Daniel Doerrfeld Mechanical design engineer @

About

Machines, fixtures, and parts designed by someone who also has to make them.

Background

Twelve years in tooling and machining.

I am a mechanical design engineer and CAM programmer with twelve years of hands-on work in tooling, machine building, and contract machining. I am a Certified SolidWorks Professional, work daily in Autodesk Inventor, Fusion 360, and AutoCAD, and program three and four axis milling and four axis wire EDM in CAMWorks, Inventor CAM, and Fusion CAM.

Running a shop.

Since 2024 I have been Operations Manager at Variable Operations Technologies, an ISO 9001:2015 contract machine shop running Haas mills and lathes and Sodick wire EDM. I model parts and fixtures, release GD&T drawings, and review customer models for manufacturability, setup sequence, and tolerance risk before we quote.

I also build the shop’s engineering tooling: a pipeline that turns customer drawings into DFM reports and pricing, an Inventor API tool that generates shop-floor drawings, and a vision pipeline that triaged a backlog of 220 RFQ drawings.

Dies, robots, and putters.

Before that I spent ten years at Lion Tool and Die as Engineering Manager, leading the design of die-cast trim dies, owning the CAD and drawing standards, and adapting trim tooling for robotic cells. In between I co-founded 616 Flatsticks, a custom CNC golf-club maker, and took its putter line from concept through parametric models, CAM, and production.

What production taught me about drawings.

Datums follow how a part is fixtured and measured, tolerances follow function, and every callout has to survive quoting, setup, and inspection without a phone call. Design changed how I run a shop too: process planning starts in the model, and the tools I build exist to shorten the distance between a customer drawing and a first good part.

Experience

  1. Variable Operations Technologies

    Operations Manager

    Aug 2024 – Present

    ISO 9001:2015 contract machine shop. Operations leadership plus hands-on design, GD&T release, DFM review, and CNC engineering.

  2. Stintera

    Founder

    2025 – Present

    AI-assisted CNC quoting and routing for job shops, built on a proven shop estimating method.

  3. 616 Flatsticks

    Founder and CEO

    Oct 2022 – Feb 2025

    Custom CNC golf-club manufacturer. Putter line from concept through parametric models, CAM, and production.

  4. Lion Tool and Die

    Engineering Manager

    May 2014 – Jul 2024

    Led design of die-cast trim dies, owned CAD and drawing standards, and adapted trim tooling for robotic cells.

Facts

Location
Rockford, Illinois
Education
B.S. Business Administration, Aquinas College
Certification
Certified SolidWorks Professional (CSWP)
Tools
SolidWorksAutodesk InventorFusion 360AutoCADAutodesk VaultiLogic and Inventor APICAMWorksInventor CAM and Fusion CAMPython and VB.NET

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