Manufacturing an Electronic Component

From Start to Finish

Indie Hackers - October 13, 2020

Michael Lynch (@deliberatecoder)

https://decks.mtlynch.io/indie-hackers-2020-10/

Background

• Raspberry Pi’s annoying power design.

• The Pi accepts power on the USB-C port
  • This is the device’s only USB-OTG port.

Background

• TinyPilot needs the USB OTG port to connect to a computer’s USB port.
  • Computer USB ports output too little power for the Pi.

Background: Y-cables?

• A Y-cable seemed like the answer!

Background: Y not?

Goal

• Split access to the Raspberry Pi’s USB-C port
  • Should accept 3 Amps of power.
  • Should also function as a USB port.
  • Prevent incorrect flows of power.
• Need it fast.

Day 1

The engineering firm begins work on the circuit board for the power connector.

It’s a simple enough board that they’re able to design it and order 100 printed circuit boards from China the same day.

Day 2

• I ask 3D printing lab to design a case for the power board.
• Within hours, they send me a work-in-progress image of the case design.

Day 5

The 3D printing lab completes their design and gets ready to begin printing a few prototype cases.

Day 8

The engineering firm receives the bare PCBs from their overseas manufacturer.

• Still need to solder on the components.
• 3D printing lab produces first two case prototypes.
  • I ship them to the electrical engineers.

Day 9

• Cases fit the boards

• Large gaps around the port because 3D printing lab erred on the side of caution.

Day 10

• I receive the first two board prototypes.
  • They’re soldered by hand as the engineers build automation
• They work!

Day 13

• 3D printing shop prints their first batch of 30 cases.
• Still a small gap around the microUSB ports, but not a showstopper.

Day 19

I receive the first completed panel of 24 PCBs from the engineering firm.

• Manufacturing process was automation + manual fixes.

Day 20

• The 3D printer finishes the remaining 70 cases.
• They include 10 experimental cases.

I like this new design so much that I switch all future production to black cases.

Day 21

I begin sending out the first completed power connectors as replacements to legacy customers.

Day 26

• I receive the remaining 74 completed boards
• With 100 cases and boards ready, the first run of production is complete.

Costs

• Boards: $2,897.70
  • Design: $241.72
  • Materials: $422.16
  • Assembly, testing, packaging: $2,579.04
  • Postage: $76.95
• Cases: $500.00
• Total: $3,297.64

Case costs are after 75% subsidy from MA Innovation Voucher.

What went well

• Luck
  • Almost everything worked well.
• Limited the number of vendors involved
  • Prevented miscommunications, friction.
• Added padding to the time estimates I received

What went well

• Communicated to everyone that I was optimizing for turnaround time
  • I estimated that I lost $50-100 for each day of delay, so I was willing to pay ~$50/day for options to expedite.
• Working in parallel with the 3D printer and electrical engineers

What could have been improved

• Underestimated total number needed
  • After sending out free replacements to ~60 legacy customers, I had only 40 left to sell to new customers.
• PCB assembly time
  • Biggest bottleneck, most costly part.
  • Possible resolution: after prototyping, outsource assembly to two redundant PCB manufacturing firms.

What could have been improved

• Functional testing
  • Some units were defective when they arrived to customers.
• Deadline slippage
  • Three week delays happen one day at a time.

Questions?

Bonus: How’d I find vendors?

• Luck
  • For both vendors, I was already in contact with them to discuss other physical improvements to TinyPilot.
• Electrical engineering firm
  • Asked PCB manufacturers for recommendations.
  • FORGE Mass: Nonprfit that connects MA startups to manufacturers.
  • Asked friends for recommendations.
• 3D Printer
  • Recommendation from a friend.