WikiSysop: Created page with "==Summary== The design of this robot is based heavily on the "HF06" robot designed by Martin Price ([http://www.heliumfrog.com/hf06robot/hf06blog.html link]). It was initially..."

2015-08-07T22:14:43Z

Created page with "==Summary== The design of this robot is based heavily on the "HF06" robot designed by Martin Price ([http://www.heliumfrog.com/hf06robot/hf06blog.html link]). It was initially..."

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==Summary==
The design of this robot is based heavily on the "HF06" robot designed by Martin Price ([http://www.heliumfrog.com/hf06robot/hf06blog.html link]). It was initially undertaken as a low-cost 3D positioning robot for use in touch-screen testing or button pressing/activation, but evolved into a 3D printer (with replacable tool head, so still capable of performing basic 3D positioner tasks). The X/Y resolution is lower than typical 3D printers, but is estimated to still be adequate (resolution is <1/4 the diameter of the extruded filament diameter).

==Subsystems==
===Z-Axis Drive===
The Z axis is driven by a 1.8 degree per step NEMA-23 motor, purchased at All Electronics ([http://www.allelectronics.com/make-a-store/item/smt-135/8-wire-stepper-motor-used/1.html link]). It uses an 8-wire interface, with 2 sets of coils wired in parallel or series for each phase). Wiring info is below:

* black to red = 3.4 ohms
* brown to blue = 3.5 ohms
* orange to green = 3.5 ohms
* yellow to white = 3.5 ohms

* black: 0 ohms to 1, 3.5 ohms to 3
* red: 0 ohms to 3, 3.5 ohms to 1
* brown: 0 ohms to 7, 3.5 ohms to 5
* blue: 0 ohms to 5, 3.5 ohms to 7
* white: 0 ohms to 4, 3.5 ohms to 2
* yellow: 0 ohms to 2, 3.5 ohms to 4
* orange: 0 ohms to 6, 3.5 ohms to 8
* green: 0 ohms to 8, 3.5 ohms to 6

The motor is coupled to a 1/4"-20 shaft which drives the SCARA X/Y positioner via an anti-backlash assembly comprised of two 1/4"-20 bolts held apart by a spring. The Z-axis assembly has 1.27 revolutions per mm, and using an 8-microstep controller gives 0.79375 um/step (1259.843 steps/mm), or 6.35 um/step (157.480 steps/mm) in full-step mode. The Z-axis print resolution will ultimately depend on machine tolerances and bed leveling, as it is clearly not limited by motor/mechanical resolution.

===X/Y-Axis Drives===
The X/Y axis are covered by the SCARA, and are driven by two 1.8 degree per step NEMA-17 motors, also purchased at All Electronics ([http://www.allelectronics.com/make-a-store/item/smt-107/stepper-motor-w/gear-train/1.html link]). Each motor is coupled to the 165mm arms via a 5:1 reduction pulley using GT2 2mm belts. Each motor will be driven by a 1/32 microstepping driver (DRV8825) for a total resolution of 0.01125 degrees/step, giving a worst-case linear step of 100um in X/Y (approximately 1/10th the resolution of a typical Cartesian bot, 1/10-1/3 that of a typical Delta, or about 1/2 to equal that of a DLP SLS printer).

==Bill of Materials==

{| border="1"
|style="text-align:center;" |'''Part'''
|style="text-align:center;" |'''Quantity'''
|style="text-align:center;" |'''Unit Cost'''
|style="text-align:center;" |'''Total Cost'''
|style="text-align:center;" |'''Source'''
|-

|NEMA-17 1.8 deg. Motor
|2
|style="text-align:right;" |$6.50
|style="text-align:right;" |$13.00
|[http://www.allelectronics.com/make-a-store/item/smt-107/stepper-motor-w/gear-train/1.html All Electronics]
|-

|NEMA-23 1.8 deg. Motor
|1
|style="text-align:right;" |$8.50
|style="text-align:right;" |$8.50
|[http://www.allelectronics.com/make-a-store/item/smt-135/8-wire-stepper-motor-used/1.html All Electronics]
|-

|Shipping (All Electronics)
|1
|style="text-align:right;" |$7.00
|style="text-align:right;" |$7.00
|All Electronics
|-

|style="text-align:center;" |'''Motors'''
|
|style="text-align:center;" |'''Total Cost'''
|style="text-align:right;" |$28.50
|
|-

|1/4"-20 Threaded Rod 12"
|1
|style="text-align:right;" |$0.96
|style="text-align:right;" |$0.96
|[http://www.homedepot.com/p/Everbilt-1-4-in-x-12-in-Zinc-Threaded-Rod-802097/204274017 Home Depot]
|-

|608ZZ Bearing
|4
|style="text-align:right;" |$0.305
|style="text-align:right;" |$1.22
|[http://www.ebay.com/itm/191219381765 eBay]
|-

|8mm x 300mm Linear Rail
|2
|style="text-align:right;" |$6.69
|style="text-align:right;" |$13.38
|[http://www.ebay.com/itm/271404988811 eBay]
|-

|LM8UU Linear Bearing
|4
|style="text-align:right;" |$0.599
|style="text-align:right;" |$2.40
|[http://www.ebay.com/itm/321354645938 eBay]
|-

|style="text-align:center;" |'''Mechanicals'''
|
|style="text-align:center;" |'''Total Cost'''
|style="text-align:right;" |$17.96
|
|-

|12V 100W Power Supply
|1
|style="text-align:right;" |$11.94
|style="text-align:right;" |$11.94
|[http://www.ebay.com/itm/261605048565 eBay]
|-

|Stepper Driver (DRV8825)
|4
|style="text-align:right;" |$2.26
|style="text-align:right;" |$9.04
|[http://www.ebay.com/itm/301402526887 eBay]
|-

|Arduino Mega
|1
|style="text-align:right;" |$11.50
|style="text-align:right;" |$11.50
|[http://www.ebay.com/itm/131305501585 eBay]
|-

|RAMPS Board
|1
|style="text-align:right;" |$6.49
|style="text-align:right;" |$6.49
|[http://www.ebay.com/itm/121503655499 eBay]
|-

|style="text-align:center;" |'''Control Electronics'''
|
|style="text-align:center;" |'''Total Cost'''
|style="text-align:right;" |$38.97
|
|-

|NEMA-17 1.8 deg. Hi-Torque Motor
|1
|style="text-align:right;" |$12.00
|style="text-align:right;" |$12.00
|[http://www.ebay.com/itm/331393418940 eBay]
|-

|MR105ZZ Bearing
|1
|style="text-align:right;" |$0.256
|style="text-align:right;" |$0.26
|[http://www.ebay.com/itm/350977403956 eBay]
|-

|Airtripper Metal Parts Kit
|1
|style="text-align:right;" |$12.79
|style="text-align:right;" |$12.79
|[http://www.ebay.com/itm/321572488544 eBay]
|-

|MK8 Drive Gear
|1
|style="text-align:right;" |$8.99
|style="text-align:right;" |$8.99
|[http://www.ebay.com/itm/321510715341 eBay]
|-

|E3D-v6 Bowden Extruder
|1
|style="text-align:right;" |$83.25
|style="text-align:right;" |$83.25
|[http://e3d-online.com/E3D-v6/Full-Kit/v6-1.75mm-Universal-Bowden E3D]
|-

|style="text-align:center;" |'''Extruder'''
|
|style="text-align:center;" |'''Total Cost'''
|style="text-align:right;" |$117.29
|
|-

|'''Total Unit Cost'''
|
|
|style="text-align:right;" |'''$202.72'''
|
|-
|}

SCARA - Revision history

WikiSysop: Created page with "==Summary== The design of this robot is based heavily on the "HF06" robot designed by Martin Price ([http://www.heliumfrog.com/hf06robot/hf06blog.html link]). It was initially..."