ConductiveMaterials
Release status: experimental
| Description | experiments into conductive materials that can be extruded
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| License | unknown
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| Author | |
| Contributors | |
| Based-on | [[]]
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| Categories | |
| CAD Models | |
| External Link |
Overview
This page lists the results of conductive materials that can be extruded by a Reprap printer. The goal being to be able to print uOhm conductive paths, N and P type semiconductor material and variable resistive paths.
Solders, paints, sealants, glues and epoxies.
Low resistive materials
- Field's metal - Melting Point: 60.5 C
- Wood's metal - Melting Point: 71 C
- Rose's metal - Melting Point: 109 C
- Solder - Melting Point: 183 C
- Carbon Powder - Melting not possible - Mix in with glue or sealant - Allows for variable resistor values
N type semiconductor material
- Cadmium selenide
- Zinc Oxide
- Cadmium arsenide - Soluble in water
- Tin Dioxide
P type semiconductor material
- Copper Sulfide
- Copper(II) Oxide
Print a Transistor
The holy grail of electronics is the transistor. If a 3D printer was able to extrude a mixture with Zinc Oxide, then place a dab of a mixture with Copper(II) Oxide and then attach two low resistive connections to the Zinc Oxide mixture and one low resistive connection to the Copper Oxide mixture, we should have an NPN transistor. Once we have transistors we can build [Logic Gates]. Once we have logic gates, we can use any [FPGA core that is available.
Experiments Results
Graphite added to Bitumen
Bitumen is a brushable waterproofer sealant used on roofs. It hardens into a flexible rubber.
Materials
- Bitumen Brushable Waterproofer - 500ml AU$ 8.64
- Graphite - Lock-Lube - 6g AU$ 6.11
Results
- 10ml of bitumen and 750 mg of graphite. Result - >2M Ohms
- 10ml of bitumen and 1.25g of graphite. Result - 34k Ohms/cm
- 10ml of bitumen and 2g of graphite. Result - 500-1k/cm Ohms
Notes
Additional graphite was added to the existing solution after the sample trace was drawn. At 2g of graphite the mixture was thick and difficult to mix and manipulate with a the toothpick I used to lay down the test trace. Paint thinner should be added to the mixture and tested.
- Bitumen and Graphite Mixture Resistance
Impure Semiconductor Tests
Materials
- Tanne Zinke 30+ SPF Zinc Oxide Sunscreen (425mg/g purity) AU$ 5.94
- Impure Copper Oxide made by cooking Copper Sulfate with Sodium Hydroxide
- Richgro Copper Sulphate (Blue stone) AU$ 12.94
- Draino - Found under bathroom sink
Results
- While making larger semiconductors do not require the purity or precision that is currently employed in the semiconductor industry to make the 5nm layers, less than 50% pure zinc oxide and sodium laced cupric oxide did not work.
- Experimenters should wait for the 99% pure compounds to arrive
Future Experiments
Diode
Overview
The diode is one of the oldest application of semiconductor material. By taking an N-type material and joining it to a P-type material we create a gate that will only allow electrons to pass in a single direction. With a diode, a rudimentary AND and OR gate can be constructed.
Expected Goals
- Validate that a diode can be constructed from semiconductor material suspended in extrudable materials.
- Determine the Voltage Drop across the diode.
Instructions
Using powdered N-type and P-type materials each mixed with a small amount of cement, apply small dab of each on a non-conductive substrate so they are touching. Allow the cement to harden. Next add two conductive glue tracks, one track leading out of the p-type and one leading out of the n-type cement. While the glue is hardening, insert two metal wires.
FET
Overview
A Field Effect Transistor utilizes a magnetic field to control the flow of electrons through a thin N-type material channel on a p-type material substrate. The magnetic field is generated by a conductive plate over the n-type channel separated by a non-conductive insulator.
Expected Goals
- Determine the feasibility of constructing a simple transistor through extrudable materials.
- Determine the Gate Voltage - depending on the final size, it is likely to be in rather high voltage (48V - 2kV)
Instructions
Using powdered P-type material, mix with cement and create the P-type substrate. Create a rectangular base with two depressions on either side which will form the source and drain. Between the two depressions should be a wide shallow channel where the gate will be located. After the base hardens enough so it will not deform, fill the depression and channel with powered N-type material mixed with cement. Allow this to harden. Cover the gate section with an insulator - a very thin plate ABS/PLA material should work. After hardening, cover the insulator with conductive glue almost to the edge and use the glue to create the source and drain leads. Attach test leads to the source, gate and drain conductive materials to test.
ALU
Overview
Arithmetic Logic Unit is the heart of any micro processor. It is responsible for performing basic operations on multiple bits inside a computer. Examples of these operations would be AND, OR, XOR, ADD, SUB(tract), MUL(tiply), DIV(ide), LSR(Logical Shift Right), LSL (LS Left), LRL (Logical Roll Left), LRR (LR Right).
Expected Goals
To validate that simple extruded gates can be connected together to produce a usable circuit
Instructions
Awaiting results of FET test
PIC
Overview
A PIC micro controller is a popular small chip used control everything from washing machines to radio controlled cars.
Expected Goals
Create a possible micro controller replacement for the electronics on the next generation of RepRap
Instructions
Awaiting results of ALU test
External Links
- More on making conductive glue circuits. An instuctable on how to make conductive glue circuits.
- MOSFET overview. Nice picture of what the FET should look like after construction.
