> ## Documentation Index > Fetch the complete documentation index at: https://docs.buildwithtrace.com/llms.txt > Use this file to discover all available pages before exploring further. # DFM & the Automated Line > Trace is step 0 of the PCB manufacturing line. Every file Trace exports is shaped for a specific machine downstream — stencil printers, SPI, pick-and-place, reflow, AOI. Here's how the pipeline fits together. A modern SMT line is a chain of machines that talk to each other — stencil printer, SPI, pick-and-place, reflow oven, AOI. The board moves through without a human touching it between load and unload. **Trace is step 0 of that line.** Every file Trace exports is shaped for a specific machine downstream. This page explains what Trace outputs, which machine consumes each output, and how our DFM tooling catches process violations before a board ever hits a stencil. ## The Line ``` Trace ──► [Stencil Printer] ──► [SPI] ──► [Pick & Place] ──► [Reflow Oven] ──► [AOI] ──► Finished Board paste deposit print component thermal profile defect on bare PCB quality placement lock-in inspection ``` Each machine needs a specific file format or parameter set. Historically those are produced by hand or scraped out of EDA tools with custom scripts. Trace produces all of them as a single coherent export. ## What Trace Outputs, and Which Machine Consumes It | Trace Output | Machine | What It Does | | --------------------------------------------- | ---------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------- | | **Paste Gerber (F.Paste / B.Paste)** | Stencil Printer | The stencil cut file. Defines where solder paste gets deposited on the bare PCB | | **Copper Gerbers + Solder Mask** | SPI (Solder Paste Inspection) | Reference geometry for 3D paste-volume scanning. Catches bad prints before you waste a board | | **Pick-and-Place CSV** (X, Y, rotation, side) | Pick-and-Place Machine | Component centroid coordinates. The machine pulls parts off reels and places them per these coordinates | | **BOM with manufacturer part numbers** | Pick-and-Place Feeder Setup | Maps each reference designator to a specific part. Feeders are loaded by MPN, not by value | | **Copper + Silkscreen Gerbers** | AOI (Automated Optical Inspection) | Reference image for defect comparison. AOI compares scanned board against expected layout to catch bridges, tombstoning, missing parts | | **Drill Files (Excellon)** | CNC Drill / Laser Drill | Hole locations and diameters for plated and non-plated through-holes | | **Board Outline (Edge.Cuts)** | V-Score / Router | Where to separate the board from its panel | All of these come out of Trace with the right formats, units, and origin conventions by default. No per-line customization. ## DFM Enforcement: Catching Problems Before the Line A line can only run as fast as it can trust its inputs. Trace enforces Design-For-Manufacturing constraints up front through two layers: ### Manufacturer DRC Presets Each supported manufacturer ships with a DRC preset that encodes their actual process tolerances. When you load a preset (via the AI: "load PCBWay 4-layer 1oz DRC rules"), Trace: 1. Replaces your project's `.kicad_dru` with the manufacturer's ruleset 2. Re-runs DRC and lists violations in the chat 3. Offers to auto-fix common issues (widen traces, grow annular rings, move silkscreen off pads) This catches things a generic DRC misses: PCBWay 4-layer minimum trace spacing is 3.5/3.5 mil; Pikkolo requires drill-to-copper clearance ≥ 10 mil and no microvias under 6 mil finished hole. A board that passes generic DRC but fails the fab's preset is a board that fails at SPI or AOI. ### AI-Assisted Order Autofill When you submit to PCBWay or Pikkolo via [one-click manufacturing](/guides/one-click-manufacturing), the backend analyzes your `.trace_pcb` and recommends order parameters that match the fab's capabilities: layer count, thickness, surface finish, copper weight, via process, silkscreen sides. If your design requests something the fab can't do (14 layers at Pikkolo, microvias without HDI), autofill flags it before you pay for a quote. ## Why This Matters for Automation In a dark-foundry line — no humans between load and unload — a single bad input stops the whole line. The machines will happily place components on a board with bad paste deposition, and AOI will catch it downstream, but by then you've burned stencil time, pick-and-place cycles, and reflow energy on a board that goes in the scrap bin. The economic case for DFM-first design is simple: every defect caught in Trace (during design, on your laptop, in seconds) costs \~\$0. Every defect caught at SPI costs the price of one bad stencil print. Every defect caught at AOI costs the price of a fully-populated scrap board plus the line time to produce it. Trace's job as step 0 is to make sure the line receives files it can trust — clean Gerbers, correct PnP coordinates, a BOM that matches real parts on the shelf, and a design that respects the fab's actual process limits. ## What Trace Does Not Do (Yet) To be honest about where the line-of-responsibility currently sits: * **Reflow profile generation** is not currently automated in Trace. The SAC305 profile (ramp to soak, peak \~217°C, time above liquidus, cooling slope) is set at the line, not derived from the design. This is on the roadmap for surface-mount components that publish thermal specs. * **Feeder setup automation** happens at the assembly partner, not in Trace. Pikkolo, for example, has their own vision-based feeder calibration. Trace provides the PnP file; the partner handles the physical setup. * **Closed-loop line feedback** — machines talking to each other, AOI flagging a drift that updates the reflow profile — is a fab-side integration, not a Trace feature. Trace provides the upstream design intent. ## Integration Surface The file formats Trace emits are standard and line-ready: * Gerber RS-274X * Excellon drill files * KiCad-style pick-and-place CSV (X, Y, rotation, side, reference, value, footprint, MPN) * BOM CSV with DigiKey, Mouser, and Nexar part identifiers No proprietary formats. Any line that accepts KiCad output can accept Trace output. If you run a fab or assembly house and want orders routed to you programmatically, reach out via the [partnerships page](https://buildwithtrace.com/partnerships). ## Related * [One-Click Manufacturing](/guides/one-click-manufacturing) — Submit orders to PCBWay and Pikkolo * [Exporting Designs](/guides/exporting) — The raw file export reference * [DRC Rule Editor](/concepts/drc-rule-editor) — How the visual rule builder produces the `.kicad_dru` that manufacturer presets replace