ME 201 - Midterm(Lectures 1-8)

Intro to Mechanical Engineering, UW-Madison spring 24

Manufacturing and Prototyping Methods

Drill Size 60

What clamping scenario do you avoid?

Two threaded holes create a gap

What are the steps to creating a threaded hole?

Punch, Drill, Tap

Through hole

hole goes through the entire object

Blind hole

A specific depth through some of the object.

Two Leading 3d Printing Technologies

Material Extrusion and Vat photopolymerization

Material: ABS

Low Cost, tough, durable, withstand high temperatures

Material: Flexible Filaments (TPE & TPU)

elasticity, stretch, and bend

Material: PLA

easy to use, dimensional accuracy, low cost,

Material: HIPS

lightweight material, dissolvable support for ABS

Material: PET & PETG

easy print, smooth finish, water resistant

Material: Nylon

tough, semi-flexible, high impact and abrasion resistance

Material: Carbon Fiber Filled

PLA or ABS infused with Carbon fiber for strength and stiffness

Material: ASA

ABS alternative, good for outdoors, UV, Temp, and impact resistance

3D printing file prep steps

CAD, STL export, slice, print

3D printing issues

Clearances, Long Bridges, Scale, Bad adhesion

Materials to avoid laser cutting

Glass, Anodized Aluminum, Powder coated metal, Glazed ceramic tile, Marble

Definition of Accurate

Spread out & True Value

Definition of Precise

Consistent and imprecise value

Finding Uncertainty in terms of one variable

Find the Partial Derivative in terms of one variable, all other variables are treated like constants.

Finding Total Uncertainty

Finding all Partial Derivatives squared, add them together, find the square root.

SI Units - Length

Meter

SI Units - Mass

Kg - Kilograms

SI Units - Time

s - Seconds

SI Units - Force

N - Newtons

SI Units - Pressure

N/m² or Pascal

SI Units - Energy

N-m or J (Joules)

SI Units - Power

N-m/s or W (Watts)

SI Units - Velocity

m/s

Types of Forces

Force - Body Weight

W (Newtons or lbf) = Mass * gravity

Statics: Sum of Forces

The sum of forces equation for a static object is:

ΣF = 0

Statics: Sum of moments

ΣM = 0

Force required for one pulley

100%

Force required for a two pulley system

50%

Force required for a 4 pulley system

25%