Introduction

Tin Whiskers Technology and FirePick Services have teamed up to create an affordable, open-source desktop electronics manufacturing system called FirePick Delta. The machine incorporates a delta robot design, computer vision and an integrated modular tool system that enables it to perform a myriad of functions including picking and placing electronic components, 3D printing, flying probe testing, hot air SMT/selective soldering, laser engraving/cutting, solder paste application, conductive ink printing, and pen plotting. 

This is a machine made for makers and designed by makers.  We wanted to make sure that it is capable of operating up to four different tools at the same time and has the ability to automatically recalibrate itself between different jobs. The versatility of the machine ensures that makers will be able to accomplish more with a single machine than ever before.  Our ultimate goal is to provide an affordable solution that can automate many of the tedious tasks involved in designing and building new devices.  

Pick and place machines are used globally to assemble electronic circuit assemblies and generally cost between $50,000 to $500,000.  Our machine can do more than just assemble electronic circuit assemblies automatically and less than $5000.  If you've ever had an electronic project that involved soldering surface-mount electronics, this machine is an affordable solution and fun way to do it. If you've ever wanted to sell an electronic board that you've created, and need a way to make lots of them, this machine is for you.

We plan to be the first successful, commercially available RepRap 3d printer to have the power of electronics self-replication. We envision a future where anyone can design (or download existing) electronic projects, and manufacture them in their own home, rather than outsourcing to a traditional factory. This approach saves time and money, and is better for the environment. FirePick Delta will enable a new wave of small businesses and entrepreneurs to provide unique, bespoke, niche items to the general public in a faster time frame and for less money. 

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Features / Specs

Intended Usage

  • Prototyping and small runs of PCB's (under 100 per run). Not intended to be used for mass production.
  • Hobbyists, Makerspaces, high school and college students, entrepreneurs, small businesses.
  • Great for those with poor eyesight, shaky hands, or those that just don't have the skills to solder on small SMT parts. We occasionally remind those that scoff at our project to check their privileges and remember that not everyone has guru SMT soldering skills or access to a full lab with hot air rework. 

Dimensions

  • Overall dimensions: 600mm H x 460mm W x 460mm D
  • Frame dimensions: 520mm H x 300mm W x 300mm D
  • Max PCB size / 3D print volume: 80mm H x 214mm W x 214mm D

Camera and Computer Vision

  • Downward looking vision: USB UVC compatible camera module with LED ring lighting
  • Upward looking vision: Supported.  Includes USB UVC compatible camera module with M12 2.8mm focal length lens, with custom LED ring lighting.
  • Flying vision: Not yet, but it would be super cool. No timeline to speak of. Forget I even mentioned it.
  • Computer Vision Software: FireSight (high-level abstraction layer on top of OpenCV), via OpenPnP custom driver.
  • CV Operations implemented: absdiff, backgroundSubtractor, blur, calcHist, calcOffset, Canny, cvtColor, dft (Discrete Fourier Transform), dftSpectrum, drawKeypoints, drawRects, FireSight, HoleRecognizer, HoughCircles, imread, imwrite, matchTemplate, minAreaRect, MSER, morph, normalize, Points2Resolution, PSNR Compare, putText, QRDecode, resize, SimpleBlobDetector, stageImage, threshold, transparent, warpAffine, warpPerspective, warpRing

Software

  • OpenPnP - Is a project to create the plans, prototype and software for a completely Open Source SMT pick and place machine that anyone can afford. This is the GUI, and the program that handles all of the feeder, camera, and general machien setup, and also the job creation and processing.
  • FireSight - A high-level computer vision framework designed for Pick and Place machines, powered by OpenCV. No programming experience required - A pipeline of image operations is specified with a JSON structure. The results of the operations are returned as a JSON structure.
  • Arduino - Needs no introduction :) We will have designed an Arduino-compatible motion controller with modified RepRap Marlin firmware.
  • OpenCV - is a library of programming functions mainly aimed at real-time computer vision. Written in optimized C/C++. Thankfully, a lot of work has been done to get it working on the Raspberry Pi.
  • Linux - Too many crappy Pick and Place machines, only running on Teh Windows :-(
  • RepRap - An initiative to develop a self-replicating 3D printer.
    • Marlin firmware - The RepRap firmware is a mashup between Sprinter,grbl and many original parts. It runs on an Arduino and handles the very timing-sensitive job of sending STEP and DIRECTION signals to the stepper motor drivers, controls temperature and extrusion. We'll be modifying it to double as a Pick and Place motion controller.
    • Greg's Wade Reloaded Extruder - Bulletproof extruder design
    • RAMPS v1.4 - Our custom board will be roughly based off the Ramps, but with the added stuff necessary for pick and place.
    • StepStick - Allegro A4988 16x microstepping motor driver
    • Slic3r - The world's best slicing program for 3d printing
    • Printrun - Pure Python 3d printing host software

Component size / Placement Accuracy

(Note many of these are not practical to place, until we get our feeders and vision 100% working)

  • Passives down to 0402
  • Diodes: SMC, SMB, SMA, SOD128, SOD80, SOD323, MicroMELF
  • SOT-23
  • QFN, DFN, QFP, SOIC, TSOP, BGA to ~0.4mm pitch
  • SOT23-3, SOT23-5, SOT23-6, SOT223, SOT89, SC70, DPAK, D2PAK
  • IC's and large/wide components to ~50mm wide
  • Aluminum capacitors and tall components <= 15mm H

Modular Auto/Rapid Tool Changing System

  • Holds up to four (4) tools in the machine at the same time
  • System will recognize tools upon insertion. EEPROM in each tool keeps track of SMT nozzle size, and 3D printing parameters like thermistor tables, etc.
  • Tools are hot swappable
  • Average cost of materials per modular tool: $10 - $500, depending on tool.
  • Current tools offered: SMT vacuum nozzle, solder paste dispense, 3D Print hotend.
  • Future tools offered: Professional shot-meter style fluid dispense system for scientific laboratory or solder paste / glue dispense.Pen plotter, laser sensitizer (not big enough to cut stuff with), pogo-pin based flying-probe (for voltage testing, etc), Atmel AVR flying-probe programer. Hot air rework station for minor rework. Note that we intend for other members of the open-source community to help us bring these tools into existence, as the need arises.

Modular SMT Component Feeder System

  • ESD-safe via conductive ABS plastic 3D printing filament.
  • Average cost of materials per feeder: $5-10
  • Auto-recognized by OpenPnP via QR code labels affixed to feeders
  • Tape feeders: 8mm, 12mm, 16mm, 24mm, 32mm, 44mm. Drag-feed with (and without) cover-tape winding, and full-auto advancing version for 8mm
  • Tray feeders: Non-JEDEC. Holds a few small loose parts. Supports pause/reload prompts.
  • Tube feeders: NOTE: We've not started these yet, but see them as minimum risk. We started the tape parts first, since they're more desirable. Will have a vibratory source (DC motor w/counterweight). Will be easy to customize and print custom tube feeders for weird non-standard chokes and coils, etc.

Construction

We chose a Delta robot configuration over a more conventional Cartesian design.  This allows us more speed, less BOM cost going bearings and linear slides, and easier build / configuration.  This will be covered in more detail in a future post.

I've taken the RepRap philosophy to heart.  There are no swiss-machined parts and crazy Japanese bearings in this machine.  I've spent weeks pulling my hair out trying to figure out the cheapest way to build  a PnP machine without sacrificing quality.  The original RepRaps used 608 bearings and LM8UU linear bearings because they're the cheapest, most-available type out there.  They built their machines around these parts, rather than designing the machine first, only to be pigeon-holed into a weird bearing size.  The best part is that the popularity of the RepRap movement has brought down the prices of these parts even further. 


I've designed FirePick Delta around the following parts:

  • Roller bearings: Use primarily 608 for anything load-heavy.  Available for $0.30 each online.  Use 623's for anything tiny. 
  • Timing belts: GT2 belts and pulleys.  Zero backlash, super cheap and available.
  • Motors: Use NEMA 17 stepper motors whenever possible, because they're the most common.  Available for $6.80 online.  
  • Custom parts, brackets, etc.: 3D print them.  Design them without overhangs so they they can be printed without support.  Since this is a Pick and Place machine, we can print with ESD-safe conductive ABS plastic :)
  • Limit switches: Vishay TCST2103 optical endstops are quite common in the RepRap community, and can be extremely accurate.
  • Frame: Misumi HFS5-series extrusion with select CO2 laser-cut acrylic pieces. 

Accuracy and Speed

SMT parts are getting smaller and smaller every year.  If we made a crappy machine, it would be outdated by the time we'd finish it.  We've taken the proactive approach, and created a set of simulations that test various configurations for accuracy and speed, that uses monte-carlo trials and evolutionary algorithms to "find" a correct delta geometry that fits our needs.  

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