Wednesday, November 8, 2023

SMTPA – Surface Mount Technology Product Assembly

SMTPA – Surface Mount Technology Product Assembly

This post is being written in response to Mr Stephen Hawes excellent article ‘Mid-Scale Manufacturing’. It is directly related to a challenge I am facing at work. How do I make four thousand of something, without making twenty batches of two hundred? I have designed and built the jigs for hand assembly, trained the staff and assembled 3000 pieces so far. Will the next 4000 simply be more staff hours and more jigs? The next 10000? A giant pick and place machine will solve the problem.




  • currently missing middle-scale automation stack, a gap is present.
  • linear relationship between staff hours and units produced, until offshore threshold reached
  • ROI threshold for onshore automation based on 90’s tech, SCARA arms etc, that were scaled down versions of high-volume high-cost machines, wrong base assumptions / starting point
  • open toolchains now exist for quick deployment of precision component location with decent UX; OpenPNP, Klipper, the whole family of GRBL derivatives, etc
  • toolchains popularity has driven hardware prices down for a decent motion platform
  • open toolchains make hiring / troubleshooting easier, more transparent and accessible
  • start slow when deploying internally to limit risk; ie the charger accessory for a product after a manual process has been established / has had its costs made known 


  • Design products as placeable assemblies
  • accept and support a slower production speed per work cell, then scale in parallel when capacity increase is required
  • product design to stay within community documented/debated walled garden, just as pcb design does
  • MAY break a DRC but that had better be the killer-feature of the product because engineering that assembly step will involve more risk/time; stepping outside the garden
  • source components on tape-and-reel or tray; a uniform and understood feed mechanism (EIA-481, 948, 960) (Thanks Stephen!)
  • can then leverage existing open source software and hardware intended for pcb assembly to assemble the entire product
  • only assemble with open source hardware; financing supply chain while demanding transparency and community inclusion
  • maintain documentation and interoperability, ease of access and staffing for engineering/assembly techs


Rules for SMTPA Products

  • all components supplied in standard feeders, as tape or trays, this includes weird stuff like the plastics and batteries
  • Vertical assembly of components, or at least, vertical loading of assembly stations in the work cell
  • certainly more to be defined, how did the SMT placement / sourcing rules evolve from zero to JLC making a last minute conference badge for $8 with only a couple hours of engineering design labour?
  • cell transfer process definitions; sub assembly moving from one cell to another, from FDM printer to assembly cell, etc. Must be positioned and delivered according to spec, fiducial etched to printed part for location during assembly, required in component model.



  • Strict focus on targeted risk-management; give the problem an ID number and tackle it with the community, the worst problems will float to the top and get the most attention; have the most positive impact when solved
  • supply chain discussion required with Digikey, McMaster-Carr and others; can we get everything in SMT packaging? What will handing exceptions look like? Cost to force exceptions into packaging to comply with toolchain too high?
  • not being applied to whole-product assembly yet due to risk for startups, inertia of existing solutions however poor their fit, startup’s focus on their product’s risk and aversion to taking on any manufacturing risk 
  • kitting / packaging will be a mess


Case Studies

  • Assembly of wearable safety device charger, 4000pcs quantity, near term requirement
  • Motorcycle ECU, 1000pcs quantity, no fixed dates on delivery



Closing Thoughts

Why hasn’t this been done? Why don’t we see this everywhere? I suspect that at thousand-plus volumes, risk management has dictated more traditional approaches to manufacturing. ‘No one ever got fired for choosing IBM’ has been the default since the risky product at their organization was the widget and not the assembly technique. Please help solve this problem, head to and get chatting in #mid-scale-mfg (ping me, L2K20) at or leave a comment here about how a board-in-a-box is weak sauce and I should think bigger!

Monday, May 15, 2023

Bike Carousel


In 2018 a massive automated bike Carousel was built by Karl, Steven and Arthur. Budget and sanity were left behind in the quest to elegantly dispense ebikes to hotel guests. Simply tapping an RFID card at the podium next to the rack selects and dispenses a bike. Six hundred watts of addressable LED lighting was installed with sequences triggered by a PLC. It is astounding to behold and has been in service ever since. 

*The hotel management has since had the lights disabled, apparently Steven's acid-trip lightshow programming was not on-brand.

Saturday, December 10, 2022

AHD: Oscilloscope Captures of Analog HD vs NTSC

I have not seen any oscilloscope captures of an AHD signal on the internet. I am installing a backup camera in my car and selected a NATIKA WD-012. It features 720p AHD mode which my deck isn't compatible with but I wanted to get an idea of what AHD looks like signal wise. Hopefully others will find these captures interesting.
The camera setup as purchased:

For reference here are some captures of the camera in standard NTSC:

Here are the signals with the camera in 720p mode:


Thursday, January 8, 2015

Koss Pro4AA headphones and a 6AS7 based amplifier

The Koss Pro4AA headphones paired with a 6AS7G based amplifier I built.

I built this amp using the chasis and power supply from an old Heathkit A7 amplifier. The output transformer is fine if anyone wants to make me an offer. The schematic is similar to Aren van Waarde's found here. My power supply is different, a 5Y3GT rectifier is used in place of the pair of 1N4007 diodes he specifies. This wasn't done out of a desire for better sound. Rather, I intended a softer start for the high voltage and glowing tubes are a delight so why not use one more eh?

*this was supposed to be an amazon review of the headphones but their site is giving me grief so it gets posted here:
Excellent sound when driven with a decent source. Playing back a FLAC recording through an Audigy 2 seems to be weak on the bass. Using a separate headphone amplifier after the sound card was great without any eq changes needed. I originally bought these for their high input impedance (250 ohms) to be used with a 6AS7/6080 based OTL tube headphone amp I built. I'm happy with how it all turned out.

They're fairly heavy though well built. The headband is not designed for people with large heads so over prolonged use the plastic ridges at the base of each side of the headband do dig in a bit. The ear-cups are great, I like pleather pads and these ones are sized and stuffed the right way. The cord is chunky, this is a good thing for stationary listening but don't expect these to be great on the go. The warrenty service offered by Koss is legendarily good so I'm confident on enjoying these for years to come.

Monday, December 24, 2012

I quit!

A while ago... Half way through August 2012 I had my last day at work and headed off into the sunset. A vacation was in order so I packed everything into the Subaru and my girlfriend and I headed to Vancouver island for 10 days of exploration. Strathcona park has a healthy mosiquito population, easily discovered at any of it's beautiful forest service campsites. Other sites of interest include the McLean steam powered sawmill museum in Port Alberni which was awesome and China creek campsite which I thought was going to be a remote getaway but turned out to be a sea of RV's and boats.

After this break from this city I returned to begin.... five years of school! I am going to become an engineer, not sure which branch is the most interesting but I'm leaning towards electrical or mechanical. I settled on Capilano University as they have a solid engineering transition program (rusty math skills need a refresher) and still cost a bit less than UBC. When I got there I discovered there's no club for people who build things, so I started one.
It's going well and I've started getting kits together to run some basic microcontroller mini-workshops. My classes have been mostly enjoyable and I managed excellent grades the first term. The spring term begins January 7th with a chemistry lecture and I can't wait.

Monday, June 4, 2012


ZAAAAAAP! It works! I found this coil in storage, after replacing a few caps and cleaning up the wiring I got it running. Nice and loud...

Friday, April 20, 2012


It's happening! The background radiation of the universe is all around us and this fully operational cloud chamber visualizes it.

The apparatus has been on the floor for several weeks now with fairly solid performance. I had to rip out a fair amount of rotten material and rebuild. This:
became this:
Add lights, it's getting there:
when if in Rome (verticle mill; perfectly fit wooden braces):

All told that was about 60 hours work, $400 in materials and an $800 bill from the refrigeration service tech for the one part of the job I couldn't do (there was a slight coolant leak in the condensor assembly).