Introduction
The MOST Delta printer is RepRap derived from the Rostock printer with the following design goals:
- Simple build process
- Safe to operate
- True to RepRap
- Maximize value
- Maximize rigidity
- Aesthetically pleasing (or at least neutral)
- All PLA printed parts
- Excellent print performance
The design utilizes plywood linking boards cut to a length that yields a desired printer radius when attached to the printed apexes. This simplifies assembly while helping to assure that printer dimensions are fixed, stable and reasonably well known. It also improves flexibility as the print area in the x-y plane can be changed simply by replacing the boards with boards of a different length. The delta design is inherently simpler to assemble as compared to virtually all it's Cartesian counterparts; this design can easily be built within a day by one person having properly prepared parts.
The design uses a 12v 5A power brick instead of the popular 12v power supplies having mains connections relatively exposed, a relative safety issue, particularly when children are present. The power supply is roughly equivalent to those found with many inkjet printers.
As many printed parts are used in the design as are practical, including printed pulleys. This in large part drove the decision to use open T5 timing belts for the drive, which also makes the design more flexible as the length of the guide rods doesn't need to be based upon the length of an off-the-shelf continuous belt.
Cost considerations drove decisions regarding everything from printer capabilities (as shown, prints PLA only) to guide rod material and length (two six foot lengths of 8mm drill steel are required, producing no waste). A Melzi controller is used as it provides all the necessary features as well as SD card support and reasonable expansion options. The power supply is a fraction of the cost of that required for powering a heated bed.
Printed apexes are very robust, probably overkill, and along with the plywood components and ample fasteners produce a very rigid structure. The printer has proven to transport very well (and can even be seat belted) with no adjustment needed prior to printing at its destination.
The end effector is actively cooled allowing for a unitized effector/hot end mount printed in PLA. The hot end is recessed within the end effector, maximizing z-axis travel and also providing for some print cooling.
Printing performance has been very good as has been the experience of printing with this design. Much less user intervention has been required as compared to experience with Cartesian RepRaps.
Printer capabilities/statistics
- Print media: PLA only (heated bed can be added, expanding media options)
- Filament diameter: 1.75mm
- Nozzle diameter: 0.5mm (can be changed)
- Print volume: ~250mm radius (with 240mm long linking boards) 270mm high
- Melzi print controller w/ integrated SD card reader
- Airtripper's Bowden Extruder
Bill of Materials
- Download and print files here: https://github.com/mtu-most/most-delta
Tools
- 5.5mm nut driver and 5.5mm wrench or a pair of 5.5mm wrenches
- 7mm wrench
- 13mm wrench
- Sharp x-acto-like knife
- Small, flat bladed screwdriver
- No.2 Phillips screwdriver (a power driver is best)
- 1.5mm allen wrench
- 2.5mm allen wrench
- 3mm allen wrench
- 3mm (1/8") drill bit
- 8mm (5/16") drill bit
- Sharp pencil
- Sharp point marker
- Tape measure (large calipers >300mm are better), preferably metric
Consumables
- Two-part epoxy
- Impermanent thread locking compound (Loctite Blue)
- Masking tape
- Muffler cement
Before you Begin
Novice builders should be aware that while this design is fairly simple to assemble, it is still not trivial. Review the RepRap MOST RepRap Primer and familiarize yourself with terminology and methods. The build process is relatively detailed and includes many images, and this is a living document so if a step is missing or difficult to understand, please make an attempt to correct it.
Building
The build process is organized by functional area. The following guides are prepared for a single person (solo) build and a two person (tandem) build:
