CALCULATORS / MOLDING, CASTING AND TOOLING

Casting metal yield calculator

Mass yield and melt requirement including runners/risers in supplied yield.

molding-casting-yield.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	pourMasskg	scrapkg
	1.53846	0.538462
	1.23077	0.430769

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

pour mass budget1.54 kg✓ passes

BASELINE INPUTS

netMass1 kgyieldFraction0.65

CALCULATED

pourMass1.5385 kg

scrap0.53846 kg

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Casting metal yield
# Scope: Mass yield and melt requirement including runners/risers in supplied yield.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

netMass = 1 kg
yieldFraction = 0.65

pourMass := netMass/yieldFraction [kg]
scrap := pourMass-netMass [kg]

check pour mass budget: pourMass <= 2 kg

scenario alternative: netMass = 0.8 kg

Calculated from your source · not saved

Baseline · Baseline

pour mass budget1.54 kg ✓ passes

alternative · alternative

pour mass budget1.23 kg ✓ passes

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

pour mass: pourMass = netMass/yieldFraction [kg]
scrap: scrap = pourMass-netMass [kg]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

net mass: 1 kg
yield fraction: 0.65

Calculated

pour mass: 1.53846 kg
scrap: 0.538462 kg

Assumptions and limits

Mass yield and melt requirement including runners/risers in supplied yield.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Casting metal yield. Inputs: net part, runner and riser volumes; returns assumption. Outputs: yield; melt requirement. Model scope: Early process estimates with material and supplier data. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: net part, runner and riser volumes, returns assumption
Outputs: yield, melt requirement
Modes: calculate, compare, sweep
Drawing: Part, cavity and runner diagram

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS