CNC Router

Our woodshop is home to a CAMaster Stinger I CNC router that is able to cut wood, plastics, and certain metals.

Certification
The CNC Basic Use & Safey class is a required certification to use this machine.

Reference Material
CAMaster Site

Feeds & Speeds Calculator

VCarve Pro CAD/CAM Software

CAMaster WinCNC Machine Controller Software

VCarve Pro Makerspace ID: 39330-F4690-16995-07DC5-70AEA-01778-91E18

FCFL References
FCFL CNC Router Tool Library - Our spreadsheet for all the cnc bits we have.

Old FCFL Bit Inventory - Old spreadsheet. Deprecated.

FCFL CAMaster WinCNC post processor for Fusion 360 (automatic tool change disabled)

FCFL CNC Router Tool Library for Fusion 360 - Complete tool library ready to import into Fusion 360.

Materials

 * Plastic: Acrylic (must be CAST acrylic), Delrin, polypropylene, etc.
 * Metal: Aluminum, brass.
 * Wood: Soft/hard grain wood, veneer wood (plywood, etc.).
 * Foam: (Urethane foam) ("prototype foam") is OK; lower density gives more dust, and 18lb is recommended for CNC. You can (buy it at Compleat Sculptor on 19th Street) or (McMaster-Carr). Despite what you might see on the internet, DO NOT use XPS insulation foam from Home Depot (it develops a static charge when cut, and clings to the exposed lead screws, requiring complete disassembly of the CNC to clean, and the dust is too light to be caught by the dust collector.)

Bit Types

 * Surfacing
 * Flat endmill
 * Ball nose end mill
 * 3D carving (ball nose conical)
 * V-groove
 * Engraving
 * T-slot
 * Drilling bits
 * Bull nose
 * Drag

Flute Types

 * Straight - pushes against work - chips evacuated sideways. Good for hogging material. Poor cutting finish over spiral flutes.
 * Spiral
 * Up-cut - pulls up on work - chips evacuated upward. Best bottom finish. Good for hard/soft grain wood. Can be plunged straight down.
 * Down-cut - pushs down on work - chips evacuated downward. Best top finish. Best for veneer wood (ex: plywood). Good for hard/soft grain wood. Use ramp when plunging.
 * Compression - at cutting depth, pulls up on bottom of work and pushes down on top of work - chips evacuated towards center of cut depth. Good for hard/soft grain wood and veneer wood.
 * O Flute - for acrylic and/or aluminum. Bits designed for particular material specified in tool bit inventory list.

Getting Started
The CNC is one of our more dangerous pieces of equipment. It can be a VERY energetic machine and cause flying metal if improperly configured possibly causing harm to the machine and humans nearby.

Do not use the CNC if you "think" you know how to use it. You need to know how to use it. Any other certified member should be willing to help out if any questions arise.

Safety
Standard Disclaimers:
 * Don't be inebriated
 * No loose items
 * Standard safety gear (safety glasses)
 * Tie back hair
 * Don't be stupid

You should sign up for a reservation on CiviCRM before using the tool

Before Operating the CNC


Before doing anything, know exactly where the Emergency Stop button is. It is the large red button on the front left side of the machine.

If you press it, you can confirm it worked by reading the code on the spindle rpm controller on the bottom right of the front of the machine which should be displaying 'ER'

You must fully power cycle the CNC and reset the switch (twist) to use the CNC

Keyboard Controls
Z = page up/ page down, X,Y: arrow keys (labeled on keyboard)

FAQ
 Stopping CNC From Software 

Emergency Stop (?): Press “Esc” key. Must reload file to start again.

Pause job: Click pause (“||”) in top menu bar.

 CNC Won't Start 

Check that the Emergency Stop Button is not depressed. Twist to reset position

Can I do a full cut through?

Yes, though you need a sacrificial piece under your main piece. The spoilboard is technically a wear item but cut through massively decrease useful lifetime.

Coordinates

Red = Machine coordinates Green = Local coordinates Blue = (only for Z) top-down perspective. Zero at limit switch.

Creating The Cut Files
CAM jobs must use inches.

Using VCarve Pro
We have a Vcarve Pro Makerspace license and you can use it to prepare VCarve files (.tap) on your computer.

You can also use Fusion 360 to make the files. Fusion 360 tool library available above.

Post-processing
Use 'in' post-processor. Should already be set in VCarve.

Pre-Check


1. Inspect the machine and bed for any debris, especially the ball screw

2. Ensure that the hose to the compressor is attached to the CNC air-assist connection.

3. Turn on the air compressor (push red toggle switch backward). Only if necessary, adjust air compressor regulator to provide 60-80 PSI pressure to CNC if it has been changed. The CNC has a second regulator regulator for the air-assist and should already be at 40-45 PSI since no one changes it.

4. Turn on the Vacuum for dust collector.

Spindle Motor Bearing Warm-Up Procedure


1. Remove dust collector boot from spindle.

2. Remove collet and collar from spindle and set aside.

3. Warm up spindle bearing using the speed control dial on front right of CNC router. This is required for the longevity of the spindle bearings. Spindle RPM digital readout (DRO) in thousands of RPM.
 * Step 1: 5k RPM for 5 mins
 * Step 2: 10k RPM for 5 mins
 * Step 3: 18k RPM for 5 mins

Zeroing Procedure
IMPORTANT NOTES:
 * Must use sacrificial board underneath stock if cutting through stock completely.
 * Must set Z zero at bottom of work if using multiple tools. You can set Z zero at top of work if just engraving with one tool or any case where the top stock reference is preserved.

1. Brush the bed clear of debris and remove any obstructions for the gantry.

2. Click “Initialize”. This will home the Z, X, and Y axes.

3. Attached collar to collet, begin thread to spindle, and insert first tool. Tighten collar with the two spindle wrenches.

4. Click “Measure tool” (at corner of screen).

5. Move gantry to back of machine with X & Y keyboard buttons.

6. Position stock squarely onto bed and clamp down. Remember to use sacrificial board underneath stock if cutting through stock completely.

7. Click “Laser On”.

8. Position laser light over corner of stock. Use the corner you chose when setting up CAM job.

9. Click “Laser X0 Y0”. This will move tool head over where laser light was initially positioned.

10. Click "Zero XY". This will zero tool head in X and Y.

11. Connect touch plate, position touch plate on top of bed surface (or on top of stock depending on your CAM job setup), position tool over touch plate and click “Touch Top”. Keep your hand over the E-stop in case something goes wrong!
 * For ‘Z0 at top’ jobs, plug in touch plate, position under tool and Press “Touch Top” button.
 * For ‘Z0 at bottom’ jobs, Make sure no local Z is set. T codes in job trigger measure tool. Ensure job rapids clear all clamps. Type G92 to clear any stored settings

Securing the Stock
Spoilboard has 1/4”-20 threaded sockets for clamping stock.

Bolts:
 * Machine screws, Phillips flat head, Stainless steel 18-8, 1/4"-20 x 1"
 * Machine screws, Phillips flat head, Stainless steel 18-8, 1/4"-20 x 1-1/2"
 * Machine screws, Phillips flat head, Stainless steel 18-8, 1/4"-20 x 2"

Flat Washers:
 * Stainless steel 18-8, 5/16"

T-Nuts: For spoil board.
 * T-Nuts, Stainless steel 18-8, 1/4"-20 x 5/16" - 115 needed.

The Cut


WEAR EYE PROTECTION. Wear earmuffs to protect your ears. Make sure hair is tied back and loose sleeves are pulled back.

Lookup the required chip load for your material! You'll need this to be able to calculate proper speeds and feeds. Try here for a start: https://cutter-shop.com/chip-load-chart/ Chip load depends on tool diameter.

Spindle speeds typically 7k-18k rpm. Typical feedrate ~200-300ipm.

Calculate feedrate with this formula: Feedrate = (Chip load) x (Number of Flutes) x (Spindle Speed)

Match chipload with this formula: (Chip load) = Feedrate / [(Number of Flutes) x (Spindle Speed)]

Better to begin at lowest end of recommended feedrate and increase feed up to:
 * the finish deteriorates because of vibration of the cutting tool
 * tight radii causes the machine to adjust to a slower speed
 * the part moves

Make sure to attach dust boot and turn on dust collector before cutting, or else use the shop vacuum tube without dust boot.

After the Cut, Clean Up

 * 1) Rotate spindle RPM knob fully counter clockwise (0 RPM).
 * 2) Power off CNC router by twisting power switch.
 * 3) Turn off air compressor (pull red toggle swithch forward).
 * 4) Turn off dust collector.
 * 5) Vacuum up all leftover debris and dust. Anything left behind can build up into a fire hazard or gunk moving parts.
 * 6) Carefully put away bits into the numbered tool location they came from.
 * 7) Put tool boxes, clamps away, and safety gear back.

Replacing the Spoilboard
Threaded holes are 4" apart.

Replacing 3D Printed Clamps
Print settings:
 * Position model on its side (bolt direction horizontal to bed)
 * 0.8 nozzle
 * 0.2 layer height
 * 10 walls
 * 50% infill, cubic subdivision
 * Generate support everywhere
 * Skirt

Spindle wont start
Hit reset button on spindle controller console. Check that speed control knob is fully clockwise.

If there's an error code on the spindle's DRO, you can power cycle the machine (wait until the DRO LED's turn off). You WILL have to re-initialize and re-home your job though!

WinCNC Wont Start
Restart software.

Z limit Error
Reboot the machine or try setting an arbitrary Z zero and reset things.

Pinned Items from Slack #cnc and Other References
Comprehensive Guide to Router Bits

Harvey Tools General Machining Guidelines

VCarvePro (Windows) FatCatFabLab serial: 39330-F4690-16995-07DC5-70AEA-01778-91E18

CNC Router Maintenance Log Sheet
Replacement CNC Router Maintenance Log Sheets can be found here: