Hello and welcome to the SLO MakerSpace Instructables for the CNC router! This is incredibly versatile tool and I am incredibly excited that you are interested in learning how to use it - millions of project possibilities await at the end of this class with the knowledge you are about to acquire. So buckle up and put those safety glasses on!
Step 1: Setup: Power Up!
There are a number of components to plug in before we can get started - three to be exact. They are:
- Coolant Pump and Stepper Drives - 5 gallon plastic bucket hums when plugged in an working properly (plugged in and not humming? contact the shop manager - do NOT cut). This pumps cool water through tubes to the router motor keeping it cool while it cuts. The stepper motors drive movement in the X, Y, and Z axes.
- VFD - powers the router blade speed controller box (located by your left knee as you sit at the CNC router computer). Keep this off until you have successfully installed an endmill to avoid injury.
- Dust Collector - Located back in the wood storage area, turn this on only while the CNC router is cutting.
- (Computer) - this should always remain plugged in so that people can still use the computer while the router is offline.
These should each be switched off once you job is finished and your work station is cleaned and ready for the next person.
Step 2: Setup: Choose Your Endmill - Intro
There are a number of different blades to choose from when conducting a project on the CNC router. The router bits we are limited to using are known as endmills, and they take on a number of different shapes and sizes.
I'll give a brief crash-course on endmills here. Following are the aspects I hope you will fully understand between completing this course and embarking on your first CNC routing project:
- Number of flutes
- Endmill shape: Flat vs. Ball nose vs. V-bits
Step 3: Setup: Choose Your Endmill - Number of Flutes
Take a look at the first picture included in this step and see if you can notice a difference between the two bits displayed.
In case you can't tell, the bit on the left appears to have four edges, whereas the bit on the right only has two edges. These 'edges' are what we call flutes and each serves its own purpose in a CNC project. What is the difference then?
I like to describe the difference between two-flute and four-flute endmills as the similar difference between a hacksaw (second photo) and a wood saw (third photo). A hack saw, in case you have never used one, has fine teeth, very close together, making it ideal for sawing though metal pipes or other hard materials. A wood saw has much larger and much fewer teeth than a hack saw - making it ideal for cutting through a softer material like wood. When choosing the correct endmill for the job, just remember that two flute endmills are used for softer materials (ie. plywood, MDF, OSB, cedar, etc.) and four flute endmills are used for harder materials (ie. plastics, mahogany, teak, etc.). Please note that it is not acceptable to cut metal of any type on this CNC router - it could cause a fire among other damages to the machine!
Step 4: Setup: Choose Your Endmill - Shape: Flat Vs. Ballnose Vs. V-bits
Aside from number of flutes, endmills come in a number of different shapes. The three shapes we have here at the MakerSpace are as follows:
Flat (aka endmill): See first photo. Notice the flat profile at the end of the shaft. This flat profile makes this endmill ideal for cutting clean profile cuts, routing pockets, or drilling holes. Look above the CNC routing table. See the wooden pterodactyl? That was cut using an endmill like this.
Ballnose: See second photo. Notice the rounded top at the end of the flutes. This shape makes this blade ideal for 3D surfacing ONLY. This type of blade is no good for profile cutting. Take a look beneath the pterodactyl at the piece of wood hanging between the window and the door - this was done as a 3D surface using a ball nose endmill.
V-bit: See the third photo. Notive the pointed tip of the bit. This shape makes this blade ideal for engraving. Words are especially easy with this bit. Take a look at the piece of wood underneath the 'Keep Shut' door on the CNC router table. Those letters were engraved with the V-bit.
Mystery bits: Maybe while searching around for a bit in the 'Endmills' cabinet you came across some interesting bit not listed here. No matter how interesting or perfect for your job that bit may seem DO NOT USE UNCLASSIFIED BITS WITHOUT FIRST CONSULTING EITHER THE SHOP MANAGER OR THE CNC ROUTER GURU. This is incredibly important in prolonging the life of this fragile machine.
Step 5: Setup: Choose Your Endmill - Sizing
The final step in understanding endmills is the simplest - diameter. We have three possibilities for endmill diameters: 1/8 inch, 1/4 inch, 1/2inch.
In general, the larger the diamer, the faster a piece gets cut. For small intricate parts, use a 1/8" endmill. For projects that span the entire length of the table, use the 1/2" endmill. Medium sized parts, use the 1/4" endmill.
Have a specialty project that's proving difficult to choose the proper endmill for the job? Consult either the shop manager or CNC guru for additional guidance!
Step 6: Changing the Blade
It's wise to always assume that the blade left in the router from the last user was not inserted correctly. Not that this is (always) true, but if you assume the blade is secured tightly when it is not then we have a major problem when the blade flies from the machine during use. Don't be that person!
If the blade already in the machine when you approach is the one you want for your job, then check for tightness.
If you need to change the blade to a different size/type, follow the following instructions:
1. Unplug the power to the spindle (labeled Spindle).
2. Take the two wrenches from the table and (carefully) loosen the collet (see photo) from the spindle - mind your knuckles.
3. First remove bit then collet before replacing these items to the Endmill bin under the table.
4. Place the new collet into the nut - it should stick in place.
5. Place the new endmill into the collet high enough to grasp a significant portion of the shank - the new endmill can (but need not) stick out of the back of the collet when properly placed (see photo). For smaller endmills, push the endmill into the collet to about 1/8" from the start of the helix.
6. Tighten nut/collet/endmill back into the spindle - do not overtighten with excessive force.
Step 7: Set Up Workpiece on Table
Start by measuring your workpiece length and width to the nearest 1/4" with a measuring tape. Next, grab a pair of calipers and measure the thickness of your wood piece to the nearest 0.01". Measuring the thickness of the wood piece accurately is very important as it will help us later to both make sure we cut all the way through the workpiece and keep the CNC router table preserved.
When placing your workpiece on the router table, keep within the red painted confines at the edges of the base board. The maximum dimensions of your cutting area are 48 inches (max X) by 93.5 inches (max Y).
Need to square your piece perfectly to the edge of the table? Measure off of the metal rails on the edge - since the CNC runs on these rails they happen to be the straightest reference line we have.
In order to secure your workpiece to the table we typically recommend that your screw your piece directly into the bed of the table itself. Don't let the screw heads poke up above the top surface of your workpiece - if they do they could later come in contact with the router blade and cause huge problems (chipping/exploding blade, ruined cutting job, injury, etc.). Please be careful! We generally recommend to secure (at least) each of the four corners of your work piece down with screws. If your corners will most definitely be within a cutting path, put your corner screws elsewhere! It's incredibly important that you don't hit a screw while cutting. Do everything in your power not to do so - measure twice, cut once.