CALCULATORS / MOLDING, CASTING AND TOOLING

Draft angle and release allowance calculator

Single-side draw-direction geometric offset.

molding-draft.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

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

Scenario	perSidemm	totalWidthChangemm
	1.39683	2.79366
	1.11746	2.23493

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.

width change budget2.79 mm✓ passes

BASELINE INPUTS

height40 mmdraftAngle2 deg

CALCULATED

perSide1.3968 mm

totalWidthChange2.7937 mm

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Draft angle and release allowance
# Scope: Single-side draw-direction geometric offset.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

height = 40 mm
draftAngle = 2 deg

perSide := height*tan(draftAngle) [mm]
totalWidthChange := 2*perSide [mm]

check width change budget: totalWidthChange <= 3 mm

scenario alternative: height = 32 mm

Calculated from your source · not saved

Baseline · Baseline

width change budget2.79 mm ✓ passes

alternative · alternative

width change budget2.23 mm ✓ 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.

per side: perSide = height*tan(draftAngle) [mm]
total width change: totalWidthChange = 2*perSide [mm]

Original worked example

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

Given

height: 40 mm
draft angle: 2 deg

Calculated

per side: 1.39683 mm
total width change: 2.79366 mm

Assumptions and limits

Single-side draw-direction geometric offset.

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: Draft angle and release allowance. Inputs: draw depth; draft angle; texture/process criterion. Outputs: wall offset; release-clearance screening. 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: draw depth, draft angle, texture/process criterion
Outputs: wall offset, release-clearance screening
Modes: calculate, compare, sweep
Drawing: Part, cavity and runner diagram

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