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CNC ROUTER LEVEL 1 - PART 1

MACHINE OPERATION

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HOUSEKEEPING

  1. Bathrooms
  2. Land acknowledgement
  3. Personal Intro & Pronouns
  4. Waivers
  5. Structure
  6. Quick demo (5 mins)
  7. Presentation (45 mins)
  8. In-depth demo (30 mins)
  9. Break (10 mins)
  10. Hands-on practice (80 mins)
  11. Wrap up (5 mins)

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**Note: you can find this Presentation on CNC Level 1 web page!**

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PROGRAM OVERVIEW

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Goal: to empower you to run the CNC router safely and achieve basic cuts

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  1. General expectations
  2. Terminology including router bits
  3. Securing your workpiece
  4. Understanding feed rate and spindle speed
  5. Practice Machine Setups

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1

General Expectations

General Expectations

Terminology

Securing your workpiece

Settings

Creating a design

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What is a CNC Router?

  • CNC - Computer Numerical Control
  • Router - A router is a tool with a rotating bit. It routs/hollows out an area in a hard material such as wood or plastic

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Z

X

Y

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Personal Protective Equipment (PPE)

  • Glasses (Polycarbonate)
  • Ear Protection
  • Dust Mask or Respirator (recommended)

Other Considerations:

  • Never leave the CNC when running!
  • Tie back long hair
  • No loose clothing
  • No gloves on machines
  • Good footwear

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  • All types of solid wood
  • Laminated Wood (plywood, OSB Board)
  • Polycarbonate, Melamine, HDPE Sheet, high pressure laminate (HPL) Sheet
  • Certain types of metals (aluminium, brass, copper)
  • Certain types of plastic (acrylic, ABS, plexiglass)

WHAT CAN YOU CUT?

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Terminology

General Expectations

Terminology

Securing your workpiece

Settings

Creating a design

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Tool sensor

Vacuum bed

Dust extractor

Pop pins

Spindle

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Vacuum Pump

Vacuum bed control

Spoil board

4th axis

Work piece

Dust shoe

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ROUTER BITS aka ENDMILLS

Cheapest

Cannot plunge

Less durable

Can leave burn marks

Rougher finish

General cutting

Can plunge

More durable

Cleaner cuts

Straight

Spiral

V-bit

Ball nose

Engraving

Limited plunge

Uses fine point for detail

Smooth contours

Not designed for plunging

3D geometry

Can it plunge?

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Avoids burring and creates clean top surface

Heats up quickly (can melt plastic)

Poor chip clearance

SPIRAL BITS - CUTTING FORCES

Up cut

Down cut

Compression

Pulls material up

Pushes material down

Compresses material into workpiece

Can blow out the top edge

Must be used on certain materials e.g. acrylic

Don’t use on thin material <¼” or cheap, layered plywood

Gives clean top and bottom edges

Must cut deeper than the upcut section

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CUTTERS - NUMBER OF FLUTES

Single Flute

Double Flute

Quad Flute

Triple Flute

Often used with Aluminium as chips are larger

Used for flattening

General wood cutting

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COLLETS

Collet nut

Collet

Router bit shank

fits in here

Spindle

Typical collet sizes:

½” or ¼”

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Securing Your Workpiece

General Expectations

Terminology

Securing your workpiece

Settings

Creating a design

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  • Uses suction through porous MDF spoil board
  • Bed is split into 4 quadrants
  • Suitable for larger sheet goods
  • Unsuitable for small or warped pieces (e.g. slab flattening)

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VACUUM BED

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CLEATS

  • Blocks of wood that are screwed down to screw board (not spoil board).
  • Vacuum holds down screw board.
  • Cleats can be made from scraps
  • Can have a ‘rabbet’ (overhanging lip)
  • Rabbet height should be slightly less than the material height, so it clamps tightly when screwed down.
  • Warped material may need shims

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Cleat

Shims

Screw Board

Spoil Board

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PRESS FIT JIG

  • The workpiece is pressed into a custom fit jig that is screwed to the table
  • Used for:
    • small workpieces
    • extra-thick stock
    • final size pieces (no room for screws)

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Good for repetitive processes where you need to switch out materials of the same shape and size.

DOOR STOP JIG

Screwed in place

Workpiece slides in

Door stop wedges material in place

20o

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SETTING FEEDRATE AND

SPINDLE SPEED

General Expectations

Terminology

Securing your workpiece

Settings

Creating a design

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  • How fast the router travels around the bed
  • Measured in inches per minute (IPM)
  • Each end mill has a preferred feed rate
  • Research this online
  • If in doubt, start slow

FEED RATE

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  • How fast the bit is spinning
  • Measured in revolutions per minute (RPM)
  • Depends on the type of cut and type of bit
  • Typical speeds:
    • Wood 12,000 -24,000 RPM
    • Aluminium 8,000 - 10,000 RPM
    • Plastic 6,000 - 8,000 RPM

SPINDLE SPEED

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Feed rate (IPM) = No. of flutes x Chip load x Spindle speed (RPM)

  • No. of flutes (see earlier slide)
  • Chip load = the amount of material removed by each flute as it goes through the material. Look up online:
  • Spindle speed = how fast bit is spinning

FEEDS AND SPEEDS FORMULA

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ISSUES

Burn marks:

Feed rate too low

Tearout:

Feed rate too high

Poor edge finish:

Wrong bit choice (upcut)

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5

TOOLPATHING CONCEPTS

General Expectations

Terminology

Securing your workpiece

Settings

Creating a design

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  • 2D design for 3D product
  • Limitations:
    • Depth of cut <= diameter of bit
    • Inside corners and tight geometry are subject to bit size

2D Design for 3D cutting

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TOOLPATHS

  • Pocket: cuts the inside of a closed vector
  • Profile: cuts along a closed vector line - either inside, outside or on the line
  • V-carve: engraves finely with a v-bit
  • Drill: drills the specified circles
  • 3D Cuts (Rough and Fine): Cuts 3D meshes

Note: When cutting through material, set the depth of the cut to 0.02” deeper than the material (Z) thickness

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  • Pass Depth - Each cut must be less than the bit’s diameter
  • Stepover - the amount each pass overlaps itself
    • Surfacing end mills: ~50%
    • Ball-Nose Bits: 5% (a lot of stepover to prevent wavy texture)

CUTTING PARAMETERS

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  • Bit pushes into the material
  • Usually used on acrylic or aluminum
  • Avoid climb cut with a hand or table router.
  • Bit pulls off the material
  • Gives a nicer finish on wood
  • Can also be used for aluminum or acrylic.

Note: every material and end mill is different and they should be tested to determine the best finish

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  • Small pieces of material that keep the piece connected to the other material
  • Always use minimum 3 tabs to avoid workpiece flying across the room
  • Place away from corners to make your life easy

TABS

RAMPS

  • Allow non-plunge end mills to descend vertically

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  • Before exporting toolpaths, double check the order they are listed in.
  • Tool path order = top to bottom. Drag to reorder.
  • General order:
    • Engraving
    • Pocket
    • Profile

DETERMINING TOOLPATH ORDER

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  • Member rate = $1.50/min + 30 mins free each month
  • Non-members = $2/min

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CNC USAGE RATES

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ACCESSING TOOLS @ CREATE

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1.

2.

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AS A SPECIAL THANK YOU FOR JOINING US TODAY

Get a 50% discount on your first month of Membership, if you sign up for 3 months!

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(See our front desk after the class for more details - must sign up within 3 days of class)

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  • FREE CONSULT
  • Free 30-minute consultation on your CNC project
  • Book through this link
  • To be used within 30 days of class

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Member Projects Google Drive

  • Member Projects - drop your files into the folder from home
  • Public CNC and Laser Projects - get inspired!

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MACHINE OPERATION PRACTICE

Each student will get a chance to:

  • Run through initial machine setup
  • Practice installing tools into the collet/spindle
  • Load a workpiece and secure to table
  • Set workpiece origin
  • Load & run a pre-made program

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While you wait for your turn, feel free to:

  • Click around in the V-Carve software - bring your questions to the next class!
  • Assemble/finish cut projects

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ICONS