Mechanical Movement Project

In 1868 Henry T. Brown published a catalog of 507 ways to turn one motion into another, drawn for engineers who would never see a computer. You'll pick one, design every part of it to come out of a 3D printer, and mount it on a square base where anyone can turn the crank. This part of the project ends when it runs in Fusion. The next one ends when it runs on the wall.

Overview

The patent project was one part. This one is several parts that move against each other, and every one has to survive a printer. You'll choose a mechanism from 507 Mechanical Movements, plan its parts and joints in your notebook, model each part with the fit it needs, assemble them with joints, draw every part, and demonstrate the assembly to the class. Printing and building it is the next project.

Builds on: Design for 3D Printing — the eight design rules and the Inspect tools; Assemblies and Joints — the project folder and rigid, revolute, and slider joints; Technical Drawings — drawing sheets on the NPA Drawing Template.

Before you start

Sign in to Autodesk Fusion and open your notebook. Keep Design Rules for 3D Printing open in another tab. Fusion stays closed until step 8.

You've got it when…

Your project folder holds one Part Design per printed piece in a Parts folder, with the assembly beside it.
Dragging the input moves every part the way the 507 animation does, and every joint in the Browser has a name.
Every hole and pin is sized from your joint table, and Interference finds nothing.
Your notebook entry holds the movement record, parts list, joint table, exceptions table, and a screenshot of the running assembly.
Every unique part has a dimensioned drawing on the NPA Drawing Template.
You've demonstrated the assembly to the class.

Collaboration & AI

Work: On your own. Compare movements with a neighbor, but the parts, the assembly, and the drawings are yours.

AI — two levels. Choosing and understanding your movement is AIAS Level 2, AI Planning: use AI to explore and explain; the decisions are yours. Modeling, assembling, and drawing are AIAS Level 1, No AI. What the levels mean.

Pacing

Eight class periods. It's a plan, not a stopwatch.

Day	Where you should be by the end of it
1	Movement approved. Notebook entry started: movement record, parts list, joint table. Project folder made.
2–4	Base and every part modeled, one Part Design each, holes and pins sized from the joint table.
5	Assembly built, joints named, mechanism runs when you drag the input.
6	Fixes. Interference and Draft Analysis clean. Exceptions recorded.
7	Drawings of every unique part.
8	Demonstrations.

What Counts as a Mechanism

A wheel on an axle moves, but it isn't a mechanism. A mechanism takes motion in at one place and hands a different motion out at another: a crank goes around and a slider goes back and forth. The input is the part a person operates; the output is the part that does something as a result.

Your movement must meet every line of this table. I'll check it against the table when you ask for approval, so check it yourself first.

Rule	What it means
It converts motion	One hand-operated input produces a different kind of motion at the output: rotation to back-and-forth, continuous to intermittent, a change of direction or speed.
At least 3 moving parts	Parts that move relative to the base. The slider-crank had three: crank, rod, slider.
At least 4 joints of at least 2 types	Not counting rigid joints to the base. Revolute, slider, cylindrical, pin-slot, and ball are the types; a pair of meshing gears (made with the Spur Gear Plug-in) counts as one too.
5 to 12 unique printed parts	Including the base. Two copies of one pin are one unique part.
One-handed input	A crank, knob, or lever a viewer can operate while the base hangs on a wall. Gravity pulls toward the floor, not toward the base.

Pick an animated one

Color thumbnails are animated. Watching the animation is the fastest way to learn what every part does. Gray ones aren't off limits, but you'll be working from a 150-year-old engraving and a paragraph.

Where the parts come from

Every part is one you print or one you bring (a rubber band as a return spring is fine; ask). Major parts are joined by printed features only: pressed pins, shoulders, caps, snaps. No screws, tape, or glue.

The Base

Every mechanism in the class mounts on the same base, so they can hang together as a set with no gaps. You model it yourself; it counts as one of your printed parts.

Base	Requirement
Size	112 mm wide, 112 mm tall, 4 mm thick
Orientation	Displayed vertically. Decide which edge is the top and stick with it.
Material removed	Fine: holes, slots, pockets. Through holes are fine.
The back face	Nothing may stand proud of it. A pin may end flush; it may not poke out.
The edges	Nothing may extend past them. The whole mechanism stays inside the 112 mm square.
Print limits	The base is exempt from the 2 h / 50 g rule. Every other part must fit it.

Grow it out, or press it in?

An axle modeled as part of the base prints standing up, with every layer line across the direction it gets pushed (Strength rule). It snaps. An axle modeled as its own part prints lying down and presses into a hole in the base. The base is a plate with holes; the things that stick out of it are separate parts.

Choose a Movement and Plan the Build

Notebook work. Fusion stays closed until step 8.

Browse 507 Mechanical Movements and pick a movement that passes every line of the rules table. Watch its animation until you can say what the input does and what the output does.
Get it approved before you continue. Show me the movement's page and be ready to point at the input, the output, and each moving part.

Read the whole engraving

A frame, bracket, or fixed pin in the drawing is a part you have to model too, even if it's just a peg in your base. Count them before you ask for approval.

Start a notebook entry titled Mechanical Movement Project. Copy the table below into it and fill in the right-hand column. Write the input and output as motions: "the crank turns continuously," not "the crank."

Movement record
Movement number and link
Name (as the site gives it)
Animated?
Input motion (what a person does)
Output motion (what happens as a result)
Which edge of the base is the top

Below it, build your parts list: one row per unique part, the base included. Face on the bed is the face that will sit on the printer (Bed contact rule).

Part Copies What it does Moves? Face on the bed

Base 1 Holds everything No Back face
Below that, build your joint table: one row for every place two parts touch. Fill the last three columns from the reference table below. Name each joint for the two parts it connects.

Joint Part A Part B Joint type Fit Gap per side

Axle-Base Axle Base Rigid Press 0.1 mm
Add an exceptions table and leave it empty for now. Every place your design breaks one of the eight design rules on purpose goes here as you build.

Rule Part What you did instead Why
In the Data Panel, create a folder in your student folder named Movement <number> - <short name>, with a Parts folder inside it. Part Designs go in Parts; the assembly goes beside it, like the slider-crank lab.
```
Movement 92 - Crank/      your project folder
    Parts/                one Part Design per printed piece
    Movement 92           your assembly
```

Fits and Joints Reference

The Fits rule gives the gap per side for three kinds of fit. This table matches each fit to the Fusion joint that goes with it.

The two parts…	Joint type	Fit	Gap per side
are pushed together once and never move (an axle in the base, a crank on its shaft, a cap on an axle end)	Rigid	Press	0.1 mm
go together by hand and stay put, but could come apart (a key in a slot)	Rigid	Close	0.2 mm
turn on each other (a wheel on an axle)	Revolute	Free	0.3 mm
slide on each other (a slider between rails)	Slider	Free	0.3 mm
turn and slide (a shaft that spins and moves along its length)	Cylindrical	Free	0.3 mm
a pin that rides in a slot	Pin-Slot	Free	0.3 mm
are gears that mesh	Motion Link, not a joint (see the gear section)	—	the plugin's backlash

Gap per side is an offset

A 6 mm axle turning in a hole needs 0.3 mm per side, so a 6.6 mm hole. Project the axle's edge into the hole's sketch and Offset it by the gap. Pins and axles are at least 3 mm across; a horizontal hole gets a teardrop top. All of it is on Design Rules for 3D Printing.

Ways to hold things on without glue

A head on one end of the axle and a press-fit cap on the other; a shoulder (a step in the axle's diameter) the part rides against; a flange on the part that sits against the base. Each is a row in your joint table.

Model the Parts

Checkpoints, not a recipe.

Create a new Part Design for the base, confirm millimeters, and save it as Base in Parts. Sketch the 112 mm square, extrude 4 mm, and add the holes and slots from your joint table, each sized by its gap. Fillet the vertical corners and chamfer the bottom edges (Edges rule).
Model every other part from your parts list, one Part Design each, saved in Parts under the name from your list. Model each part with its Face on the bed flat on the XY plane, so Draft Analysis later tells the truth.

Dimension it or it will drift

Press D and lock every diameter and every distance between holes. A hole 0.2 mm off center is a mechanism that binds.
As you finish each part, check it against the eight rules the way you inspected the hand crank. Fix what you can; record the rest in the exceptions table.
Name bodies and features as you go. Crank is a part; Body3 is a mystery.
Save at the end of every work day.

If Your Movement Has Gears

Skip this unless your movement has meshing gears. Don't draw teeth; the Fusion Spur Gear Plug-in generates them. The page covers installing it and the settings that print well.

Both gears in a pair need the same module (tooth size) to mesh.
Size the plugin's hole diameter from your joint table: axle diameter plus 2 × 0.3 mm for a gear that turns on a fixed axle; shaft diameter plus 2 × 0.1 mm for a gear pressed onto a shaft that turns with it.
Gears don't get a joint between them. Give each gear a revolute joint to its axle, then Motion ▸ Motion Link ties the two joints together. Set the ratio from the tooth counts and check Reverse if the second gear spins the wrong way.

Assemble It

Create a new Assembly Design and save it as Movement <number> in your project folder, beside Parts, not inside it.
Insert the base first with Ground To Parent checked. Insert every other part with it unchecked. Only the base is grounded.
Work down your joint table one row at a time: press J, pick the two parts, set the joint type, preview the motion, and rename the joint to the name in your table.

A joint that won't line up is a part problem

Start with the input's joint to the base and follow the motion to the output. When a joint won't line up, the hole is in the wrong place. Edit the part; the assembly updates.
Drag the input. Every moving part should follow and the output should do what your movement record says. If a part flies off or won't move, right-click its joint in the Browser and edit the type or the axis.
Select Motion ▸ Drive Joints, pick your input joint, and drive it through one full cycle. Watch for a part passing through another one.

Checkpoint

Input drives output, every joint has a name from your table, and nothing passes through anything. Now prove it will print.

Check It Against the Rules

Select Inspect ▸ Interference, select all components, and click Compute. The result should be empty. Anything found is a fit sized wrong. Fix the part.
Open each Part Design and run Draft Analysis with the direction set to Z, as on the hand crank. Decide every blue face: on the bed, a bridge under 10 mm, an overhang under 45°, or a problem.
Finish the exceptions table. Every rule your final design breaks gets a row with a reason a printer would accept ("the ratchet teeth need a 50° overhang and are only 2 mm tall," not "it looked fine"). If the table is empty, write "None" under it.

Why exceptions are allowed

The rules are the printer's preferences, not laws of physics. Writing an exception down means you decided instead of the printer deciding for you, and the next project starts by testing exactly those rows.

Draw It

For every unique part, including the base, create a drawing on the NPA Drawing Template with the views and dimensions from Technical Drawings: every feature shown, every hole and pin diameter, every distance that locates a hole. The template is in the root of Class Files.

The wrong template is the default one

When you create a drawing From Design, Fusion offers its own ASME sheet. Choose the template option and browse to the NPA Drawing Template before you click OK. A drawing on the default sheet gets sent back.
Export each drawing as a PDF and add every PDF to your notebook entry, below the exceptions table.
Add a screenshot of your running assembly with the Browser open so every joint name shows.

Show It Off

Prepare a one-minute demonstration: open your assembly, drive or drag the input, and describe what the movement does, using the description on its 507 page as your script. Name the input, the output, and how one becomes the other. No slides; Fusion on the screen is the presentation.
Demonstrate on day eight, in the order I draw from a hat. Answer one question from the class if there is one.

Go Further

Set the limits. Edit the joints that shouldn't turn forever (a rocking lever, a slider in a slot) and set their motion limits.
Render it. Give each part an appearance and render it, as in the patent project.
Animate it. In the Animation workspace, record the input driving through a cycle and export the video.

Turn It In

Your project folder Movement <number> - <short name> in your Fusion student folder: a Parts folder with one Part Design per printed piece, and your Movement <number> assembly beside it. Saving is submitting.
Your notebook entry Mechanical Movement Project: movement record, parts list, joint table, exceptions table (or "None"), a screenshot of the running assembly with its named joints, and a PDF drawing of every unique part on the NPA Drawing Template.
Your one-minute demonstration, given in class on day eight.

How It's Graded

This project is worth up to 4 points. One score covers everything you turn in.

Score	What it looks like
4 — Excellent	The movement passes every rule in the table; every printed piece is its own Part Design with holes and pins sized from a complete joint table; the assembly runs from input to output with every joint named and Interference empty; every rule broken is in the exceptions table with a reason; every unique part has a dimensioned drawing on the NPA template; the demonstration names the input, the output, and the conversion.
3 — Above Average	The mechanism runs and the drawings are on the right template, with minor slips: an unnamed joint, a fit sized by eye instead of from the table, a drawing missing a locating dimension, or a demonstration that ran long.
2 — Average	The assembly is complete but doesn't run (a joint of the wrong type, or parts that clash), or the joint table or exceptions table is missing, or the drawings are on the default ASME sheet. The row that catches people who opened Fusion before opening the notebook.
1 — Below Average	A few parts modeled with little evidence of a plan, no working assembly, or drawings with no model behind them.
0 — Failing	No project folder in your student folder, or no demonstration given.

The Short List

Everything above, boiled down. If every line is true, you're done.

Credit: Movements and their descriptions from 507 Mechanical Movements, an animated edition of Henry T. Brown's 1868 catalog of the same name.