Instructions:ShopBot 3-Axis CNC Mill

Want to learn about Aspire? See Instructions:Aspire

Want to make this page better? Edit it yourself, or talk to John Hache. North Forge would like to make sure instructions are clear and easy to use.

Safety

Fire Notice

DANGER: FIRE. The ShopBot vacuum and dust extractor make it difficult to notice a fire until it has already started spreading. Always carefully plan cuts and monitor jobs closely.

If you notice any of the following:

Burning smell
Charring
Tool damage
Unusual Vibration
Change in sound

STOP AND INSPECT THE DUST COLLECTOR FOR SIGNS OF FIRE. More details to follow here.

PPE

Wear:

Safety Glasses (to protect against flying dust and debris).

Hearing protection (to protect against noise greater than 85 dBa).

Respiratory Protection (N95 dust mask or respirator) to protect against airborne dust when cleaning or running the equipment.

Hazards


Hazard	Causes	Mitigation
Fire	Friction from tools, improperly installed tools	Use correct feeds and speeds Make sure the tool sticks out far enough Do not leave the ShopBot unattended
Projectiles	Workpiece shattering Tool shattering Tool slipping Collision with fixtures and clamps Debris in wood	Check for cracks, knots, and debris in wood Use correct feeds and speeds Clean tool holder with compressed air Program file to avoid collisions Check that actual home position matches programmed home position
Entanglement	Pinch points Rapidly moving automatic equipment	No loose hair, clothing, earbuds, hoodie strings, etc Make sure tool has stopped before reaching in (hearing protection can make it hard to tell)
Noise	Motor noise, vacuum noise, tooling noise	Wear hearing protection
Inhalation	Airborne dust	Wear dust mask or respirator (minimum N95) while operating and cleaning

E-STOP

In case of emergency, stop the ShopBot using one of three methods:

E-STOP button on the remote. This will immediately cut all power to the ShopBot. The tool will spin down naturally. E-STOP is a good default option.

Press the Spacebar. This will lift the tool up and apply the brake. This is a good option in less urgent situations, like needing to adjust the zero positions.

Click the mouse. When the job starts, the mouse will automatically lock onto the stop button. Pressing any button on the mouse will stop the job in the same way as the spacebar.

Common Problems

Most issues are caused by:

Improper feeds and speeds
Improper tooling
Improper fixturing
Improper programming/setup (offset mistakenly applied, not setting zeroes consistent with the programming, not avoiding fixtures)

Housekeeping

Empty the dust collector when the dust has piled halfway up the viewing window.

Break down large pieces before putting them garbage bins. Blunt sharp corners to avoid puncturing the bag and injuring the person carrying it.

After use, clean the equipment and surrounding area:

While wearing respiratory protection, use compressed air to clean the gantry. Focus on areas where parts interact: rack and pinion, spindle mount, motor mounts, etc.
Clean the floor using a broom and dustpan, shop vacuum, or the dust collector hose. Replace the dust collector hose when done.
Empty any garbage bins that are more than 75% full and replace the bag.
Empty the dust collector if required.
Return fab lab tools to their proper locations:
- Tool holders on the rack
- Collets in the drawer
- Collet wrench placed beside locking fixture
- Calipers, drills/impact drivers, squares, hand tools in the tool room
Remove any personal tools, materials, and removable media from the room. The workbench should only have the wrench and locking fixture on it when done. Due to local fire code, do not store stock materials in the CNC room (fixtures are OK - label with name and phone number)
Turn off the equipment per shutdown procedures.
Turn off the dust collector. If you are the last one in the room, turn off the room exhaust. The room exhaust is interlocked to the electrical system; turning off the room exhaust will turn off all equipment in the room.

Workholding Policies

Most profile cuts will cut entirely through the workpiece and into the spoilboard below. In order to cut all the way through the material without unnecessarily damaging the spoilboard, North Forge suggests programming cuts using the following formula:

Depth of Cut = Stock Thickness + 0.01”

Always measure stock thickness with calipers, never with tape measures or nominal dimensions.

If your cut penetrates deeper than 0.06” into the spoilboard, please stop and investigate. If the stock is set up correctly and the depth of cut is appropriate, the collet may be dirty or damaged and the tool slipping out, or the secondary spoilboard may not be perfectly parallel to the gantry (for example due to debris between the primary and secondary spoilboard).

SCREWS

When using North Forge’s secondary spoilboard, it is okay to screw the workpiece in place. Do not screw into the main vacuum spoilboard. Do not use excessively long screws (ie long enough to pierce both the secondary spoilboard and the vacuum spoilboard).

SPRAY ADHESIVE METHOD

It is also possible to use spray adhesive to secure the entire workpiece to the secondary spoilboard.

Cover both the bottom of the workpiece and the appropriate part of the spoilboard with masking tape or painter’s tape.
Spray both surfaces with spray adhesive.
Press the two surfaces firmly together and hold for 30 seconds.
Test the hold by trying to move the workpiece sideways.

Other

Other workholding arrangements are possible, including vices, pins, clamps, custom fixtures, and the vacuum system.

If you are cutting all the way through a large workpiece on the vacuum spoilboard, BE CAREFUL. There is a high risk of damaging the vacuum spoilboard. It’s a good idea to test cut settings on a small workpiece and a secondary spoilboard.

The primary goal of workholding is to control the movement of the workpiece in three axes: X, Y, and Z. Always carefully check toolpaths to ensure they will not collide with any fixturing.

TIP: After a cut operation, the ShopBot will move to the “Z Safe height” before moving rapidly to its next position. When using clamps or other fixturing, adjust the Z Safe Height in the CAM software such that the Z safe height is above the clamp or fixture.

Operations

Instructions and proper formatting will follow.

Room Layout

Pay attention to the axis system when programming. Maybe some text will fix the formatting.

Layout of CNC room with axis system — Room Layout

Vacuum Zones

The vacuum table has four zones. Open the valves for the zones that you are using. Close the valves for the zones that you are not using.

Setup

1. Turn on the room exhaust.

2. Turn on the computer.

3. Turn on the air.

4. Reset the E-STOP.

5. Turn on the ShopBot power (right side of machine).

6. Press RESET on the remote.

7. Start ShopBot 3 Software

8. Open the Key Pad

9. Use the arrow keys to move the head around

On the keyboard: use the arrow keys for XY movement, Page UP/Page DOWN to move Z axis
On screen: use the arrow buttons to manually move the head, or type the destination location and use GOTO

10. Load the spoilboard and/or material.

11. Start the vacuum table per vacuum table instructions.

Vacuum Table

1. Clean the table of debris (wear respiratory protection if using compressed air). Debris can affect part accuracy.

2. Open all valves on the vacuum table (OPEN = valve handle parallel to pipe)

3. Turn on the vacuum table using the remote outside the room.

4. Close the BYPASS valve (middle) and any unused zones.

5. Check the hold by pressing horizontally on the secondary spoilboard or workpiece.

Tool Holder

Assembly

1. Clean components with compressed air.

Debris caught in the tool holder can cause the tool to slip, damaging the tool and equipment.

Clean the tool holder with compressed air

2. Insert the collet into the nut.

Put the collet on the table and the nut on top.
Press on the nut until the collet snaps in place.

3. Screw the collet loosely into the holder.

4. Insert the tool.

Do not tighten on the flutes
Make sure enough of the shank is in the collet to properly hold the tool - tool should fill ~80% of the length of the collet.

Load the collet into the fixture:

Press and hold the top knob
Insert the holder; rotate and push until it's fully inserted
Shoulder must be flush with the face of the fixture

5. Tighten the collet nut.

Ensure all four teeth on the wrench are engaged
Tighten the nut until the table lifts from the floor

6. Load the tool into the ShopBot

Support the holder from the bottom
Tool goes into the conical receptor under the skirt
Press the green button briefly until the tool gets sucked in
If the tool is not sucked in, blow off the beige control box near the pillar with the air line.

Disassembly

1. Unload the tool from the ShopBot.

Support the tool holder from the bottom
Press the green button; tool holder will fall out

2. Unscrew holder and remove collet and nut.

Load the tool holder into the fixture
Use the wrench to unscrew the nut

3. Remove the collet by pushing with thumbs.

4. Replace the collet, nut, and tool holder on the shelf.

Zeroing Axes

XY Zero

XY axes are set manually (moving the tool to the desired home position).

1. Open the Key Pad.

2. Use the arrow keys to move the head to the desired home point.

3. Select ZERO AXES.

4. Check "X-Axis" and "Y-Axis" then press ZERO

Z Zero

Z zero is done automatically with the Z zero routine.

1. Attach the Z zero fixture.

Attach the clip to the collet nut or the tool
Place the plate on the spoilboard or the top of the material, depending on how your file was programmed

2. Check the connection for continuity.

Lift the plate and tap it against the tool. If input #1 flashes on screen, the connection is good. If input #1 does not flash, adjust the clip and retry.

3. Run the Z zero routine

Tool will tap twice against the plate
Watch the Z axis readout: if it continues scrolling downwards without stopping, the ShopBot has not detected the end of the tool. You must stop the routine and try again.

4. Remove and store the fixture.

Plate goes in the 3D printed holder
Clip attaches to the frame
Make sure the clip is not touching the plate

Spindle RPM Check

Occasionally, the ShopBot does not read the RPM from the file correctly. Other users may also have adjusted the default RPM away from 18,000. Use this method to manually enter the RPM.

1. Select Tools, then Spindle RPM Control

2. Click to the left of the word PREVIEW

3. Type the desired RPM and hit ENTER

4. Cursor automatically moves left. Type the RPM again and hit ENTER.

Running a Job

If you're not already wearing PPE (hearing protection, safety glasses, respiratory protection) put it on now.

1. Check the dust collector. If the dust is halfway up the viewing window, empty it before use.

2. Transfer files from USB to the computer. The ShopBot will not be able to read the files if they are left on the USB stick.

Transfer files, otherwise the ShopBot won't be able to read them

3. Select CUT PART on screen and open the cut file.

4. Press START on screen. Ignore the yellow file information screen that pops up.

5. DO NOT PRESS OKAY - warning screen will appear.

Pressing OK without starting the dust collector and spindle will damage the equipment!

WARNING: Turn on spindle and dust collector before pressing OK!

6. Turn on the dust collector.

7. Start the spindle using the START button on the remote.

Listen to make sure the sound is appropriate

8. Press OK on screen.

The job will start
Keep your hand on the space bar, mouse, or E-STOP

Shutdown

1. Turn off the dust collector. Empty it if the dust is more than halfway up the viewing window.

2. Shut down the vacuum table.

Open all valves
Wait 5 minutes for the motor to cool
Shut off using the remote outside the room

Open bypass valve, wait, then turn off the vacuum.

3. Remove the tool from the head.

4. Move the head to the front of the bed.

5. Install the rest block under the head.

Make sure the skirt isn't resting on the support block.

7. Turn off the power.

8. Turn off the air.

The head will slowly sink downwards onto the rest block.

9. Turn off the exhaust if you are the last one in the room.

If the air is visibly dusty, you may need to leave the exhaust running until it clears.
Turning off the exhaust will cut power to other equipment in the room!