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.

CAMaster Stinger I CNC Router

CAMaster Stinger I CNC router, computer, and compressor

CAMaster Stinger I SR-23 Specifications
Work Dimensions	Width, X	635 mm (25 in)
	Length, Y	914.4 mm (36 in)
	Height, Z	127 mm (5 in)
Spindle Power	1.7kW (2.28 HP)
Max RPM	18,000
Collet Type	ER25
Max Rapid Speed	15240 mm/min (600 in/min)
Max Cut Speed	8890 mm/min (350 in/min)
Repeatability	±0.0254 mm (±0.001 in)

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 Inventory spreadsheet - Our spreadsheet for all the cnc bits we have. Please add comments so we can keep it updated!

FCFL CAMaster WinCNC post processor for Fusion 360 - "FCFL_CAMaster_wincnc_m3x_171014.cps" with Automatic Tool Changer disabled.

FCFL CNC Router Tool Library for Fusion 360 - Complete tool library ready to import into Fusion 360. This tool library is version 2023_03_04.

(DEPRECATED) Old FCFL Bit Inventory - Old spreadsheet. No longer in use.

Materials

Plastic: Acrylic (must be CAST acrylic), Delrin, polypropylene, etc.
Metal: Aluminum, brass.
Wood: Soft/hard grain wood, veneer wood (plywood, etc.).
Foam: [1](Urethane foam) ("prototype foam") is OK; lower density gives more dust, and 18lb is recommended for CNC. You can [2](buy it at Compleat Sculptor on 19th Street) or [3](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

CAMaster Stinger I's power switch, E-Stop, and touch probe jack (lower right)

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

Make sure to wait for the spindle speed control panel to turn off before turning the CNC back on.

Win CNC Control Software

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.

Preparing the Cut

Pre-Check

Air compressor toggle switch (red)

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

Spindle speed control (on front right of Stinger I)

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.

(If the DRO reads "EF", this means the machine was turned on to quickly after power cycling due to the E-Stop being activated.)

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:

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

Dust collector and power switch (on right side)

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 feed rate ~200-300ipm.

Calculate feed rate with this formula: (Feed rate) = (Chip load) x (Number of Flutes) x (Spindle RPM)

Match chip load with this formula: (Chip load) = (Feed rate) / [(Number of Flutes) x (Spindle RPM)]

Better to begin at lowest end of recommended feed rate 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

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

Maintenance

Greasing Parts

Replacing the Spoil Board

Threaded holes are 4" apart.

Calibrating Tool Measure Plate

Only after resurfacing the spoil board, the tool measure plate position on the lower right of the machine needs to be recalibrated with the 'Calibrate Switch' button--this is a required and critical step. This button should not be used at any other time. This distance is the difference between the top of the tool measure plate and the top of the spoil board. The machine needs to know this height difference so tool measure operations are correct.

Follow these instructions exactly:

Attach a tool to the spindle

Any tool will work, but using the standard 1/4” flat end is ideal

Turn off all soft limits with G-code L21

This allows the ability to jog the Z past the Z bottom soft limit

Jog the bottom of the bit down to the spoil board

Jog the bit bout 1 inch over the spoil board
Switch the speed to move by 0.1" steps (not using fast, medium, or slow)
Jog the bit to about 1/4 inch from the spoil board, then switch the speed to move by 0.01" steps
Use printer paper under the bit and move it back and forth

Lowering the Z until the bit just barely snags the paper. There should be room enough for the paper to drag under the bit.

Click the 'Calibrate Switch' button. The Z lower bound is now one paper width above the spoil board (~0.004" or 0.1mm). We do this to minimize cuts into the spoil board that we prefer to resurface as rarely as possible.

The command log will first asks you to jog the bit to the bed, which is already completed
This step will start the process to reset the Z bottom at the current position of the bottom of the bit

Press 'enter' then the command log will say it will now use the Measure Tool feature and to ensure it can move freely

This step will take into account the length of whichever tool used

Press enter and the machine will move up to the Machine Z0 (the Z top hard limit), then move to the tool measure touch plate to measure the tool

The machine knows the location of Machine Z0 and the Measure Tool operation allows the machine to figure out where the Z bottom limit is, relative to the machine Z0

After the Measure Tool operation is completed, the Z bottom limit has been set
Test if the calibration has worked

Click the Park button to move the spindle to the Machine X0 Y0 Z0

This should be off the edge of the spoil board

Jog the bit downwards towards the bed

This should trip the Z bottom soft limit when the bottom of bit is just below the spoil board (0.01" below the spoil board)

Compressor/Air Tank Draining

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

Troubleshooting

Spindle Won't 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 Won't Start

Restart software.

Z Limit Error

The 'Calibrate Switch' button was probably clicked on accident. See section Calibrating Tool Measure Plate for help.

Only use this method if you are experiencing all the known issues below.

Known Issues

The Touch Top and Measure Tool feature works without errors
Before loading any G-Code, the Z Soft Limit is exceeded without the tool being close to the spoil board