A real case
A renewal price arrives with a total on it and nothing else. Build an independent should-cost off the released STEP first: an itemized ledger where every line names its rate, a confidence band naming which of four bases it rests on, and the exact quantity where a cheaper process takes over.
The situation
The renewal price on a machined 6061 manifold came back eleven percent up. Same supplier as the last four years, 250 pieces a year, and the quote is a per-piece figure, a lead time and a two-line note about material. Nothing on it can be taken apart. Engineering can send you the released STEP file and the drawing package inside the hour, and you have a week to either sign the increase or open it. You have no shop of your own to ask what the part should take, and asking the supplier why it costs that much invites a paragraph rather than a number. So build the number first, before you reply at all — the quote you already have is the thing you are trying to test, not the thing you should be starting from.
Step by step
Drop the STEP file engineering sent you. An STL or STEP model, a DXF or PDF drawing, or both on the same job go in the same way, and the first pass returns general manufacturability findings before anybody has picked a process — each one carrying the rule that caught it rather than a bare verdict. You are not reading those findings to redesign the part. You are reading them to learn which features of a part you did not draw are the ones a supplier will be pricing risk against.
Compare methods screens the same upload against casting, molding, forging, machining, sheet metal and additive together. Each family comes back marked feasible, marginal or infeasible with the constraint that drove the call — a wall section, an undercut, a bounding-box limit. For a buyer this is the first checkable fact about a part nobody has explained to you: whether the process your incumbent has always used is the one the geometry actually wants at your volume.
The comparison prices every candidate process across a range of quantities and marks the exact quantity where one method gets cheaper than another — solved closed-form, labelled as the crossover, not eyeballed off a chart. Where a method needs a tool, the tool prices off one shared block-and-machining model and its cost is spread into the per-piece figure rather than sitting beside it as a lump. Your annual 250 lands somewhere specific on that picture, and so does the volume at which the answer would change.
The estimate comes apart into cost lines, each showing the named rate behind it and what it contributes per piece, with a confidence band on the result that states its basis: a published prior, a calibration built from recorded actuals, a deterministic rule, or a flag that the figure needs a person to look at it. Read the basis before you read the number. A line resting on a deterministic rule is not where your week goes; a needs-human-review flag is exactly where it does.
Nothing here reads a supplier's price document. There is no upload path for the quote PDF sitting in your inbox and no screen that diffs their total against your ledger line by line. What you carry into the conversation is your own itemized figure and their total, compared by hand, by you. That is a real limit and it is worth knowing before you plan a workflow around it.
What you get
You go back to the supplier holding a per-piece figure at 250 off that you built yourself, the process verdict and the constraint behind it, the quantity at which a different method would win, and two or three named cost lines you have decided to ask about. The eleven percent stops being a number you either accept or push back on by feel, and becomes a question about one rate, one operation or one volume assumption — the kind of question a supplier can answer with a number instead of a paragraph, and the kind of answer you can check. None of this is a guarantee of what the part will be sold to you for; it is decision support, and every line names the rule behind it so you can see where to trust it and where to ask.
Already shipped
Built into PartDFM.
Built into MFGDFM.
Built into ProcessDFM.
Built into ProcessDFM.
Built into ToolDFM.
Built into CostDFM.
Built into CostDFM.
FAQ
The released model is enough to start. An STL or STEP file, a DXF or PDF drawing, or both on one job go in the same way, and the part comes back screened against casting, molding, forging, machining, sheet metal and additive together, each verdict naming the constraint that drove it, with a should-cost curve across quantities under it. The figure is built from the geometry and a rate model rather than from anybody's opinion about the part, which is what makes it usable by someone who has never run one.
Supplier price documents are not an input. Drawing and model intake is the only way material gets into a job, so there is no screen that reads a received quote and diffs it against a should-cost. A buyer builds the independent figure here and holds the supplier's total against it by hand. Worth knowing before you plan a process around it.
Whichever line carries the most cost per piece and names a rate you can check. Because every cost line traces to a named rate, a posture setting or a rule in the engine, and the result carries a confidence band stating whether it rests on a published prior, a calibration from recorded actuals, a deterministic rule or a flag for human review, you can rank your own lines by size and by how solid they are before deciding which one to open with.
Crossover quantity is the specific answer to that argument. The comparison prices each candidate process across quantities and marks the exact quantity where one method gets cheaper than another, closed-form rather than read off a chart, with any tooling spread into the per-piece figure. A conversation about volume then happens against a curve both sides can look at, rather than against a claim that the order is simply too small.
Where this fits
You buy parts you did not design, priced by suppliers whose numbers you cannot take apart. Partimation gives the buy side its own should-cost: an itemized ledger where every line names its rate or rule, a process verdict that names the constraint behind it, and the exact quantity where a cheaper method takes over.
A quote nobody can take apart is a quote nobody can defend. Partimation builds the price as an itemized ledger where every cost line traces to a named rate, posture setting, or engine rule — and every estimate carries a confidence band that states which of four bases it rests on.
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