How to estimate cycle time from geometry without a black box

What geometry facts tell you

A solid model carries a small number of facts that map cleanly onto time. None of them is a cycle time by itself. Each is one input to one part of the estimate.

The bounding box gives the stock. Add your allowance and round up to a stock size, and you have the material line.

Volume removed is the stock volume minus the part volume. Divided by a removal rate for that material and operation, it is the roughing time. Surface area and face count say something about finishing.

Holes come as a count, a diameter and a depth, and can be grouped by size. Count times minutes per hole from a table is the drilling time. Whether a hole is tapped is not in the solid; it is on the print, and it has to come from there.

Bends and the flat pattern give a bend count for the brake and a blank for the laser. From a 2D drawing the flat also gives cut length and pierce count, which a feed table turns into cutting minutes.

Setups are detected from which faces can be reached from which direction. The count says how many operations to expect and how many times setup hours are paid.

The turning profile says whether the part is turned at all, its maximum outside diameter, minimum inside diameter and slenderness, whether it has off-axis holes and whether those need live tooling. That is the difference between a lathe job and a lathe job followed by a mill.

Exact against estimated

Not every fact from a model deserves the same trust. A bounding box or the diameter of a true cylinder comes straight from the topology and is exact. A setup count or a wall thickness across a complex face is an estimate. An honest tool marks each number with which it is, so the estimator knows where to look twice.

Why a table plus a confirm step is better than a black box

There are two ways to turn those facts into minutes. One is a model trained on somebody's history that returns a number. The other is a table the shop owns: material by operation, minutes per hole by size, minutes per bend, feed rate by thickness.

The table wins on four counts. It is yours: it describes your machines and your tooling, not an average of shops you have never seen. It is visible: when the number is wrong, you can see which row produced it and fix the row, and every quote after that is fixed too. It is versioned: you can say which table priced last year's job. And it refuses rather than guesses: a missing row stops the price instead of returning a zero.

The confirm step is the other half. The facts from the model are proposals until an estimator has looked at them against the print and the part. Only a confirmed fact enters a formula. That keeps the judgment where it belongs and means a bad read of a bad file never prices quietly.

What a method proposal is

A method proposal is a proposed routing built from the confirmed geometry. It writes one operation per detected setup, adds drilling and tapping rows from the hole groups, and attaches a confidence band to each. It is fingerprinted to the exact geometry it came from, so a proposal can always be traced back to what was measured.

It is never selected for you. The estimator takes it as written, edits it, or ignores it and writes a routing from a template. Either way, the operations then cost through the shop's tables and rates like any other, and the print adds what the solid cannot: threads, tolerances that become inspection hours, finishes that become outside legs.

How VenturusEQ does it

• An open-source CAD kernel inside the product measures STEP, IGES, DXF, DWG and STL. Nothing leaves the container. Native SolidWorks, Parasolid and SAT files are kept and previewed, and a STEP export of the part is measured.
• The geometry summary returns bounding box, volume, area, mass, faces, holes with confidence, bends and flat pattern, wall thickness, pockets, setups and a full turning block, each with an exact-or-estimated badge.
• Twelve governed lookup tables, including removal rates, drill and tap minutes, bend minutes, laser feed and setup minutes, with typed columns, versions and CSV in and out. The product ships no rates.
• Formulas have functions for run time, setup time and setup count over confirmed geometry variables. An unconfirmed geometry value fails the formula; a missing table row refuses rather than pricing at zero.