BUILD

Bill of Vacuum

From a target pressure to a machine in service, in eight steps that each say what they cannot answer.

Every step here opens on a question an engineer actually asks, then points at what this site already carries to answer it. Nothing is duplicated: the cards, the tools and the modules stay where they are, and a step is the path between them. What a step cannot answer, it says, in a block derived from the corpus rather than written by hand.

8 steps

  1. 01 Specify What pressure do I actually need, and by when? A target pressure with no species and no time is not a specification. This step turns a number into a regime, a dominant gas and a horizon, which is what every later step reads. Open →
  2. 02 Materials What can the chamber be made of? Every material in the wall is a gas source for the life of the machine. This step reads the card, the sourced outgassing rate and the surface state it was measured in. Open →
  3. 03 Join How do these two materials become one vacuum wall? A joint is where a chamber leaks, and a ceramic-to-metal joint is where it leaks first. This step reads what a document attests about the couple, before any filler is chosen. Open →
  4. 04 Pump What pumping speed actually reaches the chamber? A pump is sold by its speed at its own flange. What the chamber sees is that speed in series with every tube, elbow, bellows and valve between them. This step computes the difference. Open →
  5. 05 Clean and bake How clean is clean enough, and how do I prove it? Cleanliness has no unit until a specification gives it one. This step reads the cleanliness class, the particle count and the bake that the target pressure demands. Open →
  6. 06 Verify Does the chamber hold, and how would I know? A gauge reads a pressure, an analyser reads a composition, and only the second one tells you what is in the chamber. This step reads both through the abacus. Open →
  7. 07 Commission How long until it reaches the number I specified? The pumpdown curve is the first honest measurement a chamber makes. This step compares the predicted curve against the specification set in step one. Open →
  8. 08 Operate It was fine yesterday. What changed? A machine in service fails in a small number of ways, and each one has a spectrum. This step reads the failure mode from the residual gas rather than from the pressure alone. Open →

The dossier

A Bill of Vacuum is the document these steps produce: the result you calculated, the source keys it read, and the list of what it had to take on trust. It lives in this browser, with no account, and it leaves as versioned JSON or as a printable sheet carrying its keys and its licence.

Open the dossier Calculate something to put in it

The 8 steps point at 26 places across 19 distinct pages of this site, and declare 17 things the base does not carry yet. Both counts are read from the data at build, so they follow the corpus rather than a promise.

About this data

Each step declares what it cannot answer. Here is the whole list, in one place, so the shape of the gaps is visible without opening eight pages.