Budget Strapped
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Release status: unknown
| Description | A low cost RepStrap
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Overview
This printer is intended to be a very low cost 3D printer that is still capable of printing useful items. The cost of filament is very significant for a printer in this price bracket. To reduce this cost, BudgetStrapped will print with HDPE filament, which can be created relativly easily from household plastic waste.
Design Goals
- under ~$100 total cost.
- ability to print will filament made from recycled household plastics. Specifically HDPE (#2 plastic).
Structure And Motion
- Printhead will move on X and Y axes, printbed will move on Z axis
- Frame will be made (primarally) out of 2"x4" lumber
- X and Y axes will use drawer slides (like WolfStrap)
- Positioning on the drawer slides will be done using 65lb test multistrand fishing line.
- Z axis will move on four 10-24 threadded rods
- Multiple 28BYJ-48 stepper motors will be used on each axis instead of NEMA 14 or 17 stepper motors
Electronics
- An Arduino Nano will be the core of the electronics.
- A shift register will be used to increase the number of digital I/O pins
- 1 darlington array driver chip per motor (These come with the motors)
- A bottom-of-the-line PC power supply will be used to provide power.
Specifications
- Cost: ~$80 - $105
- Printed Parts: None
- Electronics: $12
- Extruder: $38
- Motors: $18
- Wood: $6
- Other: ~$5 - $30
- Printing Size: ~ 7"x7"x8"
- Printing Speed: (SLOW) X & Y axis 6.23mm/s, Z axis 0.265mm/s
- Precision: ??? (position), ??? (printing)
Progress
March 10th 2014 Update:
- A design for a wood screw based cold end has been developed. This alleviates one of the largest contributors to missing the cost goal. The extruder works by having a 28BYJ-48 stepper motor turn a wood screw with the filament fed along it.
- Some of the 2x4s have been cut out.
- The new spooled drives should be able to move the X and Y axis at 6.23 mm/s
- A HDPE plastic recycler is being simultaneously developed. It should (hopefully) cost less than $100 to build.
Status as of March 5th 2014:
- Most of design is drawn out on paper (some has been modeled in SketchUp as well).
- A motor testing sketch for an Ardruino Nano has been written and used to verify the ability of the 28BYJ-48 stepper motors to reliably rotate a 10-24 threaded rod through a T-Nut. The sketch makes use of a shift register chip. The rod can be turned at ~15 rpm. This results in an ability to move that axis at 0.625"/min [0.265mm/s] which seems painfully slow for anything other than the Z-Axis. As a result it was decided to switch to a tantillus-like spooled fishing line drive to increase the movement speed.
- T-nuts and machine screws will be used to allow alignment to be adjusted.
