Delta
Release status: unknown
Description | Delta type parallel kinematic manipulator setup to be used as repstrap
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Contents
Introduction
The Clavel- or Delta-robot is mostly known for its use in pick-and-place work in PCB fabrication and generic packaging applications. It features fast and accurate positioning and is relatively easy to build. We, User:Energetic and User:Reinoud teamed up to create a both easy to fabricate and light on the budget RepPrep/RepRap. Our goal is to be well under the current prices for Mendel and/or Darwin RepRap's.
We decided to design and develop the bot trough a series of prototypes, learning and refining on each iteration.
Prototype 1
The initial prototype designed and lasered by User:Energetic. It was cut out of 1 cm acrylic sheets by a shop. It proofed the concept of the magnetic ball bearings and the overall structure of the design. Regretfully it was never driven by an Arduino/Sanguino other than simple stepping.
Prototype 2
Lessons were learned from prototype 1. It proved to be hard to reproduce the machine since non-standard 4mm shaft Nema17 motors were used and needed some intricate drilling in the side of the sheets to receive the bolts and nuts. Since acrylic also turned out to be quite expensive, we decided to go for plywood. We replaced the 10 mm acrylic with a set of three sheets of plywood with the respectively thickness of 3, 4, 3 mm so to easily accommodate the 4mm nuts and bolts.
The structure was also modified to accept larger upper-arm ranges to give it a larger work-space. As 4mm shaft steppers are hard to find, the design was modified to use the standard 5mm shaft Nema17 steppers.
Although we've learned a lot of this prototype to justify a prototype 3, we'll first try to get it to work first. We might stumble on other unforeseen challenges!
Prototype 3
Will most likely not feature the timing belts and pulleys. They proved to be too hard to get and can hopefully be replaced by either higher resolution or a lasercut gear system.
Firmware
User:Reinoud has written a [ReplicatorG]] compatible firmware that does both the needed coordinate transformation and the real-time control. The goal is to have the complete bot, including the extruder running on either a single Arduino or on a single Sanguino with standard Polulu stepper controllers and standard Nema17 steppers.
As for SDD card support, a Sanguino might be needed since the imported implementation of the FAT/MSDOS FS alone takes about the half of the Arduino 32Kb flash program space.
Mailing list
Existing Designs
"Mjcbruin" from the Netherlands designed the this delta bot for $70. It is driven by 3 hobby servos, and is controlled by an Arduino. The code has been published at the letsmakerobots link. Video Design + code
User:Reinoud has built a similar design with servos.
- Ugly Stewart Platform ( http://builders.reprap.org/2006/09/ugly-stewart-platform.html ) : crude prototype for hydraulic Stewart platform.
- first stab at a Stewart platform RepRap: http://blog.reprap.org/2006/02/reprap.html
- Biollante: a few more stabs towards making a hydraulic Stewart platform RepRap: http://burningsmell.org/biollante/
- Biollante posts: http://builders.reprap.org/search?q=Biollante
http://forums.reprap.org/read.php?178,26318
Files
Tooling
Lasercutter and standard tools are sufficient to make the current repstrap version