UNSW Making

DESN1000 Fabrication Basics

Welcome to first year Engineering! We're here to teach you the basics of material properties, and hopefully how to make things!


Laser Cutting

Getting Access to the Laser Cutters

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Intro to Laser Cutting

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Start Here!


CAD for Laser Cutting: Rhino

Rhino File Preparation

The main thing to do is separate your line work based on the type of cut you would like. The specific power-parameters and order of the cuts are handled later.

Cut Layers:

Red Layer = External Cut

Magenta Layer = Internal Cut

Scoring Layers:

Marks the surface but doesn't cut through, line is always the width of the laser

Dark Blue = Dark Score

Light Blue (Cyan) = Light Score

Engrave/Raster Layer:

This needs to be a shape rather than a line, fill the shape with a black 'Hatch'

Black Hatch = Engrave area

Laser Cutting Template - Speedy400

Printing from Rhino

In order to start laser cutting, your Rhino file needs to be sent to the machine's software 'Job Control'. To do this:

  1. File > Print (or CTRL+P)
  2. Check the preview window in the print pop-up...does everything look right?
  3. Check the output scale, it should be set to 1:1
  4. Once everything looks correct, pres 'Print'
  5. Follow the instructions on the machine for how to navigate Job Control.
rhinotojobcontrol-01

Tips & Tricks

  • Having your lines joined instead of having lots of little line segments (especially with curved shapes) will make you job much quicker. In Rhino: Select all the lines you wish to join > Use the 'Join' command.
  • Sneaky, hidden duplicate lines can cause mischief...you might not even know they are there! With nothing selected, type 'SelDup' into the command bar. Any duplicate lines will be highlighted and can then be deleted.

3D Printing

Get Acquainted with some of our 3D Printers

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FDM 3D Printers

FDM or fused deposition modeling, is a material extrusion method of additive manufacturing where plastic filament is pushed through a heated nozzle, which melts the material and deposits it in 2D layers on the build platform. While still warm, these layers fuse with each other to eventually create a three-dimensional part.

Get 3D Printing: FDM
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SLA 3D Printers

Stereolithography (SLA) belongs to a family of additive manufacturing technologies known as vat photopolymerization, commonly known as resin 3D printing. These machines are all built around the same principle, using a light source—a laser or projector—to cure liquid resin into hardened plastic.

Get 3D Printing: SLA

CAD for 3D Printing: Fusion 360

Whether you are a CAD modelling wizard or just starting on your journey to modelling, Fusion 360 is a great CAD software with a full array of capabilities from design to manufacture! Whilst we will be focusing on creating parts for 3D printing in this section, there are a range of resources that can help you in other aspects of using this great software over on the AutoDesk Website.

Get Fusion 360 (yes, for free!) Intro to Fusion 360 Tutorials for Printing from Fusion

Additive Design for Ultimaker Printers

Evaluating your design for printability


Slicing your 3D Model: CURA

So what does 'Slicing' mean? Slicing means converting the 3D model file into a machine language that can be recognized by the printer, and the printer can only print successfully after recognizing this machine language. This machine language is called the G-Code.

We use a program called CURA to slice and prepare files to be sent to our 3D Printers. You can learn all you need to know about slicing files in Cura at our learn page below.

Download CURA CURA Fundamentals
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Get 3D Printing!

To get something made, you can send us your file through our 3D printing hub. Whilst we ask that you send us the STL file and then we do the slicing for you, downloading cura yourself and playing around with slicing your file is a great way to get familiar with the process. This will also give you an idea if your file is going to print successfully (view it in 'preview' mode), and will give you a print time estimate (when you click 'slice'). If you have a preference for any settings you discover, write it to us in the notes!

3D Printing Hub

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Start Here

Tips, Tricks & Considerations

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Screenshot 2023-09-08 105802


Reducing Support Material

Supports structures are undesirable features that increase print time and produce plastic waste. Additionally, they have the potential to ruin the surfaces of prints, leading to more post-processing time.

In the end, it’s not always possible to completely avoid support structures, but we can try to minimize them as much as possible.

As a first rule of thumb, we should always consider model orientation when designing parts – that is, how parts will be positioned during printing. This should, among other things, try to eliminate overhangs and bridges, or at least reduce them to a minimum.

Secondly, think about how splitting your model could help reduce the need for supports. In the above instance, could the wheels of the car be printed separately and joined again after?

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Bed Adhesion

Bed adhesion is one of the major sources of failure in 3D prints, and printing this model could prove to be a headache. When 3D prints don’t stay in place on the build plate, you can get curled, shifted, potentially disastrous results.

The amount of surface area contacting the bed is a very important factor in its ability to stick. Think of ways in which you could increase the surface of your model that is touching the bed, could you create a little flat surface on the bottom of a curved part?

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Reducing Material

Another good tactic for reducing build time and filament wastage is removing unnecessary material from models. For functional parts, this can be more complex due to the direct impact of that material on the overall resistance of parts. For more aesthetic models, however, there’s less to worry about.

Chamfers and fillets are great tools for removing material while at the same time smoothing sharp corners and edges. Yet, there are other ways, too.

For the above example, we could save some filament by removing material from the vehicle’s underside. This region should stay hidden most of the time, anyway. How could you reduce material in your models?

Screenshot 2023-09-08 105956


Details, Details, Details

Small-sized features are not always able to be printed successfully. As a general rule we usually suggest features no smaller than 2mm. While this kind of issue is often detected during the model slicing, it’s good to think about it while still in the design stage and not waste time going back-and-forth between CAD and slicer.

The “Measure” tool can be an excellent ally for checking the printability of fine details. Let’s take, for example, the frame of our vehicle’s windshield. This should be the finest detail of the model, and it will definitely present a problem if we scale down the entire model during slicing.

Make sure to check all the measurements of your parts before sending them to us, if it's too small, we won't be able to print it!

Fasteners

Fasteners

When making something, you will most likely need fasteners to attach various parts and materials together. These are some common ones!

MechvsChem
bolts vs nuts

Bolts and Nuts

  • Bolts are used to clamp things together with the use of a nut. By tightening the nut onto the bolt, you can squeeze the materials together.
  • Bolts are commonly referenced using their 'M' sizing. E.g. M6, or M8.
  • This stands for Metric 6mm, and indicates that thread/shaft diameter is 6mm.


Figuring out Size

  • Common Bolt sizes found in the makerspace: M2.5, M3, M4, M5, M6, M8, M10, M12
  • The size of the fastener is more accurately specified using the diameter, pitch and length dimensions in millimetres

Nuts

  • Hex nuts have a six-sided drive surface to match hex bolts. They're a common type of nut used with bolts to secure wood and metal components.
  • Nylon lock nuts have a hexagonal head with a built-in nylon ring. As you install a lock nut, the bolt threading deforms the ring, helping prevent loosening caused by slipping or vibration.
  • Wing nuts are designed to allow fastening without the use of tools; the wings allow you to tighten or loosen them with a thumb and finger.
  • Cap nuts have a domed shape and hexagonal driving surface. You can often install them by hand. They screw onto the exposed threads on a bolt or threaded rod to protect against injury, or for aesthetic purposes

boltanatomy nuts

Screws

Common screw head types found in the makerspace

  • Countersunk
  • Button head

Available lengths: 15mm, 25mm, 30mm, 40mm, 50mm, 55mm, 65mm

Screws require a clearance hole, and a pilot hole. Clearance is larger than the threads and pilot is smaller, so that the screw will grab into the bottom material and clamp the material together.

Screws

Bolt & Screw Heads

There are various different screw and bolt heads for different applications, but here are some common ones!

Common bolt heads in Makerspace:

  • Socket head cap
  • Countersunk
  • Button head
  • Hex head






Common screw heads in Makerspace:

  • Countersink
  • Button head
screwheads

Drivers

Drivers are the tool or bits used to 'drive' the screw into the materials (as in screwdriver).

There are a few types of driver heads, dependent on the slot shape on the head of the screw. Here are some commonly found ones.

Common driver types that are available:

heads

For more information - here are a few interesting videos!

Chemical Fasteners/Adhesives/Glues

Glue

PVA

The Good

  • Great for wood, paper, cloth or any porous materials
  • Water based, easy to clean up
  • Dries with elasticity, can bend rather than crack

The Bad

  • Drying time varies, could be 2-4 hours, up to 24 hours
  • Soaks into materials, so cannot fill gaps

Epoxy

The Good

  • Great for gluing different materials. E.g. metal to wood, wood to plastic.
  • Can be quick drying (as little as 5 minutes)
  • High strength

The Bad

  • Can be slow drying (could set in a several days)
  • 2 part system, resin part and hardener part, if not mixed in the correct ratio it could remain liquid indefinitely

Super Glue

The Good

  • Fast Drying
  • High Strength when used appropriately
  • Low viscosity, can seep into cracks

The Bad

  • Very good at sticking fingers together (dissolve with acetone. Yes we have some.)
  • Brittle, doesn't bend - just breaks

Hot Glue

The Good

  • Great for quick fixes
  • Quite good for different materials. E.g. metals to wood, wood to plastic.

The Bad

  • Hot glue guns takes time to heat up
  • Please don't use it to hold your entire project together

Tape

Common types of tapes found in makerspaces: electrical tape, masking tape, duct tape

  • Electrical tape is used to insulate electrical solder joints where there is a possibility of creating a short circuit
  • Masking tape is used for situations where the tape might need to be removed, used to hold soft materials down in the laser cutters, general taping requirements, masking off areas when painting. Can be laser cut.
  • Duct tape is primarily used for ducting, it's made of PVC and is typically used to seal ducts to make them airtight.
  • Gaffer/Cloth Tape general tape where more strength is required than what masking tape can offer, typically has cloth fibers inside, which makes tearing quite easy

Thinking About Joints

What surfaces do you want to join and will a mechanical or chemical join be best?

  • Think about the style of joint that is to be created, is the bond to be created by a chemical or a mechanical means? What are the materials involved?
  • If you are screwing or nailing two pieces of plywood together, is the piece that is being screwed or nailed into thick enough not to split from the fastener being driven in
  • A tip for creating a good joint is to ensure that your pieces are cut neatly and you have maximum surface contact available

Material Considerations

Types of Materials

Plywood_int

Internal Plywood (No visible glue line)

Uses:

Laser Cutting + general woodworking

Source:

Shop or offcut bins in Kirby or Squarehouse (DFL)

Bunnings (Must be Interior Ply)

Sustainability:

Not great...

ext_plywood

External Plywood (Visible black glue line)

Uses:

General woodworking

Source:

Bunnings

Sustainability:

Not great...

Recycled-Timber-Perth-1

Recycled Timber

Uses:

General woodworking

Source:

Wherever you can find it (Make sure to remove all nails and screws!)

Sustainability:

Better...Good to give things a second life!

Acrylic-Cut-to-size

Acrylic

Uses:

Laser Cutting (best), drilling, bandsawing, sanding, melting

Source:

Shop or offcut bins in Kirby or Squarehouse (DFL)

Art supply stores (Kadmium)

Sustainability:

Average...but we can recycle it! Make sure to add it to our dedicated acrylic recycling bins

Time-to-get-creative

Recycled Plastic

Uses:

Great for use with the woodworking tools

Source:

Recycling bins (make sure you know what type of plastic it is)

Melt it at home (SAFELY...) or chat to Staff at the DFL

Sustainability:

Great...we love giving things a second chance

pvc pipe square

PVC Pipe

Uses:

Light-weight frames and submarines. Cut using specific cutter, ask a staff member, we have plenty.

Source:

Bunnings

Sustainability:

Terrible...definitely contributing to the end of the world

aluminium

Aluminium

Uses:

Easy to work with, can be folded, drilled and cut

Source:

Have a look in the Kirby offcut storage

Sustainability:

Pretty good, just don't chuck it in the general waste bin please

Alloy-Steel

Steel

Uses:

Very difficult to work with...avoid if possible

Source:

Steel suppliers

Sustainability:

Actually not too bad if you do the right thing with it

cardboard

Cardboard

Uses:

So easy to work with, great for fast prototyping! Can be cut by hand, in a laser cutter or on the bandsaws.

Source:

Too many places to list, try a recycling bin to start with!

Sustainability:

Excellent

Material Property Videos

Transmission

Gear Boxes

Gearboxes are mechanical devices that are used to transmit and control the speed, torque (rotational force), and direction of rotation in various machines and systems.

For these applications they are usually used to increase the torque of the motor while decreasing the speed. Different types of gearboxes have advantages such as size, efficiency, complexity, cost and ability to backdrive the motor.

Worm Gear

Worm Gear - High torque, Speed reduction

The Good:

  • Simple
  • Best for high torque, low rpm
  • Can be used for gear reductions
  • Can't be back driven
  • Some are self locking

The Bad:

  • Less gear ratio options
  • Not very efficient
Planetary Gearbox

Planetary Gear - Flexible & Compact

The Good:

  • Lots of gear ratio options
  • Can be back driven
  • Multi purposed

The Bad:

  • Complex to build - lots of parts!
  • Not very efficient
rack_pinion-4-1

Rack & Pinion - Rotation to Linear Movement

The Good:

  • Rigid
  • Quite easily laser-cuttable!
  • Rotational movement to linear movement
  • No limit on travel length (given infinitely long rack (the straight bit))

The Bad:

  • Incorrect spacing in teeth may cause backlash and unwanted slack
  • Works best with higher friction but.
  • Could wear out easily

DC Motors: Brushed VS Brushless?

Brushless-motor-and-brushless-motor-working-principle-comparison

Brushed

  • 2 wires for connection
  • Can be powered straight from power source – but works better with a motor controller
  • Inrunner design

Brushless

  • 3 wires for connection, ideally used with an ESC (electronic speed controller)
  • Requires more current
  • Outrunner design
  • Better efficiency and lower heat generation

Common Brushed Motors

YellowDcMotor
  • 3-12V
  • 150rpm
  • 1:48 in built gearbox

dc gear
  • 6-12V
  • 5-1000rpm (depends on gearbox, check before buying!)
  • Gearbox comes with the motor, there are different types, that can't be changed.
775 Dc Motor
  • 12-24V
  • 12000-15000rpm
  • Requires separate gearbox to work well.
  • Planetary gearboxes can be found, from 1:3 to 1:1000

Reading Brushless Motors

-infographic for brushless-

Common Brushless Motors

dc gear

1404

  • 3-4s (11.1-14.4V)
  • ~4500KV
  • Normally used for light drones
BR2212

2212

  • 2-4s (7.4-14.4V)
  • ~1000KV
  • Normally used for RC planes

8108

8108

  • 6-12s (22.2-44.4V)
  • ~100KV
  • High torque, could be used for robot arms

Servo Motors

Servo Motors, (usually just servos!) are used when you need to rotate to specific angles but are slower and higher torque than DC motors. There is a built-in feedback loop system that allows the servo precisely move to your desired angles (usually between 0-180°).

For continuous movement, you can find continuous rotary servos, which work in a similar fashion, without the potentiometer.

To control a servo, a servo horn can be used to link it up mechanically.

Schematic-of-an-RC-servo-motor

Common Servo Motors

BlueServo

9G Blue Servo

Typically used for aeroplanes and low load applications. Not suited for any application where a significant load is required to be lifted.

  • Plastic Gears
  • 1.6kg.cm torque
  • Fixed angle 0-180 Degrees
  • 3-5
blkservo

MG996R Metal Gear Servo

Useful for small scale robotic projects which require a heavier item to be lifted.

  • Metal Gears
  • 10kg.cm torque
  • Fixed angle 0-180 Degrees
  • 4-9V
  • Can be purchased as fixed angle or continuous
Stepper Anatomy

Stepper Motors

Stepper motors are precise electric motors using a four-wire configuration to control internal coils. Electrical pulses sent through these wires in a sequence rotate the motor in discrete steps, enabling precise positioning and speed control

With the inrunner design, and the ability to hold position even when stationary makes these motors ideal for applications such as 3D printing, CNC machining and robotics.

Control with a dedicated motor controller is required to generate precise pulses for control of the steppers. Steppers don't typically have position feedback, but encoders can be added.

Common Stepper Motors

smallReducStepper

Small Reduction Stepper Motor

  • 5-12v
  • 16-64 steps per rotation
  • 2.5kg.cm
  • Built in gearbox

Nema17 Stepper

Nema 17 Stepper Motor

  • 12v
  • 200-300 steps per rotation
  • 4.3 kg·cm

linearActuator

Linear Actuator

Linear actuators converts rotary motion to linear motion for precise position control, often incorporating feedback mechanisms. They offer high force but slower speeds.

The term 'stroke length' indicates the maximum extension distance. Mounting may require rotation, achieved with clevis or trunnion brackets designed for positioning.

Electronics

Arduino Basics

-link to arduino module-

arduinoPower

Powering Arduinos!

  • There are usually three power inputs on most arduino boards
  • The USB port will only provide 5V.
  • For batteries and power supplies that supply 6-12V, supply it through the barrel jack or Vin pins.
  • For higher power devices (like motors), sometimes it may be better to run off the battery voltage directly.

Common Sensors

15569-Ultrasonic_Distance_Sensor_-_HC-SR04-01a

Ultrasonic Sensors

Uses ultrasonic sound waves, sends a pulse, and receives the echo. Calculates distance from the time delay. Great at sensing things at medium range.

The Good: Can sense all material types, even see through objects,

The Bad: Struggles with thin, curved or soft objects that absorb/deflect ultrasonic waves.

82f459a678237753a4ed0359f8f166539ebbf0fc

Infrared Sensors

Content for this module in the infrared range (wavelength between 760nm to 1mm) to transmit data or find ranges. Infrared radiation is transmitted and bounces off objects before being picked up by the receiver.

Can also be used as a means of sending data.

The Good: Line of sight, no reliance on visible light, good for objects between 10mm to 800mm

The Bad: Ineffective at longer ranges, low data transmission rate, affected by particles such as dust or smoke.

Lidar

Lidar

Rather than Radar (Radio Detection And Ranging), we have Lidar (Light Detection And Ranging)

Send pulses of lasers and measures their echoes reflecting back from objects similar to ultrasonic sensors.

The Good: Not light dependent, better at detecting smaller objects compared to Radar, smaller beam spread than Ultrasonic.

The Bad: Expensive, doesn’t register see-through materials (lights passes through transparent obstacles!)

Accel

Accelerometers

Sensor for measuring linear force/acceleration.

Most accelerometers will give you three axes of measurement

The Good: Measuring acceleration and deceleration, typically gives X,Y,Z axis readouts.

The Bad: Gives you acceleration, NOT velocity. Tells you if you're speeding up or slowing down but not how fast you're going.

Gyro

Gyroscopes

Sensor for measuring angular rotation

Gives three axes of rotation, pitch, roll, yaw.

The Good: Measuring angular velocity (not acceleration, although you can calculate acceleration yourself)

The Bad: only provides angular velocity, not acceleration nor linear velocity.

018-gy-291

Inertial Measurement Unit (IMU)

Consists of Gyroscope and Accelerometers (and sometimes, magnetometers)

Best of both worlds!

Cam

Cameras

Uses a camera and computer vision algorithms as a sensor to find objects. Everyone's got a camera (sometimes a few now) on their phone so we're not going to explain that here..

The Good: Able to identify colours and signs using computer vision to identify obstacles

The Bad: No range sensing, doesn’t work as well in low light, expensive in price and computing power.

Arduino Sensors

Others

There are an assortment of other sensors that are compatible with Arduinos or Raspberry Pi's. We can't cover them all here, but if you look up the manual from the suppliers, they will show you how to use them - sometimes with example code!

Some examples are:

  • Temperature
  • Moisture
  • Sound (Microphones)
  • Ambient Humidity
  • Hall Effect
  • Light (Photoresistors)
  • Pressure
  • and many more!
Core and Jaycar Logo

Where to Buy?

If you need something quick - we suggest going to Jaycar as they have in-person stores.

The closest ones are:

Jaycar Sydney City
Jaycar Alexandria
Jaycar Queens Park

Otherwise Core Electronics and RS Components do quick shopping for their online stores!

In a pinch, Amazon next day delivery is also quite good!

Wiring Tips

Some tips and tricks on how to get good connections!

Breadboards

Breadboards are commonly used prototyping boards with the following layout.

breadboard


If you want can, it's usually worth it to buy a set of prototyping jumper wires like that are pre-cut and bent to fit in a breadboard.

wires

Breadboards are great for prototyping, but once you've finalised your design, it's much safer to move it to a more reliable solution. E.g. Solderable Breadboard/Veroboard/Protoboards

It helps to be organised...

Which of these do you prefer to work on?

good breadboard

bad breadboard

Connecting wires

crimp

Crimps

Crimps are mechanical connections that get squeezed or crimped onto the ends of stripped electrical cables to ensure a strong connection.

There are many shapes and sizes of crimps, the colour of the plastic (usually red, blue and yellow) are for different gauge of wires.

gauge

When using crimps, you should use a crimping tool, and ensure that the crimps are secured tightly, but not overly tight.

wago-terminal

Connectors & Terminals

Connectors and terminal blocks are another great way of connecting wires. Terminal block are typically used soldered onto PCB's to provide a stronger connection (it's screwed in to compress the wire!)

There are also various different connectors like WAGO connectors that are a little more expensive, but are great at connecting wires quickly. It even works with different gauge of wires using the same connector!

Last but not least, we have a T-splice connector, which are usually used to split a single connection into two!

T splice

soldering

Soldering

Seen as one of the strongest connections, but also the hardest one to do well! There is an art to soldering, and if you're interested, we run an induction for teaching basic soldering here!

Soldering is the process of joining metal parts by melting a metal alloy (solder) to bond them together.

Other Resources

Categories: Course Specific Modules
Tags: DESN1000