Truepath CFD

Thermal & CFD consulting · Richmond, TX · Remote

Thermal models you can trust.

Joule-heating and conjugate heat transfer simulation for multi-zone semiconductor heaters and electronics cooling. When your model and your thermocouples disagree, I find out why.

Book a 20-minute scope call See services

Most thermal models are easy to build and hard to trust. Once the simulation and the thermocouple map disagree, the model is no use for the decision that matters: which trace, zone, gap or flow change to make before you tool. That's the problem I work on.

Services

For thermal, R&D, process and mechanical leads on heaters, electrostatic chucks, pedestals and high-power electronics. Best fit when the next decision is a trace, a gap, a cold plate or a measurement, and a wrong one costs a spin.

01

Model audit

Your existing thermal model compared against your own test data. You get the root cause of the mismatch, a short memo and recommendations.

Lowest-cost way to start.

02

Diagnostic sprint

One geometry, the real boundary conditions and a written verdict: will this layout hit its temperature gate, and what is the cheapest change if it won't.

Usually 1–2 weeks. The usual first full study.

03

Calibrated design loop

Match the model to your thermal map or thermocouples, then change traces, zones or flow hardware against that model. It stops when the predicted window is tight enough to tool.

Run by milestone.

04

Production support

Drawings-ready recommendations, rating notes and a measurement list your lab can run on equipment it already has. On-site setup is a separate trip, by agreement.

Run by milestone.

What you receive

  • Annotated temperature and power plots a non-specialist can brief upward.
  • A short decision memo: keep, change allocation, change geometry, or stop and measure.
  • Native plots plus CAD notes so your team keeps the geometry.
  • A next-step list with effort, and a measurement list for equipment you already have.

How a first job starts

  1. 20-minute scope call: temperature gate, geometry class, what you already measured.
  2. One-page statement of work: fee, dates, deliverables, out of scope.
  3. Kickoff, then CAD, materials, duty cycle and any test data. Mutual NDA before proprietary geometry is exchanged.
  4. A mid-project working session, so the last day is a decision, not a reveal.

Fixed project fees, scoped on a short call. Fees move only when scope moves.

Selected work

Client projects stay confidential, so client cases are described without names or figures. Detailed case studies are available on request.

Client work

Calibrating a multi-zone wafer heater model

Challenge
The thermal model disagreed with a dense thermocouple map, so nobody could use it for design decisions.
What I found
The model was missing interface resistances between bonded layers and the heat lost through the lead wires.
Outcome
With those added, the model went from unusable to accurate enough to make redesign decisions.

Full case study with results available on request · Book a call or email

Client work

Fixing cold corners on a fast-ramp ceramic heater

Challenge
A fast-ramp multi-zone ceramic heater ran cold in the corners during ramp.
What I found
Variable-width traces could move power into the cold corners while keeping each zone’s resistance unchanged.
Outcome
Customer thermal imaging of the built heater confirmed the simulated improvement.

Full case study with results available on request · Book a call or email

Client work

Tracing a purge-gas cold spot

Challenge
An asymmetric cold spot persisted, and the suspected fix was changing the purge flow rate.
What I found
The cause was the purge-gas path, not the flow rate.
Outcome
Small machinable changes to the gas path fixed the cold spot without a redesign.

Full case study with results available on request · Book a call or email

Own R&D · patent pending

On-demand convection heater

Challenge
Heat a small volume of air on demand, fast, from a small battery.
What I found
Placing the heater directly in the air path, designed with coupled flow and Joule-heating models, gave the fastest response.
Outcome
It heats air to 345 °C in about 1.1 s from a 7.4 V battery (WO 2026/161382).

Full case study with results available on request · Book a call or email

345 °C

Air temperature reached in about 1.1 s from a 7.4 V battery by my own on-demand convection heater (patent pending, WO 2026/161382).

~200 °C/s

Ramp targets on fast-ramp heaters, with ±5 °C uniformity after ramp.

9

Patents and applications in heaters, airflow and heater control. See the list.

About

I'm David Guo. I run Truepath CFD, an independent thermal practice in Richmond, TX. I build and audit transient Joule-heating and conjugate heat transfer models of multi-zone ceramic heaters, wafer heaters, pedestals and high-power electronics. I check them against your test data, and when they don't match, I find out why.

I also built a matrix method that lets standard FEA track temperature-dependent trace resistance in multi-zone heaters.

Background

  • Oasis Materials (Fralock), 2020–2023: designed and then built high-power-density AlN heaters for semiconductor equipment.
  • JWEI Group / Vivant, 2017–2020: chief engineer on consumer rapid-heating products.
  • M.S. Physics, Cal State LA. B.A. Economics, UC Berkeley.
  • 9 patents and applications.
  • English and Mandarin.

Where to start

If you have a thermal model and test data that disagree, start with a model audit. If you have a layout and a temperature gate, start with a diagnostic sprint. Send the geometry class, the temperature gate and what you've already measured.

Book a 20-minute scope call