# The Spark Gap - Episode 26

- Show: [The Spark Gap](https://hardwarepodcasts.com/podcast/the-spark-gap)
- Published: 2015-02-11
- Length: 1h 32m
- Page: https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26
- Listen: https://thesparkgap.net/the-spark-gap-episode-26

## Summary

Bob Coggeshall of Small Batch Assembly and Cogwheel Circuit Works explains Design for Manufacturing (DFM) for PCBs, detailing how to prepare Bill of Materials (BOM) and centroid files for contract assembly. He discusses cost-saving strategies like minimizing BOM line items, using full reels instead of cut tape, and proper panelization techniques like V-scoring and tab routing. The conversation also covers critical layout requirements including fiducials, silk screen polarity marks, and thermal pad paste mask design for QFNs, before concluding with a look at his Nixie tube driver board featuring an ESP8266 module.

## Chapters

- [0:00](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=0) Introduction: Bob Coggeshall and Small Batch Assembly
- [1:26](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=86) BOM and Centroid Files for Contract Assembly
- [11:13](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=673) Reducing BOM Count and Managing Component Reels
- [29:35](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=1775) PCB Layout Errors: Origin Marks and Silk Screen Polarity
- [34:15](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=2055) Paste Mask Design for QFNs and Steel Stencils
- [46:41](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=2801) Panelization: V-Score vs. Tab Routing
- [56:20](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=3380) Moisture Sensitivity and Component Handling
- [1:02:54](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=3774) Fiducials and Solder Mask Color Issues
- [1:17:11](https://hardwarepodcasts.com/podcast/the-spark-gap/2015-02-11-the-spark-gap-episode-26#t=4631) Nixie Tube Driver Board and ESP8266 Integration

## Topics

- [PCB design & layout](https://hardwarepodcasts.com/topic/pcb-design)
- [Manufacturing partners & offshoring](https://hardwarepodcasts.com/topic/manufacturing-partners)
- [Pricing, margins & unit economics](https://hardwarepodcasts.com/topic/pricing-and-unit-economics)
- [Microcontrollers & dev platforms](https://hardwarepodcasts.com/topic/microcontrollers-and-platforms)

## Most relevant to

early-stage companies

## Mentioned

- Small Batch Assembly (company)
- Cogwheel Circuit Works (company)
- Osh Park (company)
- Digi-Key (company)
- Mouser (company)
- Octopart (company)
- parts.io (company)
- Seeed Studio (company)
- ESP8266 (chip)
- ATmega328 (chip)
- WS2812B (chip)
- Nixie tube (product)

## Related episodes from other shows

- [S7E2 WEBINAR: Your Manufacturer is Stupid: Why Your Circuit Board Design Is Making Their Job Harder with Chris Denney](https://hardwarepodcasts.com/podcast/being-an-engineer/2026-01-09-s7e2-webinar-your-manufacturer-is-stupid-why-your-circuit-board-design-is-making) (Being an Engineer)
- [I've bitten myself](https://hardwarepodcasts.com/podcast/the-amp-hour/2018-05-21-ive-bitten-myself) (The Amp Hour)
- [PCB Assembly Mistakes Designers Keep Making: PCB West 2026 Preview](https://hardwarepodcasts.com/podcast/ontrack/2026-09-09-pcb-assembly-mistakes-designers-keep-making-pcb-west-2026-preview) (OnTrack)
- [PCB Assembly and Design for Manufacturing with Duane Benson of Screaming Circuits](https://hardwarepodcasts.com/podcast/predictable-designs-podcast/2020-03-03-pcb-assembly-and-design-for-manufacturing-with-duane-benson-of-screaming-circuit) (Predictable Designs Podcast)
- [Signal Integrity, Thermal & DFM: PCB West Preview with Keven](https://hardwarepodcasts.com/podcast/ontrack/2025-08-05-signal-integrity-thermal-dfm-pcb-west-preview-with-keven) (OnTrack)

## Citing this page

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