Bill of materials (BOM) for Annin Robotcs AR2 and AR3 robotic arms.
The AR3 robotic arm is impressive work by the talented engineer Chris Annin who can be found on YouTube and GitHub.
To build the Annin Robotics AR3, one can purchase milled aluminum parts as a kit or 3D print the the STL files. The hardware kit includes all the required bearings, screws, etc., and there is a motors kit. There are covers and spacers to 3d print. And finally, there are many parts that must be purchased mainly to build the electronics enclosure.
Listed below are all the parts that I ordered to build the Annin Robotics AR2/3 robotic arm and travel track. At the time that I assembled mine, there was no online BOM and searching for each part took a lot of time. I tried to maintain the order of the parts shown in the assembly manual. If you find mistakes or have suggestions please let me know, and please share this list with other builders. The Amazon Affiliate links support the KvvCreates YouTube channel.
Budget at least $2,300USD to build the AR3 and an additional $200USD to build the Travel Track. The slowest parts took two months to arrive. Printing the spacers on a Taz5 took about three days. Building took roughly five solid days.
Finally, read the manual carefully, take your time, and enjoy the build process.
AR3 Robotic Arm hardware
The aluminum parts kit from Annin Robotics is easily worth the expense. Alternatively, STL files are available for printing the parts.
Annin Robotics also sells a hardware kit that contains all the bearings, screws, etc. They could be purchased individually on McMaster, but the hardware kit saves a lot of time. The kit contains an exact number of each item. Be careful not to lose any. If the hardware kit is purchased, you’ll benefit from having a good collection of extra metric hardware. (Including a few extra pieces of each nut, screw, washers, etc. in hardware kits is always appreciated by the customer who drops a tiny screw onto carpet.)
Omitting the encoders, the main improvement of the AR3 over the AR2, will save time wiring and about $250 (the cost of the encoders plus four Ethernet feedthrus; two Ethernet feedthrus are still required for the limit switches.) Consider ordering the dual shaft motors even if you choose not to install the encoders. The small extra cost creates the possibility to later install the encoders. The encoders have two useful functions: 1) detection of lost steps; and 2) training. If moving heavy loads, lost step detection may be critical. Using the encoders to perform training may be a compelling reason to upgrade an AR2 to AR3, if the necessary code exists. With raw access to the encoders, and some math, training by moving the arm by hand is a real possibility.
The shipping costs and duration are high on SteppersOnline orders, so get all the parts that you may need into a single order.
Some expense can be saved by ordering the six roll pack of 18 AWG wire instead of the ten roll pack listed in the table. However, to match the colors in the manual, the ten roll pack is needed. The six roll pack will require some substitution throughout the manual.
| Link | Est. cost each | Quantity | Est. cost | Description |
|---|---|---|---|---|
| Annin Robotics | $839.00 | 1 | $839.00 | AR2 & AR3 Aluminum and Hardware Kits Combo |
| StepperOnline | $489.62 | 1 | $489.62 | AR3 Open Source Robot Package Kit – Stepper Motor, Driver, Power Supply and Bracket |
  | $38.85 | 1 | $38.85 | BUD Industries NBF-32026 Plastic ABS NEMA Economy Box with Solid Door, 15-47/64″ Length x 11-51/64″ Width x 6-9/32″ Height, Light Gray Finish |
  | $20.10 | 1 | $20.10 | BUD Industries NBX-32926-PL ABS Plastic Internal Panel, 14-1/4″ Length x 10-27/64″ Width x 9/64″ Thick, for NBF Series Boxes |
  | $8.70 | 1 | $8.70 | BUD Industries IPV-1116 IP32 Air Vent, 3.9″ x 3.9″ |
| McMaster | $7.92 | 1 | $7.92 | Phillips Rounded Head Thread-Forming Screws for Plastic, Zinc-Plated Steel, Number 6 Size, 3/8″ Long |
  | $18.99 | 1 | $18.99 | Striveday™Flexible Silicone Wire 18awg Electric wire 18 gauge Coper Hook Up Wire 300V Cables electronic stranded wire cable electrics DIY BOX-1 |
  | $6.48 | 1 | $6.48 | BNTECHGO 22 Gauge Silicone wire 10 ft red and 10 ft black Flexible 22 AWG Stranded Copper Wire |
  | $11.98 | 1 | $11.98 | BNTECHGO 22 Gauge Silicone wire spool 50 ft White Flexible 22 AWG Stranded Tinned Copper Wire |
  | $31.99 | 1 | $31.99 | Monoprice Access Series 18 Gauge AWG CL2 Rated 4 Conductor Speaker Wire/Cable – 100ft Fire Safety in Wall Rated, Jacketed in White PVC Material 99.9% Oxygen-Free Pure Bare Copper |
  | $8.99 | 1 | $8.99 | Striveday™ 2547 26 AWG 5 Meter black 4-core Control Cable Copper Wire Shielded Audio Cable Headphone Cable Signal Line |
  | $41.95 | 1 | $41.95 | 18 Gauge Primary Wire – 10 Roll Assortment Pack – 100 Ft of Copper Clad Aluminum Wire per Roll |
  | $10.49 | 1 | $10.49 | CAT6 Ethernet Cable (6 Feet) LAN, UTP (1.8 m) CAT 6 RJ45, Network, Patch, Internet Cable – 6 Pack (6 ft) |
  | $5.79 | 1 | $5.79 | EDGELEC 120pcs Breadboard Jumper Wires 10cm 15cm 20cm 30cm 40cm 50cm 100cm Optional Arduino Wire Dupont Cable Assorted Kit Male to Female Male to Male Female to Female Multicolored Ribbon Cables |
  | $7.99 | 1 | $7.99 | Ginsco 580 pcs 2:1 Heat Shrink Tube 6 Colors 11 Sizes Tubing Set Combo Assorted Sleeving Wrap Cable Wire Kit for DIY |
  | $9.99 | 1 | $9.99 | Besteek 50ft – 1/2 Inch & 1/4 Inch Nylon Expandable Braided Cable Sleeving, Braided Wire Sleeve, Cable Sheath Mesh Wire Loom |
  | $5.99 | 1 | $5.99 | Uxcell a15062500ux0366 5 Pcs PG21 Compression Waterproof Stuffing 16-21mm Cable Glands White (Pack of 5) |
  | $28.99 | 1 | $28.99 | Dinkle UL Every Color DIN Rail Terminal Block Kit 20 DK2.5N 12 AWG Gauge 20A 600V Ground DK4N-PE Jumper DSS2.5N-10P End Covers End Brackets |
  | $8.29 | 1 | $8.29 | OdiySurveil (TM) XV-152-1C25 Hinge Lever Type Miniature Micro Switch(Pack of 5) |
  | $9.99 | 1 | $9.99 | 5Pcs 250V AC SPDT 1NO 1NC Limit Switch Micro Switch SV-166-1C25 Long Lever with Wheel Automatic Reset |
  | $6.99 | 1 | $6.99 | URBEST 10A 250V AC Rocker Switch 3 Pin IEC320 C14 Inlet Module Plug Fuse |
  | $9.20 | 1 | $9.20 | 22mm Red Mushroom Emergency Stop Push Button Switch 600V 10A ZB2-BE102C 2PCS |
  | $10.80 | 6 | $64.80 | Switchcraft EHRJ45P5ES RJ45 CAT5e Feedthru Panel Mount Jack, Shielded, Plastic Black Housing |
  | $11.38 | 2 | $22.76 | Switchcraft EHUSBBABX USB-B to USB-A Feedthru Panel Mount Jack, Black Finish |
  | $11.09 | 1 | $11.09 | uxcell 5pcs Aviation Connector, 16mm 2P 7A 125V GX16-2 Waterproof Female/Male Wire Panel Power Chassis Metal Fittings Connector Aviation Silver Tone |
  | $10.90 | 2 | $21.80 | Aviation Plug Connector 10 Pairs Male Female Panel Metal Wire Connector 16mm Socket (4 Pins 10-Pack) |
  | $9.89 | 1 | $9.89 | XHF 22-18 AWG Flag Shaped Spade Connectors Terminals Nylon Fully Insulated Quick Crimp Wire Connectors 100 Pcs Red |
  | $25.99 | 1 | $25.99 | Ferrule Crimping Tool Kit – Sopoby Ferrule Crimper Plier (AWG 28-7) w/ 1800pcs Wire Ferrules Kit Wire Ends Terminals |
  | $32.56 | 6 | $195.36 | CUI Inc AMT102-V AMT10X Series 3.6 to 5.5 V 2-8 mm Open Center Capacitive Encoder Switch Kit – 1 item(s) |
| Phidgets.com | $5.00 | 3 | $15.00 | HighSpeed Encoder Cable 50cm |
  | $8.29 | 1 | $8.29 | FTCBlock 8 Channel DC 5V Relay Module with Optocoupler for Arduino UNO R3 MEGA 2560 1280 DSP ARM PIC AVR STM32 Raspberry Pi (8 Channel, DC 5V) |
  | $5.60 | 1 | $5.60 | Haobase 10 Pcs 40 Pin 2.54mm Pitch Straight Single Row PCB Female Pin Headers |
  | $26.10 | 1 | $26.10 | Teensy 3.5 |
  | $14.99 | 1 | $14.99 | ELEGOO MEGA 2560 R3 Board ATmega2560 ATMEGA16U2 + USB Cable Compatible with Arduino IDE, RoHS Compliant |
  | $12.49 | 1 | $12.49 | MEAN WELL RS-15-5 AC to DC Power Supply Single Output, 5V 3 Amp 15W |
| eBay | $120.00 | 1 | $120.00 | SMC MHF2-8D1R Low-Profile Air Gripper, 8mm Bore, 16mm Stroke w/ Auto Switches |
  | $8.89 | 1 | $8.89 | uxcell Silicone Tube 1.5mm ID X 3mm OD 32.8′ Flexible Silicone Rubber Tubing Water Air Hose Pipe Transparent for Pump Transfer |
  | $3.23 | 1 | $3.23 | uxcell M3 Male Thread to 3mm 3/25 inches Pneumatic Tube Hose Mini Barb Fittings 5 Pcs |
  | $9.83 | 1 | $9.83 | Gardner Bender 48-308UVB Mounting Cable Tie, 8 inch, 50 lb, Electrical Wire and Cord Management, Nylon Zip Tie, 100 Pk, UV Resistant Black |
Travel track hardware
The Travel Track sliding plate is sized to minimize waste and make building the plate with common tools convenient. Increasing the length to 13″ and width to 6.5″ would better support the AR3 electronics box, but regardless, a plate with the standard 12×6″ dimensions will support the weight of the AR2 or AR3 well.
If you have access to a mill, consider milling the features.
Consider ordering a dual-shaft motor, possibly the slightly larger motor, to create the possibility to add an encoder to the travel track. Related, consider the slightly smaller, but suitable driver. (These items are listed in the BOM below.)
Consider using full-size aviation plugs on travel track. The listed aviation plug is a mini 4-pin type while full-size plugs are used on the AR2/3. The full-size plugs are generally less expensive. If building the AR2/3, there may be spare aviation plugs.
Consider using socket head cap screws (SHCS), instead of flat head cap screws (FHCS) to secure the plate to the bearing blocks. Counterbored SHCS and countersunk FHCS can be used to create a flush surface. Generally, SHCS allow for adjustment while FHCS are used to ensure concentrically. For aligning the bearing blocks and bearing rails on the plate, some adjustment range is desirable.
Consider using low-profile socket head cap screws to attach the bearing blocks to the aluminum plate. Counterboring full-head SHCS in 1/4″ thick plate will leave only about 0.050″ of material which if counterboring with a drill press or hand drill does not leave much room for error. Low profile SHCS will increase the margin.
Consider using 3/8″ thick aluminum plate . Extruded aluminum is generally slightly cupped, and especially noticeable on thinner plate. 3/8″ thick aluminum plate which will have a less pronounced cup than 1/4″. Ideally, the plate thickness would be oversized and milled flat and parallel.
The Travel Track manual had not been updated for the AR3 when the BOM below was assembled. The AR3 electrical box is now integrated into the base of the AR3 and is secured with with the arm.
Also needed, x16 M5x18 SHCS (the manual calls for M5x20 FHCS), x4 #4×1/2″screws (the manual calls for #2 but these were too small for the printed part), x4 M4x10 SHCS (the manual calls for M4x20), x4 M3x8 SHCS (the manual calls for M3x10), 4x M8x35 SHCS (with washers and lock washers), 24 x #6 screws, a few additional screws and washers.
| Link | Est. cost each | Quantity | Est. cost | Description |
|---|---|---|---|---|
| StepperOnline | $11.62 | 1 | $11.62 | Dual Shaft Nema 17 Bipolar 59Ncm (83.78oz.in) 2A 2.8v 42x42x48mm 4 Wires (dual shaft replacement for the original motor) |
| StepperOnline | $14.52 | 1 | $14.52 | Dual Shaft Nema 17 Bipolar 1.8deg 65Ncm (92.3oz.in) 2.10A 3.36V 42x42x60mm 4 Wires (slightly more powerful dual shaft replacement for the original motor) |
| StepperOnline | $32.29 | 1 | $32.29 | Digital Stepper Driver 1.0-4.2A 20-50VDC for Nema 17, 23, 24 Stepper Motor (original driver) |
| StepperOnline | $23.19 | 1 | $23.19 | Digital Stepper Drive 1.0-3.2A 10-30VDC for Nema 17, 23 Stepper Motor (alternative to the original driver) |
| StepperOnline | $1.43 | 1 | $1.43 | Nema 17 Bracket for Stepper Motor and Geared Stepper Motor Alloy Steel Bracket |
  | $10.24 | 1 | $10.24 | TOOGOO T8 8mm 500mm Lead Screw Rod with Nut Pillow Block Mounted CNC Set for 3D Printer |
  | $84.29 | 1 | $84.29 | CNC Linear Guide Way Rail Kit Set – 2pcs Fully Support SBR 12-500mm 12mm Ball Bearing Linear Slide Rail Shaft + 4pcs SBR12UU Blockbearing |
  | $6.38 | 1 | $6.38 | Hammond 1591BSBK ABS Project Box Black |
  | $9.99 | 1 | $9.99 | Hilitchi 30 Piece Nylon Plastic Waterproof Adjustable 3.5-13mm Cable Glands Joints Cable Gland – PG7, PG9, PG11, PG13.5, PG16 |
  | ||||
| McMaster | $14.89 | 1 | $14.89 | Multipurpose 6061 Aluminum 1/4″ Thick x 6″ Wide, 1 Foot Long |
Extra tools
Here is a mostly (in-)complete list of tools that will be needed. I only listed the tools that I needed to order, but may come back to list more of the tools later.
| Link | Est. cost each | Quantity | Est. cost | Description |
|---|---|---|---|---|
  | $54.90 | 1 | $54.90 | Insulated Flag Terminal Crimping Kit – Red Blue Yellow Connectors AWG 22-10 |
Experimental
For the brave experimenter, some items to considers.
| Link | Est. cost each | Quantity | Est. cost | Description |
|---|---|---|---|---|
| StepperOnline | $49.63 | 1 | $49.63 | Closed Loop Stepper Driver 0-3.0A 24-48VDC for Nema 11, 14, 17 Stepper Motor |
| StepperOnline | $55.47 | 1 | $55.47 | Closed Loop Stepper Driver 0-8.0A 24-48VDC for Nema 17, 23, 24 Stepper Motor |
| StepperOnline | $42.02 | 1 | $42.02 | Y Series Closed Loop Stepper Driver 0-7.0A 24-50VDC for Nema 17, 23, 24 Stepper Motor |