TRap

TRap

Release status: unknown

Description	Documentation of TRap development
License	GPL
Author	User:mccand
Contributors
Based-on	none
Categories	Gada Prize
CAD Models
External Link

The TRap will be an alternate mechanical structure for the reprap project. Team TRap intends to make it an entry in the Kartik M. Gada Personal Manufacturing Prize. Before I go any further, I want to thank Team Columbus: I have used Isaac's basic layout for this page.

Overview

The Gada Prize

The main requirements of the Gada Prize are:

1. Print at least three different materials, including one that is usefully electrically conductive.
2. Demonstrate the ability to print electronic circuit boards.
3. Any print beds must be of a material which may be reused with minimal refurbishment for at least 20 print cycles.
4. Maintain a total materials and parts cost under $200.
5. 90% of the volume of the device's components shall be printed.
6. Demonstrate a build volume greater than 300mm[11.81in] x 300mm[11.81in] x 100mm[3.94in].
7. The capacity to print a full set of components for a complete replica of itself within 10 days unattended save for clearing no more than one printer head jam.
8. The ability to print autonomously without a PC attached.
9. Uses no more than 60 watts of electrical power.

TRapSpecifications

The table below outlines the specifications of the machine.

	Metric[Imperial]
Manufacturer	Anyone
Model	TRap
Technology	FFF (Fused Filament Fabrication)/Thermoplastic extrusion
Price of all materials	TBD
Annual Service Cost	TBD
Size	400mm[15.75in] x 400mm[15.75in] x TBDmm[TBDin]
Weight	TBDkg[TBDlbs]
Build Envelope	300mm[11.81in] x 300mm[11.81in] x TBDmm[TBDin]
Materials	TBD
Material Cost	TBD
Speed	TBD
Accuracy	TBD
Finish	TBD
Volume of printed parts to replicate	TBD

Design Philosophy

1. The number of unique parts shall be kept to a minimum
2. Parts shall be made as simple as possible
3. Identical parts will be used wherever possible
4. Orthogonality shall be preserved wherever possible
5. Non printed parts shall be "Off-the-Shelf" (OTS) whenever possible
6. Substitution of similar OTS parts should require a minimum number of changes to the design (i.e. a change of bearing size)

Structure

Axes

• 3 Identical Axes assemblies

Extruder

• TBD, possibly Bowden

Control Systems

• TBD

Workbook

2010 September 01

• Registered team on the RepRap wiki
• Started concept generation

2010 September 02

• Created this wiki page; thanks again to Team Columbus, who provided the format.

2010 September 03

• Finished mocking up Concept 1.

File:TRap A.png

Concept A: Structural sketch.

This is worth taking some time to explain. TRap is a manipulator with a parallel kinematic chain. I am using a variation on the normal delta robot design that is most often seen in "Pick-and-place" robots. This design approach has two major advantages: it can be very fast, as the arms manipulator platform has a very low intertia (servos are all stationary); and all three axes are totally identical, reducing part count. The major disadvantage is that the control problem is not trivial: getting the end effector to move with constant velocity along a straight line involves all three servos.

General Notes

In accordance with the official Gada Prize rules regarding documentation and transparency - as interpreted by the RepRap Core Team and others - all documentation for this project will take place here in this wiki. If there happen to be any "Other Spaces" out there that have documentation for this project, then such information is posted there only after it is posted here.

• The following notes help to keep this workbook in a neat and orderly condition and shall be generally adhered to throughout all levels of documentation.

1. All dimension and temperature nomenclature shall include both SI and Imperial units. SI units shall be first followed by Imperial units in brackets. Examples: 100mm[3.94in] and 40°C[104°F]