Budget Strapped
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BudgetStrapped
Release status: unknown
Description | A low cost RepStrap
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Contents
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).
Remaining Work and Concerns
- The hot end I currently have is a knock-off J-head nozzle. Based on some searching it seems likely it will not work very well.
- SLOW print speed. The X & Y axis print speed of 6.23mm/s is slower than I have seen anyone mentioning printing. (I saw 15mm/s for a first layer.) will the printer still function if it is printing this slowly?
- My household plastic recycler needs to be completed. Until this is completed I have only a few feet of 3mm PLA to work with.
- I have not yet recieved the fishing line. I still need to verify the spooled fishing line drive method will work as planned.
- Additional NiChrome wire may be required to build heated print bed.
- The simplified electronics used do not use stepper boards. I have written a functioning motor test arduino sketch for this setup, but I haven't yet verified that an existing firmware can work with this setup. (I may have to modify the firmware myself.)
Printer Details
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 70lb 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.
Extruder
- The current hot end is a knock-off J-head. (hopefully it works...)
- The cold end is a WoodScrew Extruder.
Printer Specifications
- Cost: ~$85 - $105
- Printed Parts: None
- Electronics: $12
- Extruder: $38
- Motors: $18
- Wood: $6
- Other: ~$10 - $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. A wiki page WoodScrew Extruder has been started.
- 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.