CNC Router

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Introduction

The CNC Router is a powerful and possibly dangerous tool. It can harm itself and you. There are some safety guidelines you should read before you attempt to use the machine.

The CNC Router Full Training Presenation is also available for deeper reference.

Safety Guidelines

  • The cutting bits can be extremely sharp, you can cut yourself by handling them incorrectly. Use caution when changing or moving bits. Safety gloves are recommended
  • Safety Glasses should always be worn in the CNC room if the machine is on or off.
  • If a bit breaks, sharp metal shrapnel can be sent flying in any direction, always wear safety glasses.
  • The router motor requires water-cooling during normal operation. Running it without cooling can damage the motor. (install interconnect)
  • The cutting of materials can create very fine dust that could be hazardous to your lungs. Wear a respirator or dust mask if the environment becomes dusty. Consult the MSDS of the material you are cutting for proper PPE.
  • The dust collector, CNC router, and Vacuum Pump create loud noises that can damage your hearing if exposed for long periods of time. Wear hearing protection when sound pressure levels become uncomfortable.
  • Work pieces that are improperly clamped can be moved by the router. At best this will ruin your work, at worst it can send a small piece flying or shatter a cutting bit. Ensure all work is properly clamped.
  • The spoil board has bolts that hold it to the surface below, if the cutting tool hits one of the bolts it will destroy the bit. Make sure cuts do not go below the height of the spoil board.
  • If your work slips, stop the job. The movement of the work can cause the cutting bit to take a cut that is too deep. Clamp the work properly and start over.
  • If the machine is cutting into the table, stop the job. Cutting <1mm into the spoil board on the last pass is acceptable but if it's cutting any more than that (usually because of a bad tool path) stop the job.
  • There are several pinch points around the machine where you could catch a digit or limb. The machine has no eyes or mercy, do not go near the machine while it is running.
  • When loosening or tightening the collet, use controlled strength. If a wrench slips or the thread loosens suddenly, you can pinch fingers or smash knuckles.
  • Carbide bits can shatter if dropped on the concrete floor. Shrapnel can fly off at high speed and it will ruin the bit.

Glossary

Kerf: The width of “path” that your cutter makes when it’s cutting a straight line; effectively, the kerf you’ll cut will be the the width or diameter of your cutter. The actual material removed by the cutting operation is called swarf.

End mill: A cutter for the CNC router that has parallel sides and a flat end. An end mill can cut along the edges and also on its end (i.e. drilling or plunging cuts.) The cutting edges spiral down along the end mill’s length.

Flutes: The spiral cutting edges on an end mill cutter. A cutter with two flutes is the most versatile cutter for the CNC router. A cutter with only one flute might occasionally be useful; a cutter with four flutes is almost never appropriate for the materials cut on STEAMLabs' CNC router.

Shank: The smooth part of a cutter that is intended to be gripped by the cutting machine.

Collet: the precisely-machined holding device that grabs a cutter’s shank, attaching the cutter to the cutting machine. A collet is labeled with the the size shank it’s meant to hold.

Work holding: Any tool or system that holds the work material securely.

Bitmap: A graphic made from a grid of pixels. A bitmap has a set resolution and no data about the “shapes” it represents, so a bitmap isn’t useful for designing for CNC machining.

Vector: A graphic created with a “stretchy” line that is generated with mathematical formulas. We can translate those formulas into movement instructions for a CNC machine, so designing for CNC machining is done with vector graphics.

CNC: Computer Numerical Control, the system of directing a tool by means of a programmable robotic arm.

CAD: Computer Aided Design, digital design work. CAD tends to refer to vector-based designs and design software.

CAM: Computer Aided Machining, colloquially refers to the coding language and code files used to direct a CNC machine. GCode is the CAM language we use for the CNC router at STEAMLabs.

Feeds and Speeds: The movement settings for the CNC router.

  • The “feed” is how fast the cutter is moving through the material
  • The “speed” is how fast the cutter itself is spinning as it cuts.
  • The feed and speed values are calculated based on the material the cutter is made of, its shape and dimensions, the number of flutes it has, and the kind of material it’s cutting.
  • The easiest way to get feed and speed values is from a chart.

Tabs: A bridge of material that keeps a cut-out part from breaking entirely loose during cutting. A good rule of thumb for tab dimensions and placement:

  • Use at least 3 tabs to hold each part
  • Place tabs in locations where they’ll be easy to remove/clean up
  • In VCarve, choose a tab “length” (width) that’s about ½ inch, and a tab thickness that’s between ⅓ and ½ the total thickness of your material.
  • Larger parts need more tabs and heftier tabs!

Machine Maintenance

There are several tasks that are required to maintain the CNC machine. Some need to be done with every use, and some monthly.

Every use Maintenance

These things need to be done every time you use the machine

  • Ensure the water chiller is on whenever the Router spindle motor is running.
  • Vacuum all the dust and chips from the cutting job you've done.
  • Remove all work and debris from the CNC table.

Weekly Maintenance

  • Pump the way oiler one full pump.

Monthly Maintenance

These things need to be done once a month

  • Ensure the way oiler is topped up.
  • Empty the dust collector if it is getting full.
  • Empty and clean/replace the 2 filters in the vacuum pump.
  • Check the water level in the chiller
  • Clean the ways of all 3 axes.
  • Make a surfacing cut into the spoil board if it is needed.
  • Replace the spoil board if it is surfaced down to the bolts.
  • Inspect the Vacuum pump vanes. They wear away over time and will need to be replaced.


V Carve Pro

V carve pro is the software that we've chosen as the standard toolchain for the CNC router. This program is a CAM (Computer Aided Modeling) software that takes a vector (2D) or 3D model and creates toolpaths (GCODE) that the machine can understand. You can also use the software to create your own vectors and/or 3d shapes.

You can download the software from the steamserver or from the vectric website.

More detailed tutorials can be found at support.vectric.com/

Initial Software Setup

To transfer files from your unlicensed version of V-carve pro to the licensed version on the computer in the CNC room, you first need to copy the makerspace ID from the licensed computer and paste it in your computer's copy.

Your Makerspace ID can be obtained from the computer in the CNC Room by clicking "Help > About VCarve Pro - Makerspace Edition" and clicking the "Display Makerspace ID" button.

VCarve-Help-About.png

Copy the key and paste it into the same window on your computer.

VCarve-Makerspace-ID.png

Now you should be able to transfer files to the CNC computer to generate Gcode.

Material setup

When you create a new file, the first thing the program will ask of you is the material you will be cutting. It is important to be accurate in your measurements to create accurate parts and protect the machine. The best process for measuring the material is as follows:

  1. Use a caliper to measure the thickness of the material you will be cutting to the nearest 0.1mm and write down the value on the upper side of the piece.
  2. Clamp the piece to the CNC bed as securely as possible. If you are vacuum clamping, test to see that the vacuum works on your piece and turn it off for the time being.
  3. Choose an origin point on your material and mark it with an "X". If using clamps, place the origin inside the clamping area.
  4. Measure the width and height of your piece to the nearest mm. If using clamps, measure inside the clamping area with 10mm clearance from any clamp.
  5. In V-carve, make sure that you have mm selected and insert the values. Make sure the Z zero is set to the machine bed and XY datum in the lower left then hit OK.

Create a vector

You can create simple shapes, lines and curves with the vector tools in V-carve. If dimensions are important, you can also add them with the dimension tool. You can also add text.

Import a vector

You can import vector files that you have created in other programs. With the transform and editing tools, you can move, rotate and scale your vectors.

Joining open vectors

Often times, imported vectors are not closed. Vectors need to be closed to cut properly. After importing, select all (Ctrl+A) and click join open vectors. Another method for closing vectors with large gaps is to insert a line to close the vector. V-carve can do this automatically with the 3 tools next to join open vectors.

Nesting

Nesting is a useful feature that will automatically place vectors in a tight formation with the proper spacing for the tool being used. It can also duplicate vectors or groups of vectors a number of times.

Create a Toolpath

To create a toolpath, select the vectors you would like to reference, then click on the toolpaths tab on the right hand side of the screen. Select the type of toolpath you want to create (eg profile), select the tool bit you will be using and the depth of cut. Click calculate. If you get a warning message that the toolpath will cut through the material, go back and edit it so that you're not cutting into the table.

Feeds and Speeds

Check out Feeds and Speeds for tool bit info.

Export a gcode file

To export a gcode file, click save toolpath in the toolpaths tab. Ensure the post processor is set to Gcode MM (.iso) and save the file to a usb stick. If you have multiple toolpaths, click the name of the toolpath so it appears in bold and click save toolpath to save it. NOTE: only licensed copies of V-carve can export gcode. If you are working from a trial version, save your work and open it on the computer in the CNC room, it has a licensed version.

Clamping and hold downs

One of the most important parts about using the CNC router is how to clamp your work. There are two main ways of holding down workpieces

Vacuum Table

The CNC router has a vacuum table built in to hold down work. The vacuum is divided into 4 quadrants, each 2 feet by 4 feet, with valves to open or close each one. The fewer valves are open, the better the vacuum will perform. To turn on the vacuum pump, turn on the switch on the back wall. Ensure the main valve is open and open the valve(s) that correspond with the size and placement of your work piece. If your work piece is smaller than 2 feet by 4 feet or there are exposed vacuum channels where a valve has been opened, cover the exposed channels with a piece of scrap material to maintain a proper vacuum. When used properly the vacuum table can provide 1800 lbs of clamping force per square foot without damaging the surface.

Hold-down clamps

The spoil board has a series of 6mm holes in a 100mm grid pattern that can be threaded for 5/16" bolts. Use the available hardware to clamp as many spots as possible on your work piece. Take note of where you place your clamps to ensure they do not interfere with the toolpath or router head. Be careful not to over tighten the clamps as to pull the threads out of the spoil board.

Other ways of clamping your work

  • Double sided tape
  • Spray adhesive (please don't get spray adhesive on the tools)
  • Jigs
  • Pins and wedges
  • Cam clamps
  • Wood screws
  • A vice

Keep parts constrained while through cutting

If a part comes free or "jumps" during cutting, it can (will) ruin the piece and possible break the cutting tool. There are three main ways to keep parts from jumping while through cutting.

  • "Onion skin"
    • This technique involves leaving a 0.5-1mm layer on the bottom uncut. This small skin will keep the part from jumping and is easy to remove.
    • Warning! this only works if the piece you are cutting is perfectly flat (not warped) and your thickness measurements are spot on.
  • Tabs
    • Tabs are small pieces that are not cut away to hold the part in place.
    • They are inserted with V-carve in places of your choosing.
    • Tabs can be cut afterward with an oscillating tool or saw, and the nub sanded or routed off.
  • Hold downs
    • If there is a hole in the part being through cut, you can use a bolt or screw to hold it to the table inside the boundary of the part.

Turning on the Machine

Clear the table and surrounding area of obstructions. To turn on the machine, turn the black switch on the front of the cabinet to "ON" then push the green "ON/Off" button. Use the Pendant to "Home All Axes".

Changing Tool Bits

To change a tool bit, first home the machine then place a piece of scrap wood beneath the collet. The scrap wood is there to prevent the tool bit from shattering if it falls from the collet. Use the two wrenches (22mm and 30mm) to loosen the collet chuck, "lefty loosey" when looked at from below (look at the threads if you're confused). Protect your knuckles! Used controlled strength! If the new tool bit requires a different collet size, unscrew the collet chuck all the way and remove the existing collet and replace it with the correct size. Ensure that the collet is snapped into the collet chuck straight and securely before screwing it in place. Tightening the collet chuck while the collet is misaligned will permanently damage the collet receiver. Make sure the collet and collet receiver are free of dust and dirt.

ER Collet Mounting.jpg

Thread the collet chuck on a few threads and carefully insert the new tool bit into the collet ensuring that there is a good amount of contact between collet and shank, the more the better. At the same time, make sure that there is enough tool bit sticking out to make the deepest of your cuts. Tighten the collet chuck with 25-50% of your strength (depending on how close or far you are from average). Every time a bit is changed, the machine has to be zeroed in the "Z" direction.

Zeroing the machine

The machine needs to be zeroed on every new job and whenever new material or a bit is changed. The X and Y are zeroed simultaneously and the Z independently.

Z Axis

Accurately setting the Z axis zero point is crucial to protecting the machine and cutting bits as well as making accurate parts. The second aspect of setting proper Z zero is measuring your material thickness with a vernier caliper and setting the proper reference corner in the CAM program. All of these steps must be done each time and to a high degree of accuracy. Zeroing the Z axis should only be done after clamping the work piece, this includes vacuum clamping. Bring the router head over your work piece and bring the Z axis down slowly! Use the low setting to move slower. Place the brass touch plate below the tool bit (make sure the collet is tight). Press the [MENU] and [ON/OFF] buttons simultaneously to begin the zeroing process. Hold the brass plate still until the bit contacts and retracts. The Z zero is now set.

X and Y axis

The X and Y axis zero points are less crucial and can be done by eye. The zero position can be any corner or even the center of the material but the default position is the bottom left corner when looked at from above. As with the Z axis, inserting the correct dimensions into the CAM program and choosing the correct zero position go hand and hand with the physical setting of the machine. If either one is done incorrectly, the results could be catastrophic. Move each axis until the center of the cutting bit is half on and half off the work piece in each direction. Bring the Z axis close to the work but not touching to be more precise. When you are satisfied, press the zero X,Y button.

Running a File

Set the spindle speed

Open the tool database and find the tool that you will be using. Reference the text file on the desktop to find the closest speed (S1-S8) it's safer to chose a higher speed if the speeds don't match exactly. To set the speed, press and hold the [ON/OFF] button and simultaneously press either the [Z+] or [Z-] and release the buttons to change the speed of the spindle.

Set the feed rate

To run a file, hit [RUN/PAUSE/DELETE] -> Udisk File(USB) [OK] -> Select the file you want to run with [X+] and [X-] ([Y+] and [Y-] for page up/page down) then press [OK] -> Enter the Workspeed (feed rate) from the tool database in V-carve -> press [RUN/PAUSE/DELETE] to edit, units are mm/min. Press [OK] ONLY ONCE to confirm your edit -> Enter the Fastspeed (Rapid feed rate) (default 6000) -> Select the speed ratio (default 1.0)

Run through the checklist

  • The bit matches the toolpath you are running.
  • There is enough stickout of the bit for your deepest cut.
  • You zero'd the x and y axis.
  • You zero'd the z axis with the touchplate for this bit.
  • The water chiller is on.
  • your work is securely clamped.
  • you set the proper feedrate for this bit.
  • Your z datum position in V-Carve job setup is set to Machine bed.
  • You checked the size of your cut with a ruler or an air pass and are 100% sure that the spindle will not hit any clamps.

Begin the job

Press [OK] and the machine will start. Hold your finger over [RUN/PAUSE/DELETE] just in case something goes wrong. Watch the machine for the first few minutes to ensure that nothing is out of the ordinary. Keep your hand near the e-stop button until you've determined that the program is running correctly. If you notice a problem before it has happened, you can hit the pause button to pause the machine and the on/off button to stop the spindle. At this point, you can correct the problem and resume where you left off.

Pause the job

You can pause the job at any time by pressing [RUN/PAUSE/DELETE] this will just stop it in place and leave the spindle running (which could be bad). You can unpause at any time by pressing [RUN/PAUSE/DELETE] again. If you pause the job, you can turn off the spindle by pressing [ON/OFF], if you resume the job after that, it will automatically turn the spindle back on before it begins moving again, but just to be safe you should start it manually and let it get up to speed. Do not pull the USB while a job is paused, Cancel it first.

Cancel the job

You can cancel the job at any time by pressing [CANCEL] and select "Discard Break" -> [OK]. Do not pull the USB before selecting OK.

Issues

Bold letters 1X, 1Y, 1Z or Home machine error

on the pendant home screen (with the numbers) if the left hand column is Highlighted (colors inverted) and reads 1X, 1Y, 1Y that means that the machine wasn't home'd when it was turned on. To fix it press [HOME] and select "All axis Home" [OK].

Pull the USB while the job is still running

If you pull out the USB stick before the job has finished running, sometimes it will freeze the machine. None of the buttons will work. To fix it cycle the main power on and off.

Machine offsets

Sometimes if you push the wrong button or pull the USB while the job is still running, The machine will enter a different state of machine coordinates. The main screen will read (1-9)X, (1-9)Y, (1-9)Z in the left column. To fix it, press and hold [MENU] while simultaneously pressing [0] and then release the buttons.