolts. Now before your set the top platform, carefully slide an lm8uu bearing onto each rail. Putting these on individually helps keep them in good condition rather than tying them to their printed mount and having to align them together. They may slide a bit rough, but after a couple travels and some 3-in-1 or other non greasy lubricant, they should move effortlessly. Add the top platform at your desired level (this dictates your z travel) and secure it with the necessary hardware.
Belts and Pulleys
We are using a modified belt system from the original Rostock, due to the fact that GT2 (2mm tooth pitch) belts and pulleys are sometimes hard to come by in the specified closed loop, we've adapted MXL belt (2.03mm pitch) to fit our needs, with a cool zip tie tensioning trick found on the Reprap Open X designs. Make sure you don't take up too much space making the zip tensioner, too long and it could catch on the pulley for low movements of an axis.
The carriage is pretty straighforward, make sure that hardware doesn't interfere with the movement anywhere, and then you can use zip ties to attach it to the bearings on each axis.
Assembly Instructions can be found here:http://reprap.org/wiki/PCB_Heatbed
With the carriage sitting on the bed, adjust the bed so that the center of the carriage is aligned to the center of the heated bed, and the bed is square with the outer edges. It will be offset, but in a uniform way.
UPCOMING UPDATE: Bowden and Hotend Assembly
Two major forks of firmware that have been modified for Delta are:
Modified Marlin: https://github.com/jcrocholl/Marlin
I have used the Marlin fork successfully. for the sake of curiosity, let's try Repetier too!
In the screenshot you see the major definitions that you must define for calibrating in Marlin. Another major setting is the Z home setting, or how far up the frame it can travel, and how close it can get to the build surface.
The above definitions relate to these physical characterics on the Rostock, as shown in this conceptual example of a Rostock derivative: